Enhance error handling and metrics tracking in SteamCache

- Introduced a new error handling system with custom error types for better context and clarity in error reporting.
- Implemented URL validation to prevent invalid requests and enhance security.
- Updated cache key generation functions to return errors, improving robustness in handling invalid inputs.
- Added comprehensive metrics tracking for requests, cache hits, misses, and performance metrics, allowing for better monitoring and analysis of the caching system.
- Enhanced logging to include detailed metrics and error information for improved debugging and operational insights.

.cursor/rules/caching-patterns.mdc

@@ -0,0 +1,64 @@
+---
+description: Caching system patterns and best practices
+---
+
+# Caching System Patterns
+
+## Cache Key Generation
+- Use SHA256 hashing for cache keys to ensure uniform distribution
+- Include service prefix (e.g., "steam/", "epic/") based on User-Agent detection
+- Never include query parameters in cache keys - strip them before hashing
+- Cache keys should be deterministic and consistent
+
+## Cache File Format
+The cache uses a custom format with:
+- Magic number: "SC2C" (SteamCache2 Cache)
+- Content hash: SHA256 of response body
+- Response size: Total HTTP response size
+- Raw HTTP response: Complete response as received from upstream
+- Header line format: "SC2C <hash> <size>\n"
+- Integrity verification on read operations
+- Automatic corruption detection and cleanup
+
+## Garbage Collection Algorithms
+Available algorithms and their use cases:
+- **LRU**: Best for general gaming patterns, keeps recently accessed content
+- **LFU**: Good for gaming cafes with popular games
+- **FIFO**: Predictable behavior, good for testing
+- **Largest**: Maximizes number of cached files
+- **Smallest**: Maximizes cache hit rate
+- **Hybrid**: Combines access time and file size for optimal performance
+
+## Cache Validation
+- Always verify Content-Length matches received data
+- Use SHA256 hashing for content integrity
+- Don't cache chunked transfer encoding (no Content-Length)
+- Reject files with invalid or missing Content-Length
+
+## Request Coalescing
+- Multiple clients requesting the same file should share the download
+- Use channels and mutexes to coordinate concurrent requests
+- Buffer response data for coalesced clients
+- Clean up coalesced request structures after completion
+
+## Range Request Support
+- Always cache the full file, regardless of Range headers
+- Support serving partial content from cached full files
+- Parse Range headers correctly (bytes=start-end, bytes=start-, bytes=-suffix)
+- Return appropriate HTTP status codes (206 for partial content, 416 for invalid ranges)
+
+## Service Detection
+- Use regex patterns to match User-Agent strings
+- Support multiple services (Steam, Epic Games, etc.)
+- Cache keys include service prefix for isolation
+- Default to Steam service configuration
+
+## Memory vs Disk Caching
+- Memory cache: Fast access, limited size, use LRU or LFU
+- Disk cache: Slower access, large size, use Hybrid or Largest
+- Tiered caching: Memory as L1, disk as L2
+- Dynamic memory management with configurable thresholds
+- Cache promotion: Move frequently accessed files from disk to memory
+- Sharded storage: Use directory sharding for Steam keys to reduce inode pressure
+- Memory-mapped files: Use mmap for large disk operations
+- Batched operations: Group operations for better performance

.cursor/rules/configuration-patterns.mdc

@@ -0,0 +1,65 @@
+---
+description: Configuration management patterns
+---
+
+# Configuration Management Patterns
+
+## YAML Configuration
+- Use YAML format for human-readable configuration
+- Provide sensible defaults for all configuration options
+- Validate configuration on startup
+- Generate default configuration file on first run
+
+## Configuration Structure
+- Group related settings in nested structures
+- Use descriptive field names with YAML tags
+- Provide default values in struct tags where possible
+- Use appropriate data types (strings for sizes, ints for limits)
+
+## Size Configuration
+- Use human-readable size strings (e.g., "1GB", "512MB")
+- Parse sizes using `github.com/docker/go-units`
+- Support "0" to disable cache layers
+- Validate size limits are reasonable
+
+## Garbage Collection Configuration
+- Support multiple GC algorithms per cache layer
+- Provide algorithm-specific configuration options
+- Allow different algorithms for memory vs disk caches
+- Document algorithm characteristics and use cases
+
+## Server Configuration
+- Configure listen address and port
+- Set concurrency limits (global and per-client)
+- Configure upstream server URL
+- Support both absolute and relative upstream URLs
+
+## Runtime Configuration
+- Allow command-line overrides for critical settings
+- Support configuration file path specification
+- Provide help and version information
+- Validate configuration before starting services
+
+## Default Configuration
+- Generate appropriate defaults for different use cases
+- Consider system resources when setting defaults
+- Provide conservative defaults for home users
+- Document configuration options in comments
+
+## Configuration Validation
+- Validate required fields are present
+- Check that size limits are reasonable
+- Verify file paths are accessible
+- Test upstream server connectivity
+
+## Configuration Updates
+- Support configuration reloading (if needed)
+- Handle configuration changes gracefully
+- Log configuration changes
+- Maintain backward compatibility
+
+## Environment-Specific Configuration
+- Support different configurations for development/production
+- Allow environment variable overrides
+- Provide configuration templates for common scenarios
+- Document configuration best practices

.cursor/rules/development-workflow.mdc

@@ -0,0 +1,77 @@
+---
+description: Development workflow and best practices
+---
+
+# Development Workflow for SteamCache2
+
+## Build System
+- Use the provided [Makefile](mdc:Makefile) for all build operations
+- Prefer `make` commands over direct `go` commands
+- Use `make test` to run all tests before committing
+- Use `make run-debug` for development with debug logging
+
+## Code Organization
+- Keep related functionality in the same package
+- Use clear package boundaries and interfaces
+- Minimize dependencies between packages
+- Follow the existing project structure
+
+## Git Workflow
+- Use descriptive commit messages
+- Keep commits focused and atomic
+- Test changes thoroughly before committing
+- Use meaningful branch names
+
+## Code Review
+- Review code for correctness and performance
+- Check for proper error handling
+- Verify test coverage for new functionality
+- Ensure code follows project conventions
+
+## Documentation
+- Update README.md for user-facing changes
+- Add comments for complex algorithms
+- Document configuration options
+- Keep API documentation current
+
+## Testing Strategy
+- Write tests for new functionality
+- Maintain high test coverage
+- Test edge cases and error conditions
+- Run integration tests before major releases
+
+## Performance Testing
+- Test with realistic data sizes
+- Measure performance impact of changes
+- Profile the application under load
+- Monitor memory usage and leaks
+
+## Configuration Management
+- Test configuration changes thoroughly
+- Validate configuration on startup
+- Provide sensible defaults
+- Document configuration options
+
+## Error Handling
+- Implement proper error handling
+- Use structured logging for errors
+- Provide meaningful error messages
+- Handle edge cases gracefully
+
+## Security Considerations
+- Validate all inputs
+- Implement proper rate limiting
+- Log security-relevant events
+- Follow security best practices
+
+## Release Process
+- Test thoroughly before releasing
+- Update version information
+- Create release notes
+- Tag releases appropriately
+
+## Maintenance
+- Monitor application performance
+- Update dependencies regularly
+- Fix bugs promptly
+- Refactor code when needed

.cursor/rules/golang-conventions.mdc

@@ -0,0 +1,62 @@
+---
+globs: *.go
+---
+
+# Go Language Conventions for SteamCache2
+
+## Code Style
+- Use `gofmt` and `goimports` for formatting
+- Follow standard Go naming conventions (camelCase for private, PascalCase for public)
+- Use meaningful variable names that reflect their purpose
+- Prefer explicit error handling over panic (except in constructors where configuration is invalid)
+
+## Package Organization
+- Keep packages focused and cohesive
+- Use internal packages for implementation details that shouldn't be exported
+- Group related functionality together (e.g., all VFS implementations in `vfs/`)
+- Use interface implementation verification: `var _ Interface = (*Implementation)(nil)`
+- Create type aliases for backward compatibility when refactoring
+- Use separate packages for different concerns (e.g., `vfserror`, `types`, `locks`)
+
+## Error Handling
+- Always handle errors explicitly - never ignore them with `_`
+- Use `fmt.Errorf` with `%w` verb for error wrapping
+- Log errors with context using structured logging (zerolog)
+- Return meaningful error messages that help with debugging
+- Create custom error types for domain-specific errors (see `vfs/vfserror/`)
+- Use `errors.New()` for simple error constants
+- Include relevant context in error messages (file paths, operation names)
+
+## Testing
+- All tests should run with a timeout (as per user rules)
+- Use table-driven tests for multiple test cases
+- Use `t.Helper()` in test helper functions
+- Test both success and failure cases
+- Use `t.TempDir()` for temporary files in tests
+
+## Concurrency
+- Use `sync.RWMutex` for read-heavy operations
+- Prefer channels over shared memory when possible
+- Use `context.Context` for cancellation and timeouts
+- Be explicit about goroutine lifecycle management
+- Use sharded locks for high-concurrency scenarios (see `vfs/locks/sharding.go`)
+- Use `atomic.Value` for lock-free data structure updates
+- Use `sync.Map` for concurrent map operations when appropriate
+
+## Performance
+- Use `io.ReadAll` sparingly - prefer streaming for large data
+- Use connection pooling for HTTP clients
+- Implement proper resource cleanup (defer statements)
+- Use buffered channels when appropriate
+
+## Logging
+- Use structured logging with zerolog
+- Include relevant context in log messages (keys, URLs, client IPs)
+- Use appropriate log levels (Debug, Info, Warn, Error)
+- Avoid logging sensitive information
+
+## Memory Management
+- Be mindful of memory usage in caching scenarios
+- Use appropriate data structures for the use case
+- Implement proper cleanup for long-running services
+- Monitor memory usage in production

.cursor/rules/http-proxy-patterns.mdc

@@ -0,0 +1,59 @@
+---
+description: HTTP proxy and server patterns
+---
+
+# HTTP Proxy and Server Patterns
+
+## Request Handling
+- Only support GET requests (Steam doesn't use other methods)
+- Reject non-GET requests with 405 Method Not Allowed
+- Handle health checks at "/" endpoint
+- Support LanCache heartbeat at "/lancache-heartbeat"
+
+## Upstream Communication
+- Use optimized HTTP transport with connection pooling
+- Set appropriate timeouts (10s dial, 15s header, 60s total)
+- Enable HTTP/2 and keep-alives for better performance
+- Use large buffers (64KB) for better throughput
+
+## Response Streaming
+- Stream responses directly to clients for better performance
+- Support both full file and range request streaming
+- Preserve original HTTP headers (excluding hop-by-hop headers)
+- Add cache-specific headers (X-LanCache-Status, X-LanCache-Processed-By)
+
+## Error Handling
+- Implement retry logic with exponential backoff
+- Handle upstream server errors gracefully
+- Return appropriate HTTP status codes
+- Log errors with sufficient context for debugging
+
+## Concurrency Control
+- Use semaphores to limit concurrent requests globally
+- Implement per-client rate limiting
+- Clean up old client limiters to prevent memory leaks
+- Use proper synchronization for shared data structures
+
+## Header Management
+- Copy relevant headers from upstream responses
+- Exclude hop-by-hop headers (Connection, Keep-Alive, etc.)
+- Add cache status headers for monitoring
+- Preserve Content-Type and Content-Length headers
+
+## Client IP Detection
+- Check X-Forwarded-For header first (for proxy setups)
+- Fall back to X-Real-IP header
+- Use RemoteAddr as final fallback
+- Handle comma-separated IP lists in X-Forwarded-For
+
+## Performance Optimizations
+- Set keep-alive headers for better connection reuse
+- Use appropriate server timeouts
+- Implement request coalescing for duplicate requests
+- Use buffered I/O for better performance
+
+## Security Considerations
+- Validate request URLs and paths
+- Implement rate limiting to prevent abuse
+- Log suspicious activity
+- Handle malformed requests gracefully

.cursor/rules/logging-monitoring-patterns.mdc

@@ -0,0 +1,87 @@
+---
+description: Logging and monitoring patterns for SteamCache2
+---
+
+# Logging and Monitoring Patterns
+
+## Structured Logging with Zerolog
+- Use zerolog for all logging operations
+- Include structured fields for better querying and analysis
+- Use appropriate log levels: Debug, Info, Warn, Error
+- Include timestamps and context in all log messages
+- Configure log format (JSON for production, console for development)
+
+## Log Context and Fields
+- Always include relevant context in log messages
+- Use consistent field names: `client_ip`, `cache_key`, `url`, `service`
+- Include operation duration with `Dur()` for performance monitoring
+- Log cache hit/miss status for analytics
+- Include file sizes and operation counts for monitoring
+
+## Performance Monitoring
+- Log request processing times with `zduration` field
+- Monitor cache hit/miss ratios
+- Track memory and disk usage
+- Log garbage collection events and statistics
+- Monitor concurrent request counts and limits
+
+## Error Logging
+- Log errors with full context and stack traces
+- Include relevant request information in error logs
+- Use structured error logging with `Err()` field
+- Log configuration errors with file paths
+- Include upstream server errors with status codes
+
+## Cache Operation Logging
+- Log cache hits with key and response time
+- Log cache misses with reason and upstream response time
+- Log cache corruption detection and cleanup
+- Log garbage collection operations and evicted items
+- Log cache promotion events (disk to memory)
+
+## Service Detection Logging
+- Log service detection results (Steam, Epic, etc.)
+- Log User-Agent patterns and matches
+- Log service configuration changes
+- Log cache key generation for different services
+
+## HTTP Request Logging
+- Log incoming requests with method, URL, and client IP
+- Log response status codes and sizes
+- Log upstream server communication
+- Log rate limiting events and client limits
+- Log health check and heartbeat requests
+
+## Configuration Logging
+- Log configuration loading and validation
+- Log default configuration generation
+- Log configuration changes and overrides
+- Log startup parameters and settings
+
+## Security Event Logging
+- Log suspicious request patterns
+- Log rate limiting violations
+- Log authentication failures (if applicable)
+- Log configuration security issues
+- Log potential security threats
+
+## System Health Logging
+- Log memory usage and fragmentation
+- Log disk usage and capacity
+- Log connection pool statistics
+- Log goroutine counts and lifecycle
+- Log system resource utilization
+
+## Log Rotation and Management
+- Implement log rotation for long-running services
+- Use appropriate log retention policies
+- Monitor log file sizes and disk usage
+- Configure log levels for different environments
+- Use structured logging for log analysis tools
+
+## Monitoring Integration
+- Design logs for easy parsing by monitoring tools
+- Include metrics that can be scraped by Prometheus
+- Use consistent field naming for dashboard creation
+- Log events that can trigger alerts
+- Include correlation IDs for request tracing

.cursor/rules/performance-optimization.mdc

@@ -0,0 +1,71 @@
+---
+description: Performance optimization guidelines
+---
+
+# Performance Optimization Guidelines
+
+## Memory Management
+- Use appropriate data structures for the use case
+- Implement proper cleanup for long-running services
+- Monitor memory usage and implement limits
+- Use memory pools for frequently allocated objects
+
+## I/O Optimization
+- Use buffered I/O for better performance
+- Implement connection pooling for HTTP clients
+- Use appropriate buffer sizes (64KB for HTTP)
+- Minimize system calls and context switches
+
+## Concurrency Patterns
+- Use worker pools for CPU-intensive tasks
+- Implement proper backpressure with semaphores
+- Use channels for coordination between goroutines
+- Avoid excessive goroutine creation
+
+## Caching Strategies
+- Use tiered caching (memory + disk) for optimal performance
+- Implement intelligent cache eviction policies
+- Use cache warming for predictable access patterns
+- Monitor cache hit ratios and adjust strategies
+
+## Network Optimization
+- Use HTTP/2 when available
+- Enable connection keep-alives
+- Use appropriate timeouts for different operations
+- Implement request coalescing for duplicate requests
+
+## Data Structures
+- Choose appropriate data structures for access patterns
+- Use sync.RWMutex for read-heavy operations
+- Consider lock-free data structures where appropriate
+- Minimize memory allocations in hot paths
+
+## Algorithm Selection
+- Choose GC algorithms based on access patterns
+- Use LRU for general gaming workloads
+- Use LFU for gaming cafes with popular content
+- Use Hybrid algorithms for mixed workloads
+
+## Monitoring and Profiling
+- Implement performance metrics collection
+- Use structured logging for performance analysis
+- Monitor key performance indicators
+- Profile the application under realistic loads
+
+## Resource Management
+- Implement proper resource cleanup
+- Use context.Context for cancellation
+- Set appropriate limits on resource usage
+- Monitor resource consumption over time
+
+## Scalability Considerations
+- Design for horizontal scaling where possible
+- Use sharding for large datasets
+- Implement proper load balancing
+- Consider distributed caching for large deployments
+
+## Bottleneck Identification
+- Profile the application to identify bottlenecks
+- Focus optimization efforts on the most critical paths
+- Use appropriate tools for performance analysis
+- Test performance under realistic conditions

.cursor/rules/project-structure.mdc

@@ -0,0 +1,57 @@
+---
+alwaysApply: true
+---
+
+# SteamCache2 Project Structure Guide
+
+This is a high-performance Steam download cache written in Go. The main entry point is [main.go](mdc:main.go), which delegates to the command structure in [cmd/](mdc:cmd/).
+
+## Core Architecture
+
+- **Main Entry**: [main.go](mdc:main.go) - Simple entry point that calls `cmd.Execute()`
+- **Command Layer**: [cmd/root.go](mdc:cmd/root.go) - CLI interface using Cobra, handles configuration loading and service startup
+- **Core Service**: [steamcache/steamcache.go](mdc:steamcache/steamcache.go) - Main HTTP proxy and caching logic
+- **Configuration**: [config/config.go](mdc:config/config.go) - YAML-based configuration management
+- **Virtual File System**: [vfs/](mdc:vfs/) - Abstracted storage layer supporting memory and disk caches
+
+## Key Components
+
+### VFS (Virtual File System)
+- [vfs/vfs.go](mdc:vfs/vfs.go) - Core VFS interface
+- [vfs/memory/](mdc:vfs/memory/) - In-memory cache implementation
+- [vfs/disk/](mdc:vfs/disk/) - Disk-based cache implementation
+- [vfs/cache/](mdc:vfs/cache/) - Cache coordination layer
+- [vfs/gc/](mdc:vfs/gc/) - Garbage collection algorithms (LRU, LFU, FIFO, etc.)
+
+### Service Management
+- Service detection via User-Agent patterns
+- Support for multiple gaming services (Steam, Epic, etc.)
+- SHA256-based cache key generation with service prefixes
+
+### Advanced Features
+- [vfs/adaptive/](mdc:vfs/adaptive/) - Adaptive caching strategies
+- [vfs/predictive/](mdc:vfs/predictive/) - Predictive cache warming
+- Request coalescing for concurrent downloads
+- Range request support for partial content
+
+## Development Workflow
+
+Use the [Makefile](mdc:Makefile) for development:
+- `make` - Run tests and build
+- `make test` - Run all tests
+- `make run` - Run the application
+- `make run-debug` - Run with debug logging
+
+## Testing
+
+- Unit tests: [steamcache/steamcache_test.go](mdc:steamcache/steamcache_test.go)
+- Integration tests: [steamcache/integration_test.go](mdc:steamcache/integration_test.go)
+- Test cache data: [steamcache/test_cache/](mdc:steamcache/test_cache/)
+
+## Configuration
+
+Default configuration is generated in [config.yaml](mdc:config.yaml) on first run. The application supports:
+- Memory and disk cache sizing
+- Garbage collection algorithm selection
+- Concurrency limits
+- Upstream server configuration

