package testserver

import (
	"context"
	"database/sql"
	"fmt"
	"net/http"
	"os"
	"strings"
	"time"

	"dance-lessons-coach/pkg/config"
	"dance-lessons-coach/pkg/server"

	_ "github.com/lib/pq"
	"github.com/rs/zerolog/log"
	"github.com/spf13/viper"
)

// getPostgresHost returns the appropriate PostgreSQL host based on environment

type Server struct {
	httpServer *http.Server
	port       int
	baseURL    string
	db         *sql.DB
}

func NewServer() *Server {
	return &Server{
		port: 9191,
	}
}

func (s *Server) Start() error {
	s.baseURL = fmt.Sprintf("http://localhost:%d", s.port)

	// Create real server instance from pkg/server
	cfg := createTestConfig(s.port)
	realServer := server.NewServer(cfg, context.Background())

	// Initialize database connection for cleanup
	if err := s.initDBConnection(); err != nil {
		return fmt.Errorf("failed to initialize database connection: %w", err)
	}

	// Start HTTP server in same process
	s.httpServer = &http.Server{
		Addr:    fmt.Sprintf(":%d", s.port),
		Handler: realServer.Router(),
	}

	go func() {
		if err := s.httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			if err != http.ErrServerClosed {
				log.Error().Err(err).Msg("Test server failed")
			}
		}
	}()

	// Wait for server to be ready
	if err := s.waitForServerReady(); err != nil {
		return err
	}

	// Start config file monitoring for test config changes
	go s.monitorConfigFile()

	return nil
}

// monitorConfigFile monitors the test config file for changes and reloads configuration
func (s *Server) monitorConfigFile() {
	testConfigPath := "test-config.yaml"
	lastModTime := time.Time{}
	fileExists := false

	for {
		// Check if test config file exists
		if _, err := os.Stat(testConfigPath); os.IsNotExist(err) {
			if fileExists {
				// File was deleted, reload with default config
				fileExists = false
				log.Debug().Str("file", testConfigPath).Msg("Test config file deleted, reloading with default config")
				if err := s.ReloadConfig(); err != nil {
					log.Warn().Err(err).Msg("Failed to reload test server config after file deletion")
				}
			}
			time.Sleep(1 * time.Second)
			continue
		}

		fileExists = true

		// Get file modification time
		fileInfo, err := os.Stat(testConfigPath)
		if err != nil {
			time.Sleep(1 * time.Second)
			continue
		}

		// If file has changed, reload config
		if !fileInfo.ModTime().Equal(lastModTime) {
			lastModTime = fileInfo.ModTime()
			log.Debug().Str("file", testConfigPath).Msg("Test config file changed, reloading server")

			// Reload server configuration
			if err := s.ReloadConfig(); err != nil {
				log.Warn().Err(err).Msg("Failed to reload test server config")
			}
		}

		time.Sleep(1 * time.Second)
	}
}

// ReloadConfig reloads the server configuration by restarting the server
func (s *Server) ReloadConfig() error {
	log.Debug().Msg("Reloading test server configuration")

	// Stop current server
	if s.httpServer != nil {
		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
		defer cancel()
		if err := s.httpServer.Shutdown(ctx); err != nil {
			log.Warn().Err(err).Msg("Failed to shutdown server for reload")
			return err
		}
	}

	// Recreate server with new config
	cfg := createTestConfig(s.port)
	realServer := server.NewServer(cfg, context.Background())
	s.httpServer = &http.Server{
		Addr:    fmt.Sprintf(":%d", s.port),
		Handler: realServer.Router(),
	}

	// Start server in background
	go func() {
		if err := s.httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			if err != http.ErrServerClosed {
				log.Error().Err(err).Msg("Test server failed after reload")
			}
		}
	}()

