package database

import (
	"os"
	"testing"
	"time"
)

func TestOptimizationManager_VacuumDatabase(t *testing.T) {
	db, cleanup := setupTestDatabase(t)
	defer cleanup()

	config := &Config{Path: db.config.Path}
	optimizer := NewOptimizationManager(db, config)

	err := optimizer.VacuumDatabase()
	if err != nil {
		t.Fatal("VacuumDatabase failed:", err)
	}

	// Verify vacuum was successful by checking database integrity
	conn := db.GetConnection()
	var result string
	err = conn.QueryRow("PRAGMA integrity_check").Scan(&result)
	if err != nil {
		t.Error("Failed to run integrity check:", err)
	}
	if result != "ok" {
		t.Errorf("Database integrity check failed: %s", result)
	}
}

func TestOptimizationManager_OptimizeDatabase(t *testing.T) {
	db, cleanup := setupTestDatabase(t)
	defer cleanup()

	config := &Config{Path: db.config.Path}
	optimizer := NewOptimizationManager(db, config)

	err := optimizer.OptimizeDatabase()
	if err != nil {
		t.Fatal("OptimizeDatabase failed:", err)
	}

	// Check that auto_vacuum was set
	conn := db.GetConnection()
	var autoVacuum int
	err = conn.QueryRow("PRAGMA auto_vacuum").Scan(&autoVacuum)
	if err != nil {
		t.Error("Failed to check auto_vacuum setting:", err)
	}
	// Should be 2 (INCREMENTAL) after optimization
	if autoVacuum != 2 {
		t.Errorf("Expected auto_vacuum = 2 (INCREMENTAL), got %d", autoVacuum)
	}
}

func TestOptimizationManager_OptimizePageSize(t *testing.T) {
	db, cleanup := setupTestDatabase(t)
	defer cleanup()

	config := &Config{Path: db.config.Path}
	optimizer := NewOptimizationManager(db, config)

	// Get current page size
	conn := db.GetConnection()
	var currentPageSize int
	err := conn.QueryRow("PRAGMA page_size").Scan(&currentPageSize)
	if err != nil {
		t.Fatal("Failed to get current page size:", err)
	}

	// Set a different page size
	targetPageSize := 8192
	if currentPageSize == targetPageSize {
		targetPageSize = 4096 // Use different size if already at target
	}

	err = optimizer.OptimizePageSize(targetPageSize)
	if err != nil {
		t.Fatal("OptimizePageSize failed:", err)
	}

	// Verify page size was changed
	var newPageSize int
	err = conn.QueryRow("PRAGMA page_size").Scan(&newPageSize)
	if err != nil {
		t.Error("Failed to get new page size:", err)
	}
	if newPageSize != targetPageSize {
		t.Errorf("Expected page size %d, got %d", targetPageSize, newPageSize)
	}

	// Test setting same page size (should be no-op)
	err = optimizer.OptimizePageSize(targetPageSize)
	if err != nil {
		t.Error("OptimizePageSize failed for same page size:", err)
	}
}

func TestOptimizationManager_GetOptimizationStats(t *testing.T) {
	db, cleanup := setupTestDatabase(t)
	defer cleanup()

	config := &Config{Path: db.config.Path}
	optimizer := NewOptimizationManager(db, config)

	// Insert some test data to make stats more meaningful
	conn := db.GetConnection()
	_, err := conn.Exec(`
		INSERT INTO airlines (id, name, alias, iata_code, icao_code, callsign, country, active, data_source)
		VALUES (1, 'Test Airways', 'Test', 'TA', 'TST', 'TESTAIR', 'United States', 1, 'test')
	`)
	if err != nil {
		t.Error("Failed to insert test data:", err)
	}

	stats, err := optimizer.GetOptimizationStats()
	if err != nil {
		t.Fatal("GetOptimizationStats failed:", err)
	}

	if stats == nil {
		t.Fatal("Expected stats, got nil")
	}

	// Check basic stats
	if stats.DatabaseSize <= 0 {
		t.Error("Database size should be greater than 0")
	}
	if stats.PageSize <= 0 {
		t.Error("Page size should be greater than 0")
	}
	if stats.PageCount <= 0 {
		t.Error("Page count should be greater than 0")
	}
	if stats.UsedPages < 0 {
		t.Error("Used pages should be non-negative")
	}
	if stats.FreePages < 0 {
		t.Error("Free pages should be non-negative")
	}
	if stats.Efficiency < 0 || stats.Efficiency > 100 {
		t.Errorf("Efficiency should be between 0-100%%, got %.2f%%", stats.Efficiency)
	}

	t.Logf("Database stats: Size=%d bytes, Pages=%d (used=%d, free=%d), Efficiency=%.1f%%",
		stats.DatabaseSize, stats.PageCount, stats.UsedPages, stats.FreePages, stats.Efficiency)
}

func TestOptimizationManager_PerformMaintenance(t *testing.T) {
	db, cleanup := setupTestDatabase(t)
	defer cleanup()

	config := &Config{
		Path:           db.config.Path,
		VacuumInterval: time.Millisecond, // Very short interval for testing
	}
	optimizer := NewOptimizationManager(db, config)