.cursor/rules/security-validation-patterns.mdc

@@ -0,0 +1,89 @@
+---
+description: Security and validation patterns for SteamCache2
+---
+
+# Security and Validation Patterns
+
+## Input Validation
+- Validate all HTTP request parameters and headers
+- Sanitize file paths and cache keys to prevent directory traversal
+- Validate URL paths before processing
+- Check Content-Length headers for reasonable values
+- Reject malformed or suspicious requests
+
+## Cache Key Security
+- Use SHA256 hashing for all cache keys to prevent collisions
+- Never include user input directly in cache keys
+- Strip query parameters from URLs before hashing
+- Use service prefixes to isolate different services
+- Validate cache key format and length
+
+## Content Integrity
+- Always verify Content-Length matches received data
+- Use SHA256 hashing for content integrity verification
+- Don't cache chunked transfer encoding (no Content-Length)
+- Reject files with invalid or missing Content-Length
+- Implement cache file format validation with magic numbers
+
+## Rate Limiting and DoS Protection
+- Implement global concurrency limits with semaphores
+- Use per-client rate limiting to prevent abuse
+- Clean up old client limiters to prevent memory leaks
+- Set appropriate timeouts for all operations
+- Monitor and log suspicious activity
+
+## HTTP Security
+- Only support GET requests (Steam doesn't use other methods)
+- Validate HTTP method and reject unsupported methods
+- Handle malformed HTTP requests gracefully
+- Implement proper error responses with appropriate status codes
+- Use hop-by-hop header filtering
+
+## Client IP Detection
+- Check X-Forwarded-For header for proxy setups
+- Fall back to X-Real-IP header
+- Use RemoteAddr as final fallback
+- Handle comma-separated IP lists in X-Forwarded-For
+- Log client IPs for monitoring and debugging
+
+## Service Detection Security
+- Use regex patterns for User-Agent matching
+- Validate service configurations before use
+- Support multiple services with proper isolation
+- Default to Steam service configuration
+- Log service detection for monitoring
+
+## Error Handling Security
+- Don't expose internal system information in error messages
+- Log detailed errors for debugging but return generic messages to clients
+- Handle errors gracefully without crashing
+- Implement proper cleanup on errors
+- Use structured logging for security events
+
+## Configuration Security
+- Validate configuration values on startup
+- Use sensible defaults for security-sensitive settings
+- Validate file paths and permissions
+- Check upstream server connectivity
+- Log configuration changes
+
+## Memory and Resource Security
+- Implement memory limits to prevent OOM attacks
+- Use proper resource cleanup and garbage collection
+- Monitor memory usage and implement alerts
+- Use bounded data structures where possible
+- Implement proper connection limits
+
+## Logging Security
+- Don't log sensitive information (passwords, tokens)
+- Use structured logging for security events
+- Include relevant context (IPs, URLs, timestamps)
+- Implement log rotation and retention policies
+- Monitor logs for security issues
+
+## Network Security
+- Use HTTPS for upstream connections when possible
+- Implement proper TLS configuration
+- Use connection pooling with appropriate limits
+- Set reasonable timeouts for network operations
+- Monitor network traffic for anomalies

.cursor/rules/steamcache2-overview.mdc

@@ -0,0 +1,48 @@
+---
+alwaysApply: true
+---
+
+# SteamCache2 Overview
+
+SteamCache2 is a high-performance HTTP proxy cache specifically designed for Steam game downloads. It reduces bandwidth usage and speeds up downloads by caching game files locally.
+
+## Key Features
+- **Tiered Caching**: Memory + disk cache with intelligent promotion
+- **Service Detection**: Automatically detects Steam clients via User-Agent
+- **Request Coalescing**: Multiple clients share downloads of the same file
+- **Range Support**: Serves partial content from cached full files
+- **Garbage Collection**: Multiple algorithms (LRU, LFU, FIFO, Hybrid, etc.)
+- **Adaptive Caching**: Learns from access patterns for better performance
+
+## Architecture
+- **HTTP Proxy**: Intercepts Steam requests and serves from cache when possible
+- **VFS Layer**: Abstracted storage supporting memory and disk caches
+- **Service Manager**: Handles multiple gaming services (Steam, Epic, etc.)
+- **GC System**: Intelligent cache eviction with configurable algorithms
+
+## Development
+- **Language**: Go 1.23+
+- **Build**: Use `make` commands (see [Makefile](mdc:Makefile))
+- **Testing**: Comprehensive unit and integration tests
+- **Configuration**: YAML-based with automatic generation
+
+## Performance
+- **Concurrency**: Configurable request limits and rate limiting
+- **Memory**: Dynamic memory management with configurable thresholds
+- **Network**: Optimized HTTP transport with connection pooling
+- **Storage**: Efficient cache file format with integrity verification
+
+## Use Cases
+- **Gaming Cafes**: Reduce bandwidth costs and improve download speeds
+- **LAN Events**: Share game downloads across multiple clients
+- **Home Networks**: Speed up game updates for multiple gamers
+- **Development**: Test game downloads without hitting Steam servers
+
+## Configuration
+Default configuration is generated on first run. Key settings:
+- Cache sizes (memory/disk)
+- Garbage collection algorithms
+- Concurrency limits
+- Upstream server configuration
+
+See [config.yaml](mdc:config.yaml) for configuration options and [README.md](mdc:README.md) for detailed setup instructions.

.cursor/rules/testing-guidelines.mdc

@@ -0,0 +1,78 @@
+---
+globs: *_test.go
+---
+
+# Testing Guidelines for SteamCache2
+
+## Test Structure
+- Use table-driven tests for multiple test cases
+- Group related tests in the same test function when appropriate
+- Use descriptive test names that explain what is being tested
+- Include both positive and negative test cases
+
+## Test Data Management
+- Use `t.TempDir()` for temporary files and directories
+- Clean up resources in defer statements
+- Use unique temporary directories for each test to avoid conflicts
+- Don't rely on external services in unit tests
+
+## Integration Testing
+- Mark integration tests with `testing.Short()` checks
+- Use real Steam URLs for integration tests when appropriate
+- Test both cache hits and cache misses
+- Verify response integrity between direct and cached responses
+- Test against actual Steam servers for real-world validation
+- Use `httptest.NewServer` for local testing scenarios
+- Compare direct vs cached responses byte-for-byte
+
+## Mocking and Stubbing
+- Use `httptest.NewServer` for HTTP server mocking
+- Create mock responses that match real Steam responses
+- Test error conditions and edge cases
+- Use `httptest.NewRecorder` for response testing
+
+## Performance Testing
+- Test with realistic data sizes
+- Measure cache hit/miss ratios
+- Test concurrent request handling
+- Verify memory usage doesn't grow unbounded
+
+## Cache Testing
+- Test cache key generation and uniqueness
+- Verify cache file format serialization/deserialization
+- Test garbage collection algorithms
+- Test cache eviction policies
+- Test cache corruption scenarios and recovery
+- Verify cache file format integrity (magic numbers, hashes)
+- Test range request handling from cached files
+- Test request coalescing behavior
+
+## Service Detection Testing
+- Test User-Agent pattern matching
+- Test service configuration management
+- Test cache key generation for different services
+- Test service expandability (adding new services)
+
+## Error Handling Testing
+- Test network failures and timeouts
+- Test malformed requests and responses
+- Test cache corruption scenarios
+- Test resource exhaustion conditions
+
+## Test Timeouts
+- All tests should run with appropriate timeouts
+- Use `context.WithTimeout` for long-running operations
+- Set reasonable timeouts for network operations
+- Fail fast on obvious errors
+
+## Test Coverage
+- Aim for high test coverage on critical paths
+- Test edge cases and error conditions
+- Test concurrent access patterns
+- Test resource cleanup and memory management
+
+## Test Documentation
+- Document complex test scenarios
+- Explain the purpose of integration tests
+- Include comments for non-obvious test logic
+- Document expected behavior and assumptions

.cursor/rules/vfs-patterns.mdc

@@ -0,0 +1,72 @@
+---
+description: VFS (Virtual File System) patterns and architecture
+---
+
+# VFS (Virtual File System) Patterns
+
+## Core VFS Interface
+- Implement the `vfs.VFS` interface for all storage backends
+- Use interface implementation verification: `var _ vfs.VFS = (*Implementation)(nil)`
+- Support both memory and disk-based storage with the same interface
+- Provide size and capacity information for monitoring
+
+## Tiered Cache Architecture
+- Use `vfs/cache/cache.go` for two-tier caching (memory + disk)
+- Implement lock-free tier switching with `atomic.Value`
+- Prefer disk tier for persistence, memory tier for speed
+- Support cache promotion from disk to memory
+
+## Sharded File Systems
+- Use sharded directory structures for Steam cache keys
+- Implement 2-level sharding: `steam/XX/YY/hash` for optimal performance
+- Use `vfs/locks/sharding.go` for sharded locking
+- Reduce inode pressure with directory sharding
+
+## Memory Management
+- Use `bytes.Buffer` for in-memory file storage
+- Implement batched time updates for performance
+- Use LRU lists for eviction tracking
+- Monitor memory fragmentation and usage
+
+## Disk Storage
+- Use memory-mapped files (`mmap`) for large file operations
+- Implement efficient file path sharding
+- Use batched operations for better I/O performance
+- Support concurrent access with proper locking
+
+## Garbage Collection Integration
+- Wrap VFS implementations with `vfs/gc/gc.go`
+- Support multiple GC algorithms (LRU, LFU, FIFO, etc.)
+- Implement async GC with configurable thresholds
+- Use eviction functions from `vfs/eviction/eviction.go`
+
+## Performance Optimizations
+- Use sharded locks to reduce contention
+- Implement batched time updates (100ms intervals)
+- Use atomic operations for lock-free updates
+- Monitor and log performance metrics
+
+## Error Handling
+- Use custom VFS errors from `vfs/vfserror/vfserror.go`
+- Handle capacity exceeded scenarios gracefully
+- Implement proper cleanup on errors
+- Log VFS operations with context
+
+## File Information Management
+- Use `vfs/types/types.go` for file metadata
+- Track access times, sizes, and other statistics
+- Implement efficient file info storage and retrieval
+- Support batched metadata updates
+
+## Adaptive and Predictive Features
+- Integrate with `vfs/adaptive/adaptive.go` for learning patterns
+- Use `vfs/predictive/predictive.go` for cache warming
+- Implement intelligent cache promotion strategies
+- Monitor access patterns for optimization
+
+## Testing VFS Implementations
+- Test with realistic file sizes and access patterns
+- Verify concurrent access scenarios
+- Test garbage collection behavior
+- Validate sharding and path generation
+- Test error conditions and edge cases

steamcache/errors/errors.go

@@ -0,0 +1,120 @@
+// steamcache/errors/errors.go
+package errors
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+)
+
+// Common SteamCache errors
+var (
+	ErrInvalidURL           = errors.New("steamcache: invalid URL")
+	ErrUnsupportedService   = errors.New("steamcache: unsupported service")
+	ErrUpstreamUnavailable  = errors.New("steamcache: upstream server unavailable")
+	ErrCacheCorrupted       = errors.New("steamcache: cache file corrupted")
+	ErrInvalidContentLength = errors.New("steamcache: invalid content length")
+	ErrRequestTimeout       = errors.New("steamcache: request timeout")
+	ErrRateLimitExceeded    = errors.New("steamcache: rate limit exceeded")
+	ErrInvalidUserAgent     = errors.New("steamcache: invalid user agent")
+)
+
+// SteamCacheError represents a SteamCache-specific error with context
+type SteamCacheError struct {
+	Op         string      // Operation that failed
+	URL        string      // URL that caused the error
+	ClientIP   string      // Client IP address
+	StatusCode int         // HTTP status code if applicable
+	Err        error       // Underlying error
+	Context    interface{} // Additional context
+}
+
+// Error implements the error interface
+func (e *SteamCacheError) Error() string {
+	if e.URL != "" && e.ClientIP != "" {
+		return fmt.Sprintf("steamcache: %s failed for URL %q from client %s: %v", e.Op, e.URL, e.ClientIP, e.Err)
+	}
+	if e.URL != "" {
+		return fmt.Sprintf("steamcache: %s failed for URL %q: %v", e.Op, e.URL, e.Err)
+	}
+	return fmt.Sprintf("steamcache: %s failed: %v", e.Op, e.Err)
+}
+
+// Unwrap returns the underlying error
+func (e *SteamCacheError) Unwrap() error {
+	return e.Err
+}
+
+// NewSteamCacheError creates a new SteamCache error with context
+func NewSteamCacheError(op, url, clientIP string, err error) *SteamCacheError {
+	return &SteamCacheError{
+		Op:       op,
+		URL:      url,
+		ClientIP: clientIP,
+		Err:      err,
+	}
+}
+
+// NewSteamCacheErrorWithStatus creates a new SteamCache error with HTTP status
+func NewSteamCacheErrorWithStatus(op, url, clientIP string, statusCode int, err error) *SteamCacheError {
+	return &SteamCacheError{
+		Op:         op,
+		URL:        url,
+		ClientIP:   clientIP,
+		StatusCode: statusCode,
+		Err:        err,
+	}
+}
+
+// NewSteamCacheErrorWithContext creates a new SteamCache error with additional context
+func NewSteamCacheErrorWithContext(op, url, clientIP string, context interface{}, err error) *SteamCacheError {
+	return &SteamCacheError{
+		Op:       op,
+		URL:      url,
+		ClientIP: clientIP,
+		Context:  context,
+		Err:      err,
+	}
+}
+
+// IsRetryableError determines if an error is retryable
+func IsRetryableError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	// Check for specific retryable errors
+	if errors.Is(err, ErrUpstreamUnavailable) ||
+		errors.Is(err, ErrRequestTimeout) {
+		return true
+	}
+
+	// Check for HTTP status codes that are retryable
+	if steamErr, ok := err.(*SteamCacheError); ok {
+		switch steamErr.StatusCode {
+		case http.StatusServiceUnavailable,
+			http.StatusGatewayTimeout,
+			http.StatusTooManyRequests,
+			http.StatusInternalServerError:
+			return true
+		}
+	}
+
+	return false
+}
+
+// IsClientError determines if an error is a client error (4xx)
+func IsClientError(err error) bool {
+	if steamErr, ok := err.(*SteamCacheError); ok {
+		return steamErr.StatusCode >= 400 && steamErr.StatusCode < 500
+	}
+	return false
+}
+
+// IsServerError determines if an error is a server error (5xx)
+func IsServerError(err error) bool {
+	if steamErr, ok := err.(*SteamCacheError); ok {
+		return steamErr.StatusCode >= 500
+	}
+	return false
+}

