package main

import (
	"context"
	"embed"
	"flag"
	"fmt"
	"io/fs"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
	"github.com/seu-usuario/go-react-web-tail/internal/broker"
	"github.com/seu-usuario/go-react-web-tail/internal/config"
	"github.com/seu-usuario/go-react-web-tail/internal/handlers"
	"github.com/seu-usuario/go-react-web-tail/internal/middleware"
	"github.com/seu-usuario/go-react-web-tail/internal/tail"
)

//go:embed dist
var staticFiles embed.FS

var version = "2.0.0"

func main() {
	if err := run(); err != nil {
		log.Fatal().Err(err).Msg("Application failed")
	}
}

func run() error {
	// Carregar configuração
	cfg, err := config.Load()
	if err != nil {
		return fmt.Errorf("failed to load config: %w", err)
	}

	// Configurar logging
	setupLogging(cfg.Logging)

	log.Info().
		Str("version", version).
		Str("port", cfg.Server.Port).
		Bool("auth_enabled", cfg.Auth.Enabled).
		Bool("tls_enabled", cfg.Server.TLSEnabled).
		Bool("rate_limit_enabled", cfg.Security.RateLimitEnabled).
		Msg("Starting Web Tail Pro")

	// Obter arquivos de log dos argumentos
	logFiles := flag.Args()
	if len(logFiles) < 1 {
		fmt.Println("Uso: web-tail-pro [opções] <arquivo1.log> <arquivo2.log> ...")
		fmt.Println("\nOpções:")
		flag.PrintDefaults()
		fmt.Println("\nVariáveis de Ambiente:")
		fmt.Println("  PORT              - Porta do servidor (padrão: :8080)")
		fmt.Println("  USERNAME          - Nome de usuário (padrão: admin)")
		fmt.Println("  PASSWORD          - Senha de autenticação")
		fmt.Println("  LOG_LEVEL         - Nível de log: debug, info, warn, error (padrão: info)")
		fmt.Println("  LOG_FORMAT        - Formato: json, console (padrão: console)")
		fmt.Println("  RATE_LIMIT_ENABLED - Habilitar rate limiting (padrão: true)")
		fmt.Println("  RATE_LIMIT_RPS    - Requisições por segundo (padrão: 100)")
		fmt.Println("  CORS_ORIGINS      - Origens CORS permitidas, separadas por vírgula")
		fmt.Println("  TLS_ENABLED       - Habilitar TLS (padrão: false)")
		fmt.Println("  TLS_CERT_FILE     - Arquivo de certificado TLS")
		fmt.Println("  TLS_KEY_FILE      - Arquivo de chave TLS")
		os.Exit(1)
	}

	// Criar context para graceful shutdown
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Inicializar broker
	brk := broker.New(ctx)

	// Inicializar tailer
	tailer := tail.New(ctx, logFiles, brk.Broadcast)
	if err := tailer.Start(); err != nil {
		return fmt.Errorf("failed to start tailer: %w", err)
	}

	// Configurar servidor HTTP
	server, err := setupServer(cfg, brk, logFiles)
	if err != nil {
		return fmt.Errorf("failed to setup server: %w", err)
	}

	// Iniciar servidor em goroutine
	serverErrors := make(chan error, 1)
	go func() {
		log.Info().Str("address", cfg.Server.Port).Msg("HTTP server listening")

		if cfg.Server.TLSEnabled {
			serverErrors <- server.ListenAndServeTLS(cfg.Server.TLSCertFile, cfg.Server.TLSKeyFile)
		} else {
			serverErrors <- server.ListenAndServe()
		}
	}()

	// Aguardar sinal de shutdown
	shutdown := make(chan os.Signal, 1)
	signal.Notify(shutdown, syscall.SIGINT, syscall.SIGTERM)

	select {
	case err := <-serverErrors:
		return fmt.Errorf("server error: %w", err)

	case sig := <-shutdown:
		log.Info().Str("signal", sig.String()).Msg("Shutdown signal received")

		// Graceful shutdown
		shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), cfg.Server.ShutdownTimeout)
		defer shutdownCancel()

		log.Info().Msg("Shutting down HTTP server...")
		if err := server.Shutdown(shutdownCtx); err != nil {
			log.Error().Err(err).Msg("HTTP server shutdown error")
		}

		log.Info().Msg("Stopping tailer...")
		if err := tailer.Shutdown(); err != nil {
			log.Error().Err(err).Msg("Tailer shutdown error")
		}

		log.Info().Msg("Stopping broker...")
		brk.Shutdown()

		log.Info().Msg("Shutdown complete")
	}

	return nil
}

func setupLogging(cfg config.LoggingConfig) {
	// Configurar nível de log
	level, err := zerolog.ParseLevel(cfg.Level)
	if err != nil {
		level = zerolog.InfoLevel
	}
	zerolog.SetGlobalLevel(level)

	// Configurar formato
	if cfg.Format == "console" {
		log.Logger = log.Output(zerolog.ConsoleWriter{
			Out:        os.Stderr,
			TimeFormat: time.RFC3339,
		})
	}
}

func setupServer(cfg *config.Config, brk *broker.Broker, logFiles []string) (*http.Server, error) {
	// Configurar handlers
	h := handlers.New(brk, logFiles)

	// Configurar arquivos estáticos
	distFS, err := fs.Sub(staticFiles, "dist")
	if err != nil {
		return nil, fmt.Errorf("failed to create sub-filesystem: %w", err)
	}

	// Configurar rotas
	mux := http.NewServeMux()
	mux.Handle("/", http.FileServer(http.FS(distFS)))
	mux.HandleFunc("/logs", h.HandleSSE)
	mux.HandleFunc("/api/files", h.HandleFiles)
	mux.HandleFunc("/api/last", h.HandleLastLines)
	mux.HandleFunc("/health", h.HandleHealth)
	mux.HandleFunc("/metrics", h.HandleMetrics)

	// Aplicar cadeia de middleware
	var handler http.Handler = mux

	// Security headers
	handler = middleware.SecurityHeadersMiddleware(handler)

	// CORS
	corsMiddleware := middleware.NewCORSMiddleware(cfg.Security.CORSOrigins)
	handler = corsMiddleware.Handler(handler)

	// Rate limiting
	if cfg.Security.RateLimitEnabled {
		rateLimitMiddleware := middleware.NewRateLimitMiddleware(cfg.Security.RateLimitRPS)
		handler = rateLimitMiddleware.Handler(handler)
		log.Info().Int("rps", cfg.Security.RateLimitRPS).Msg("Rate limiting enabled")
	}

	// Authentication
	authMiddleware := middleware.NewAuthMiddleware(cfg.Auth.Enabled, cfg.Auth.Username, cfg.Auth.Password)
	handler = authMiddleware.Handler(handler)

	// Logging
	handler = middleware.LoggingMiddleware(handler)

	// Criar servidor
	server := &http.Server{
		Addr:         cfg.Server.Port,
		Handler:      handler,
		ReadTimeout:  cfg.Server.ReadTimeout,
		WriteTimeout: cfg.Server.WriteTimeout,
	}

	return server, nil
}