package imgcache

import (
	"context"
	"database/sql"
	"os"
	"testing"
	"time"

	_ "modernc.org/sqlite"
)

func setupTestDB(t *testing.T) *sql.DB {
	t.Helper()

	db, err := sql.Open("sqlite", ":memory:")
	if err != nil {
		t.Fatalf("failed to open test db: %v", err)
	}

	// Create schema
	schema := `
		CREATE TABLE source_content (
			source_key TEXT PRIMARY KEY,
			source_host TEXT NOT NULL,
			source_path TEXT NOT NULL,
			source_query TEXT NOT NULL DEFAULT '',
			content_type TEXT NOT NULL,
			size_bytes INTEGER NOT NULL,
			fetched_at DATETIME DEFAULT CURRENT_TIMESTAMP,
			last_accessed_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
		);
		CREATE TABLE output_content (
			content_hash TEXT PRIMARY KEY,
			content_type TEXT NOT NULL,
			size_bytes INTEGER NOT NULL,
			fetched_at DATETIME DEFAULT CURRENT_TIMESTAMP
		);
		CREATE TABLE request_cache (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			cache_key TEXT NOT NULL UNIQUE,
			source_metadata_id INTEGER NOT NULL,
			output_hash TEXT NOT NULL,
			width INTEGER NOT NULL,
			height INTEGER NOT NULL,
			format TEXT NOT NULL,
			quality INTEGER NOT NULL DEFAULT 85,
			fit_mode TEXT NOT NULL DEFAULT 'cover',
			fetched_at DATETIME DEFAULT CURRENT_TIMESTAMP,
			access_count INTEGER NOT NULL DEFAULT 1
		);
		CREATE TABLE negative_cache (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			source_host TEXT NOT NULL,
			source_path TEXT NOT NULL,
			source_query TEXT NOT NULL DEFAULT '',
			status_code INTEGER NOT NULL,
			error_message TEXT,
			fetched_at DATETIME DEFAULT CURRENT_TIMESTAMP,
			expires_at DATETIME NOT NULL,
			UNIQUE(source_host, source_path, source_query)
		);
		CREATE TABLE cache_stats (
			id INTEGER PRIMARY KEY CHECK (id = 1),
			hit_count INTEGER NOT NULL DEFAULT 0,
			miss_count INTEGER NOT NULL DEFAULT 0,
			upstream_fetch_count INTEGER NOT NULL DEFAULT 0,
			upstream_fetch_bytes INTEGER NOT NULL DEFAULT 0,
			transform_count INTEGER NOT NULL DEFAULT 0,
			last_updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
		);
		INSERT INTO cache_stats (id) VALUES (1);
	`

	_, err = db.ExecContext(t.Context(), schema)
	if err != nil {
		t.Fatalf("failed to create schema: %v", err)
	}

	return db
}

func setupTestCache(t *testing.T) *Cache {
	t.Helper()

	tmpDir := t.TempDir()
	db := setupTestDB(t)

	cache, err := NewCache(db, CacheConfig{
		StateDir:    tmpDir,
		NegativeTTL: 5 * time.Minute,
	})
	if err != nil {
		t.Fatalf("failed to create cache: %v", err)
	}

	return cache
}

func TestCache_Stats(t *testing.T) {
	t.Parallel()

	cache := setupTestCache(t)
	ctx := context.Background()

	// Increment some stats
	cache.IncrementStats(true, 0)
	cache.IncrementStats(true, 0)
	cache.IncrementStats(false, 1024)

	stats, err := cache.Stats(ctx)
	if err != nil {
		t.Fatalf("Stats() error = %v", err)
	}

	if stats.HitCount != 2 {
		t.Errorf("Stats() HitCount = %d, want 2", stats.HitCount)
	}

	if stats.MissCount != 1 {
		t.Errorf("Stats() MissCount = %d, want 1", stats.MissCount)
	}
}

func TestCache_CleanExpired(t *testing.T) {
	t.Parallel()

	tmpDir := t.TempDir()
	db := setupTestDB(t)

	cache, _ := NewCache(db, CacheConfig{
		StateDir:    tmpDir,
		NegativeTTL: 1 * time.Millisecond,
	})

	ctx := context.Background()

	// Insert expired negative cache entry directly
	_, err := db.ExecContext(ctx, `
		INSERT INTO negative_cache
			(source_host, source_path, source_query, status_code, expires_at)
		VALUES ('example.com', '/old.jpg', '', 404, datetime('now', '-1 hour'))
	`)
	if err != nil {
		t.Fatalf("failed to insert test data: %v", err)
	}

	// Verify it exists
	var count int

	err = db.QueryRowContext(ctx, `SELECT COUNT(*) FROM negative_cache`).Scan(&count)
	if err != nil {
		t.Fatalf("failed to count negative cache entries: %v", err)
	}

	if count != 1 {
		t.Fatalf("expected 1 negative cache entry, got %d", count)
	}

	// Clean expired
	err = cache.CleanExpired(ctx)
	if err != nil {
		t.Fatalf("CleanExpired() error = %v", err)
	}

	// Verify it's gone
	err = db.QueryRowContext(ctx, `SELECT COUNT(*) FROM negative_cache`).Scan(&count)
	if err != nil {
		t.Fatalf("failed to count negative cache entries: %v", err)
	}

	if count != 0 {
		t.Errorf("expected 0 negative cache entries after clean, got %d", count)
	}
}

func TestCache_StorageDirectoriesCreated(t *testing.T) {
	t.Parallel()

	tmpDir := t.TempDir()
	db := setupTestDB(t)

	_, err := NewCache(db, CacheConfig{
		StateDir: tmpDir,
	})
	if err != nil {
		t.Fatalf("NewCache() error = %v", err)
	}

	// Verify directories were created
	dirs := []string{
		"cache/sources",
		"cache/variants",
	}

	for _, dir := range dirs {
		path := tmpDir + "/" + dir

		_, err := os.Stat(path)
		if os.IsNotExist(err) {
			t.Errorf("directory %s was not created", dir)
		}
	}
}