steamcache/metrics/metrics.go

@@ -0,0 +1,213 @@
+// steamcache/metrics/metrics.go
+package metrics
+
+import (
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+// Metrics tracks various performance and operational metrics
+type Metrics struct {
+	// Request metrics
+	TotalRequests  int64
+	CacheHits      int64
+	CacheMisses    int64
+	CacheCoalesced int64
+	Errors         int64
+	RateLimited    int64
+
+	// Performance metrics
+	TotalResponseTime int64 // in nanoseconds
+	TotalBytesServed  int64
+	TotalBytesCached  int64
+
+	// Cache metrics
+	MemoryCacheSize int64
+	DiskCacheSize   int64
+	MemoryCacheHits int64
+	DiskCacheHits   int64
+
+	// Service metrics
+	ServiceRequests map[string]int64
+	serviceMutex    sync.RWMutex
+
+	// Time tracking
+	StartTime     time.Time
+	LastResetTime time.Time
+}
+
+// NewMetrics creates a new metrics instance
+func NewMetrics() *Metrics {
+	now := time.Now()
+	return &Metrics{
+		ServiceRequests: make(map[string]int64),
+		StartTime:       now,
+		LastResetTime:   now,
+	}
+}
+
+// IncrementTotalRequests increments the total request counter
+func (m *Metrics) IncrementTotalRequests() {
+	atomic.AddInt64(&m.TotalRequests, 1)
+}
+
+// IncrementCacheHits increments the cache hit counter
+func (m *Metrics) IncrementCacheHits() {
+	atomic.AddInt64(&m.CacheHits, 1)
+}
+
+// IncrementCacheMisses increments the cache miss counter
+func (m *Metrics) IncrementCacheMisses() {
+	atomic.AddInt64(&m.CacheMisses, 1)
+}
+
+// IncrementCacheCoalesced increments the coalesced request counter
+func (m *Metrics) IncrementCacheCoalesced() {
+	atomic.AddInt64(&m.CacheCoalesced, 1)
+}
+
+// IncrementErrors increments the error counter
+func (m *Metrics) IncrementErrors() {
+	atomic.AddInt64(&m.Errors, 1)
+}
+
+// IncrementRateLimited increments the rate limited counter
+func (m *Metrics) IncrementRateLimited() {
+	atomic.AddInt64(&m.RateLimited, 1)
+}
+
+// AddResponseTime adds response time to the total
+func (m *Metrics) AddResponseTime(duration time.Duration) {
+	atomic.AddInt64(&m.TotalResponseTime, int64(duration))
+}
+
+// AddBytesServed adds bytes served to the total
+func (m *Metrics) AddBytesServed(bytes int64) {
+	atomic.AddInt64(&m.TotalBytesServed, bytes)
+}
+
+// AddBytesCached adds bytes cached to the total
+func (m *Metrics) AddBytesCached(bytes int64) {
+	atomic.AddInt64(&m.TotalBytesCached, bytes)
+}
+
+// SetMemoryCacheSize sets the current memory cache size
+func (m *Metrics) SetMemoryCacheSize(size int64) {
+	atomic.StoreInt64(&m.MemoryCacheSize, size)
+}
+
+// SetDiskCacheSize sets the current disk cache size
+func (m *Metrics) SetDiskCacheSize(size int64) {
+	atomic.StoreInt64(&m.DiskCacheSize, size)
+}
+
+// IncrementMemoryCacheHits increments memory cache hits
+func (m *Metrics) IncrementMemoryCacheHits() {
+	atomic.AddInt64(&m.MemoryCacheHits, 1)
+}
+
+// IncrementDiskCacheHits increments disk cache hits
+func (m *Metrics) IncrementDiskCacheHits() {
+	atomic.AddInt64(&m.DiskCacheHits, 1)
+}
+
+// IncrementServiceRequests increments requests for a specific service
+func (m *Metrics) IncrementServiceRequests(service string) {
+	m.serviceMutex.Lock()
+	defer m.serviceMutex.Unlock()
+	m.ServiceRequests[service]++
+}
+
+// GetServiceRequests returns the number of requests for a service
+func (m *Metrics) GetServiceRequests(service string) int64 {
+	m.serviceMutex.RLock()
+	defer m.serviceMutex.RUnlock()
+	return m.ServiceRequests[service]
+}
+
+// GetStats returns a snapshot of current metrics
+func (m *Metrics) GetStats() *Stats {
+	totalRequests := atomic.LoadInt64(&m.TotalRequests)
+	cacheHits := atomic.LoadInt64(&m.CacheHits)
+	cacheMisses := atomic.LoadInt64(&m.CacheMisses)
+
+	var hitRate float64
+	if totalRequests > 0 {
+		hitRate = float64(cacheHits) / float64(totalRequests)
+	}
+
+	var avgResponseTime time.Duration
+	if totalRequests > 0 {
+		avgResponseTime = time.Duration(atomic.LoadInt64(&m.TotalResponseTime) / totalRequests)
+	}
+
+	m.serviceMutex.RLock()
+	serviceRequests := make(map[string]int64)
+	for k, v := range m.ServiceRequests {
+		serviceRequests[k] = v
+	}
+	m.serviceMutex.RUnlock()
+
+	return &Stats{
+		TotalRequests:    totalRequests,
+		CacheHits:        cacheHits,
+		CacheMisses:      cacheMisses,
+		CacheCoalesced:   atomic.LoadInt64(&m.CacheCoalesced),
+		Errors:           atomic.LoadInt64(&m.Errors),
+		RateLimited:      atomic.LoadInt64(&m.RateLimited),
+		HitRate:          hitRate,
+		AvgResponseTime:  avgResponseTime,
+		TotalBytesServed: atomic.LoadInt64(&m.TotalBytesServed),
+		TotalBytesCached: atomic.LoadInt64(&m.TotalBytesCached),
+		MemoryCacheSize:  atomic.LoadInt64(&m.MemoryCacheSize),
+		DiskCacheSize:    atomic.LoadInt64(&m.DiskCacheSize),
+		MemoryCacheHits:  atomic.LoadInt64(&m.MemoryCacheHits),
+		DiskCacheHits:    atomic.LoadInt64(&m.DiskCacheHits),
+		ServiceRequests:  serviceRequests,
+		Uptime:           time.Since(m.StartTime),
+		LastResetTime:    m.LastResetTime,
+	}
+}
+
+// Reset resets all metrics to zero
+func (m *Metrics) Reset() {
+	atomic.StoreInt64(&m.TotalRequests, 0)
+	atomic.StoreInt64(&m.CacheHits, 0)
+	atomic.StoreInt64(&m.CacheMisses, 0)
+	atomic.StoreInt64(&m.CacheCoalesced, 0)
+	atomic.StoreInt64(&m.Errors, 0)
+	atomic.StoreInt64(&m.RateLimited, 0)
+	atomic.StoreInt64(&m.TotalResponseTime, 0)
+	atomic.StoreInt64(&m.TotalBytesServed, 0)
+	atomic.StoreInt64(&m.TotalBytesCached, 0)
+	atomic.StoreInt64(&m.MemoryCacheHits, 0)
+	atomic.StoreInt64(&m.DiskCacheHits, 0)
+
+	m.serviceMutex.Lock()
+	m.ServiceRequests = make(map[string]int64)
+	m.serviceMutex.Unlock()
+
+	m.LastResetTime = time.Now()
+}
+
+// Stats represents a snapshot of metrics
+type Stats struct {
+	TotalRequests    int64
+	CacheHits        int64
+	CacheMisses      int64
+	CacheCoalesced   int64
+	Errors           int64
+	RateLimited      int64
+	HitRate          float64
+	AvgResponseTime  time.Duration
+	TotalBytesServed int64
+	TotalBytesCached int64
+	MemoryCacheSize  int64
+	DiskCacheSize    int64
+	MemoryCacheHits  int64
+	DiskCacheHits    int64
+	ServiceRequests  map[string]int64
+	Uptime           time.Duration
+	LastResetTime    time.Time
+}

steamcache/steamcache.go

@@ -13,7 +13,9 @@ import (
 	"net/url"
 	"os"
 	"regexp"
+	"s1d3sw1ped/steamcache2/steamcache/errors"
 	"s1d3sw1ped/steamcache2/steamcache/logger"
+	"s1d3sw1ped/steamcache2/steamcache/metrics"
 	"s1d3sw1ped/steamcache2/vfs"
 	"s1d3sw1ped/steamcache2/vfs/adaptive"
 	"s1d3sw1ped/steamcache2/vfs/cache"
@@ -21,7 +23,6 @@ import (
 	"s1d3sw1ped/steamcache2/vfs/gc"
 	"s1d3sw1ped/steamcache2/vfs/memory"
 	"s1d3sw1ped/steamcache2/vfs/predictive"
-	"s1d3sw1ped/steamcache2/vfs/warming"
 	"strconv"
 	"strings"
 	"sync"
@@ -361,13 +362,14 @@ func (sc *SteamCache) streamCachedResponse(w http.ResponseWriter, r *http.Reques
 		w.Write(rangeData)
 
 		logger.Logger.Info().
-			Str("key", cacheKey).
+			Str("cache_key", cacheKey).
 			Str("url", r.URL.String()).
 			Str("host", r.Host).
 			Str("client_ip", clientIP).
-			Str("status", "HIT").
+			Str("cache_status", "HIT").
 			Str("range", fmt.Sprintf("%d-%d/%d", start, end, totalSize)).
-			Dur("zduration", time.Since(tstart)).
+			Int64("range_size", end-start+1).
+			Dur("response_time", time.Since(tstart)).
 			Msg("cache request")
 
 		return
@@ -395,12 +397,13 @@ func (sc *SteamCache) streamCachedResponse(w http.ResponseWriter, r *http.Reques
 	w.Write(bodyData)
 
 	logger.Logger.Info().
-		Str("key", cacheKey).
+		Str("cache_key", cacheKey).
 		Str("url", r.URL.String()).
 		Str("host", r.Host).
 		Str("client_ip", clientIP).
-		Str("status", "HIT").
+		Str("cache_status", "HIT").
-		Dur("zduration", time.Since(tstart)).
+		Int64("file_size", int64(len(bodyData))).
+		Dur("response_time", time.Since(tstart)).
 		Msg("cache request")
 }
 
@@ -496,14 +499,19 @@ func parseRangeHeader(rangeHeader string, totalSize int64) (start, end, total in
 }
 
 // generateURLHash creates a SHA256 hash of the entire URL path for cache key
-func generateURLHash(urlPath string) string {
+func generateURLHash(urlPath string) (string, error) {
 	// Validate input to prevent cache key pollution
 	if urlPath == "" {
-		return ""
+		return "", errors.NewSteamCacheError("generateURLHash", urlPath, "", errors.ErrInvalidURL)
+	}
+
+	// Additional validation for suspicious patterns
+	if strings.Contains(urlPath, "..") || strings.Contains(urlPath, "//") {
+		return "", errors.NewSteamCacheError("generateURLHash", urlPath, "", errors.ErrInvalidURL)
 	}
 
 	hash := sha256.Sum256([]byte(urlPath))
-	return hex.EncodeToString(hash[:])
+	return hex.EncodeToString(hash[:]), nil
 }
 
 // calculateSHA256 calculates SHA256 hash of the given data
@@ -513,6 +521,35 @@ func calculateSHA256(data []byte) string {
 	return hex.EncodeToString(hasher.Sum(nil))
 }
 
+// validateURLPath validates URL path for security concerns
+func validateURLPath(urlPath string) error {
+	if urlPath == "" {
+		return errors.NewSteamCacheError("validateURLPath", urlPath, "", errors.ErrInvalidURL)
+	}
+
+	// Check for directory traversal attempts
+	if strings.Contains(urlPath, "..") {
+		return errors.NewSteamCacheError("validateURLPath", urlPath, "", errors.ErrInvalidURL)
+	}
+
+	// Check for double slashes (potential path manipulation)
+	if strings.Contains(urlPath, "//") {
+		return errors.NewSteamCacheError("validateURLPath", urlPath, "", errors.ErrInvalidURL)
+	}
+
+	// Check for suspicious characters
+	if strings.ContainsAny(urlPath, "<>\"'&") {
+		return errors.NewSteamCacheError("validateURLPath", urlPath, "", errors.ErrInvalidURL)
+	}
+
+	// Check for reasonable length (prevent DoS)
+	if len(urlPath) > 2048 {
+		return errors.NewSteamCacheError("validateURLPath", urlPath, "", errors.ErrInvalidURL)
+	}
+
+	return nil
+}
+
 // verifyCompleteFile verifies that we received the complete file by checking Content-Length
 // Returns true if the file is complete, false if it's incomplete (allowing retry)
 func (sc *SteamCache) verifyCompleteFile(bodyData []byte, resp *http.Response, urlPath string, cacheKey string) bool {
@@ -572,9 +609,20 @@ func (sc *SteamCache) detectService(r *http.Request) (*ServiceConfig, bool) {
 // The prefix indicates which service the request came from (detected via User-Agent)
 // Input: /depot/1684171/chunk/0016cfc5019b8baa6026aa1cce93e685d6e06c6e, "steam"
 // Output: steam/a1b2c3d4e5f678901234567890123456789012345678901234567890
-func generateServiceCacheKey(urlPath string, servicePrefix string) string {
+func generateServiceCacheKey(urlPath string, servicePrefix string) (string, error) {
+	// Validate service prefix
+	if servicePrefix == "" {
+		return "", errors.NewSteamCacheError("generateServiceCacheKey", urlPath, "", errors.ErrUnsupportedService)
+	}
+
+	// Generate hash for URL path
+	hash, err := generateURLHash(urlPath)
+	if err != nil {
+		return "", err
+	}
+
 	// Create a SHA256 hash of the entire path for all service client requests
-	return servicePrefix + "/" + generateURLHash(urlPath)
+	return servicePrefix + "/" + hash, nil
 }
 
 var hopByHopHeaders = map[string]struct{}{
@@ -781,14 +829,17 @@ type SteamCache struct {
 	// Adaptive and predictive caching
 	adaptiveManager   *adaptive.AdaptiveCacheManager
 	predictiveManager *predictive.PredictiveCacheManager
-	cacheWarmer       *warming.CacheWarmer
+	cacheWarmer       *predictive.CacheWarmer
 	lastAccessKey     string // Track last accessed key for sequence analysis
 	lastAccessKeyMu   sync.RWMutex
 	adaptiveEnabled   bool // Flag to enable/disable adaptive features
 
 	// Dynamic memory management
 	memoryMonitor   *memory.MemoryMonitor
-	dynamicCacheMgr *memory.DynamicCacheManager
+	dynamicCacheMgr *memory.MemoryMonitor
+
+	// Metrics
+	metrics *metrics.Metrics
 }
 
 func New(address string, memorySize string, diskSize string, diskPath, upstream, memoryGC, diskGC string, maxConcurrentRequests int64, maxRequestsPerClient int64) *SteamCache {
@@ -925,17 +976,20 @@ func New(address string, memorySize string, diskSize string, diskPath, upstream,
 		// Initialize adaptive and predictive caching (lightweight)
 		adaptiveManager:   adaptive.NewAdaptiveCacheManager(5 * time.Minute), // Much longer interval
 		predictiveManager: predictive.NewPredictiveCacheManager(),
-		cacheWarmer:       warming.NewCacheWarmer(c, 2), // Reduced to 2 concurrent warmers
+		cacheWarmer:       predictive.NewCacheWarmer(), // Use predictive cache warmer
-		adaptiveEnabled:   true,                         // Enable by default but can be disabled
+		adaptiveEnabled:   true,                        // Enable by default but can be disabled
 
 		// Initialize dynamic memory management
 		memoryMonitor:   memory.NewMemoryMonitor(uint64(memorysize), 10*time.Second, 0.1), // 10% threshold
 		dynamicCacheMgr: nil,                                                              // Will be set after cache creation
+
+		// Initialize metrics
+		metrics: metrics.NewMetrics(),
 	}
 
 	// Initialize dynamic cache manager if we have memory cache
 	if m != nil && sc.memoryMonitor != nil {
-		sc.dynamicCacheMgr = memory.NewDynamicCacheManager(mgc, uint64(memorysize), sc.memoryMonitor)
+		sc.dynamicCacheMgr = memory.NewMemoryMonitorWithCache(uint64(memorysize), 10*time.Second, 0.1, mgc, uint64(memorysize))
 		sc.dynamicCacheMgr.Start()
 		sc.memoryMonitor.Start()
 	}
@@ -1001,21 +1055,44 @@ func (sc *SteamCache) Shutdown() {
 	sc.wg.Wait()
 }
 
+// GetMetrics returns current metrics
+func (sc *SteamCache) GetMetrics() *metrics.Stats {
+	// Update cache sizes
+	if sc.memory != nil {
+		sc.metrics.SetMemoryCacheSize(sc.memory.Size())
+	}
+	if sc.disk != nil {
+		sc.metrics.SetDiskCacheSize(sc.disk.Size())
+	}
+
+	return sc.metrics.GetStats()
+}
+
+// ResetMetrics resets all metrics to zero
+func (sc *SteamCache) ResetMetrics() {
+	sc.metrics.Reset()
+}
+
 func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	clientIP := getClientIP(r)
+
 	// Set keep-alive headers for better performance
 	w.Header().Set("Connection", "keep-alive")
 	w.Header().Set("Keep-Alive", "timeout=300, max=1000")
 
 	// Apply global concurrency limit first
 	if err := sc.requestSemaphore.Acquire(context.Background(), 1); err != nil {
-		logger.Logger.Warn().Str("client_ip", getClientIP(r)).Msg("Server at capacity, rejecting request")
+		sc.metrics.IncrementRateLimited()
+		logger.Logger.Warn().Str("client_ip", clientIP).Msg("Server at capacity, rejecting request")
 		http.Error(w, "Server busy, please try again later", http.StatusServiceUnavailable)
 		return
 	}
 	defer sc.requestSemaphore.Release(1)
 
+	// Track total requests
+	sc.metrics.IncrementTotalRequests()
+
 	// Apply per-client rate limiting
-	clientIP := getClientIP(r)
 	clientLimiter := sc.getOrCreateClientLimiter(clientIP)
 
 	if err := clientLimiter.semaphore.Acquire(context.Background(), 1); err != nil {
@@ -1055,19 +1132,56 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if r.URL.String() == "/metrics" {
+		// Return metrics in a simple text format
+		stats := sc.GetMetrics()
+		w.Header().Set("Content-Type", "text/plain")
+		w.WriteHeader(http.StatusOK)
+		fmt.Fprintf(w, "# SteamCache2 Metrics\n")
+		fmt.Fprintf(w, "total_requests %d\n", stats.TotalRequests)
+		fmt.Fprintf(w, "cache_hits %d\n", stats.CacheHits)
+		fmt.Fprintf(w, "cache_misses %d\n", stats.CacheMisses)
+		fmt.Fprintf(w, "cache_coalesced %d\n", stats.CacheCoalesced)
+		fmt.Fprintf(w, "errors %d\n", stats.Errors)
+		fmt.Fprintf(w, "rate_limited %d\n", stats.RateLimited)
+		fmt.Fprintf(w, "hit_rate %.4f\n", stats.HitRate)
+		fmt.Fprintf(w, "avg_response_time_ms %.2f\n", float64(stats.AvgResponseTime.Nanoseconds())/1e6)
+		fmt.Fprintf(w, "total_bytes_served %d\n", stats.TotalBytesServed)
+		fmt.Fprintf(w, "total_bytes_cached %d\n", stats.TotalBytesCached)
+		fmt.Fprintf(w, "memory_cache_size %d\n", stats.MemoryCacheSize)
+		fmt.Fprintf(w, "disk_cache_size %d\n", stats.DiskCacheSize)
+		fmt.Fprintf(w, "uptime_seconds %.2f\n", stats.Uptime.Seconds())
+		return
+	}
+
 	// Check if this is a request from a supported service
 	if service, isSupported := sc.detectService(r); isSupported {
 		// trim the query parameters from the URL path
 		// this is necessary because the cache key should not include query parameters
 		urlPath, _, _ := strings.Cut(r.URL.String(), "?")
 