	// Should perform vacuum due to short interval
	err := optimizer.PerformMaintenance()
	if err != nil {
		t.Fatal("PerformMaintenance failed:", err)
	}

	// Check that lastVacuum was updated
	if optimizer.lastVacuum.IsZero() {
		t.Error("lastVacuum should be set after maintenance")
	}

	// Wait a bit and run again with longer interval
	config.VacuumInterval = time.Hour // Long interval
	err = optimizer.PerformMaintenance()
	if err != nil {
		t.Fatal("Second PerformMaintenance failed:", err)
	}
}

func TestOptimizationManager_getDatabaseSize(t *testing.T) {
	db, cleanup := setupTestDatabase(t)
	defer cleanup()

	config := &Config{Path: db.config.Path}
	optimizer := NewOptimizationManager(db, config)

	size, err := optimizer.getDatabaseSize()
	if err != nil {
		t.Fatal("getDatabaseSize failed:", err)
	}

	if size <= 0 {
		t.Error("Database size should be greater than 0")
	}

	// Verify size matches actual file size
	stat, err := os.Stat(db.config.Path)
	if err != nil {
		t.Fatal("Failed to stat database file:", err)
	}

	if size != stat.Size() {
		t.Errorf("getDatabaseSize returned %d, but file size is %d", size, stat.Size())
	}
}

func TestOptimizationManager_InvalidPath(t *testing.T) {
	db, cleanup := setupTestDatabase(t)
	defer cleanup()

	// Test with invalid path
	config := &Config{Path: "/nonexistent/path/database.db"}
	optimizer := NewOptimizationManager(db, config)

	_, err := optimizer.getDatabaseSize()
	if err == nil {
		t.Error("getDatabaseSize should fail with invalid path")
	}
}

func TestOptimizationStats_JSON(t *testing.T) {
	stats := &OptimizationStats{
		DatabaseSize:      1024000,
		PageSize:          4096,
		PageCount:         250,
		UsedPages:         200,
		FreePages:         50,
		Efficiency:        80.0,
		AutoVacuumEnabled: true,
		LastVacuum:        time.Now(),
	}

	// Test that all fields are accessible
	if stats.DatabaseSize != 1024000 {
		t.Error("DatabaseSize not preserved")
	}
	if stats.PageSize != 4096 {
		t.Error("PageSize not preserved")
	}
	if stats.Efficiency != 80.0 {
		t.Error("Efficiency not preserved")
	}
	if !stats.AutoVacuumEnabled {
		t.Error("AutoVacuumEnabled not preserved")
	}
}

func TestOptimizationManager_WithRealData(t *testing.T) {
	db, cleanup := setupTestDatabase(t)
	defer cleanup()

	// Load some real data to make optimization more realistic
	// Skip actual data loading in tests as it requires network access
	// Just insert minimal test data
	conn := db.GetConnection()
	_, err := conn.Exec(`INSERT INTO airlines (id, name, alias, iata_code, icao_code, callsign, country, active, data_source)
		VALUES (1, 'Test Airways', 'Test', 'TA', 'TST', 'TESTAIR', 'United States', 1, 'test')`)
	if err != nil {
		t.Fatal("Failed to insert test data:", err)
	}

	config := &Config{Path: db.config.Path}
	optimizer := NewOptimizationManager(db, config)

	// Get stats before optimization
	statsBefore, err := optimizer.GetOptimizationStats()
	if err != nil {
		t.Fatal("Failed to get stats before optimization:", err)
	}

	// Run optimization
	err = optimizer.OptimizeDatabase()
	if err != nil {
		t.Fatal("OptimizeDatabase failed:", err)
	}

	err = optimizer.VacuumDatabase()
	if err != nil {
		t.Fatal("VacuumDatabase failed:", err)
	}

	// Get stats after optimization
	statsAfter, err := optimizer.GetOptimizationStats()
	if err != nil {
		t.Fatal("Failed to get stats after optimization:", err)
	}

	// Compare efficiency
	t.Logf("Optimization results: %.2f%% → %.2f%% efficiency",
		statsBefore.Efficiency, statsAfter.Efficiency)

	// After optimization, we should have auto-vacuum enabled
	if !statsAfter.AutoVacuumEnabled {
		t.Error("Auto-vacuum should be enabled after optimization")
	}

	// Database should still be functional
	conn = db.GetConnection()
	var count int
	err = conn.QueryRow("SELECT COUNT(*) FROM airlines").Scan(&count)
	if err != nil {
		t.Error("Database not functional after optimization:", err)
	}
	if count == 0 {
		t.Error("Data lost during optimization")
	}
}