	// Wait for server to be ready again
	return s.waitForServerReady()
}

// initDBConnection initializes a direct database connection for cleanup operations
func (s *Server) initDBConnection() error {
	cfg := createTestConfig(s.port)
	dsn := fmt.Sprintf(
		"host=%s port=%d user=%s password=%s dbname=%s sslmode=%s",
		cfg.Database.Host,
		cfg.Database.Port,
		cfg.Database.User,
		cfg.Database.Password,
		cfg.Database.Name,
		cfg.Database.SSLMode,
	)

	var err error
	s.db, err = sql.Open("postgres", dsn)
	if err != nil {
		return fmt.Errorf("failed to open database connection: %w", err)
	}

	// Test the connection
	if err := s.db.Ping(); err != nil {
		return fmt.Errorf("failed to ping database: %w", err)
	}

	return nil
}

// CleanupDatabase deletes all test data from all tables
// This uses raw SQL to avoid dependency on repositories and handles foreign keys properly
// Uses SET CONSTRAINTS ALL DEFERRED to temporarily disable foreign key checks
func (s *Server) CleanupDatabase() error {
	if s.db == nil {
		log.Debug().Msg("No database connection, skipping cleanup")
		return nil // No database connection, skip cleanup
	}

	// Start a transaction for atomic cleanup
	tx, err := s.db.Begin()
	if err != nil {
		return fmt.Errorf("failed to start cleanup transaction: %w", err)
	}
	// Ensure transaction is rolled back if cleanup fails
	defer func() {
		if err != nil {
			tx.Rollback()
		}
	}()

	// Disable foreign key constraints temporarily
	// This is valid PostgreSQL syntax: https://www.postgresql.org/docs/current/sql-set-constraints.html
	if _, err := tx.Exec("SET CONSTRAINTS ALL DEFERRED"); err != nil {
		log.Warn().Err(err).Msg("Failed to set constraints deferred, continuing cleanup")
		// Continue anyway, some constraints might still work
	}

	// Get all tables in the database
	rows, err := tx.Query(`
		SELECT table_name 
		FROM information_schema.tables 
		WHERE table_schema = 'public' 
		AND table_type = 'BASE TABLE'
	`)
	if err != nil {
		return fmt.Errorf("failed to query tables: %w", err)
	}
	// Ensure rows are closed
	defer func() {
		if rows != nil {
			rows.Close()
		}
	}()

	// Collect all tables
	var tables []string
	for rows.Next() {
		var tableName string
		if err := rows.Scan(&tableName); err != nil {
			log.Warn().Err(err).Str("table", tableName).Msg("Failed to scan table name")
			continue
		}
		// Skip system tables and internal tables
		if strings.HasPrefix(tableName, "pg_") ||
			strings.HasPrefix(tableName, "sql_") ||
			tableName == "spatial_ref_sys" ||
			tableName == "goose_db_version" {
			continue
		}
		tables = append(tables, tableName)
	}

	// Check for errors during table scanning
	if err = rows.Err(); err != nil {
		return fmt.Errorf("error during table scanning: %w", err)
	}

	// Delete from tables in reverse order to handle foreign keys
	// This works better when constraints are deferred
	for i := len(tables) - 1; i >= 0; i-- {
		table := tables[i]
		query := fmt.Sprintf("DELETE FROM %s", table)
		if _, err := tx.Exec(query); err != nil {
			log.Warn().Err(err).Str("table", table).Msg("Failed to cleanup table")
			// Continue with other tables even if one fails
			continue
		}
		log.Debug().Str("table", table).Msg("Cleaned up table")
	}

	// Reset sequence counters for all tables
	for _, table := range tables {
		// Try the common pattern first: table_id_seq
		query := fmt.Sprintf("ALTER SEQUENCE IF EXISTS %s_id_seq RESTART WITH 1", table)
		if _, err := tx.Exec(query); err != nil {
			// Try alternative sequence naming patterns
			altQueries := []string{
				fmt.Sprintf("ALTER SEQUENCE IF EXISTS %s_seq RESTART WITH 1", table),
				fmt.Sprintf("ALTER SEQUENCE IF EXISTS %s RESTART WITH 1", table),
			}
			for _, altQuery := range altQueries {
				if _, err := tx.Exec(altQuery); err == nil {
					break
				}
			}
		}
	}