+		// Validate URL path for security
+		if err := validateURLPath(urlPath); err != nil {
+			logger.Logger.Warn().
+				Err(err).
+				Str("url", urlPath).
+				Str("client_ip", clientIP).
+				Msg("Invalid URL path detected")
+			http.Error(w, "Invalid URL", http.StatusBadRequest)
+			return
+		}
+
 		tstart := time.Now()
 
 		// Generate service cache key: {service}/{hash} (prefix indicates service via User-Agent)
-		cacheKey := generateServiceCacheKey(urlPath, service.Prefix)
+		cacheKey, err := generateServiceCacheKey(urlPath, service.Prefix)
-
+		if err != nil {
-		if cacheKey == "" {
+			logger.Logger.Warn().
-			logger.Logger.Warn().Str("url", urlPath).Msg("Invalid URL")
+				Err(err).
+				Str("url", urlPath).
+				Str("service", service.Name).
+				Str("client_ip", clientIP).
+				Msg("Failed to generate cache key")
 			http.Error(w, "Invalid URL", http.StatusBadRequest)
 			return
 		}
@@ -1111,6 +1225,12 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 					// Cache validation passed - record access for adaptive/predictive analysis
 					sc.recordCacheAccess(cacheKey, int64(len(cachedData)))
 
+					// Track cache hit metrics
+					sc.metrics.IncrementCacheHits()
+					sc.metrics.AddResponseTime(time.Since(tstart))
+					sc.metrics.AddBytesServed(int64(len(cachedData)))
+					sc.metrics.IncrementServiceRequests(service.Name)
+
 					logger.Logger.Debug().
 						Str("key", cacheKey).
 						Str("url", urlPath).
@@ -1176,13 +1296,21 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 				w.WriteHeader(coalescedReq.statusCode)
 				w.Write(responseData)
 
+				// Track coalesced cache hit metrics
+				sc.metrics.IncrementCacheCoalesced()
+				sc.metrics.AddResponseTime(time.Since(tstart))
+				sc.metrics.AddBytesServed(int64(len(responseData)))
+				sc.metrics.IncrementServiceRequests(service.Name)
+
 				logger.Logger.Info().
-					Str("key", cacheKey).
+					Str("cache_key", cacheKey).
 					Str("url", urlPath).
 					Str("host", r.Host).
 					Str("client_ip", clientIP).
-					Str("status", "HIT-COALESCED").
+					Str("cache_status", "HIT-COALESCED").
-					Dur("zduration", time.Since(tstart)).
+					Int("waiting_clients", coalescedReq.waitingCount).
+					Int64("file_size", int64(len(responseData))).
+					Dur("response_time", time.Since(tstart)).
 					Msg("cache request")
 
 				return
@@ -1360,6 +1488,12 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(resp.StatusCode)
 		w.Write(bodyData)
 
+		// Track cache miss metrics
+		sc.metrics.IncrementCacheMisses()
+		sc.metrics.AddResponseTime(time.Since(tstart))
+		sc.metrics.AddBytesServed(int64(len(bodyData)))
+		sc.metrics.IncrementServiceRequests(service.Name)
+
 		// Cache the file if validation passed
 		if validationPassed {
 			// Verify we received the complete file by checking Content-Length
@@ -1400,6 +1534,8 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 							Msg("Cache write failed or incomplete - removing corrupted entry")
 						sc.vfs.Delete(cachePath)
 					} else {
+						// Track successful cache write
+						sc.metrics.AddBytesCached(int64(len(cacheData)))
 						logger.Logger.Debug().
 							Str("key", cacheKey).
 							Str("url", urlPath).
@@ -1457,12 +1593,14 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		}
 
 		logger.Logger.Info().
-			Str("key", cacheKey).
+			Str("cache_key", cacheKey).
 			Str("url", urlPath).
 			Str("host", r.Host).
 			Str("client_ip", clientIP).
-			Str("status", "MISS").
+			Str("service", service.Name).
-			Dur("zduration", time.Since(tstart)).
+			Str("cache_status", "MISS").
+			Int64("file_size", int64(len(bodyData))).
+			Dur("response_time", time.Since(tstart)).
 			Msg("cache request")
 
 		return
@@ -1535,6 +1673,6 @@ func (sc *SteamCache) recordCacheMiss(key string, size int64) {
 
 	// Only trigger warming for very large files to reduce overhead
 	if size > 10*1024*1024 { // Only warm files > 10MB
-		sc.cacheWarmer.RequestWarming(key, 3, "cache_miss", size, "cache_miss_analyzer")
+		sc.cacheWarmer.RequestWarming(key, 3, "cache_miss", size)
 	}
 }

steamcache/steamcache_test.go

@@ -3,20 +3,27 @@ package steamcache
 
 import (
 	"io"
-	"os"
+	"s1d3sw1ped/steamcache2/steamcache/errors"
-	"path/filepath"
+	"s1d3sw1ped/steamcache2/vfs/vfserror"
 	"strings"
 	"testing"
+	"time"
 )
 
 func TestCaching(t *testing.T) {
 	td := t.TempDir()
 
-	os.WriteFile(filepath.Join(td, "key2"), []byte("value2"), 0644)
-
 	sc := New("localhost:8080", "1G", "1G", td, "", "lru", "lru", 200, 5)
 
-	w, err := sc.vfs.Create("key", 5)
+	// Create key2 through the VFS system instead of directly
+	w, err := sc.vfs.Create("key2", 6)
+	if err != nil {
+		t.Errorf("Create key2 failed: %v", err)
+	}
+	w.Write([]byte("value2"))
+	w.Close()
+
+	w, err = sc.vfs.Create("key", 5)
 	if err != nil {
 		t.Errorf("Create failed: %v", err)
 	}
@@ -82,9 +89,18 @@ func TestCaching(t *testing.T) {
 		t.Errorf("Total size too large: got %d, want at most 34", sc.vfs.Size())
 	}
 
+	// First ensure the file is indexed by opening it
+	rc, err = sc.vfs.Open("key2")
+	if err != nil {
+		t.Errorf("Open key2 failed: %v", err)
+	}
+	rc.Close()
+
+	// Give promotion goroutine time to complete before deleting
+	time.Sleep(100 * time.Millisecond)
+
 	sc.memory.Delete("key2")
 	sc.disk.Delete("key2") // Also delete from disk cache
-	os.Remove(filepath.Join(td, "key2"))
 
 	if _, err := sc.vfs.Open("key2"); err == nil {
 		t.Errorf("Open failed: got nil, want error")
@@ -150,10 +166,13 @@ func TestURLHashing(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.desc, func(t *testing.T) {
-			result := generateServiceCacheKey(tc.input, "steam")
+			result, err := generateServiceCacheKey(tc.input, "steam")
 
 			if tc.shouldCache {
 				// Should return a cache key with "steam/" prefix
+				if err != nil {
+					t.Errorf("generateServiceCacheKey(%s, \"steam\") returned error: %v", tc.input, err)
+				}
 				if !strings.HasPrefix(result, "steam/") {
 					t.Errorf("generateServiceCacheKey(%s, \"steam\") = %s, expected steam/ prefix", tc.input, result)
 				}
@@ -162,9 +181,9 @@ func TestURLHashing(t *testing.T) {
 					t.Errorf("generateServiceCacheKey(%s, \"steam\") length = %d, expected 70", tc.input, len(result))
 				}
 			} else {
-				// Should return empty string for non-Steam URLs
+				// Should return error for invalid URLs
-				if result != "" {
+				if err == nil {
-					t.Errorf("generateServiceCacheKey(%s, \"steam\") = %s, expected empty string", tc.input, result)
+					t.Errorf("generateServiceCacheKey(%s, \"steam\") should have returned error", tc.input)
 				}
 			}
 		})
@@ -308,8 +327,14 @@ func TestServiceManagerExpandability(t *testing.T) {
 	}
 
 	// Test cache key generation for different services
-	steamKey := generateServiceCacheKey("/depot/123/chunk/abc", "steam")
+	steamKey, err := generateServiceCacheKey("/depot/123/chunk/abc", "steam")
-	epicKey := generateServiceCacheKey("/epic/123/chunk/abc", "epic")
+	if err != nil {
+		t.Errorf("Failed to generate Steam cache key: %v", err)
+	}
+	epicKey, err := generateServiceCacheKey("/epic/123/chunk/abc", "epic")
+	if err != nil {
+		t.Errorf("Failed to generate Epic cache key: %v", err)
+	}
 
 	if !strings.HasPrefix(steamKey, "steam/") {
 		t.Errorf("Steam cache key should start with 'steam/', got: %s", steamKey)
@@ -353,4 +378,139 @@ func TestSteamKeySharding(t *testing.T) {
 	// and be readable, whereas without sharding it might not work correctly
 }
 
+// TestURLValidation tests the URL validation function
+func TestURLValidation(t *testing.T) {
+	testCases := []struct {
+		urlPath     string
+		shouldPass  bool
+		description string
+	}{
+		{
+			urlPath:     "/depot/123/chunk/abc",
+			shouldPass:  true,
+			description: "valid Steam URL",
+		},
+		{
+			urlPath:     "/appinfo/456",
+			shouldPass:  true,
+			description: "valid app info URL",
+		},
+		{
+			urlPath:     "",
+			shouldPass:  false,
+			description: "empty URL",
+		},
+		{
+			urlPath:     "/depot/../etc/passwd",
+			shouldPass:  false,
+			description: "directory traversal attempt",
+		},
+		{
+			urlPath:     "/depot//123/chunk/abc",
+			shouldPass:  false,
+			description: "double slash",
+		},
+		{
+			urlPath:     "/depot/123/chunk/abc<script>",
+			shouldPass:  false,
+			description: "suspicious characters",
+		},
+		{
+			urlPath:     strings.Repeat("/depot/123/chunk/abc", 200), // This will be much longer than 2048 chars
+			shouldPass:  false,
+			description: "URL too long",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.description, func(t *testing.T) {
+			err := validateURLPath(tc.urlPath)
+			if tc.shouldPass && err != nil {
+				t.Errorf("validateURLPath(%q) should pass but got error: %v", tc.urlPath, err)
+			}
+			if !tc.shouldPass && err == nil {
+				t.Errorf("validateURLPath(%q) should fail but passed", tc.urlPath)
+			}
+		})
+	}
+}
+
+// TestErrorTypes tests the custom error types
+func TestErrorTypes(t *testing.T) {
+	// Test VFS error
+	vfsErr := vfserror.NewVFSError("test", "key1", vfserror.ErrNotFound)
+	if vfsErr.Error() == "" {
+		t.Error("VFS error should have a message")
+	}
+	if vfsErr.Unwrap() != vfserror.ErrNotFound {
+		t.Error("VFS error should unwrap to the underlying error")
+	}
+
+	// Test SteamCache error
+	scErr := errors.NewSteamCacheError("test", "/test/url", "127.0.0.1", errors.ErrInvalidURL)
+	if scErr.Error() == "" {
+		t.Error("SteamCache error should have a message")
+	}
+	if scErr.Unwrap() != errors.ErrInvalidURL {
+		t.Error("SteamCache error should unwrap to the underlying error")
+	}
+
+	// Test retryable error detection
+	if !errors.IsRetryableError(errors.ErrUpstreamUnavailable) {
+		t.Error("Upstream unavailable should be retryable")
+	}
+	if errors.IsRetryableError(errors.ErrInvalidURL) {
+		t.Error("Invalid URL should not be retryable")
+	}
+}
+
+// TestMetrics tests the metrics functionality
+func TestMetrics(t *testing.T) {
+	td := t.TempDir()
+	sc := New("localhost:8080", "1G", "1G", td, "", "lru", "lru", 200, 5)
+
+	// Test initial metrics
+	stats := sc.GetMetrics()
+	if stats.TotalRequests != 0 {
+		t.Error("Initial total requests should be 0")
+	}
+	if stats.CacheHits != 0 {
+		t.Error("Initial cache hits should be 0")
+	}
+
+	// Test metrics increment
+	sc.metrics.IncrementTotalRequests()
+	sc.metrics.IncrementCacheHits()
+	sc.metrics.IncrementCacheMisses()
+	sc.metrics.AddBytesServed(1024)
+	sc.metrics.IncrementServiceRequests("steam")
+
+	stats = sc.GetMetrics()
+	if stats.TotalRequests != 1 {
+		t.Error("Total requests should be 1")
+	}
+	if stats.CacheHits != 1 {
+		t.Error("Cache hits should be 1")
+	}
+	if stats.CacheMisses != 1 {
+		t.Error("Cache misses should be 1")
+	}
+	if stats.TotalBytesServed != 1024 {
+		t.Error("Total bytes served should be 1024")
+	}
+	if stats.ServiceRequests["steam"] != 1 {
+		t.Error("Steam service requests should be 1")
+	}
+
+	// Test metrics reset
+	sc.ResetMetrics()
+	stats = sc.GetMetrics()
+	if stats.TotalRequests != 0 {
+		t.Error("After reset, total requests should be 0")
+	}
+	if stats.CacheHits != 0 {
+		t.Error("After reset, cache hits should be 0")
+	}
+}
+
 // Removed old TestKeyGeneration - replaced with TestURLHashing that uses SHA256

vfs/cache/cache.go

@@ -5,56 +5,47 @@ import (
 	"io"
 	"s1d3sw1ped/steamcache2/vfs"
 	"s1d3sw1ped/steamcache2/vfs/vfserror"
-	"sync"
 	"sync/atomic"
 )
 
-// TieredCache implements a two-tier cache with fast (memory) and slow (disk) storage
+// TieredCache implements a lock-free two-tier cache for better concurrency
 type TieredCache struct {
-	fast vfs.VFS // Memory cache (fast)
-	slow vfs.VFS // Disk cache (slow)
-
-	mu sync.RWMutex
-}
-
-// LockFreeTieredCache implements a lock-free two-tier cache for better concurrency
-type LockFreeTieredCache struct {
 	fast *atomic.Value // Memory cache (fast) - atomic.Value for lock-free access
 	slow *atomic.Value // Disk cache (slow) - atomic.Value for lock-free access
 }
 
 // New creates a new tiered cache
 func New() *TieredCache {
-	return &TieredCache{}
+	return &TieredCache{
+		fast: &atomic.Value{},
+		slow: &atomic.Value{},
+	}
 }
 
-// SetFast sets the fast (memory) tier
+// SetFast sets the fast (memory) tier atomically
 func (tc *TieredCache) SetFast(vfs vfs.VFS) {
-	tc.mu.Lock()
+	tc.fast.Store(vfs)
-	defer tc.mu.Unlock()
-	tc.fast = vfs
 }
 
-// SetSlow sets the slow (disk) tier
+// SetSlow sets the slow (disk) tier atomically
 func (tc *TieredCache) SetSlow(vfs vfs.VFS) {
-	tc.mu.Lock()
+	tc.slow.Store(vfs)
-	defer tc.mu.Unlock()
-	tc.slow = vfs
 }
 
-// Create creates a new file, preferring the slow tier for persistence testing
+// Create creates a new file, preferring the slow tier for persistence
 func (tc *TieredCache) Create(key string, size int64) (io.WriteCloser, error) {
-	tc.mu.RLock()
-	defer tc.mu.RUnlock()
-
 	// Try slow tier first (disk) for better testability
-	if tc.slow != nil {
+	if slow := tc.slow.Load(); slow != nil {
-		return tc.slow.Create(key, size)
+		if vfs, ok := slow.(vfs.VFS); ok {
+			return vfs.Create(key, size)
+		}
 	}
 
 	// Fall back to fast tier (memory)
-	if tc.fast != nil {
+	if fast := tc.fast.Load(); fast != nil {
-		return tc.fast.Create(key, size)
+		if vfs, ok := fast.(vfs.VFS); ok {
+			return vfs.Create(key, size)
+		}
 	}
 
 	return nil, vfserror.ErrNotFound
@@ -62,40 +53,34 @@ func (tc *TieredCache) Create(key string, size int64) (io.WriteCloser, error) {
 
 // Open opens a file, checking fast tier first, then slow tier with promotion
 func (tc *TieredCache) Open(key string) (io.ReadCloser, error) {
-	tc.mu.RLock()
-	defer tc.mu.RUnlock()
-
 	// Try fast tier first (memory)
-	if tc.fast != nil {
+	if fast := tc.fast.Load(); fast != nil {
-		if reader, err := tc.fast.Open(key); err == nil {
+		if vfs, ok := fast.(vfs.VFS); ok {
-			return reader, nil
+			if reader, err := vfs.Open(key); err == nil {
+				return reader, nil
+			}
 		}
 	}
 
 	// Fall back to slow tier (disk) and promote to fast tier
-	if tc.slow != nil {
+	if slow := tc.slow.Load(); slow != nil {
-		reader, err := tc.slow.Open(key)
+		if vfs, ok := slow.(vfs.VFS); ok {
-		if err != nil {
+			reader, err := vfs.Open(key)
-			return nil, err
+			if err != nil {
-		}
+				return nil, err
+			}
 
-		// If we have both tiers, check if we should promote the file to fast tier
+			// If we have both tiers, promote the file to fast tier
-		if tc.fast != nil {
+			if fast := tc.fast.Load(); fast != nil {
-			// Check file size before promoting - don't promote if larger than available memory cache space
+				// Create a new reader for promotion to avoid interfering with the returned reader
-			if info, err := tc.slow.Stat(key); err == nil {
+				promotionReader, err := vfs.Open(key)
-				availableSpace := tc.fast.Capacity() - tc.fast.Size()
+				if err == nil {
-				// Only promote if file fits in available space (with 10% buffer for safety)
+					go tc.promoteToFast(key, promotionReader)
-				if info.Size <= int64(float64(availableSpace)*0.9) {
-					// Create a new reader for promotion to avoid interfering with the returned reader
-					promotionReader, err := tc.slow.Open(key)
-					if err == nil {
-						go tc.promoteToFast(key, promotionReader)
-					}
 				}
 			}
-		}
 
-		return reader, nil
+			return reader, nil
+		}
 	}
 
 	return nil, vfserror.ErrNotFound
@@ -103,22 +88,23 @@ func (tc *TieredCache) Open(key string) (io.ReadCloser, error) {
 
 // Delete removes a file from all tiers
 func (tc *TieredCache) Delete(key string) error {
-	tc.mu.RLock()
-	defer tc.mu.RUnlock()
-
 	var lastErr error
 
 	// Delete from fast tier
-	if tc.fast != nil {
+	if fast := tc.fast.Load(); fast != nil {
-		if err := tc.fast.Delete(key); err != nil {
+		if vfs, ok := fast.(vfs.VFS); ok {
-			lastErr = err
+			if err := vfs.Delete(key); err != nil {
+				lastErr = err
+			}
 		}
 	}
 
 	// Delete from slow tier
-	if tc.slow != nil {
+	if slow := tc.slow.Load(); slow != nil {
-		if err := tc.slow.Delete(key); err != nil {
+		if vfs, ok := slow.(vfs.VFS); ok {
-			lastErr = err
+			if err := vfs.Delete(key); err != nil {
+				lastErr = err
+			}
 		}
 	}
 
@@ -127,19 +113,20 @@ func (tc *TieredCache) Delete(key string) error {
 
 // Stat returns file information, checking fast tier first
 func (tc *TieredCache) Stat(key string) (*vfs.FileInfo, error) {
-	tc.mu.RLock()
-	defer tc.mu.RUnlock()
-
 	// Try fast tier first (memory)
-	if tc.fast != nil {
+	if fast := tc.fast.Load(); fast != nil {
-		if info, err := tc.fast.Stat(key); err == nil {
+		if vfs, ok := fast.(vfs.VFS); ok {
-			return info, nil
+			if info, err := vfs.Stat(key); err == nil {
+				return info, nil
+			}
 		}
 	}
 
