// steamcache/steamcache_test.go
package steamcache

import (
	"io"
	"s1d3sw1ped/steamcache2/steamcache/errors"
	"s1d3sw1ped/steamcache2/vfs/vfserror"
	"strings"
	"testing"
	"time"
)

func TestCaching(t *testing.T) {
	td := t.TempDir()

	sc := New("localhost:8080", "1G", "1G", td, "", "lru", "lru", 200, 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)
	}
	w.Write([]byte("value"))
	w.Close()

	w, err = sc.vfs.Create("key1", 6)
	if err != nil {
		t.Errorf("Create failed: %v", err)
	}
	w.Write([]byte("value1"))
	w.Close()

	if sc.diskgc.Size() != 17 {
		t.Errorf("Size failed: got %d, want %d", sc.diskgc.Size(), 17)
	}

	if sc.vfs.Size() != 17 {
		t.Errorf("Size failed: got %d, want %d", sc.vfs.Size(), 17)
	}

	rc, err := sc.vfs.Open("key")
	if err != nil {
		t.Errorf("Open failed: %v", err)
	}
	d, _ := io.ReadAll(rc)
	rc.Close()
	if string(d) != "value" {
		t.Errorf("Get failed: got %s, want %s", d, "value")
	}

	rc, err = sc.vfs.Open("key1")
	if err != nil {
		t.Errorf("Open failed: %v", err)
	}
	d, _ = io.ReadAll(rc)
	rc.Close()
	if string(d) != "value1" {
		t.Errorf("Get failed: got %s, want %s", d, "value1")
	}

	rc, err = sc.vfs.Open("key2")
	if err != nil {
		t.Errorf("Open failed: %v", err)
	}
	d, _ = io.ReadAll(rc)
	rc.Close()
	if string(d) != "value2" {
		t.Errorf("Get failed: got %s, want %s", d, "value2")
	}

	// With size-based promotion filtering, not all files may be promoted
	// The total size should be at least the disk size (17 bytes) but may be less than 34 bytes
	// if some files are filtered out due to size constraints
	if sc.diskgc.Size() != 17 {
		t.Errorf("Disk size failed: got %d, want %d", sc.diskgc.Size(), 17)
	}

	if sc.vfs.Size() < 17 {
		t.Errorf("Total size too small: got %d, want at least 17", sc.vfs.Size())
	}
	if sc.vfs.Size() > 34 {
		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

	if _, err := sc.vfs.Open("key2"); err == nil {
		t.Errorf("Open failed: got nil, want error")
	}
}

func TestCacheMissAndHit(t *testing.T) {
	sc := New("localhost:8080", "0", "1G", t.TempDir(), "", "lru", "lru", 200, 5)

	key := "testkey"
	value := []byte("testvalue")

	// Simulate miss: but since no upstream, skip full ServeHTTP, test VFS
	w, err := sc.vfs.Create(key, int64(len(value)))
	if err != nil {
		t.Fatal(err)
	}
	w.Write(value)
	w.Close()

	rc, err := sc.vfs.Open(key)
	if err != nil {
		t.Fatal(err)
	}
	got, _ := io.ReadAll(rc)
	rc.Close()

	if string(got) != string(value) {
		t.Errorf("expected %s, got %s", value, got)
	}
}

func TestURLHashing(t *testing.T) {
	// Test the SHA256-based cache key generation for Steam client requests
	// The "steam/" prefix indicates the request came from a Steam client (User-Agent based)

	testCases := []struct {
		input       string
		desc        string
		shouldCache bool
	}{
		{
			input:       "/depot/1684171/chunk/abcdef1234567890",
			desc:        "chunk file URL",
			shouldCache: true,
		},
		{
			input:       "/depot/1684171/manifest/944076726177422892/5/abcdef1234567890",
			desc:        "manifest file URL",
			shouldCache: true,
		},
		{
			input:       "/appinfo/123456",
			desc:        "app info URL",
			shouldCache: true,
		},
		{
			input:       "/some/other/path",
			desc:        "any URL from Steam client",
			shouldCache: true, // All URLs from Steam clients (detected via User-Agent) are cached
		},
	}

	for _, tc := range testCases {
		t.Run(tc.desc, func(t *testing.T) {
			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)
				}
				// Should be exactly 70 characters (6 for "steam/" + 64 for SHA256 hex)
				if len(result) != 70 {
					t.Errorf("generateServiceCacheKey(%s, \"steam\") length = %d, expected 70", tc.input, len(result))
				}
			} else {
				// Should return error for invalid URLs
				if err == nil {
					t.Errorf("generateServiceCacheKey(%s, \"steam\") should have returned error", tc.input)
				}
			}
		})
	}
}

func TestServiceDetection(t *testing.T) {
	// Create a service manager for testing
	sm := NewServiceManager()

