package main

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"strings"
	"syscall"
	"time"

	"ezops/config"
	"ezops/controller"
	"ezops/migrations"
	"ezops/model"
	"ezops/pkg/appdir"
	"ezops/pkg/auditcleaner"
	"ezops/pkg/billingsync"
	"ezops/pkg/cronscheduler"
	"ezops/pkg/database"
	"ezops/pkg/logger"
	ezredis "ezops/pkg/redis"
	"ezops/pkg/retention"
	"ezops/pkg/systask"
	"ezops/router"
	"ezops/seed"

	"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: local (SQLite+redka), development, production, release")
	flagLogLevel        = flag.String("log-level", "", "日志级别: debug, info, warn, error")
	flagSkipAutoMigrate = flag.Bool("skip-auto-migrate", false, "已废弃：服务启动不再执行自动迁移") // Logan.Li

	// 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")
	flagRedisDriver   = flag.String("redis-driver", "", "Redis 驱动: redis (外部Redis), redka (内嵌,需CGO)")

	// 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

// @BasePath /api/v1

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

// printVersion 输出编译时注入的版本信息 // Logan.Li
func printVersion() {
	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)
}

func main() {
	// 支持 ./aiops version 子命令（无需启动服务）// Logan.Li
	if len(os.Args) > 1 {
		switch os.Args[1] {
		case "version", "-v", "--version":
			printVersion()
			os.Exit(0)
		case "migrate":
			runMigrationCLI(os.Args[2:])
			return
		}
	}

	// 解析 CLI 参数 // Logan.Li
	flag.Parse()

	// 显示版本信息 // Logan.Li
	if *flagVersion {
		printVersion()
		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（local 与 release 一样走 ReleaseMode）// Logan.Li
	switch cfg.Mode {
	case "production", "release", "local":
		gin.SetMode(gin.ReleaseMode)
	default:
		gin.SetMode(gin.DebugMode)
	}

	// 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))
	}

	// 数据库结构只能通过 `aiops migrate up` 显式变更，避免启动期重建表和 WAL 写放大。 // Logan.Li
	if *flagSkipAutoMigrate {
		log.Warn("--skip-auto-migrate 已废弃；服务启动始终不会执行数据库迁移")
	}

	// 初始化种子数据
	seed.SeedData(db)
	// 中间件监控默认目标（aiops-redis / aiops-mysql）// Logan.Li
	controller.SeedDefaultMiddlewareTargets(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:  appdir.Root(),
	})
	if err != nil {
		if cfg.Mode == "local" {
			log.Fatal("local 模式缓存(redka)初始化失败", zap.Error(err))
		}
		log.Warn("缓存初始化失败，继续启动", zap.Error(err))
		cache = nil
	} else {
		caps := cache.Capabilities()
		log.Info("缓存已就绪",
			zap.String("driver", cfg.Redis.Driver),
			zap.Bool("sorted_set", caps.SortedSet),
			zap.Bool("pubsub", caps.PubSub),
		)
		if cfg.Mode == "local" && (!caps.SortedSet || !caps.PubSub) {
			log.Info("local 模式：Agent 热指标走 DB 直读，流水线日志走轮询")
		}
		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) {
		resp := gin.H{
			"version":      Version,
			"build_time":   BuildTime,
			"git_commit":   GitCommit,
			"mode":         cfg.Mode,
			"db_driver":    cfg.Database.Driver,
			"redis_driver": cfg.Redis.Driver,
		}
		if cache != nil {
			resp["features"] = cache.Capabilities()
		}
		c.JSON(http.StatusOK, resp)
	})

	systask.Init(db)

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

	// 用户定时任务调度（Linux 5 段 crontab）// Logan.Li
	cronSched := cronscheduler.Start(db, func(jobID uint) {
		if _, err := controller.RunCronJobByID(db, jobID); err != nil {
			log.Warn("定时任务自动执行失败", zap.Uint("job_id", jobID), zap.Error(err))
		}
	})
	defer cronSched.Stop()