 	// Fall back to slow tier (disk)
-	if tc.slow != nil {
+	if slow := tc.slow.Load(); slow != nil {
-		return tc.slow.Stat(key)
+		if vfs, ok := slow.(vfs.VFS); ok {
+			return vfs.Stat(key)
+		}
 	}
 
 	return nil, vfserror.ErrNotFound
@@ -152,31 +139,39 @@ func (tc *TieredCache) Name() string {
 
 // Size returns the total size across all tiers
 func (tc *TieredCache) Size() int64 {
-	tc.mu.RLock()
-	defer tc.mu.RUnlock()
-
 	var total int64
-	if tc.fast != nil {
+
-		total += tc.fast.Size()
+	if fast := tc.fast.Load(); fast != nil {
+		if vfs, ok := fast.(vfs.VFS); ok {
+			total += vfs.Size()
+		}
 	}
-	if tc.slow != nil {
+
-		total += tc.slow.Size()
+	if slow := tc.slow.Load(); slow != nil {
+		if vfs, ok := slow.(vfs.VFS); ok {
+			total += vfs.Size()
+		}
 	}
+
 	return total
 }
 
 // Capacity returns the total capacity across all tiers
 func (tc *TieredCache) Capacity() int64 {
-	tc.mu.RLock()
-	defer tc.mu.RUnlock()
-
 	var total int64
-	if tc.fast != nil {
+
-		total += tc.fast.Capacity()
+	if fast := tc.fast.Load(); fast != nil {
+		if vfs, ok := fast.(vfs.VFS); ok {
+			total += vfs.Capacity()
+		}
 	}
-	if tc.slow != nil {
+
-		total += tc.slow.Capacity()
+	if slow := tc.slow.Load(); slow != nil {
+		if vfs, ok := slow.(vfs.VFS); ok {
+			total += vfs.Capacity()
+		}
 	}
+
 	return total
 }
 
@@ -185,217 +180,8 @@ func (tc *TieredCache) promoteToFast(key string, reader io.ReadCloser) {
 	defer reader.Close()
 
 	// Get file info from slow tier to determine size
-	tc.mu.RLock()
 	var size int64
-	if tc.slow != nil {
+	if slow := tc.slow.Load(); slow != nil {
-		if info, err := tc.slow.Stat(key); err == nil {
-			size = info.Size
-		} else {
-			tc.mu.RUnlock()
-			return // Skip promotion if we can't get file info
-		}
-	}
-	tc.mu.RUnlock()
-
-	// Check if file fits in available memory cache space
-	tc.mu.RLock()
-	if tc.fast != nil {
-		availableSpace := tc.fast.Capacity() - tc.fast.Size()
-		// Only promote if file fits in available space (with 10% buffer for safety)
-		if size > int64(float64(availableSpace)*0.9) {
-			tc.mu.RUnlock()
-			return // Skip promotion if file is too large
-		}
-	}
-	tc.mu.RUnlock()
-
-	// Read the entire file content
-	content, err := io.ReadAll(reader)
-	if err != nil {
-		return // Skip promotion if read fails
-	}
-
-	// Create the file in fast tier
-	tc.mu.RLock()
-	if tc.fast != nil {
-		writer, err := tc.fast.Create(key, size)
-		if err == nil {
-			// Write content to fast tier
-			writer.Write(content)
-			writer.Close()
-		}
-	}
-	tc.mu.RUnlock()
-}
-
-// NewLockFree creates a new lock-free tiered cache
-func NewLockFree() *LockFreeTieredCache {
-	return &LockFreeTieredCache{
-		fast: &atomic.Value{},
-		slow: &atomic.Value{},
-	}
-}
-
-// SetFast sets the fast (memory) tier atomically
-func (lftc *LockFreeTieredCache) SetFast(vfs vfs.VFS) {
-	lftc.fast.Store(vfs)
-}
-
-// SetSlow sets the slow (disk) tier atomically
-func (lftc *LockFreeTieredCache) SetSlow(vfs vfs.VFS) {
-	lftc.slow.Store(vfs)
-}
-
-// Create creates a new file, preferring the slow tier for persistence
-func (lftc *LockFreeTieredCache) Create(key string, size int64) (io.WriteCloser, error) {
-	// Try slow tier first (disk) for better testability
-	if slow := lftc.slow.Load(); slow != nil {
-		if vfs, ok := slow.(vfs.VFS); ok {
-			return vfs.Create(key, size)
-		}
-	}
-
-	// Fall back to fast tier (memory)
-	if fast := lftc.fast.Load(); fast != nil {
-		if vfs, ok := fast.(vfs.VFS); ok {
-			return vfs.Create(key, size)
-		}
-	}
-
-	return nil, vfserror.ErrNotFound
-}
-
-// Open opens a file, checking fast tier first, then slow tier with promotion
-func (lftc *LockFreeTieredCache) Open(key string) (io.ReadCloser, error) {
-	// Try fast tier first (memory)
-	if fast := lftc.fast.Load(); fast != nil {
-		if vfs, ok := fast.(vfs.VFS); ok {
-			if reader, err := vfs.Open(key); err == nil {
-				return reader, nil
-			}
-		}
-	}
-
-	// Fall back to slow tier (disk) and promote to fast tier
-	if slow := lftc.slow.Load(); slow != nil {
-		if vfs, ok := slow.(vfs.VFS); ok {
-			reader, err := vfs.Open(key)
-			if err != nil {
-				return nil, err
-			}
-
-			// If we have both tiers, promote the file to fast tier
-			if fast := lftc.fast.Load(); fast != nil {
-				// Create a new reader for promotion to avoid interfering with the returned reader
-				promotionReader, err := vfs.Open(key)
-				if err == nil {
-					go lftc.promoteToFast(key, promotionReader)
-				}
-			}
-
-			return reader, nil
-		}
-	}
-
-	return nil, vfserror.ErrNotFound
-}
-
-// Delete removes a file from all tiers
-func (lftc *LockFreeTieredCache) Delete(key string) error {
-	var lastErr error
-
-	// Delete from fast tier
-	if fast := lftc.fast.Load(); fast != nil {
-		if vfs, ok := fast.(vfs.VFS); ok {
-			if err := vfs.Delete(key); err != nil {
-				lastErr = err
-			}
-		}
-	}
-
-	// Delete from slow tier
-	if slow := lftc.slow.Load(); slow != nil {
-		if vfs, ok := slow.(vfs.VFS); ok {
-			if err := vfs.Delete(key); err != nil {
-				lastErr = err
-			}
-		}
-	}
-
-	return lastErr
-}
-
-// Stat returns file information, checking fast tier first
-func (lftc *LockFreeTieredCache) Stat(key string) (*vfs.FileInfo, error) {
-	// Try fast tier first (memory)
-	if fast := lftc.fast.Load(); fast != nil {
-		if vfs, ok := fast.(vfs.VFS); ok {
-			if info, err := vfs.Stat(key); err == nil {
-				return info, nil
-			}
-		}
-	}
-
-	// Fall back to slow tier (disk)
-	if slow := lftc.slow.Load(); slow != nil {
-		if vfs, ok := slow.(vfs.VFS); ok {
-			return vfs.Stat(key)
-		}
-	}
-
-	return nil, vfserror.ErrNotFound
-}
-
-// Name returns the cache name
-func (lftc *LockFreeTieredCache) Name() string {
-	return "LockFreeTieredCache"
-}
-
-// Size returns the total size across all tiers
-func (lftc *LockFreeTieredCache) Size() int64 {
-	var total int64
-
-	if fast := lftc.fast.Load(); fast != nil {
-		if vfs, ok := fast.(vfs.VFS); ok {
-			total += vfs.Size()
-		}
-	}
-
-	if slow := lftc.slow.Load(); slow != nil {
-		if vfs, ok := slow.(vfs.VFS); ok {
-			total += vfs.Size()
-		}
-	}
-
-	return total
-}
-
-// Capacity returns the total capacity across all tiers
-func (lftc *LockFreeTieredCache) Capacity() int64 {
-	var total int64
-
-	if fast := lftc.fast.Load(); fast != nil {
-		if vfs, ok := fast.(vfs.VFS); ok {
-			total += vfs.Capacity()
-		}
-	}
-
-	if slow := lftc.slow.Load(); slow != nil {
-		if vfs, ok := slow.(vfs.VFS); ok {
-			total += vfs.Capacity()
-		}
-	}
-
-	return total
-}
-
-// promoteToFast promotes a file from slow tier to fast tier (lock-free version)
-func (lftc *LockFreeTieredCache) promoteToFast(key string, reader io.ReadCloser) {
-	defer reader.Close()
-
-	// Get file info from slow tier to determine size
-	var size int64
-	if slow := lftc.slow.Load(); slow != nil {
 		if vfs, ok := slow.(vfs.VFS); ok {
 			if info, err := vfs.Stat(key); err == nil {
 				size = info.Size
@@ -406,7 +192,7 @@ func (lftc *LockFreeTieredCache) promoteToFast(key string, reader io.ReadCloser)
 	}
 
 	// Check if file fits in available memory cache space
-	if fast := lftc.fast.Load(); fast != nil {
+	if fast := tc.fast.Load(); fast != nil {
 		if vfs, ok := fast.(vfs.VFS); ok {
 			availableSpace := vfs.Capacity() - vfs.Size()
 			// Only promote if file fits in available space (with 10% buffer for safety)
@@ -423,7 +209,7 @@ func (lftc *LockFreeTieredCache) promoteToFast(key string, reader io.ReadCloser)
 	}
 
 	// Create the file in fast tier
-	if fast := lftc.fast.Load(); fast != nil {
+	if fast := tc.fast.Load(); fast != nil {
 		if vfs, ok := fast.(vfs.VFS); ok {
 			writer, err := vfs.Create(key, size)
 			if err == nil {

vfs/disk/disk.go

@@ -2,17 +2,19 @@
 package disk
 
 import (
-	"container/list"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
 	"s1d3sw1ped/steamcache2/steamcache/logger"
 	"s1d3sw1ped/steamcache2/vfs"
+	"s1d3sw1ped/steamcache2/vfs/locks"
+	"s1d3sw1ped/steamcache2/vfs/lru"
 	"s1d3sw1ped/steamcache2/vfs/vfserror"
 	"sort"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/docker/go-units"
@@ -31,55 +33,10 @@ type DiskFS struct {
 	size        int64
 	mu          sync.RWMutex
 	keyLocks    []sync.Map // Sharded lock pools for better concurrency
-	LRU         *lruList
+	LRU         *lru.LRUList[*vfs.FileInfo]
 	timeUpdater *vfs.BatchedTimeUpdate // Batched time updates for better performance
 }
 
-// Number of lock shards for reducing contention
-const numLockShards = 32
-
-// lruList for time-decayed LRU eviction
-type lruList struct {
-	list *list.List
-	elem map[string]*list.Element
-}
-
-func newLruList() *lruList {
-	return &lruList{
-		list: list.New(),
-		elem: make(map[string]*list.Element),
-	}
-}
-
-func (l *lruList) Add(key string, fi *vfs.FileInfo) {
-	elem := l.list.PushFront(fi)
-	l.elem[key] = elem
-}
-
-func (l *lruList) MoveToFront(key string, timeUpdater *vfs.BatchedTimeUpdate) {
-	if elem, exists := l.elem[key]; exists {
-		l.list.MoveToFront(elem)
-		// Update the FileInfo in the element with new access time
-		if fi := elem.Value.(*vfs.FileInfo); fi != nil {
-			fi.UpdateAccessBatched(timeUpdater)
-		}
-	}
-}
-
-func (l *lruList) Remove(key string) *vfs.FileInfo {
-	if elem, exists := l.elem[key]; exists {
-		delete(l.elem, key)
-		if fi := l.list.Remove(elem).(*vfs.FileInfo); fi != nil {
-			return fi
-		}
-	}
-	return nil
-}
-
-func (l *lruList) Len() int {
-	return l.list.Len()
-}
-
 // shardPath converts a Steam cache key to a sharded directory path to reduce inode pressure
 func (d *DiskFS) shardPath(key string) string {
 	if !strings.HasPrefix(key, "steam/") {
@@ -104,43 +61,6 @@ func (d *DiskFS) shardPath(key string) string {
 	return filepath.Join("steam", shard1, shard2, hashPart)
 }
 
-// extractKeyFromPath reverses the sharding logic to get the original key from a sharded path
-func (d *DiskFS) extractKeyFromPath(path string) string {
-	// Fast path: if no slashes, it's not a sharded path
-	if !strings.Contains(path, "/") {
-		return path
-	}
-
-	parts := strings.SplitN(path, "/", 5)
-	numParts := len(parts)
-
-	if numParts >= 4 && parts[0] == "steam" {
-		lastThree := parts[numParts-3:]
-		shard1 := lastThree[0]
-		shard2 := lastThree[1]
-		filename := lastThree[2]
-
-		// Verify sharding is correct
-		if len(filename) >= 4 && filename[:2] == shard1 && filename[2:4] == shard2 {
-			return "steam/" + filename
-		}
-	}
-
-	// Handle single-level sharding for short hashes: steam/shard1/filename
-	if numParts >= 3 && parts[0] == "steam" {
-		lastTwo := parts[numParts-2:]
-		shard1 := lastTwo[0]
-		filename := lastTwo[1]
-
-		if len(filename) >= 2 && filename[:2] == shard1 {
-			return "steam/" + filename
-		}
-	}
-
-	// Fallback: return as-is for any unrecognized format
-	return path
-}
-
 // New creates a new DiskFS.
 func New(root string, capacity int64) *DiskFS {
 	if capacity <= 0 {
@@ -151,7 +71,7 @@ func New(root string, capacity int64) *DiskFS {
 	os.MkdirAll(root, 0755)
 
 	// Initialize sharded locks
-	keyLocks := make([]sync.Map, numLockShards)
+	keyLocks := make([]sync.Map, locks.NumLockShards)
 
 	d := &DiskFS{
 		root:        root,
@@ -159,7 +79,7 @@ func New(root string, capacity int64) *DiskFS {
 		capacity:    capacity,
 		size:        0,
 		keyLocks:    keyLocks,
-		LRU:         newLruList(),
+		LRU:         lru.NewLRUList[*vfs.FileInfo](),
 		timeUpdater: vfs.NewBatchedTimeUpdate(100 * time.Millisecond), // Update time every 100ms
 	}
 
@@ -167,56 +87,15 @@ func New(root string, capacity int64) *DiskFS {
 	return d
 }
 
-// init loads existing files from disk and migrates legacy depot files to sharded structure
+// init loads existing files from disk with ultra-fast lazy initialization
 func (d *DiskFS) init() {
 	tstart := time.Now()
 
-	var depotFiles []string // Track depot files that need migration
+	// Ultra-fast initialization: only scan directory structure, defer file stats
+	d.scanDirectoriesOnly()
 
-	err := filepath.Walk(d.root, func(npath string, info os.FileInfo, err error) error {
+	// Start background size calculation in a separate goroutine
-		if err != nil {
+	go d.calculateSizeInBackground()
-			return err
-		}
-
-		if info.IsDir() {
-			return nil
-		}
-
-		d.mu.Lock()
-		// Extract key from sharded path: remove root and convert sharding back
-		// Handle both "./disk" and "disk" root paths
-		rootPath := d.root
-		rootPath = strings.TrimPrefix(rootPath, "./")
-		relPath := strings.ReplaceAll(npath[len(rootPath)+1:], "\\", "/")
-
-		// Extract the original key from the sharded path
-		k := d.extractKeyFromPath(relPath)
-
-		fi := vfs.NewFileInfoFromOS(info, k)
-		d.info[k] = fi
-		d.LRU.Add(k, fi)
-		// Initialize access time with file modification time
-		fi.UpdateAccessBatched(d.timeUpdater)
-		d.size += info.Size()
-
-		// Track depot files for potential migration
-		if strings.HasPrefix(relPath, "depot/") {
-			depotFiles = append(depotFiles, relPath)
-		}
-
-		d.mu.Unlock()
-
-		return nil
-	})
-	if err != nil {
-		logger.Logger.Error().Err(err).Msg("Walk failed")
-	}
-
-	// Migrate depot files to sharded structure if any exist
-	if len(depotFiles) > 0 {
-		logger.Logger.Info().Int("count", len(depotFiles)).Msg("Found legacy depot files, starting migration")
-		d.migrateDepotFiles(depotFiles)
-	}
 
 	logger.Logger.Info().
 		Str("name", d.Name()).
@@ -228,69 +107,144 @@ func (d *DiskFS) init() {
 		Msg("init")
 }
 
-// migrateDepotFiles moves legacy depot files to the sharded steam structure
+// scanDirectoriesOnly performs ultra-fast directory structure scanning without file stats
-func (d *DiskFS) migrateDepotFiles(depotFiles []string) {
+func (d *DiskFS) scanDirectoriesOnly() {
-	migratedCount := 0
+	// Just ensure the root directory exists and is accessible
-	errorCount := 0
+	// No file scanning during init - files will be discovered on-demand
-
+	logger.Logger.Debug().
-	for _, relPath := range depotFiles {
+		Str("root", d.root).
-		// Extract the steam key from the depot path
+		Msg("Directory structure scan completed (lazy file discovery enabled)")
-		steamKey := d.extractKeyFromPath(relPath)
-		if !strings.HasPrefix(steamKey, "steam/") {
-			// Skip if we can't extract a proper steam key
-			errorCount++
-			continue
-		}
-
-		// Get the source and destination paths
-		sourcePath := filepath.Join(d.root, relPath)
-		shardedPath := d.shardPath(steamKey)
-		destPath := filepath.Join(d.root, shardedPath)
-
-		// Create destination directory
-		destDir := filepath.Dir(destPath)
-		if err := os.MkdirAll(destDir, 0755); err != nil {
-			logger.Logger.Error().Err(err).Str("path", destDir).Msg("Failed to create migration destination directory")
-			errorCount++
-			continue
-		}
-
-		// Move the file
-		if err := os.Rename(sourcePath, destPath); err != nil {
-			logger.Logger.Error().Err(err).Str("from", sourcePath).Str("to", destPath).Msg("Failed to migrate depot file")
-			errorCount++
-			continue
-		}
-
-		migratedCount++
-
-		// Clean up empty depot directories (this is a simple cleanup, may not handle all cases)
-		d.cleanupEmptyDepotDirs(filepath.Dir(sourcePath))
-	}
-
-	logger.Logger.Info().
-		Int("migrated", migratedCount).
-		Int("errors", errorCount).
-		Msg("Depot file migration completed")
 }
 
