package main

import (
	"context"
	"flag"
	"fmt"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"ezops/internal/api/routes"
	"ezops/internal/config"
	"ezops/pkg/database"
	"ezops/pkg/logger"
	ezredis "ezops/pkg/redis"

	"github.com/gin-gonic/gin"
	"github.com/spf13/viper"
	"go.uber.org/zap"
)

// 版本信息（通过编译时 ldflags 注入）// Logan.Li
var (
	Version   = "dev"
	BuildTime = "unknown"
	GitCommit = "unknown"
)

// CLI 参数定义 // Logan.Li
var (
	flagPort        = flag.String("port", "", "服务端口 (默认: 8080)")
	flagConfig      = flag.String("config", "", "配置文件路径 (默认: config.yaml)")
	flagMode        = flag.String("mode", "", "运行模式: development, production, release")
	flagLogLevel    = flag.String("log-level", "", "日志级别: debug, info, warn, error")

	// 数据库参数
	flagDBDriver   = flag.String("db-driver", "", "数据库驱动: sqlite, mysql, postgres (默认: sqlite)")
	flagDBHost     = flag.String("db-host", "", "数据库主机")
	flagDBPort     = flag.Int("db-port", 0, "数据库端口")
	flagDBUser     = flag.String("db-user", "", "数据库用户名")
	flagDBPassword = flag.String("db-password", "", "数据库密码")
	flagDBName     = flag.String("db-name", "", "数据库名 / SQLite 文件路径")
	flagDBCharset  = flag.String("db-charset", "", "数据库字符集")

	// Redis 参数
	flagRedisHost     = flag.String("redis-host", "", "Redis 主机")
	flagRedisPort     = flag.Int("redis-port", 0, "Redis 端口")
	flagRedisPassword = flag.String("redis-password", "", "Redis 密码")
	flagRedisDB       = flag.Int("redis-db", 0, "Redis 数据库编号")

	// JWT 参数
	flagJWTSecret  = flag.String("jwt-secret", "", "JWT 密钥")
	flagJWTExpire  = flag.Int("jwt-expire", 0, "JWT 过期时间 (小时)")

	// 显示版本
	flagVersion = flag.Bool("version", false, "显示版本信息")
)

// @title AIOps运维平台 API
// @version 1.0
// @description AIOps智能运维平台后端API文档
// @termsOfService http://swagger.io/terms/

// @contact.name API Support
// @contact.url http://www.swagger.io/support
// @contact.email support@swagger.io

// @license.name Apache 2.0
// @license.url http://www.apache.org/licenses/LICENSE-2.0.html

// @host localhost:8080
// @BasePath /api/v1

// @securityDefinitions.apikey Bearer
// @in header
// @name Authorization
// @description Type "Bearer" followed by a space and JWT token.

func main() {
	// 解析 CLI 参数 // Logan.Li
	flag.Parse()

	// 显示版本信息 // Logan.Li
	if *flagVersion {
		fmt.Printf("AIOps 智能运维平台\n")
		fmt.Printf("  版本:    %s\n", Version)
		fmt.Printf("  构建:    %s\n", BuildTime)
		fmt.Printf("  提交:    %s\n", GitCommit)
		os.Exit(0)
	}

	// 加载配置 // Logan.Li
	cfg := loadConfig()

	// 初始化日志
	log := logger.New(cfg.LogLevel)
	defer log.Sync()

	log.Info("AIOps 启动中",
		zap.String("version", Version),
		zap.String("mode", cfg.Mode),
		zap.String("port", cfg.Port),
	)

	// 设置Gin模式
	if cfg.Mode == "production" || cfg.Mode == "release" {
		gin.SetMode(gin.ReleaseMode)
	}

	// 初始化数据库
	db, err := database.New(cfg.Database)
	if err != nil {
		log.Fatal("数据库连接失败", zap.Error(err))
	}

	// 自动迁移
	if err := database.AutoMigrate(db); err != nil {
		log.Fatal("数据库迁移失败", zap.Error(err))
	}

	// 初始化种子数据
	seedData(db)

	// 初始化缓存（Redka 内嵌 / Redis 外部）// Logan.Li
	cache, err := ezredis.New(ezredis.Config{
		Driver:   cfg.Redis.Driver, // 从配置读取 driver
		Host:     cfg.Redis.Host,
		Port:     cfg.Redis.Port,
		Password: cfg.Redis.Password,
		DB:       cfg.Redis.DB,
		DataDir:  "data/redka",
	})
	if err != nil {
		log.Warn("缓存初始化失败，继续启动", zap.Error(err))
		cache = nil
	} else {
		log.Info("缓存已就绪", zap.String("driver", cfg.Redis.Driver))
		defer cache.Close()
	}

	// 创建Gin实例
	r := gin.New()

	// 中间件
	r.Use(gin.Recovery())
	r.Use(logger.GinLogger(log))
	r.Use(CORS())

	// 版本信息 API
	r.GET("/version", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{
			"version":    Version,
			"build_time": BuildTime,
			"git_commit": GitCommit,
			"mode":       cfg.Mode,
			"db_driver":  cfg.Database.Driver,
		})
	})

	// 注册路由
	routes.Register(r, db, log, cfg, cache)

	// 前端静态文件服务（go:embed 模式，二进制部署用） // Logan.Li
	setupFrontend(r)

	// 创建HTTP服务器
	srv := &http.Server{
		Addr:    ":" + cfg.Port,
		Handler: r,
	}

	// 优雅关闭
	go func() {
		log.Info("服务已启动", zap.String("addr", srv.Addr))
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatal("服务启动失败", zap.Error(err))
		}
	}()

	// 等待中断信号
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit

	log.Info("正在关闭服务...")