	testCases := []struct {
		userAgent     string
		expectedName  string
		expectedFound bool
		desc          string
	}{
		{
			userAgent:     "Valve/Steam HTTP Client 1.0",
			expectedName:  "steam",
			expectedFound: true,
			desc:          "Valve Steam HTTP Client",
		},
		{
			userAgent:     "Steam",
			expectedName:  "steam",
			expectedFound: true,
			desc:          "Simple Steam user agent",
		},
		{
			userAgent:     "SteamClient/1.0",
			expectedName:  "steam",
			expectedFound: true,
			desc:          "SteamClient with version",
		},
		{
			userAgent:     "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36",
			expectedName:  "",
			expectedFound: false,
			desc:          "Browser user agent",
		},
		{
			userAgent:     "",
			expectedName:  "",
			expectedFound: false,
			desc:          "Empty user agent",
		},
		{
			userAgent:     "curl/7.68.0",
			expectedName:  "",
			expectedFound: false,
			desc:          "curl user agent",
		},
	}

	for _, tc := range testCases {
		t.Run(tc.desc, func(t *testing.T) {
			service, found := sm.DetectService(tc.userAgent)

			if found != tc.expectedFound {
				t.Errorf("DetectService(%s) found = %v, expected %v", tc.userAgent, found, tc.expectedFound)
			}

			if found && service.Name != tc.expectedName {
				t.Errorf("DetectService(%s) service name = %s, expected %s", tc.userAgent, service.Name, tc.expectedName)
			}
		})
	}
}

func TestServiceManagerExpandability(t *testing.T) {
	// Create a service manager for testing
	sm := NewServiceManager()

	// Test adding a new service (Epic Games)
	epicConfig := &ServiceConfig{
		Name:   "epic",
		Prefix: "epic",
		UserAgents: []string{
			`EpicGamesLauncher`,
			`EpicGames`,
			`Epic.*Launcher`,
		},
	}

	err := sm.AddService(epicConfig)
	if err != nil {
		t.Fatalf("Failed to add Epic service: %v", err)
	}

	// Test Epic Games detection
	epicTestCases := []struct {
		userAgent     string
		expectedName  string
		expectedFound bool
		desc          string
	}{
		{
			userAgent:     "EpicGamesLauncher/1.0",
			expectedName:  "epic",
			expectedFound: true,
			desc:          "Epic Games Launcher",
		},
		{
			userAgent:     "EpicGames/2.0",
			expectedName:  "epic",
			expectedFound: true,
			desc:          "Epic Games client",
		},
		{
			userAgent:     "Epic Launcher 1.5",
			expectedName:  "epic",
			expectedFound: true,
			desc:          "Epic Launcher with regex match",
		},
		{
			userAgent:     "Steam",
			expectedName:  "steam",
			expectedFound: true,
			desc:          "Steam should still work",
		},
		{
			userAgent:     "Mozilla/5.0",
			expectedName:  "",
			expectedFound: false,
			desc:          "Browser should not match any service",
		},
	}

	for _, tc := range epicTestCases {
		t.Run(tc.desc, func(t *testing.T) {
			service, found := sm.DetectService(tc.userAgent)

			if found != tc.expectedFound {
				t.Errorf("DetectService(%s) found = %v, expected %v", tc.userAgent, found, tc.expectedFound)
			}

			if found && service.Name != tc.expectedName {
				t.Errorf("DetectService(%s) service name = %s, expected %s", tc.userAgent, service.Name, tc.expectedName)
			}
		})
	}

	// Test cache key generation for different services
	steamKey, err := generateServiceCacheKey("/depot/123/chunk/abc", "steam")
	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)
	}
	if !strings.HasPrefix(epicKey, "epic/") {
		t.Errorf("Epic cache key should start with 'epic/', got: %s", epicKey)
	}
}

// Removed hash calculation tests since we switched to lightweight validation

func TestSteamKeySharding(t *testing.T) {
	sc := New("localhost:8080", "0", "1G", t.TempDir(), "", "lru", "lru", 200, 5)

	// Test with a Steam-style key that should trigger sharding
	steamKey := "steam/0016cfc5019b8baa6026aa1cce93e685d6e06c6e"
	testData := []byte("test steam cache data")

	// Create a file with the steam key
	w, err := sc.vfs.Create(steamKey, int64(len(testData)))
	if err != nil {
		t.Fatalf("Failed to create file with steam key: %v", err)
	}
	w.Write(testData)
	w.Close()

	// Verify we can read it back
	rc, err := sc.vfs.Open(steamKey)
	if err != nil {
		t.Fatalf("Failed to open file with steam key: %v", err)
	}
	got, _ := io.ReadAll(rc)
	rc.Close()

	if string(got) != string(testData) {
		t.Errorf("Data mismatch: expected %s, got %s", testData, got)
	}

	// Verify that the file was created (sharding is working if no error occurred)
	// The key difference is that with sharding, the file should be created successfully
	// 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