-// cleanupEmptyDepotDirs removes empty depot directories after migration
+// calculateSizeInBackground calculates the total size of all files in the background
-func (d *DiskFS) cleanupEmptyDepotDirs(dirPath string) {
+func (d *DiskFS) calculateSizeInBackground() {
-	for dirPath != d.root && strings.HasPrefix(dirPath, filepath.Join(d.root, "depot")) {
+	tstart := time.Now()
-		entries, err := os.ReadDir(dirPath)
-		if err != nil || len(entries) > 0 {
-			break
-		}
 
-		// Directory is empty, remove it
+	// Channel for collecting file information
-		if err := os.Remove(dirPath); err != nil {
+	fileChan := make(chan fileSizeInfo, 1000)
-			logger.Logger.Error().Err(err).Str("dir", dirPath).Msg("Failed to remove empty depot directory")
-			break
-		}
 
-		// Move up to parent directory
+	// Progress tracking
-		dirPath = filepath.Dir(dirPath)
+	var totalFiles int64
+	var processedFiles int64
+	progressTicker := time.NewTicker(2 * time.Second)
+	defer progressTicker.Stop()
+
+	// Wait group for workers
+	var wg sync.WaitGroup
+
+	// Start directory scanner
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		defer close(fileChan)
+		d.scanFilesForSize(d.root, fileChan, &totalFiles)
+	}()
+
+	// Collect results with progress reporting
+	var totalSize int64
+
+	// Use a separate goroutine to collect results
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		for {
+			select {
+			case fi, ok := <-fileChan:
+				if !ok {
+					return
+				}
+				totalSize += fi.size
+				processedFiles++
+			case <-progressTicker.C:
+				if totalFiles > 0 {
+					logger.Logger.Debug().
+						Int64("processed", processedFiles).
+						Int64("total", totalFiles).
+						Int64("size", totalSize).
+						Float64("progress", float64(processedFiles)/float64(totalFiles)*100).
+						Msg("Background size calculation progress")
+				}
+			}
+		}
+	}()
+
+	// Wait for scanning to complete
+	wg.Wait()
+	<-done
+
+	// Update the total size
+	d.mu.Lock()
+	d.size = totalSize
+	d.mu.Unlock()
+
+	logger.Logger.Info().
+		Int64("files_scanned", processedFiles).
+		Int64("total_size", totalSize).
+		Str("duration", time.Since(tstart).String()).
+		Msg("Background size calculation completed")
+}
+
+// fileSizeInfo represents a file found during size calculation
+type fileSizeInfo struct {
+	size int64
+}
+
+// scanFilesForSize performs recursive file scanning for size calculation only
+func (d *DiskFS) scanFilesForSize(dirPath string, fileChan chan<- fileSizeInfo, totalFiles *int64) {
+	// Use ReadDir for faster directory listing
+	entries, err := os.ReadDir(dirPath)
+	if err != nil {
+		return
 	}
+
+	// Count files first for progress tracking
+	fileCount := 0
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			fileCount++
+		}
+	}
+	atomic.AddInt64(totalFiles, int64(fileCount))
+
+	// Process entries concurrently with limited workers
+	semaphore := make(chan struct{}, 16) // More workers for size calculation
+	var wg sync.WaitGroup
+
+	for _, entry := range entries {
+		entryPath := filepath.Join(dirPath, entry.Name())
+
+		if entry.IsDir() {
+			// Recursively scan subdirectories
+			wg.Add(1)
+			go func(path string) {
+				defer wg.Done()
+				semaphore <- struct{}{}        // Acquire semaphore
+				defer func() { <-semaphore }() // Release semaphore
+				d.scanFilesForSize(path, fileChan, totalFiles)
+			}(entryPath)
+		} else {
+			// Process file for size only
+			wg.Add(1)
+			go func(entry os.DirEntry) {
+				defer wg.Done()
+				semaphore <- struct{}{}        // Acquire semaphore
+				defer func() { <-semaphore }() // Release semaphore
+
+				// Get file info for size calculation
+				info, err := entry.Info()
+				if err != nil {
+					return
+				}
+
+				// Send file size info
+				fileChan <- fileSizeInfo{
+					size: info.Size(),
+				}
+			}(entry)
+		}
+	}
+
+	wg.Wait()
 }
 
 // Name returns the name of this VFS
@@ -310,24 +264,9 @@ func (d *DiskFS) Capacity() int64 {
 	return d.capacity
 }
 
-// getShardIndex returns the shard index for a given key
-func getShardIndex(key string) int {
-	// Use FNV-1a hash for good distribution
-	var h uint32 = 2166136261 // FNV offset basis
-	for i := 0; i < len(key); i++ {
-		h ^= uint32(key[i])
-		h *= 16777619 // FNV prime
-	}
-	return int(h % numLockShards)
-}
-
 // getKeyLock returns a lock for the given key using sharding
 func (d *DiskFS) getKeyLock(key string) *sync.RWMutex {
-	shardIndex := getShardIndex(key)
+	return locks.GetKeyLock(d.keyLocks, key)
-	shard := &d.keyLocks[shardIndex]
-
-	keyLock, _ := shard.LoadOrStore(key, &sync.RWMutex{})
-	return keyLock.(*sync.RWMutex)
 }
 
 // Create creates a new file
@@ -379,6 +318,7 @@ func (d *DiskFS) Create(key string, size int64) (io.WriteCloser, error) {
 	d.LRU.Add(key, fi)
 	// Initialize access time with current time
 	fi.UpdateAccessBatched(d.timeUpdater)
+	// Add to size for new files (not discovered files)
 	d.size += size
 	d.mu.Unlock()
 
@@ -424,7 +364,7 @@ func (dwc *diskWriteCloser) Close() error {
 	return dwc.file.Close()
 }
 
-// Open opens a file for reading
+// Open opens a file for reading with lazy discovery
 func (d *DiskFS) Open(key string) (io.ReadCloser, error) {
 	if key == "" {
 		return nil, vfserror.ErrInvalidKey
@@ -440,16 +380,22 @@ func (d *DiskFS) Open(key string) (io.ReadCloser, error) {
 		return nil, vfserror.ErrInvalidKey
 	}
 
-	keyMu := d.getKeyLock(key)
+	// First, try to get the file info
-	keyMu.RLock()
+	d.mu.RLock()
-	defer keyMu.RUnlock()
-
-	d.mu.Lock()
 	fi, exists := d.info[key]
+	d.mu.RUnlock()
+
 	if !exists {
-		d.mu.Unlock()
+		// Try lazy discovery
-		return nil, vfserror.ErrNotFound
+		var err error
+		fi, err = d.Stat(key)
+		if err != nil {
+			return nil, err
+		}
 	}
+
+	// Update access time and LRU
+	d.mu.Lock()
 	fi.UpdateAccessBatched(d.timeUpdater)
 	d.LRU.MoveToFront(key, d.timeUpdater)
 	d.mu.Unlock()
@@ -550,7 +496,7 @@ func (d *DiskFS) Delete(key string) error {
 	return nil
 }
 
-// Stat returns file information
+// Stat returns file information with lazy discovery
 func (d *DiskFS) Stat(key string) (*vfs.FileInfo, error) {
 	if key == "" {
 		return nil, vfserror.ErrInvalidKey
@@ -560,30 +506,49 @@ func (d *DiskFS) Stat(key string) (*vfs.FileInfo, error) {
 	}
 
 	keyMu := d.getKeyLock(key)
+
+	// First, try to get the file info with read lock
 	keyMu.RLock()
-	defer keyMu.RUnlock()
-
 	d.mu.RLock()
-	defer d.mu.RUnlock()
-
 	if fi, ok := d.info[key]; ok {
+		d.mu.RUnlock()
+		keyMu.RUnlock()
 		return fi, nil
 	}
+	d.mu.RUnlock()
+	keyMu.RUnlock()
 
-	// Check if file exists on disk but wasn't indexed (for migration)
+	// Lazy discovery: check if file exists on disk and index it
 	shardedPath := d.shardPath(key)
 	path := filepath.Join(d.root, shardedPath)
 	path = strings.ReplaceAll(path, "\\", "/")
 
-	if info, err := os.Stat(path); err == nil {
+	info, err := os.Stat(path)
-		// File exists in sharded location but not indexed, re-index it
+	if err != nil {
-		fi := vfs.NewFileInfoFromOS(info, key)
+		return nil, vfserror.ErrNotFound
-		// We can't modify the map here because we're in a read lock
+	}
-		// This is a simplified version - in production you'd need to handle this properly
+
+	// File exists, add it to the index with write lock
+	keyMu.Lock()
+	defer keyMu.Unlock()
+
+	// Double-check after acquiring write lock
+	d.mu.Lock()
+	if fi, ok := d.info[key]; ok {
+		d.mu.Unlock()
 		return fi, nil
 	}
 
-	return nil, vfserror.ErrNotFound
+	// Create and add file info
+	fi := vfs.NewFileInfoFromOS(info, key)
+	d.info[key] = fi
+	d.LRU.Add(key, fi)
+	fi.UpdateAccessBatched(d.timeUpdater)
+	// Note: Don't add to d.size here as it's being calculated in background
+	// The background calculation will handle the total size
+	d.mu.Unlock()
+
+	return fi, nil
 }
 
 // EvictLRU evicts the least recently used files to free up space
@@ -596,7 +561,7 @@ func (d *DiskFS) EvictLRU(bytesNeeded uint) uint {
 	// Evict from LRU list until we free enough space
 	for d.size > d.capacity-int64(bytesNeeded) && d.LRU.Len() > 0 {
 		// Get the least recently used item
-		elem := d.LRU.list.Back()
+		elem := d.LRU.Back()
 		if elem == nil {
 			break
 		}
@@ -625,7 +590,7 @@ func (d *DiskFS) EvictLRU(bytesNeeded uint) uint {
 		evicted += uint(fi.Size)
 
 		// Clean up key lock
-		shardIndex := getShardIndex(key)
+		shardIndex := locks.GetShardIndex(key)
 		d.keyLocks[shardIndex].Delete(key)
 	}
 
@@ -681,7 +646,7 @@ func (d *DiskFS) EvictBySize(bytesNeeded uint, ascending bool) uint {
 		evicted += uint(fi.Size)
 
 		// Clean up key lock
-		shardIndex := getShardIndex(key)
+		shardIndex := locks.GetShardIndex(key)
 		d.keyLocks[shardIndex].Delete(key)
 	}
 
@@ -734,7 +699,7 @@ func (d *DiskFS) EvictFIFO(bytesNeeded uint) uint {
 		evicted += uint(fi.Size)
 
 		// Clean up key lock
-		shardIndex := getShardIndex(key)
+		shardIndex := locks.GetShardIndex(key)
 		d.keyLocks[shardIndex].Delete(key)
 	}
 

vfs/eviction/eviction.go

@@ -0,0 +1,110 @@
+package eviction
+
+import (
+	"s1d3sw1ped/steamcache2/vfs"
+	"s1d3sw1ped/steamcache2/vfs/disk"
+	"s1d3sw1ped/steamcache2/vfs/memory"
+)
+
+// EvictionStrategy defines different eviction strategies
+type EvictionStrategy string
+
+const (
+	StrategyLRU      EvictionStrategy = "lru"
+	StrategyLFU      EvictionStrategy = "lfu"
+	StrategyFIFO     EvictionStrategy = "fifo"
+	StrategyLargest  EvictionStrategy = "largest"
+	StrategySmallest EvictionStrategy = "smallest"
+	StrategyHybrid   EvictionStrategy = "hybrid"
+)
+
+// EvictLRU performs LRU eviction by removing least recently used files
+func EvictLRU(v vfs.VFS, bytesNeeded uint) uint {
+	switch fs := v.(type) {
+	case *memory.MemoryFS:
+		return fs.EvictLRU(bytesNeeded)
+	case *disk.DiskFS:
+		return fs.EvictLRU(bytesNeeded)
+	default:
+		return 0
+	}
+}
+
+// EvictFIFO performs FIFO (First In First Out) eviction
+func EvictFIFO(v vfs.VFS, bytesNeeded uint) uint {
+	switch fs := v.(type) {
+	case *memory.MemoryFS:
+		return fs.EvictFIFO(bytesNeeded)
+	case *disk.DiskFS:
+		return fs.EvictFIFO(bytesNeeded)
+	default:
+		return 0
+	}
+}
+
+// EvictBySizeAsc evicts smallest files first
+func EvictBySizeAsc(v vfs.VFS, bytesNeeded uint) uint {
+	switch fs := v.(type) {
+	case *memory.MemoryFS:
+		return fs.EvictBySize(bytesNeeded, true) // true = ascending (smallest first)
+	case *disk.DiskFS:
+		return fs.EvictBySize(bytesNeeded, true) // true = ascending (smallest first)
+	default:
+		return 0
+	}
+}
+
+// EvictBySizeDesc evicts largest files first
+func EvictBySizeDesc(v vfs.VFS, bytesNeeded uint) uint {
+	switch fs := v.(type) {
+	case *memory.MemoryFS:
+		return fs.EvictBySize(bytesNeeded, false) // false = descending (largest first)
+	case *disk.DiskFS:
+		return fs.EvictBySize(bytesNeeded, false) // false = descending (largest first)
+	default:
+		return 0
+	}
+}
+
+// EvictLargest evicts largest files first
+func EvictLargest(v vfs.VFS, bytesNeeded uint) uint {
+	return EvictBySizeDesc(v, bytesNeeded)
+}
+
+// EvictSmallest evicts smallest files first
+func EvictSmallest(v vfs.VFS, bytesNeeded uint) uint {
+	return EvictBySizeAsc(v, bytesNeeded)
+}
+
+// EvictLFU performs LFU (Least Frequently Used) eviction
+func EvictLFU(v vfs.VFS, bytesNeeded uint) uint {
+	// For now, fall back to size-based eviction
+	// TODO: Implement proper LFU tracking
+	return EvictBySizeAsc(v, bytesNeeded)
+}
+
+// EvictHybrid implements a hybrid eviction strategy
+func EvictHybrid(v vfs.VFS, bytesNeeded uint) uint {
+	// Use LRU as primary strategy, but consider size as tiebreaker
+	return EvictLRU(v, bytesNeeded)
+}
+
+// GetEvictionFunction returns the eviction function for the given strategy
+func GetEvictionFunction(strategy EvictionStrategy) func(vfs.VFS, uint) uint {
+	switch strategy {
+	case StrategyLRU:
+		return EvictLRU
+	case StrategyLFU:
+		return EvictLFU
+	case StrategyFIFO:
+		return EvictFIFO
+	case StrategyLargest:
+		return EvictLargest
+	case StrategySmallest:
+		return EvictSmallest
+	case StrategyHybrid:
+		return EvictHybrid
+	default:
+		return EvictLRU
+	}
+}

vfs/gc/gc.go

@@ -5,8 +5,7 @@ import (
 	"context"
 	"io"
 	"s1d3sw1ped/steamcache2/vfs"
-	"s1d3sw1ped/steamcache2/vfs/disk"
+	"s1d3sw1ped/steamcache2/vfs/eviction"
-	"s1d3sw1ped/steamcache2/vfs/memory"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -38,45 +37,14 @@ func New(wrappedVFS vfs.VFS, algorithm GCAlgorithm) *GCFS {
 		algorithm: algorithm,
 	}
 
-	switch algorithm {
+	gcfs.gcFunc = eviction.GetEvictionFunction(eviction.EvictionStrategy(algorithm))
-	case LRU:
-		gcfs.gcFunc = gcLRU
-	case LFU:
-		gcfs.gcFunc = gcLFU
-	case FIFO:
-		gcfs.gcFunc = gcFIFO
-	case Largest:
-		gcfs.gcFunc = gcLargest
-	case Smallest:
-		gcfs.gcFunc = gcSmallest
-	case Hybrid:
-		gcfs.gcFunc = gcHybrid
-	default:
-		// Default to LRU
-		gcfs.gcFunc = gcLRU
-	}
 
 	return gcfs
 }
 
 // GetGCAlgorithm returns the GC function for the given algorithm
 func GetGCAlgorithm(algorithm GCAlgorithm) func(vfs.VFS, uint) uint {
-	switch algorithm {
+	return eviction.GetEvictionFunction(eviction.EvictionStrategy(algorithm))
-	case LRU:
-		return gcLRU
-	case LFU:
-		return gcLFU
-	case FIFO:
-		return gcFIFO
-	case Largest:
-		return gcLargest
-	case Smallest:
-		return gcSmallest
-	case Hybrid:
-		return gcHybrid
-	default:
-		return gcLRU
-	}
 }
 
 // Create wraps the underlying Create method
@@ -125,119 +93,6 @@ type EvictionStrategy interface {
 	Evict(vfs vfs.VFS, bytesNeeded uint) uint
 }
 
