package main

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

	"github.com/alchemistkay/guestguard/internal/api"
	"github.com/alchemistkay/guestguard/internal/config"
	"github.com/alchemistkay/guestguard/internal/fraud"
	"github.com/alchemistkay/guestguard/internal/natspub"
	"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("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()

	srv := &http.Server{
		Addr: cfg.HTTPAddr,
		Handler: api.NewServer(api.ServerDeps{
			Logger:          logger,
			DB:              db,
			Hub:             hub,
			AccessPublisher: natsClient,
			RSVPPublisher:   natsClient,
			FraudScorer:     fraudClient,
			TokenTTL:        cfg.TokenTTL,
		}).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}))
}