	// 每日分批清理 Agent、指标、SNMP、拨测与旧日志，执行结果写入系统任务状态。 // Logan.Li
	go func() {
		ticker := time.NewTicker(24 * time.Hour)
		defer ticker.Stop()
		runRetentionCleanup := func() {
			start := time.Now()
			result, err := retention.Run(db, cfg.Retention)
			if err != nil {
				systask.Record("retention_cleanup", "failed", err.Error(), time.Since(start))
				log.Warn("高频数据保留清理失败", zap.Error(err))
				return
			}
			message, marshalErr := json.Marshal(result)
			if marshalErr != nil {
				systask.Record("retention_cleanup", "failed", marshalErr.Error(), time.Since(start))
				log.Warn("高频数据保留结果序列化失败", zap.Error(marshalErr))
				return
			}
			systask.Record("retention_cleanup", "success", string(message), time.Since(start))
			log.Info("高频数据保留清理完成", zap.Int64("rows", result.Total))
		}
		time.Sleep(2 * time.Minute)
		runRetentionCleanup()
		for range ticker.C {
			runRetentionCleanup()
		}
	}()

	// 每日按审计保留策略清理操作/登录/终端审计日志 // Logan.Li
	go func() {
		ticker := time.NewTicker(24 * time.Hour)
		defer ticker.Stop()
		runAuditRetentionCleanup := func() {
			start := time.Now()
			result, err := auditcleaner.RunFromSettings(db)
			if err != nil {
				systask.Record("audit_log_cleanup", "failed", err.Error(), time.Since(start))
				log.Warn("审计日志定时清理失败", zap.Error(err))
				return
			}
			msg := fmt.Sprintf("清理 %d 条（保留 %d 天）", result.Total, result.RetentionDays)
			systask.Record("audit_log_cleanup", "success", msg, time.Since(start))
			if result.Total > 0 {
				log.Info("审计日志定时清理完成",
					zap.Int("retention_days", result.RetentionDays),
					zap.Int64("total", result.Total),
				)
			}
			now := time.Now()
			summary := result.SummaryJSON()
			db.Model(&model.AuditSettings{}).Where("id > 0").Updates(map[string]interface{}{
				"last_cleanup_at":      now,
				"last_cleanup_summary": summary,
			})
		}
		time.Sleep(time.Minute)
		runAuditRetentionCleanup()
		for range ticker.C {
			runAuditRetentionCleanup()
		}
	}()

	// 每日 10:30 同步云账号昨日账单（阿里云 T+1 出账） // Logan.Li
	go func() {
		runBillingSync := func() {
			start := time.Now()
			result := billingsync.SyncDate(db, billingsync.Yesterday(), nil)
			msg := billingsync.SummaryMessage(result)
			status := "success"
			if result.Accounts == 0 {
				status = "failed"
				msg = "没有可同步的活跃云账号"
			} else if result.Created == 0 && result.Updated == 0 && len(result.Errors) > 0 {
				status = "failed"
				msg = result.Errors[0]
			} else if len(result.Errors) > 0 {
				msg += "；" + result.Errors[0]
			}
			systask.Record("cloud_billing_sync", status, msg, time.Since(start))
			if status == "success" && (result.Created > 0 || result.Updated > 0) {
				log.Info("云账单定时同步完成",
					zap.String("date", result.BillingDate),
					zap.Int("created", result.Created),
					zap.Int("updated", result.Updated),
				)
			}
		}
		for {
			now := time.Now()
			next := time.Date(now.Year(), now.Month(), now.Day(), 10, 30, 0, 0, now.Location())
			if !now.Before(next) {
				next = next.Add(24 * time.Hour)
			}
			time.Sleep(time.Until(next))
			runBillingSync()
		}
	}()

	// 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")
}

// runMigrationCLI 执行独立的数据库迁移命令，不启动 HTTP 服务或定时任务。 // Logan.Li
func runMigrationCLI(args []string) {
	action, flagArgs, err := parseMigrationArgs(args)
	if err != nil {
		fmt.Fprintf(os.Stderr, "迁移命令错误: %v\n用法: aiops migrate <up|status|baseline> [全局参数]\n", err)
		os.Exit(2)
	}

