// vfs/vfserror/vfserror.go
package vfserror

import (
	"errors"
	"fmt"
)

// Common VFS errors
var (
	ErrNotFound         = errors.New("vfs: key not found")
	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,
	}
}