// Package main 是 notification service 的入口程序。
//
// 设计要点（参考 socialService/main.go 的结构）：
//   - 通过 flag + 环境变量注入运行参数（端口、DB 等）。
//   - 启动顺序：logger -> DB -> AutoMigrate -> service -> provider -> Dubbo server。
//   - 使用 Dubbo Triple 协议暴露 notification.proto 中的 NotificationService。
//   - 优雅关闭：监听 SIGINT/SIGTERM，关停 health server 与 DB 连接。
package main

import (
	"flag"
	"fmt"
	"os"
	"os/signal"
	"strconv"
	"syscall"

	"dubbo.apache.org/dubbo-go/v3/protocol"
	"dubbo.apache.org/dubbo-go/v3/server"

	_ "dubbo.apache.org/dubbo-go/v3/imports"

	"github.com/topfans/backend/pkg/database"
	"github.com/topfans/backend/pkg/health"
	"github.com/topfans/backend/pkg/logger"
	notifPb "github.com/topfans/backend/pkg/proto/notification"
	"github.com/topfans/backend/services/notificationService/model"
	"github.com/topfans/backend/services/notificationService/provider"
	"github.com/topfans/backend/services/notificationService/service"
)

var (
	port        = flag.Int("port", getEnvInt("PORT", 20010), "Dubbo service port")
	dbHost      = flag.String("db-host", getEnv("DB_HOST", "localhost"), "Database host")
	dbPort      = flag.Int("db-port", getEnvInt("DB_PORT", 5432), "Database port")
	dbUser      = flag.String("db-user", getEnv("DB_USER", "postgres"), "Database user")
	dbPassword  = flag.String("db-password", getEnv("DB_PASSWORD", ""), "Database password")
	dbName      = flag.String("db-name", getEnv("DB_NAME", "top-fans"), "Database name")
	healthHndl  *health.Handler
)

func getEnv(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}

func getEnvInt(key string, fallback int) int {
	if v := os.Getenv(key); v != "" {
		if n, err := strconv.Atoi(v); err == nil {
			return n
		}
	}
	return fallback
}

func main() {
	flag.Parse()

	// 1) 初始化日志（必须在最前面，便于后续捕获启动错误）
	env := os.Getenv("ENV")
	if env == "" {
		env = "development"
	}

	if err := logger.Init(logger.Config{
		ServiceName: "notification-service",
		Environment: env,
		LogLevel:    os.Getenv("LOG_LEVEL"),
	}); err != nil {
		panic(fmt.Sprintf("Failed to initialize logger: %v", err))
	}
	defer logger.Sync()

	logger.Sugar.Info("Starting Notification Service...")

	// 2) 初始化数据库
	if err := initDatabase(); err != nil {
		logger.Sugar.Fatalf("Failed to initialize database: %v", err)
	}

	// 3) 自动迁移数据库表（notification + notification_stats）
	if err := autoMigrate(); err != nil {
		logger.Sugar.Fatalf("Failed to migrate database: %v", err)
	}

	// 4) 启动 Dubbo server + 注册 NotificationService
	if err := initDubboService(); err != nil {
		logger.Sugar.Fatalf("Failed to initialize Dubbo service: %v", err)
	}

	// 5) 等待退出信号（优雅关闭）
	logger.Sugar.Info("Notification service started successfully. Press Ctrl+C to exit.")
	gracefulShutdown()
}

// initDatabase 初始化数据库连接（复用 socialService 的写法）。
func initDatabase() error {
	config := database.Config{
		Host:     *dbHost,
		Port:     *dbPort,
		User:     *dbUser,
		Password: *dbPassword,
		DBName:   *dbName,
		SSLMode:  "disable",
		TimeZone: "Asia/Shanghai",
	}

	return database.Init(config)
}

// autoMigrate 自动迁移 notification 相关表。
func autoMigrate() error {
	db := database.GetDB()
	if db == nil {
		return fmt.Errorf("database is not initialized")
	}

	tables := []interface{}{
		&model.Notification{},
		&model.NotificationStats{},
	}

	for _, table := range tables {
		if err := db.AutoMigrate(table); err != nil {
			return fmt.Errorf("failed to migrate table: %w", err)
		}
	}

	logger.Sugar.Info("Database migration completed successfully")
	return nil
}

// gracefulShutdown 优雅关闭（health server + DB）。
func gracefulShutdown() {
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit

	logger.Sugar.Info("Shutting down server...")

	if healthHndl != nil {
		healthHndl.Stop()
	}

	if err := database.Close(); err != nil {
		logger.Sugar.Errorf("Error closing database: %v", err)
	}

	logger.Sugar.Info("Server exited")
}

// initDubboService 初始化 Dubbo-go 服务。
//
// 启动健康检查 HTTP server（端口 = dubbo port + 1000，例如 21010），
// 然后构造 service / provider，注册到 Triple 协议的 Dubbo server。
func initDubboService() error {
	// 健康检查 HTTP server
	healthPort := *port + 1000 // e.g., 20010 -> 21010
	healthHndl = health.NewHandler("notification-service", healthPort)
	healthHndl.Start()

	db := database.GetDB()
	if db == nil {
		return fmt.Errorf("database is not initialized")
	}

	// 业务层（service 只依赖 DB；repository 内部自行 New）
	notifService := service.NewNotificationService(db)

	// RPC Provider
	notifProvider := provider.NewNotificationProvider(notifService)

	// Dubbo Server（Triple 协议）
	srv, err := server.NewServer(
		server.WithServerProtocol(
			protocol.WithPort(*port),
			protocol.WithTriple(),
		),
	)
	if err != nil {
		return fmt.Errorf("failed to create Dubbo server: %w", err)
	}

	// 注册 NotificationServiceHandler（来自 notification.triple.go）
	if err := notifPb.RegisterNotificationServiceHandler(srv, notifProvider); err != nil {
		return fmt.Errorf("failed to register NotificationService handler: %w", err)
	}

	logger.Sugar.Info("Dubbo-go notification provider registered successfully",
		"service", notifPb.NotificationServiceName,
		"port", *port,
	)

	// 后台启动 Dubbo server（阻塞当前 goroutine 时 main 会卡在 srv.Serve 上，
	// 所以放 goroutine 里，由 gracefulShutdown 通过 os.Signal 触发退出）。
	go func() {
		if err := srv.Serve(); err != nil {
			logger.Sugar.Fatalf("Failed to serve Dubbo: %v", err)
		}
	}()

	return nil
}