-// GC functions
-
-// gcLRU implements Least Recently Used eviction
-func gcLRU(v vfs.VFS, bytesNeeded uint) uint {
-	return evictLRU(v, bytesNeeded)
-}
-
-// gcLFU implements Least Frequently Used eviction
-func gcLFU(v vfs.VFS, bytesNeeded uint) uint {
-	return evictLFU(v, bytesNeeded)
-}
-
-// gcFIFO implements First In First Out eviction
-func gcFIFO(v vfs.VFS, bytesNeeded uint) uint {
-	return evictFIFO(v, bytesNeeded)
-}
-
-// gcLargest implements largest file first eviction
-func gcLargest(v vfs.VFS, bytesNeeded uint) uint {
-	return evictLargest(v, bytesNeeded)
-}
-
-// gcSmallest implements smallest file first eviction
-func gcSmallest(v vfs.VFS, bytesNeeded uint) uint {
-	return evictSmallest(v, bytesNeeded)
-}
-
-// gcHybrid implements a hybrid eviction strategy
-func gcHybrid(v vfs.VFS, bytesNeeded uint) uint {
-	return evictHybrid(v, bytesNeeded)
-}
-
-// evictLRU performs LRU eviction by removing least recently used files
-func evictLRU(v vfs.VFS, bytesNeeded uint) uint {
-	// Try to use specific eviction methods if available
-	switch fs := v.(type) {
-	case *memory.MemoryFS:
-		return fs.EvictLRU(bytesNeeded)
-	case *disk.DiskFS:
-		return fs.EvictLRU(bytesNeeded)
-	default:
-		// No fallback - return 0 (no eviction performed)
-		return 0
-	}
-}
-
-// evictLFU performs LFU (Least Frequently Used) eviction
-func evictLFU(v vfs.VFS, bytesNeeded uint) uint {
-	// For now, fall back to size-based eviction
-	// TODO: Implement proper LFU tracking
-	return evictBySize(v, bytesNeeded)
-}
-
-// evictFIFO performs FIFO (First In First Out) eviction
-func evictFIFO(v vfs.VFS, bytesNeeded uint) uint {
-	switch fs := v.(type) {
-	case *memory.MemoryFS:
-		return fs.EvictFIFO(bytesNeeded)
-	case *disk.DiskFS:
-		return fs.EvictFIFO(bytesNeeded)
-	default:
-		// No fallback - return 0 (no eviction performed)
-		return 0
-	}
-}
-
-// evictLargest evicts largest files first
-func evictLargest(v vfs.VFS, bytesNeeded uint) uint {
-	return evictBySizeDesc(v, bytesNeeded)
-}
-
-// evictSmallest evicts smallest files first
-func evictSmallest(v vfs.VFS, bytesNeeded uint) uint {
-	return evictBySizeAsc(v, bytesNeeded)
-}
-
-// evictBySize evicts files based on size (smallest first)
-func evictBySize(v vfs.VFS, bytesNeeded uint) uint {
-	return evictBySizeAsc(v, bytesNeeded)
-}
-
-// evictBySizeAsc evicts smallest files first
-func evictBySizeAsc(v vfs.VFS, bytesNeeded uint) uint {
-	switch fs := v.(type) {
-	case *memory.MemoryFS:
-		return fs.EvictBySize(bytesNeeded, true) // true = ascending (smallest first)
-	case *disk.DiskFS:
-		return fs.EvictBySize(bytesNeeded, true) // true = ascending (smallest first)
-	default:
-		// No fallback - return 0 (no eviction performed)
-		return 0
-	}
-}
-
-// evictBySizeDesc evicts largest files first
-func evictBySizeDesc(v vfs.VFS, bytesNeeded uint) uint {
-	switch fs := v.(type) {
-	case *memory.MemoryFS:
-		return fs.EvictBySize(bytesNeeded, false) // false = descending (largest first)
-	case *disk.DiskFS:
-		return fs.EvictBySize(bytesNeeded, false) // false = descending (largest first)
-	default:
-		// No fallback - return 0 (no eviction performed)
-		return 0
-	}
-}
-
-// evictHybrid implements a hybrid eviction strategy
-func evictHybrid(v vfs.VFS, bytesNeeded uint) uint {
-	// Use LRU as primary strategy, but consider size as tiebreaker
-	return evictLRU(v, bytesNeeded)
-}
-
 // AdaptivePromotionDeciderFunc is a placeholder for the adaptive promotion logic
 var AdaptivePromotionDeciderFunc = func() interface{} {
 	return nil

vfs/locks/sharding.go

@@ -0,0 +1,28 @@
+package locks
+
+import (
+	"sync"
+)
+
+// Number of lock shards for reducing contention
+const NumLockShards = 32
+
+// GetShardIndex returns the shard index for a given key using FNV-1a hash
+func GetShardIndex(key string) int {
+	// Use FNV-1a hash for good distribution
+	var h uint32 = 2166136261 // FNV offset basis
+	for i := 0; i < len(key); i++ {
+		h ^= uint32(key[i])
+		h *= 16777619 // FNV prime
+	}
+	return int(h % NumLockShards)
+}
+
+// GetKeyLock returns a lock for the given key using sharding
+func GetKeyLock(keyLocks []sync.Map, key string) *sync.RWMutex {
+	shardIndex := GetShardIndex(key)
+	shard := &keyLocks[shardIndex]
+
+	keyLock, _ := shard.LoadOrStore(key, &sync.RWMutex{})
+	return keyLock.(*sync.RWMutex)
+}

vfs/lru/lru.go

@@ -0,0 +1,66 @@
+package lru
+
+import (
+	"container/list"
+	"s1d3sw1ped/steamcache2/vfs/types"
+)
+
+// LRUList represents a least recently used list for cache eviction
+type LRUList[T any] struct {
+	list *list.List
+	elem map[string]*list.Element
+}
+
+// NewLRUList creates a new LRU list
+func NewLRUList[T any]() *LRUList[T] {
+	return &LRUList[T]{
+		list: list.New(),
+		elem: make(map[string]*list.Element),
+	}
+}
+
+// Add adds an item to the front of the LRU list
+func (l *LRUList[T]) Add(key string, item T) {
+	elem := l.list.PushFront(item)
+	l.elem[key] = elem
+}
+
+// MoveToFront moves an item to the front of the LRU list
+func (l *LRUList[T]) MoveToFront(key string, timeUpdater *types.BatchedTimeUpdate) {
+	if elem, exists := l.elem[key]; exists {
+		l.list.MoveToFront(elem)
+		// Update the FileInfo in the element with new access time
+		if fi, ok := any(elem.Value).(interface {
+			UpdateAccessBatched(*types.BatchedTimeUpdate)
+		}); ok {
+			fi.UpdateAccessBatched(timeUpdater)
+		}
+	}
+}
+
+// Remove removes an item from the LRU list
+func (l *LRUList[T]) Remove(key string) (T, bool) {
+	if elem, exists := l.elem[key]; exists {
+		delete(l.elem, key)
+		if item, ok := l.list.Remove(elem).(T); ok {
+			return item, true
+		}
+	}
+	var zero T
+	return zero, false
+}
+
+// Len returns the number of items in the LRU list
+func (l *LRUList[T]) Len() int {
+	return l.list.Len()
+}
+
+// Back returns the least recently used item (at the back of the list)
+func (l *LRUList[T]) Back() *list.Element {
+	return l.list.Back()
+}
+
+// Front returns the most recently used item (at the front of the list)
+func (l *LRUList[T]) Front() *list.Element {
+	return l.list.Front()
+}

vfs/memory/dynamic.go

@@ -1,130 +0,0 @@
-package memory
-
-import (
-	"s1d3sw1ped/steamcache2/vfs"
-	"sync"
-	"sync/atomic"
-	"time"
-)
-
-// DynamicCacheManager manages cache size adjustments based on system memory usage
-type DynamicCacheManager struct {
-	originalCacheSize  uint64
-	currentCacheSize   uint64
-	memoryMonitor      *MemoryMonitor
-	cache              vfs.VFS
-	adjustmentInterval time.Duration
-	lastAdjustment     time.Time
-	mu                 sync.RWMutex
-	adjustmentCount    int64
-	isAdjusting        int32
-}
-
-// NewDynamicCacheManager creates a new dynamic cache manager
-func NewDynamicCacheManager(cache vfs.VFS, originalSize uint64, memoryMonitor *MemoryMonitor) *DynamicCacheManager {
-	return &DynamicCacheManager{
-		originalCacheSize:  originalSize,
-		currentCacheSize:   originalSize,
-		memoryMonitor:      memoryMonitor,
-		cache:              cache,
-		adjustmentInterval: 30 * time.Second, // Adjust every 30 seconds
-	}
-}
-
-// Start begins the dynamic cache size adjustment process
-func (dcm *DynamicCacheManager) Start() {
-	go dcm.adjustmentLoop()
-}
-
-// GetCurrentCacheSize returns the current cache size
-func (dcm *DynamicCacheManager) GetCurrentCacheSize() uint64 {
-	dcm.mu.RLock()
-	defer dcm.mu.RUnlock()
-	return atomic.LoadUint64(&dcm.currentCacheSize)
-}
-
-// GetOriginalCacheSize returns the original cache size
-func (dcm *DynamicCacheManager) GetOriginalCacheSize() uint64 {
-	dcm.mu.RLock()
-	defer dcm.mu.RUnlock()
-	return dcm.originalCacheSize
-}
-
-// GetAdjustmentCount returns the number of adjustments made
-func (dcm *DynamicCacheManager) GetAdjustmentCount() int64 {
-	return atomic.LoadInt64(&dcm.adjustmentCount)
-}
-
-// adjustmentLoop runs the cache size adjustment loop
-func (dcm *DynamicCacheManager) adjustmentLoop() {
-	ticker := time.NewTicker(dcm.adjustmentInterval)
-	defer ticker.Stop()
-
-	for range ticker.C {
-		dcm.performAdjustment()
-	}
-}
-
-// performAdjustment performs a cache size adjustment if needed
-func (dcm *DynamicCacheManager) performAdjustment() {
-	// Prevent concurrent adjustments
-	if !atomic.CompareAndSwapInt32(&dcm.isAdjusting, 0, 1) {
-		return
-	}
-	defer atomic.StoreInt32(&dcm.isAdjusting, 0)
-
-	// Check if enough time has passed since last adjustment
-	if time.Since(dcm.lastAdjustment) < dcm.adjustmentInterval {
-		return
-	}
-
-	// Get recommended cache size
-	recommendedSize := dcm.memoryMonitor.GetRecommendedCacheSize(dcm.originalCacheSize)
-	currentSize := atomic.LoadUint64(&dcm.currentCacheSize)
-
-	// Only adjust if there's a significant difference (more than 5%)
-	sizeDiff := float64(recommendedSize) / float64(currentSize)
-	if sizeDiff < 0.95 || sizeDiff > 1.05 {
-		dcm.adjustCacheSize(recommendedSize)
-		dcm.lastAdjustment = time.Now()
-		atomic.AddInt64(&dcm.adjustmentCount, 1)
-	}
-}
-
-// adjustCacheSize adjusts the cache size to the recommended size
-func (dcm *DynamicCacheManager) adjustCacheSize(newSize uint64) {
-	dcm.mu.Lock()
-	defer dcm.mu.Unlock()
-
-	oldSize := atomic.LoadUint64(&dcm.currentCacheSize)
-	atomic.StoreUint64(&dcm.currentCacheSize, newSize)
-
-	// If we're reducing the cache size, trigger GC to free up memory
-	if newSize < oldSize {
-		// Calculate how much to free
-		bytesToFree := oldSize - newSize
-
-		// Trigger GC on the cache to free up the excess memory
-		// This is a simplified approach - in practice, you'd want to integrate
-		// with the actual GC system to free the right amount
-		if gcCache, ok := dcm.cache.(interface{ ForceGC(uint) }); ok {
-			gcCache.ForceGC(uint(bytesToFree))
-		}
-	}
-}
-
-// GetStats returns statistics about the dynamic cache manager
-func (dcm *DynamicCacheManager) GetStats() map[string]interface{} {
-	dcm.mu.RLock()
-	defer dcm.mu.RUnlock()
-
-	return map[string]interface{}{
-		"original_cache_size":  dcm.originalCacheSize,
-		"current_cache_size":   atomic.LoadUint64(&dcm.currentCacheSize),
-		"adjustment_count":     atomic.LoadInt64(&dcm.adjustmentCount),
-		"last_adjustment":      dcm.lastAdjustment,
-		"memory_utilization":   dcm.memoryMonitor.GetMemoryUtilization(),
-		"target_memory_usage":  dcm.memoryMonitor.GetTargetMemoryUsage(),
-		"current_memory_usage": dcm.memoryMonitor.GetCurrentMemoryUsage(),
-	}
-}

vfs/memory/memory.go

@@ -3,8 +3,10 @@ package memory
 
 import (
 	"bytes"
-	"container/list"
 	"io"
+	"s1d3sw1ped/steamcache2/vfs"
+	"s1d3sw1ped/steamcache2/vfs/locks"
+	"s1d3sw1ped/steamcache2/vfs/lru"
 	"s1d3sw1ped/steamcache2/vfs/types"
 	"s1d3sw1ped/steamcache2/vfs/vfserror"
 	"sort"
@@ -13,32 +15,8 @@ import (
 	"time"
 )
 
-// VFS defines the interface for virtual file systems
-type VFS interface {
-	// Create creates a new file at the given key
-	Create(key string, size int64) (io.WriteCloser, error)
-
-	// Open opens the file at the given key for reading
-	Open(key string) (io.ReadCloser, error)
-
-	// Delete removes the file at the given key
-	Delete(key string) error
-
-	// Stat returns information about the file at the given key
-	Stat(key string) (*types.FileInfo, error)
-
-	// Name returns the name of this VFS
-	Name() string
-
-	// Size returns the current size of the VFS
-	Size() int64
-
-	// Capacity returns the maximum capacity of the VFS
-	Capacity() int64
-}
-
 // Ensure MemoryFS implements VFS.
-var _ VFS = (*MemoryFS)(nil)
+var _ vfs.VFS = (*MemoryFS)(nil)
 
 // MemoryFS is an in-memory virtual file system
 type MemoryFS struct {
@@ -48,55 +26,10 @@ type MemoryFS struct {
 	size        int64
 	mu          sync.RWMutex
 	keyLocks    []sync.Map // Sharded lock pools for better concurrency
-	LRU         *lruList
+	LRU         *lru.LRUList[*types.FileInfo]
 	timeUpdater *types.BatchedTimeUpdate // Batched time updates for better performance
 }
 
-// Number of lock shards for reducing contention
-const numLockShards = 32
-
-// lruList for time-decayed LRU eviction
-type lruList struct {
-	list *list.List
-	elem map[string]*list.Element
-}
-
-func newLruList() *lruList {
-	return &lruList{
-		list: list.New(),
-		elem: make(map[string]*list.Element),
-	}
-}
-
-func (l *lruList) Add(key string, fi *types.FileInfo) {
-	elem := l.list.PushFront(fi)
-	l.elem[key] = elem
-}
-
-func (l *lruList) MoveToFront(key string, timeUpdater *types.BatchedTimeUpdate) {
-	if elem, exists := l.elem[key]; exists {
-		l.list.MoveToFront(elem)
-		// Update the FileInfo in the element with new access time
-		if fi := elem.Value.(*types.FileInfo); fi != nil {
-			fi.UpdateAccessBatched(timeUpdater)
-		}
-	}
-}
-
-func (l *lruList) Remove(key string) *types.FileInfo {
-	if elem, exists := l.elem[key]; exists {
-		delete(l.elem, key)
-		if fi := l.list.Remove(elem).(*types.FileInfo); fi != nil {
-			return fi
-		}
-	}
-	return nil
-}
-
-func (l *lruList) Len() int {
-	return l.list.Len()
-}
-
 // New creates a new MemoryFS
 func New(capacity int64) *MemoryFS {
 	if capacity <= 0 {
@@ -104,7 +37,7 @@ func New(capacity int64) *MemoryFS {
 	}
 
 	// Initialize sharded locks
-	keyLocks := make([]sync.Map, numLockShards)
+	keyLocks := make([]sync.Map, locks.NumLockShards)
 
 	return &MemoryFS{
 		data:        make(map[string]*bytes.Buffer),
@@ -112,7 +45,7 @@ func New(capacity int64) *MemoryFS {
 		capacity:    capacity,
 		size:        0,
 		keyLocks:    keyLocks,
-		LRU:         newLruList(),
+		LRU:         lru.NewLRUList[*types.FileInfo](),
 		timeUpdater: types.NewBatchedTimeUpdate(100 * time.Millisecond), // Update time every 100ms
 	}
 }
@@ -163,24 +96,9 @@ func (m *MemoryFS) GetFragmentationStats() map[string]interface{} {
 	}
 }
 
-// getShardIndex returns the shard index for a given key
-func getShardIndex(key string) int {
-	// Use FNV-1a hash for good distribution
-	var h uint32 = 2166136261 // FNV offset basis
-	for i := 0; i < len(key); i++ {
-		h ^= uint32(key[i])
-		h *= 16777619 // FNV prime
-	}
-	return int(h % numLockShards)
-}
-
 // getKeyLock returns a lock for the given key using sharding
 func (m *MemoryFS) getKeyLock(key string) *sync.RWMutex {
-	shardIndex := getShardIndex(key)
+	return locks.GetKeyLock(m.keyLocks, key)
-	shard := &m.keyLocks[shardIndex]
-
-	keyLock, _ := shard.LoadOrStore(key, &sync.RWMutex{})
-	return keyLock.(*sync.RWMutex)
 }
 
 // Create creates a new file
@@ -391,7 +309,7 @@ func (m *MemoryFS) EvictLRU(bytesNeeded uint) uint {
 	// Evict from LRU list until we free enough space
 	for m.size > m.capacity-int64(bytesNeeded) && m.LRU.Len() > 0 {
 		// Get the least recently used item
-		elem := m.LRU.list.Back()
+		elem := m.LRU.Back()
 		if elem == nil {
 			break
 		}
@@ -411,7 +329,7 @@ func (m *MemoryFS) EvictLRU(bytesNeeded uint) uint {
 		evicted += uint(fi.Size)
 
 		// Clean up key lock
-		shardIndex := getShardIndex(key)
+		shardIndex := locks.GetShardIndex(key)
 		m.keyLocks[shardIndex].Delete(key)
 	}
 
@@ -459,7 +377,7 @@ func (m *MemoryFS) EvictBySize(bytesNeeded uint, ascending bool) uint {
 		evicted += uint(fi.Size)
 
 		// Clean up key lock
-		shardIndex := getShardIndex(key)
+		shardIndex := locks.GetShardIndex(key)
 		m.keyLocks[shardIndex].Delete(key)
 	}
 
@@ -504,7 +422,7 @@ func (m *MemoryFS) EvictFIFO(bytesNeeded uint) uint {
 		evicted += uint(fi.Size)
 
 		// Clean up key lock
-		shardIndex := getShardIndex(key)
+		shardIndex := locks.GetShardIndex(key)
 		m.keyLocks[shardIndex].Delete(key)
 	}
 

vfs/memory/monitor.go

@@ -17,6 +17,15 @@ type MemoryMonitor struct {
 	ctx                 chan struct{}
 	stopChan            chan struct{}
 	isMonitoring        int32
+
+	// Dynamic cache management fields
+	originalCacheSize  uint64
+	currentCacheSize   uint64
+	cache              interface{} // Generic cache interface
+	adjustmentInterval time.Duration
+	lastAdjustment     time.Time
+	adjustmentCount    int64
+	isAdjusting        int32
 }
 
 // NewMemoryMonitor creates a new memory monitor
@@ -27,9 +36,19 @@ func NewMemoryMonitor(targetMemoryUsage uint64, monitoringInterval time.Duration
 		adjustmentThreshold: adjustmentThreshold,
 		ctx:                 make(chan struct{}),
 		stopChan:            make(chan struct{}),
+		adjustmentInterval:  30 * time.Second, // Default adjustment interval
 	}
 }
 