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	if err := srv.Shutdown(ctx); err != nil {
		log.Fatal("强制关闭服务", zap.Error(err))
	}

	log.Info("服务已退出")
}

// loadConfig 加载配置（CLI flags 优先于 config.yaml）// Logan.Li
func loadConfig() *config.Config {
	viper.SetConfigName("config")
	viper.SetConfigType("yaml")
	viper.AddConfigPath("./configs")
	viper.AddConfigPath(".")

	// 如果指定了配置文件路径，使用它 // Logan.Li
	if *flagConfig != "" {
		viper.SetConfigFile(*flagConfig)
	}

	// 默认值（独立二进制模式：SQLite + 无 Redis）// Logan.Li
	viper.SetDefault("mode", "release")
	viper.SetDefault("port", "8080")
	viper.SetDefault("log_level", "info")

	viper.SetDefault("database.driver", "sqlite")
	viper.SetDefault("database.host", "localhost")
	viper.SetDefault("database.port", 3306)
	viper.SetDefault("database.user", "")
	viper.SetDefault("database.password", "")
	viper.SetDefault("database.dbname", "data/aiops.db")
	viper.SetDefault("database.charset", "utf8mb4")
	viper.SetDefault("database.max_conn", 100)
	viper.SetDefault("database.max_idle", 10)

	viper.SetDefault("redis.host", "localhost")
	viper.SetDefault("redis.port", 6379)
	viper.SetDefault("redis.driver", "redka")
	viper.SetDefault("redis.password", "")
	viper.SetDefault("redis.db", 0)

	viper.SetDefault("jwt.secret", "")  // 生产环境必须通过配置或 JWT_SECRET 环境变量设置
	viper.SetDefault("jwt.expire_hour", 24)

	viper.SetDefault("websocket.read_buffer_size", 1024)
	viper.SetDefault("websocket.write_buffer_size", 1024)

	// 读取配置文件（不存在也不报错）// Logan.Li
	if err := viper.ReadInConfig(); err != nil {
		// 配置文件不存在是正常的（独立二进制模式）
		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
			fmt.Fprintf(os.Stderr, "警告: 读取配置文件失败: %v，使用默认配置\n", err)
		}
	}

	// 环境变量覆盖 // Logan.Li
	viper.AutomaticEnv()

	// CLI flags 覆盖（最高优先级）// Logan.Li
	applyFlags()

	// 解析配置 // Logan.Li
	var cfg config.Config
	if err := viper.Unmarshal(&cfg); err != nil {
		fmt.Fprintf(os.Stderr, "配置解析失败: %v\n", err)
		os.Exit(1)
	}

	return &cfg
}

// applyFlags 将 CLI 参数映射到 viper（覆盖 config.yaml 和默认值）// Logan.Li
func applyFlags() {
	// 检查是否有任何 flag 被显式设置 // Logan.Li
	flag.Visit(func(f *flag.Flag) {
		switch f.Name {
		case "port":
			viper.Set("port", *flagPort)
		case "mode":
			viper.Set("mode", *flagMode)
		case "log-level":
			viper.Set("log_level", *flagLogLevel)

		case "db-driver":
			viper.Set("database.driver", *flagDBDriver)
		case "db-host":
			viper.Set("database.host", *flagDBHost)
		case "db-port":
			viper.Set("database.port", *flagDBPort)
		case "db-user":
			viper.Set("database.user", *flagDBUser)
		case "db-password":
			viper.Set("database.password", *flagDBPassword)
		case "db-name":
			viper.Set("database.dbname", *flagDBName)
		case "db-charset":
			viper.Set("database.charset", *flagDBCharset)

		case "redis-host":
			viper.Set("redis.host", *flagRedisHost)
		case "redis-port":
			viper.Set("redis.port", *flagRedisPort)
		case "redis-password":
			viper.Set("redis.password", *flagRedisPassword)
		case "redis-db":
			viper.Set("redis.db", *flagRedisDB)

		case "jwt-secret":
			viper.Set("jwt.secret", *flagJWTSecret)
		case "jwt-expire":
			viper.Set("jwt.expire_hour", *flagJWTExpire)
		}
	})
}

// CORS 跨域中间件
func CORS() gin.HandlerFunc {
	return func(c *gin.Context) {
		c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
		c.Writer.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, PATCH, OPTIONS")
		c.Writer.Header().Set("Access-Control-Allow-Headers", "Origin, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization")
		c.Writer.Header().Set("Access-Control-Expose-Headers", "Content-Length")
		c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")

		if c.Request.Method == "OPTIONS" {
			c.AbortWithStatus(204)
			return
		}

		c.Next()
	}
}