	// 复用既有全局配置参数解析，确保 migrate 与服务使用同一数据库连接。 // Logan.Li
	os.Args = append([]string{os.Args[0]}, flagArgs...)
	if err := flag.CommandLine.Parse(flagArgs); err != nil {
		fmt.Fprintf(os.Stderr, "迁移参数错误: %v\n", err)
		os.Exit(2)
	}
	cfg := loadConfig()
	db, err := database.New(cfg.Database)
	if err != nil {
		fmt.Fprintf(os.Stderr, "数据库连接失败: %v\n", err)
		os.Exit(1)
	}

	switch action {
	case "up":
		applied, err := migrations.Up(db)
		if err != nil {
			fmt.Fprintf(os.Stderr, "迁移失败: %v\n", err)
			os.Exit(1)
		}
		if len(applied) == 0 {
			fmt.Println("迁移已是最新状态")
			return
		}
		fmt.Printf("已应用迁移: %s\n", strings.Join(applied, ", "))
	case "baseline":
		if err := migrations.Baseline(db); err != nil {
			fmt.Fprintf(os.Stderr, "基线登记失败: %v\n", err)
			os.Exit(1)
		}
		fmt.Printf("已登记基线: %s（未修改业务表）\n", migrations.BaselineVersion)
	case "status":
		rows, err := migrations.Status(db)
		if err != nil {
			fmt.Fprintf(os.Stderr, "读取迁移状态失败: %v\n", err)
			os.Exit(1)
		}
		for _, row := range rows {
			status := "pending"
			appliedAt := "-"
			if row.Applied {
				status = "applied"
				appliedAt = row.AppliedAt.Format(time.RFC3339)
			}
			fmt.Printf("%-30s %-8s %-25s %s\n", row.Version, status, appliedAt, row.Description)
		}
	}
}

// parseMigrationArgs 提取动作并保留其他全局参数，允许 `migrate up --config ...`。 // Logan.Li
func parseMigrationArgs(args []string) (string, []string, error) {
	if len(args) == 0 {
		return "", nil, fmt.Errorf("缺少动作")
	}
	var action string
	flagArgs := make([]string, 0, len(args)-1)
	for _, arg := range args {
		if action == "" && (arg == "up" || arg == "status" || arg == "baseline") {
			action = arg
			continue
		}
		flagArgs = append(flagArgs, arg)
	}
	if action == "" {
		return "", nil, fmt.Errorf("动作必须是 up、status 或 baseline")
	}
	return action, flagArgs, nil
}

// 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(".")
	viper.AddConfigPath(appdir.Root())

	// 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", "sqlite3.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("agent.enforce_auth", false)
	viper.SetDefault("retention.agent_reports_days", 7)
	viper.SetDefault("retention.metric_history_days", 30)
	viper.SetDefault("retention.metric_aggregate_days", 365)
	viper.SetDefault("retention.snmp_samples_days", 30)
	viper.SetDefault("retention.site_results_days", 30)
	viper.SetDefault("retention.log_entries_days", 30)
	viper.SetDefault("retention.cleanup_batch_size", 10000)

	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.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
	viper.AutomaticEnv()

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

	// mode=local：强制 SQLite + redka（CLI 显式传 --db-driver/--redis-driver 时可覆盖）// Logan.Li
	applyLocalMode()

	// 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)
	}

	// SQLite / redka 相对路径统一解析到可执行文件目录 // Logan.Li
	if cfg.Database.Driver == "sqlite" && cfg.Database.DBName != "" && !filepath.IsAbs(cfg.Database.DBName) {
		cfg.Database.DBName = appdir.Resolve(cfg.Database.DBName)
	}

	return &cfg
}

// isFlagSet 判断 CLI 参数是否被显式传入 // Logan.Li
func isFlagSet(name string) bool {
	found := false
	flag.Visit(func(f *flag.Flag) {
		if f.Name == name {
			found = true
		}
	})
	return found
}

// applyLocalMode local 模式：不依赖外部 MySQL/Redis，使用 SQLite + redka // Logan.Li
func applyLocalMode() {
	if viper.GetString("mode") != "local" {
		return
	}
	if !isFlagSet("db-driver") {
		viper.Set("database.driver", "sqlite")
	}
	if !isFlagSet("db-name") {
		viper.Set("database.dbname", "sqlite3.db")
	}
	if !isFlagSet("redis-driver") {
		viper.Set("redis.driver", "redka")
	}
}

// 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 "redis-driver":
			viper.Set("redis.driver", *flagRedisDriver)

		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()
	}
}