	// Commit the transaction
	if err := tx.Commit(); err != nil {
		return fmt.Errorf("failed to commit cleanup transaction: %w", err)
	}

	log.Debug().Msg("Database cleanup completed successfully")
	return nil
}

// CloseDatabase closes the database connection
func (s *Server) CloseDatabase() error {
	if s.db != nil {
		return s.db.Close()
	}
	return nil
}

func (s *Server) waitForServerReady() error {
	maxAttempts := 30
	attempt := 0

	for attempt < maxAttempts {
		resp, err := http.Get(fmt.Sprintf("%s/api/ready", s.baseURL))
		if err == nil && resp.StatusCode == http.StatusOK {
			resp.Body.Close()
			return nil
		}
		if resp != nil {
			resp.Body.Close()
		}
		attempt++
		time.Sleep(100 * time.Millisecond)
	}

	return fmt.Errorf("server did not become ready after %d attempts", maxAttempts)
}

func (s *Server) Stop() error {
	if s.httpServer == nil {
		return nil
	}

	// Shutdown HTTP server gracefully
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	return s.httpServer.Shutdown(ctx)
}

func (s *Server) GetBaseURL() string {
	return s.baseURL
}

func createTestConfig(port int) *config.Config {
	// Check if there's a test config file (used by config hot reloading tests)
	// If it exists, use it. Otherwise, use default config.
	testConfigPath := "test-config.yaml"
	if _, err := os.Stat(testConfigPath); err == nil {
		// Test config file exists, use it
		v := viper.New()
		v.SetConfigFile(testConfigPath)
		v.SetConfigType("yaml")

		// Read the test config file
		if err := v.ReadInConfig(); err == nil {
			var cfg config.Config
			if err := v.Unmarshal(&cfg); err == nil {
				// Override server port for testing
				cfg.Server.Port = port

				// Set default auth values if not configured
				if cfg.Auth.JWTSecret == "" {
					cfg.Auth.JWTSecret = "default-secret-key-please-change-in-production"
				}
				if cfg.Auth.AdminMasterPassword == "" {
					cfg.Auth.AdminMasterPassword = "admin123"
				}

				return &cfg
			}
		}
	}

	// No test config file, use default config
	cfg, err := config.LoadConfig()
	if err != nil {
		log.Warn().Err(err).Msg("Failed to load config, using defaults")
		// Fallback to defaults if config loading fails
		return &config.Config{
			Server: config.ServerConfig{
				Host: "localhost",
				Port: port,
			},
			Shutdown: config.ShutdownConfig{
				Timeout: 5 * time.Second,
			},
			Logging: config.LoggingConfig{
				JSON:  false,
				Level: "trace",
			},
			Telemetry: config.TelemetryConfig{
				Enabled: false,
			},
			API: config.APIConfig{
				V2Enabled: true, // Enable v2 by default for most tests
			},
			Auth: config.AuthConfig{
				JWTSecret:           "default-secret-key-please-change-in-production",
				AdminMasterPassword: "admin123",
			},
			Database: config.DatabaseConfig{
				Host:            "localhost", // Fallback if env vars not set
				Port:            5432,
				User:            "postgres",
				Password:        "postgres",
				Name:            "dance_lessons_coach_bdd_test", // Separate BDD test database
				SSLMode:         "disable",
				MaxOpenConns:    10,
				MaxIdleConns:    5,
				ConnMaxLifetime: time.Hour,
			},
		}
	}

	// Override server port for testing
	cfg.Server.Port = port

	// Set default auth values if not configured
	if cfg.Auth.JWTSecret == "" {
		cfg.Auth.JWTSecret = "default-secret-key-please-change-in-production"
	}
	if cfg.Auth.AdminMasterPassword == "" {
		cfg.Auth.AdminMasterPassword = "admin123"
	}

	return cfg
}