package main

import (
	"bytes"
	"crypto/rand"
	"encoding/hex"
	"flag"
	"fmt"
	"log"
	"os"
	"os/signal"
	"syscall"

	"local/sneedchatbridge/config"
	"local/sneedchatbridge/cookie"
	"local/sneedchatbridge/matrix"
	"local/sneedchatbridge/sneed"
)

func main() {
	// ------------------------------------------------------------
	//                COMMAND-LINE FLAG HANDLING
	// ------------------------------------------------------------
	genReg := flag.Bool("generate-registration", false, "Generate registration.yaml and exit")
	outPath := flag.String("out", "registration.yaml", "Output path for generated registration.yaml")
	flag.Parse()

	// ------------------------------------------------------------
	//                LOAD CONFIG
	// ------------------------------------------------------------
	cfg, err := config.Load(".env")
	if err != nil {
		log.Fatalf("❌ Failed to load configuration: %v", err)
	}

	// If --generate-registration was passed, output registration.yaml and exit.
	if *genReg {
		err := generateRegistrationFile(cfg, *outPath)
		if err != nil {
			log.Fatalf("❌ Failed to generate registration file: %v", err)
		}
		log.Printf("🟢 Registration file written to %s", *outPath)
		return
	}

	// ------------------------------------------------------------
	//          NORMAL BRIDGE STARTUP (APPSERVICE MODE ONLY)
	// ------------------------------------------------------------
	fmt.Println("===============================================")
	fmt.Println("  Matrix Appservice ↔ Sneedchat Bridge")
	fmt.Println("===============================================")

	log.Printf("Using Sneedchat room ID: %d", cfg.SneedchatRoomID)
	log.Printf("Matrix Appservice listen address: %s", cfg.AppserviceListenAddr)
	log.Printf("Ghost MXID domain: %s (prefix=%q)", cfg.MatrixGhostUserDomain, cfg.MatrixGhostUserPrefix)

	// ------------------------------------------------------------
	//                COOKIE REFRESH SERVICE
	// ------------------------------------------------------------
	ck, err := cookie.NewCookieRefreshServiceWithDebug(
		cfg.BridgeUsername,
		cfg.BridgePassword,
		kiwiDomain(),
		cfg.Debug,
	)
	if err != nil {
		log.Fatalf("❌ Cannot create cookie refresh service: %v", err)
	}

	ck.Start()
	ck.WaitForCookie()
	log.Println("🟢 Initial XenForo session cookie acquired.")

	// ------------------------------------------------------------
	//                SNEEDCHAT CLIENT INIT
	// ------------------------------------------------------------
	sneedClient := sneed.NewClient(cfg.SneedchatRoomID, ck)

	// ------------------------------------------------------------
	//                MATRIX BRIDGE INIT (APPSERVICE)
	// ------------------------------------------------------------
	bridge := matrix.NewBridge(cfg, sneedClient)

	// ------------------------------------------------------------
	//                START COMPONENTS
	// ------------------------------------------------------------

	// Start Sneedchat WebSocket client
	if err := sneedClient.Connect(); err != nil {
		log.Fatalf("❌ Sneedchat initial connect failed: %v", err)
	}

	// Start Matrix Appservice HTTP server
	go func() {
		if err := bridge.StartAppserviceServer(cfg); err != nil {
			log.Fatalf("❌ Appservice HTTP server error: %v", err)
		}
	}()

	// ------------------------------------------------------------
	//                WAIT FOR SHUTDOWN SIGNAL
	// ------------------------------------------------------------
	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)

	s := <-sigCh
	log.Printf("🔻 Shutdown signal received: %v", s)

	// ------------------------------------------------------------
	//                SHUT DOWN GRACEFULLY
	// ------------------------------------------------------------
	// If Bridge implements Stop() we call it. (Optional)
	if stopper, ok := interface{}(bridge).(interface{ Stop() }); ok {
		stopper.Stop()
	}

	sneedClient.Disconnect()
	ck.Stop()

	log.Println("🟡 Bridge stopped.")
}

// ------------------------------------------------------------
//                   REGISTRATION GENERATOR
// ------------------------------------------------------------

// generateRegistrationFile writes the appservice registration.yaml
// based on values loaded from .env.
func generateRegistrationFile(cfg *config.Config, outPath string) error {
	template := `id: sneedchat
url: "http://127.0.0.1:29333"
as_token: "%s"
hs_token: "%s"
sender_localpart: "sneedbridge"
rate_limited: false

namespaces:
  users:
    - regex: "^@sneedbridge:%s$"
      exclusive: true
    - regex: "^@.*:%s$"
      exclusive: true
  aliases: []
  rooms: []

push_ephemeral: true
de.sorunome.msc2409.push_ephemeral: true
`

	var buf bytes.Buffer

	hsToken := randomHex(64) // Synapse expects strong token

	buf.WriteString(fmt.Sprintf(
		template,
		cfg.MatrixAppserviceToken,
		hsToken,
		cfg.MatrixGhostUserDomain,
		cfg.MatrixGhostUserDomain,
	))

	return os.WriteFile(outPath, buf.Bytes(), 0600)
}

// randomHex generates a cryptographically random hex token.
func randomHex(n int) string {
	b := make([]byte, n/2)
	_, err := rand.Read(b)
	if err != nil {
		panic(err)
	}
	return hex.EncodeToString(b)
}

// kiwiDomain returns the XenForo/Sneedchat domain name.
func kiwiDomain() string {
	return "kiwifarms.st"
}