+// NewMemoryMonitorWithCache creates a new memory monitor with cache management
+func NewMemoryMonitorWithCache(targetMemoryUsage uint64, monitoringInterval time.Duration, adjustmentThreshold float64, cache interface{}, originalCacheSize uint64) *MemoryMonitor {
+	mm := NewMemoryMonitor(targetMemoryUsage, monitoringInterval, adjustmentThreshold)
+	mm.cache = cache
+	mm.originalCacheSize = originalCacheSize
+	mm.currentCacheSize = originalCacheSize
+	return mm
+}
+
 // Start begins monitoring memory usage
 func (mm *MemoryMonitor) Start() {
 	if atomic.CompareAndSwapInt32(&mm.isMonitoring, 0, 1) {
@@ -151,3 +170,105 @@ func (mm *MemoryMonitor) GetMemoryStats() map[string]interface{} {
 		"gc_pause_total": m.PauseTotalNs,
 	}
 }
+
+// Dynamic Cache Management Methods
+
+// StartDynamicAdjustment begins the dynamic cache size adjustment process
+func (mm *MemoryMonitor) StartDynamicAdjustment() {
+	if mm.cache != nil {
+		go mm.adjustmentLoop()
+	}
+}
+
+// GetCurrentCacheSize returns the current cache size
+func (mm *MemoryMonitor) GetCurrentCacheSize() uint64 {
+	mm.mu.RLock()
+	defer mm.mu.RUnlock()
+	return atomic.LoadUint64(&mm.currentCacheSize)
+}
+
+// GetOriginalCacheSize returns the original cache size
+func (mm *MemoryMonitor) GetOriginalCacheSize() uint64 {
+	mm.mu.RLock()
+	defer mm.mu.RUnlock()
+	return mm.originalCacheSize
+}
+
+// GetAdjustmentCount returns the number of adjustments made
+func (mm *MemoryMonitor) GetAdjustmentCount() int64 {
+	return atomic.LoadInt64(&mm.adjustmentCount)
+}
+
+// adjustmentLoop runs the cache size adjustment loop
+func (mm *MemoryMonitor) adjustmentLoop() {
+	ticker := time.NewTicker(mm.adjustmentInterval)
+	defer ticker.Stop()
+
+	for range ticker.C {
+		mm.performAdjustment()
+	}
+}
+
+// performAdjustment performs a cache size adjustment if needed
+func (mm *MemoryMonitor) performAdjustment() {
+	// Prevent concurrent adjustments
+	if !atomic.CompareAndSwapInt32(&mm.isAdjusting, 0, 1) {
+		return
+	}
+	defer atomic.StoreInt32(&mm.isAdjusting, 0)
+
+	// Check if enough time has passed since last adjustment
+	if time.Since(mm.lastAdjustment) < mm.adjustmentInterval {
+		return
+	}
+
+	// Get recommended cache size
+	recommendedSize := mm.GetRecommendedCacheSize(mm.originalCacheSize)
+	currentSize := atomic.LoadUint64(&mm.currentCacheSize)
+
+	// Only adjust if there's a significant difference (more than 5%)
+	sizeDiff := float64(recommendedSize) / float64(currentSize)
+	if sizeDiff < 0.95 || sizeDiff > 1.05 {
+		mm.adjustCacheSize(recommendedSize)
+		mm.lastAdjustment = time.Now()
+		atomic.AddInt64(&mm.adjustmentCount, 1)
+	}
+}
+
+// adjustCacheSize adjusts the cache size to the recommended size
+func (mm *MemoryMonitor) adjustCacheSize(newSize uint64) {
+	mm.mu.Lock()
+	defer mm.mu.Unlock()
+
+	oldSize := atomic.LoadUint64(&mm.currentCacheSize)
+	atomic.StoreUint64(&mm.currentCacheSize, newSize)
+
+	// If we're reducing the cache size, trigger GC to free up memory
+	if newSize < oldSize {
+		// Calculate how much to free
+		bytesToFree := oldSize - newSize
+
+		// Trigger GC on the cache to free up the excess memory
+		// This is a simplified approach - in practice, you'd want to integrate
+		// with the actual GC system to free the right amount
+		if gcCache, ok := mm.cache.(interface{ ForceGC(uint) }); ok {
+			gcCache.ForceGC(uint(bytesToFree))
+		}
+	}
+}
+
+// GetDynamicStats returns statistics about the dynamic cache manager
+func (mm *MemoryMonitor) GetDynamicStats() map[string]interface{} {
+	mm.mu.RLock()
+	defer mm.mu.RUnlock()
+
+	return map[string]interface{}{
+		"original_cache_size":  mm.originalCacheSize,
+		"current_cache_size":   atomic.LoadUint64(&mm.currentCacheSize),
+		"adjustment_count":     atomic.LoadInt64(&mm.adjustmentCount),
+		"last_adjustment":      mm.lastAdjustment,
+		"memory_utilization":   mm.GetMemoryUtilization(),
+		"target_memory_usage":  mm.GetTargetMemoryUsage(),
+		"current_memory_usage": mm.GetCurrentMemoryUsage(),
+	}
+}

vfs/predictive/predictive.go

@@ -70,9 +70,35 @@ type PopularContent struct {
 
 // WarmRequest represents a cache warming request
 type WarmRequest struct {
-	Key      string
+	Key         string
-	Priority int
+	Priority    int
-	Reason   string
+	Reason      string
+	Size        int64
+	RequestedAt time.Time
+	Source      string // Where the warming request came from
+}
+
+// ActiveWarmer tracks an active warming operation
+type ActiveWarmer struct {
+	Key       string
+	StartTime time.Time
+	Priority  int
+	Reason    string
+	mu        sync.RWMutex
+}
+
+// WarmingStats tracks cache warming statistics
+type WarmingStats struct {
+	WarmRequests      int64
+	WarmSuccesses     int64
+	WarmFailures      int64
+	WarmBytes         int64
+	WarmDuration      time.Duration
+	PrefetchRequests  int64
+	PrefetchSuccesses int64
+	PrefetchFailures  int64
+	PrefetchBytes     int64
+	PrefetchDuration  time.Duration
 }
 
 // NewPredictiveCacheManager creates a new predictive cache manager
@@ -114,6 +140,21 @@ func NewCacheWarmer() *CacheWarmer {
 	}
 }
 
+// NewWarmingStats creates a new warming stats tracker
+func NewWarmingStats() *WarmingStats {
+	return &WarmingStats{}
+}
+
+// NewActiveWarmer creates a new active warmer tracker
+func NewActiveWarmer(key string, priority int, reason string) *ActiveWarmer {
+	return &ActiveWarmer{
+		Key:       key,
+		StartTime: time.Now(),
+		Priority:  priority,
+		Reason:    reason,
+	}
+}
+
 // RecordAccess records a file access for prediction analysis (lightweight version)
 func (pcm *PredictiveCacheManager) RecordAccess(key string, previousKey string, size int64) {
 	// Only record if we have a previous key to avoid overhead
@@ -282,6 +323,23 @@ func (cw *CacheWarmer) GetPopularContent(limit int) []*PopularContent {
 	return popular
 }
 
+// RequestWarming requests warming of a specific key
+func (cw *CacheWarmer) RequestWarming(key string, priority int, reason string, size int64) {
+	select {
+	case cw.warmerQueue <- WarmRequest{
+		Key:         key,
+		Priority:    priority,
+		Reason:      reason,
+		Size:        size,
+		RequestedAt: time.Now(),
+		Source:      "predictive",
+	}:
+		// Successfully queued
+	default:
+		// Queue full, skip warming
+	}
+}
+
 // prefetchWorker processes prefetch requests
 func (pcm *PredictiveCacheManager) prefetchWorker() {
 	defer pcm.wg.Done()

vfs/vfserror/vfserror.go

@@ -1,7 +1,10 @@
 // vfs/vfserror/vfserror.go
 package vfserror
 
-import "errors"
+import (
+	"errors"
+	"fmt"
+)
 
 // Common VFS errors
 var (
@@ -9,4 +12,47 @@ var (
 	ErrInvalidKey       = errors.New("vfs: invalid key")
 	ErrAlreadyExists    = errors.New("vfs: key already exists")
 	ErrCapacityExceeded = errors.New("vfs: capacity exceeded")
+	ErrCorruptedFile    = errors.New("vfs: corrupted file")
+	ErrInvalidSize      = errors.New("vfs: invalid size")
+	ErrOperationTimeout = errors.New("vfs: operation timeout")
 )
+
+// VFSError represents a VFS-specific error with context
+type VFSError struct {
+	Op   string // Operation that failed
+	Key  string // Key that caused the error
+	Err  error  // Underlying error
+	Size int64  // Size information if relevant
+}
+
+// Error implements the error interface
+func (e *VFSError) Error() string {
+	if e.Key != "" {
+		return fmt.Sprintf("vfs: %s failed for key %q: %v", e.Op, e.Key, e.Err)
+	}
+	return fmt.Sprintf("vfs: %s failed: %v", e.Op, e.Err)
+}
+
+// Unwrap returns the underlying error
+func (e *VFSError) Unwrap() error {
+	return e.Err
+}
+
+// NewVFSError creates a new VFS error with context
+func NewVFSError(op, key string, err error) *VFSError {
+	return &VFSError{
+		Op:  op,
+		Key: key,
+		Err: err,
+	}
+}
+
+// NewVFSErrorWithSize creates a new VFS error with size context
+func NewVFSErrorWithSize(op, key string, size int64, err error) *VFSError {
+	return &VFSError{
+		Op:   op,
+		Key:  key,
+		Size: size,
+		Err:  err,
+	}
+}

vfs/warming/warming.go

@@ -1,300 +0,0 @@
-package warming
-
-import (
-	"context"
-	"s1d3sw1ped/steamcache2/vfs"
-	"sync"
-	"sync/atomic"
-	"time"
-)
-
-// CacheWarmer implements intelligent cache warming strategies
-type CacheWarmer struct {
-	vfs            vfs.VFS
-	warmingQueue   chan WarmRequest
-	activeWarmers  map[string]*ActiveWarmer
-	stats          *WarmingStats
-	ctx            context.Context
-	cancel         context.CancelFunc
-	wg             sync.WaitGroup
-	mu             sync.RWMutex
-	maxConcurrent  int
-	warmingEnabled bool
-}
-
-// WarmRequest represents a cache warming request
-type WarmRequest struct {
-	Key         string
-	Priority    int
-	Reason      string
-	Size        int64
-	RequestedAt time.Time
-	Source      string // Where the warming request came from
-}
-
-// ActiveWarmer tracks an active warming operation
-type ActiveWarmer struct {
-	Key       string
-	StartTime time.Time
-	Priority  int
-	Reason    string
-	mu        sync.RWMutex
-}
-
-// WarmingStats tracks cache warming statistics
-type WarmingStats struct {
-	WarmRequests  int64
-	WarmSuccesses int64
-	WarmFailures  int64
-	WarmBytes     int64
-	WarmDuration  time.Duration
-	ActiveWarmers int64
-	mu            sync.RWMutex
-}
-
-// WarmingStrategy defines different warming strategies
-type WarmingStrategy int
-
-const (
-	StrategyImmediate WarmingStrategy = iota
-	StrategyBackground
-	StrategyScheduled
-	StrategyPredictive
-)
-
-// NewCacheWarmer creates a new cache warmer
-func NewCacheWarmer(vfs vfs.VFS, maxConcurrent int) *CacheWarmer {
-	ctx, cancel := context.WithCancel(context.Background())
-
-	cw := &CacheWarmer{
-		vfs:            vfs,
-		warmingQueue:   make(chan WarmRequest, 1000),
-		activeWarmers:  make(map[string]*ActiveWarmer),
-		stats:          &WarmingStats{},
-		ctx:            ctx,
-		cancel:         cancel,
-		maxConcurrent:  maxConcurrent,
-		warmingEnabled: true,
-	}
-
-	// Start warming workers
-	for i := 0; i < maxConcurrent; i++ {
-		cw.wg.Add(1)
-		go cw.warmingWorker(i)
-	}
-
-	// Start cleanup worker
-	cw.wg.Add(1)
-	go cw.cleanupWorker()
-
-	return cw
-}
-
-// RequestWarming requests warming of content
-func (cw *CacheWarmer) RequestWarming(key string, priority int, reason string, size int64, source string) {
-	if !cw.warmingEnabled {
-		return
-	}
-
-	// Check if already warming
-	cw.mu.RLock()
-	if _, exists := cw.activeWarmers[key]; exists {
-		cw.mu.RUnlock()
-		return // Already warming
-	}
-	cw.mu.RUnlock()
-
-	// Check if already cached
-	if _, err := cw.vfs.Stat(key); err == nil {
-		return // Already cached
-	}
-
-	select {
-	case cw.warmingQueue <- WarmRequest{
-		Key:         key,
-		Priority:    priority,
-		Reason:      reason,
-		Size:        size,
-		RequestedAt: time.Now(),
-		Source:      source,
-	}:
-		atomic.AddInt64(&cw.stats.WarmRequests, 1)
-	default:
-		// Queue full, skip warming
-	}
-}
-
-// warmingWorker processes warming requests
-func (cw *CacheWarmer) warmingWorker(workerID int) {
-	defer cw.wg.Done()
-
-	for {
-		select {
-		case <-cw.ctx.Done():
-			return
-		case req := <-cw.warmingQueue:
-			cw.processWarmingRequest(req, workerID)
-		}
-	}
-}
-
-// processWarmingRequest processes a warming request
-func (cw *CacheWarmer) processWarmingRequest(req WarmRequest, workerID int) {
-	// Mark as active warmer
-	cw.mu.Lock()
-	cw.activeWarmers[req.Key] = &ActiveWarmer{
-		Key:       req.Key,
-		StartTime: time.Now(),
-		Priority:  req.Priority,
-		Reason:    req.Reason,
-	}
-	cw.mu.Unlock()
-
-	atomic.AddInt64(&cw.stats.ActiveWarmers, 1)
-
-	// Simulate warming process
-	// In a real implementation, this would:
-	// 1. Fetch content from upstream
-	// 2. Store in cache
-	// 3. Update statistics
-
-	startTime := time.Now()
-
-	// Simulate warming delay based on priority
-	warmingDelay := time.Duration(100-req.Priority*10) * time.Millisecond
-	if warmingDelay < 10*time.Millisecond {
-		warmingDelay = 10 * time.Millisecond
-	}
-
-	select {
-	case <-time.After(warmingDelay):
-		// Warming completed successfully
-		atomic.AddInt64(&cw.stats.WarmSuccesses, 1)
-		atomic.AddInt64(&cw.stats.WarmBytes, req.Size)
-	case <-cw.ctx.Done():
-		// Context cancelled
-		atomic.AddInt64(&cw.stats.WarmFailures, 1)
-	}
-
-	duration := time.Since(startTime)
-	cw.stats.mu.Lock()
-	cw.stats.WarmDuration += duration
-	cw.stats.mu.Unlock()
-
-	// Remove from active warmers
-	cw.mu.Lock()
-	delete(cw.activeWarmers, req.Key)
-	cw.mu.Unlock()
-
-	atomic.AddInt64(&cw.stats.ActiveWarmers, -1)
-}
-
-// cleanupWorker cleans up old warming requests
-func (cw *CacheWarmer) cleanupWorker() {
-	defer cw.wg.Done()
-
-	ticker := time.NewTicker(1 * time.Minute)
-	defer ticker.Stop()
-
-	for {
-		select {
-		case <-cw.ctx.Done():
-			return
-		case <-ticker.C:
-			cw.cleanupOldWarmers()
-		}
-	}
-}
-
-// cleanupOldWarmers removes old warming requests
-func (cw *CacheWarmer) cleanupOldWarmers() {
-	cw.mu.Lock()
-	defer cw.mu.Unlock()
-
-	now := time.Now()
-	cutoff := now.Add(-5 * time.Minute) // Remove warmers older than 5 minutes
-
-	for key, warmer := range cw.activeWarmers {
-		warmer.mu.RLock()
-		if warmer.StartTime.Before(cutoff) {
-			warmer.mu.RUnlock()
-			delete(cw.activeWarmers, key)
-			atomic.AddInt64(&cw.stats.WarmFailures, 1)
-		} else {
-			warmer.mu.RUnlock()
-		}
-	}
-}
-
-// GetActiveWarmers returns currently active warming operations
-func (cw *CacheWarmer) GetActiveWarmers() []*ActiveWarmer {
-	cw.mu.RLock()
-	defer cw.mu.RUnlock()
-
-	warmers := make([]*ActiveWarmer, 0, len(cw.activeWarmers))
-	for _, warmer := range cw.activeWarmers {
-		warmers = append(warmers, warmer)
-	}
-
-	return warmers
-}
-
-// GetStats returns warming statistics
-func (cw *CacheWarmer) GetStats() *WarmingStats {
-	cw.stats.mu.RLock()
-	defer cw.stats.mu.RUnlock()
-
-	return &WarmingStats{
-		WarmRequests:  atomic.LoadInt64(&cw.stats.WarmRequests),
-		WarmSuccesses: atomic.LoadInt64(&cw.stats.WarmSuccesses),
-		WarmFailures:  atomic.LoadInt64(&cw.stats.WarmFailures),
-		WarmBytes:     atomic.LoadInt64(&cw.stats.WarmBytes),
-		WarmDuration:  cw.stats.WarmDuration,
-		ActiveWarmers: atomic.LoadInt64(&cw.stats.ActiveWarmers),
-	}
-}
-
-// SetWarmingEnabled enables or disables cache warming
-func (cw *CacheWarmer) SetWarmingEnabled(enabled bool) {
-	cw.mu.Lock()
-	defer cw.mu.Unlock()
-	cw.warmingEnabled = enabled
-}
-
-// IsWarmingEnabled returns whether warming is enabled
-func (cw *CacheWarmer) IsWarmingEnabled() bool {
-	cw.mu.RLock()
-	defer cw.mu.RUnlock()
-	return cw.warmingEnabled
-}
-
-// Stop stops the cache warmer
-func (cw *CacheWarmer) Stop() {
-	cw.cancel()
-	cw.wg.Wait()
-}
-
-// WarmPopularContent warms popular content based on access patterns
-func (cw *CacheWarmer) WarmPopularContent(popularKeys []string, priority int) {
-	for _, key := range popularKeys {
-		cw.RequestWarming(key, priority, "popular_content", 0, "popular_analyzer")
-	}
-}
-
-// WarmPredictedContent warms predicted content
-func (cw *CacheWarmer) WarmPredictedContent(predictedKeys []string, priority int) {
-	for _, key := range predictedKeys {
-		cw.RequestWarming(key, priority, "predicted_access", 0, "predictor")
-	}
-}
-
-// WarmSequentialContent warms content in sequential order
-func (cw *CacheWarmer) WarmSequentialContent(sequentialKeys []string, priority int) {
-	for i, key := range sequentialKeys {
-		// Stagger warming requests to avoid overwhelming the system
-		go func(k string, delay time.Duration) {
-			time.Sleep(delay)
-			cw.RequestWarming(k, priority, "sequential_access", 0, "sequential_analyzer")
-		}(key, time.Duration(i)*100*time.Millisecond)
-	}
-}