package main

import (
	"context"
	"log"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"syscall"
	"time"

	"github.com/alexei/docker-watcher/internal/api"
	"github.com/alexei/docker-watcher/internal/config"
	"github.com/alexei/docker-watcher/internal/crypto"
	"github.com/alexei/docker-watcher/internal/deployer"
	"github.com/alexei/docker-watcher/internal/docker"
	"github.com/alexei/docker-watcher/internal/health"
	"github.com/alexei/docker-watcher/internal/notify"
	"github.com/alexei/docker-watcher/internal/npm"
	"github.com/alexei/docker-watcher/internal/registry"
	"github.com/alexei/docker-watcher/internal/store"
	"github.com/alexei/docker-watcher/internal/webhook"
)

func main() {
	dataDir := envOrDefault("DATA_DIR", "./data")

	if err := os.MkdirAll(dataDir, 0o755); err != nil {
		log.Fatalf("create data directory: %v", err)
	}

	// Open database.
	dbPath := filepath.Join(dataDir, "docker-watcher.db")
	db, err := store.New(dbPath)
	if err != nil {
		log.Fatalf("open store: %v", err)
	}
	defer db.Close()

	// Import seed config on first launch (idempotent).
	seedPath := envOrDefault("SEED_FILE", "./docker-watcher.yaml")
	if err := config.ImportSeed(db, seedPath); err != nil {
		log.Fatalf("seed import: %v", err)
	}

	// Derive encryption key from environment.
	encKey, err := crypto.KeyFromEnv()
	if err != nil {
		log.Printf("WARNING: %v — encrypted fields will not work", err)
		encKey = crypto.DeriveKey("docker-watcher-default-key")
	}

	// Initialize Docker client.
	dockerClient, err := docker.New()
	if err != nil {
		log.Fatalf("create docker client: %v", err)
	}
	defer dockerClient.Close()

	// Read settings for NPM URL and polling interval.
	settings, err := db.GetSettings()
	if err != nil {
		log.Fatalf("get settings: %v", err)
	}

	// Initialize NPM client.
	npmURL := envOrDefault("NPM_URL", settings.NpmURL)
	npmClient := npm.New(npmURL)

	// Initialize services.
	healthChecker := health.New()
	notifier := notify.New()

	dep := deployer.New(dockerClient, npmClient, db, healthChecker, notifier, encKey)

	// Initialize webhook handler.
	webhookHandler := webhook.NewHandler(db, dep, dockerClient)

	// Ensure webhook secret exists.
	secret, err := webhook.EnsureWebhookSecret(db)
	if err != nil {
		log.Fatalf("ensure webhook secret: %v", err)
	}
	log.Printf("Webhook secret: %s", secret)

	// Initialize registry poller.
	poller := registry.NewPoller(db, dep, encKey)
	pollingInterval := envOrDefault("POLLING_INTERVAL", settings.PollingInterval)
	if pollingInterval != "" {
		if err := poller.Start(pollingInterval); err != nil {
			log.Printf("WARNING: failed to start poller: %v", err)
		}
	}

	// Build API server.
	apiServer := api.NewServer(db, dockerClient, dep, webhookHandler, encKey)
	router := apiServer.Router()

	// Start HTTP server.
	addr := envOrDefault("LISTEN_ADDR", ":8080")
	httpServer := &http.Server{
		Addr:         addr,
		Handler:      router,
		ReadTimeout:  30 * time.Second,
		WriteTimeout: 60 * time.Second,
		IdleTimeout:  120 * time.Second,
	}

	// Graceful shutdown.
	done := make(chan os.Signal, 1)
	signal.Notify(done, os.Interrupt, syscall.SIGTERM)

	go func() {
		log.Printf("Docker Watcher started. Listening on %s", addr)
		if err := httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatalf("HTTP server error: %v", err)
		}
	}()

	<-done
	log.Println("Shutting down...")

	poller.Stop()

	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	if err := httpServer.Shutdown(ctx); err != nil {
		log.Printf("HTTP server shutdown error: %v", err)
	}

	log.Println("Docker Watcher stopped.")
}

// envOrDefault reads an environment variable or returns the fallback value.
func envOrDefault(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}