package main

import (
	"context"
	"encoding/json"
	"errors"
	"log/slog"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/redis/go-redis/v9"

	"github.com/alchemistkay/guestguard/internal/api"
	"github.com/alchemistkay/guestguard/internal/auth"
	"github.com/alchemistkay/guestguard/internal/billing"
	"github.com/alchemistkay/guestguard/internal/config"
	"github.com/alchemistkay/guestguard/internal/fraud"
	"github.com/alchemistkay/guestguard/internal/natspub"
	"github.com/alchemistkay/guestguard/internal/notification"
	"github.com/alchemistkay/guestguard/internal/storage"
)

func main() {
	if err := run(); err != nil {
		slog.Error("fatal", "err", err)
		os.Exit(1)
	}
}

func run() error {
	cfg, err := config.Load()
	if err != nil {
		return err
	}

	logger := newLogger(cfg.Env)
	slog.SetDefault(logger)

	rootCtx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer stop()

	logger.Info("connecting to database")
	db, err := storage.NewDB(rootCtx, cfg.DatabaseURL)
	if err != nil {
		return err
	}
	defer db.Close()

	logger.Info("running migrations")
	if err := db.Migrate(rootCtx); err != nil {
		return err
	}

	logger.Info("connecting to nats", "url", cfg.NATSURL)
	natsClient, err := natspub.Connect(rootCtx, cfg.NATSURL, logger)
	if err != nil {
		return err
	}
	defer natsClient.Close()

	logger.Info("connecting to redis", "addr", cfg.RedisAddr)
	rdb := redis.NewClient(&redis.Options{Addr: cfg.RedisAddr})
	if err := rdb.Ping(rootCtx).Err(); err != nil {
		logger.Warn("redis ping failed — rate limits + lockout disabled", "err", err)
		_ = rdb.Close()
		rdb = nil
	} else {
		defer rdb.Close()
	}

	logger.Info("dialing fraud engine", "addr", cfg.FraudGRPCAddr)
	fraudClient, err := fraud.Dial(rootCtx, cfg.FraudGRPCAddr, cfg.FraudGRPCTimeout, logger)
	if err != nil {
		return err
	}
	defer fraudClient.Close()

	hub := api.NewHub(logger)

	accessLogs := storage.NewAccessLogRepo(db)
	fraudSub, err := natspub.NewFraudScoredSubscriber(
		rootCtx, natsClient, "core-api-fraud-scored",
		func(ctx context.Context, evt natspub.FraudScored) error {
			if err := accessLogs.ApplyScore(ctx, storage.ApplyScoreParams{
				AccessLogID: evt.AccessLogID,
				Score:       evt.Score,
				Reasons:     evt.Reasons,
				Flagged:     evt.Score >= 60,
			}); err != nil {
				return err
			}
			payload, _ := json.Marshal(evt)
			hub.Broadcast(api.WSEvent{
				Type:    "fraud.scored",
				EventID: evt.EventID,
				Payload: payload,
			})
			return nil
		},
		logger,
	)
	if err != nil {
		return err
	}
	fraudConsumeCtx, err := fraudSub.Start(rootCtx)
	if err != nil {
		return err
	}
	defer fraudConsumeCtx.Stop()

	rsvpSub, err := natspub.NewRSVPConfirmedSubscriber(
		rootCtx, natsClient, "core-api-rsvp-confirmed-ws",
		func(ctx context.Context, evt natspub.RSVPConfirmed) error {
			payload, _ := json.Marshal(evt)
			hub.Broadcast(api.WSEvent{
				Type:    "rsvp.confirmed",
				EventID: evt.EventID,
				Payload: payload,
			})
			return nil
		},
		logger,
	)
	if err != nil {
		return err
	}
	rsvpConsumeCtx, err := rsvpSub.Start(rootCtx)
	if err != nil {
		return err
	}
	defer rsvpConsumeCtx.Stop()

