// NextNVR v0.1.0 — Main entry point
// Lightweight NVR application for recording and monitoring IP cameras.
package main

import (
	"fmt"
	"log"
	"os"
	"os/signal"
	"syscall"
)

var (
	// Version is set at build time via ldflags.
	Version = "0.1.0"

	// BuildTime is set at build time via ldflags.
	BuildTime = "unknown"
)

func main() {
	log.SetFlags(log.LstdFlags | log.Lshortfile)
	log.Printf("NextNVR v%s (built %s)", Version, BuildTime)

	// Parse command-line flags.
	configPath := flagConfigPath()

	// Load or create configuration.
	cfg, err := LoadConfig(configPath)
	if err != nil {
		log.Printf("No existing config found at %s — starting in setup mode", configPath)
		cfg = DefaultConfig()
		// Don't auto-save; wait for the user to complete setup via the web UI.
	}

	log.Printf("Server: %s", cfg.Server.Port)
	log.Printf("Storage: %s (retention: %d days)", cfg.Storage.RecordingsPath, cfg.Storage.RetentionDays)
	log.Printf("Cameras configured: %d", len(cfg.Cameras))

	if cfg.Go2RTC.Enabled {
		log.Printf("go2rtc: enabled on port %s (binary: %s)", cfg.Go2RTC.Port, cfg.Go2RTC.Binary)
	}

	// Signal handling for graceful shutdown.
	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)

	// Initialize application.
	app := &App{Config: cfg, ConfigPath: configPath}

	// Start go2rtc if enabled.
	if cfg.Go2RTC.Enabled {
		go2rtc := NewGo2RTCManager(cfg.Go2RTC)
		if err := go2rtc.Start(cfg.Cameras); err != nil {
			log.Printf("go2rtc: start failed: %v", err)
		}
		app.go2rtc = go2rtc
	}

	// Start snapshot engine for all enabled cameras.
	snaps := NewSnapshotEngine(cfg.Storage)
	snaps.StartAll(cfg.Cameras)
	app.snapshots = snaps

	// Start the HTTP server (blocks).
	errCh := make(chan error, 1)
	go func() {
		errCh <- app.StartServer()
	}()

	select {
	case sig := <-sigCh:
		log.Printf("Received signal: %v — shutting down", sig)
	case err := <-errCh:
		if err != nil {
			log.Printf("Server error: %v", err)
		}
	}

	app.Shutdown()
	log.Println("NextNVR stopped.")
}

// flagConfigPath resolves the config file path from CLI flags.
func flagConfigPath() string {
	// Look for --config flag in os.Args.
	for i, arg := range os.Args[1:] {
		if arg == "--config" && i+1 < len(os.Args[1:]) {
			return os.Args[i+2] // +2 because Args[0] is binary name, Args[1:] starts at index 1
		}
		if len(arg) > 9 && arg[:9] == "--config=" {
			return arg[9:]
		}
	}

	// Default: look next to the binary, then /opt/nextnvr.
	if _, err := os.Stat("config.yaml"); err == nil {
		return "config.yaml"
	}
	if _, err := os.Stat("/opt/nextnvr/config.yaml"); err == nil {
		return "/opt/nextnvr/config.yaml"
	}
	return "config.yaml"
}

// App holds the application runtime state.
type App struct {
	Config     Config
	ConfigPath string
	server     *Server
	go2rtc     *Go2RTCManager
	snapshots  *SnapshotEngine
}

// StartServer initializes and starts the HTTP server.
func (a *App) StartServer() error {
	srv, err := NewServer(a.Config)
	if err != nil {
		return fmt.Errorf("creating server: %w", err)
	}
	a.server = srv
	return srv.ListenAndServe()
}

// Shutdown performs a graceful shutdown of all services.
func (a *App) Shutdown() {
	if a.snapshots != nil {
		a.snapshots.StopAll()
	}
	if a.go2rtc != nil {
		a.go2rtc.Stop()
	}
	if a.server != nil {
		a.server.Close()
	}
}