	// Notification senders. If SES creds are configured, route auth +
	// guest emails through SES. Otherwise the log stub keeps the dev flow
	// (verification link in API logs) intact.
	tpls, err := notification.NewTemplates()
	if err != nil {
		return err
	}
	suppressions := notification.NewSuppressionRepo(db)
	notifRepo := notification.NewRepo(db)
	unsubSigner := notification.NewUnsubscribeSigner(cfg.UnsubscribeSecret)

	emailSenderCombined, backend, err := notification.PickEmailSender(rootCtx, notification.EmailSenderConfig{
		Resend: notification.ResendConfig{
			APIKey:    cfg.ResendAPIKey,
			FromEmail: cfg.ResendFromEmail,
			FromName:  cfg.ResendFromName,
		},
		SMTP: notification.SMTPConfig{
			Host:      cfg.SMTPHost,
			Port:      cfg.SMTPPort,
			Username:  cfg.SMTPUsername,
			Password:  cfg.SMTPPassword,
			FromEmail: cfg.SMTPFromEmail,
			FromName:  cfg.SMTPFromName,
			TLS:       cfg.SMTPTLS,
		},
		SES: notification.SESConfig{
			Region:           cfg.SESRegion,
			FromEmail:        cfg.SESFromEmail,
			FromName:         cfg.SESFromName,
			ConfigurationSet: cfg.SESConfigurationSet,
			PublicBaseURL:    cfg.PublicBaseURL,
		},
	}, tpls, logger)
	if err != nil {
		return err
	}
	logger.Info("email backend selected", "backend", backend)
	var emailSender auth.EmailSender = emailSenderCombined

	stripeClient, err := billing.NewClient(billing.Config{
		SecretKey:       cfg.StripeSecretKey,
		WebhookSecret:   cfg.StripeWebhookSecret,
		PriceProMonthly: cfg.StripePricePro,
		PriceBusiness:   cfg.StripePriceBusiness,
	})
	if err != nil {
		return err
	}
	if stripeClient != nil && stripeClient.Enabled() {
		logger.Info("billing enabled via stripe")
	} else {
		logger.Info("billing disabled — free tier limits apply to all users")
	}

	apiSrv, err := api.NewServer(api.ServerDeps{
		Logger:               logger,
		DB:                   db,
		Hub:                  hub,
		AccessPublisher:      natsClient,
		RSVPPublisher:        natsClient,
		InvitationPublisher:  natsClient,
		FraudScorer:          fraudClient,
		TokenTTL:             cfg.TokenTTL,
		JWTSecret:            cfg.JWTSecret,
		JWTIssuer:            cfg.JWTIssuer,
		AccessTokenTTL:       cfg.AccessTokenTTL,
		RefreshTokenTTL:      cfg.RefreshTokenTTL,
		EmailVerificationTTL: cfg.EmailVerificationTTL,
		PasswordResetTTL:     cfg.PasswordResetTTL,
		PublicBaseURL:        cfg.PublicBaseURL,
		RefreshCookieDomain:  cfg.RefreshCookieDomain,
		RefreshCookieSecure:  cfg.RefreshCookieSecure,
		Redis:                rdb,
		EmailSender:          emailSender,
		NotificationRepo:     notifRepo,
		SuppressionRepo:      suppressions,
		UnsubscribeSigner:    unsubSigner,
		StripeClient:         stripeClient,
	})
	if err != nil {
		return err
	}

	srv := &http.Server{
		Addr:              cfg.HTTPAddr,
		Handler:           apiSrv.Handler(),
		ReadHeaderTimeout: 5 * time.Second,
		ReadTimeout:       30 * time.Second,
		WriteTimeout:      0, // 0 lets WS connections live; per-request handlers still bound by their own ctx
		IdleTimeout:       60 * time.Second,
	}

	errCh := make(chan error, 1)
	go func() {
		logger.Info("http server starting", "addr", cfg.HTTPAddr, "env", cfg.Env)
		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			errCh <- err
		}
		close(errCh)
	}()

	select {
	case <-rootCtx.Done():
		logger.Info("shutdown signal received")
	case err := <-errCh:
		if err != nil {
			return err
		}
	}

	shutdownCtx, cancel := context.WithTimeout(context.Background(), cfg.ShutdownTimeout)
	defer cancel()
	if err := srv.Shutdown(shutdownCtx); err != nil {
		logger.Error("graceful shutdown failed", "err", err)
		return err
	}
	logger.Info("shutdown complete")
	return nil
}

func newLogger(env string) *slog.Logger {
	level := slog.LevelInfo
	if env == "development" {
		level = slog.LevelDebug
	}
	return slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: level}))
}