package main

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

	"proxy-platform/internal/config"
	"proxy-platform/internal/handler"
	"proxy-platform/internal/models"
	"proxy-platform/internal/repository"
	"proxy-platform/internal/socks5"
	"proxy-platform/internal/scheduler"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
	"gorm.io/driver/postgres"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
)

func main() {
	// 加载配置
	cfg, err := config.Load("configs/scheduler.yaml")
	if err != nil {
		log.Fatalf("加载配置失败: %v", err)
	}

	// 初始化日志
	logger, err := zap.NewProduction()
	if err != nil {
		log.Fatalf("初始化日志失败: %v", err)
	}
	defer logger.Sync()

	// 检查是否已安装
	if !cfg.Install.Installed {
		logger.Info("系统未安装，启动安装模式")
		startInstallMode(cfg, logger)
		return
	}

	// 连接数据库
	var db *gorm.DB
	if cfg.Database.Type == "sqlite" {
		// SQLite 连接
		db, err = gorm.Open(sqlite.Open(cfg.Database.DSN()), &gorm.Config{})
	} else {
		// PostgreSQL 连接
		db, err = gorm.Open(postgres.Open(cfg.Database.DSN()), &gorm.Config{})
	}
	
	if err != nil {
		logger.Fatal("连接数据库失败", zap.Error(err))
	}

	// 自动迁移
	if err := db.AutoMigrate(
		&models.User{},
		&models.Node{},
		&models.NodeGroup{},
		&models.UnlockStatus{},
		&models.IPChangeLog{},
		&models.ConnectionLog{},
		&models.IPRefreshRule{},
		&models.InstallStatus{},
	); err != nil {
		logger.Fatal("数据库迁移失败", zap.Error(err))
	}

	logger.Info("数据库迁移完成")

	// 初始化仓库
	repos := repository.NewRepositories(db)

	// 初始化认证器
	auth := NewSimpleAuthenticator(repos.User)

	// 初始化节点缓存
	cache := NewMemoryNodeCache()

	// 初始化节点选择器
	selector := scheduler.NewSelector(repos.Node, cache, scheduler.StrategyLeastLatency, logger)

	// 初始化后端选择器
	backendSelector := NewBackendSelector(repos.Node, selector, logger)

	// 启动 SOCKS5 服务器
	socks5Server := socks5.NewServer(
		cfg.SOCKS5.Host,
		cfg.SOCKS5.Port,
		cfg.SOCKS5.MaxConnections,
		cfg.SOCKS5.Timeout,
		auth,
		backendSelector,
		logger,
	)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// 启动 SOCKS5 服务器
	go func() {
		if err := socks5Server.Start(ctx); err != nil {
			logger.Error("SOCKS5 服务器错误", zap.Error(err))
		}
	}()

	// 启动健康检查
	healthChecker := scheduler.NewHealthChecker(repos.Node, cache, logger)
	go startHealthCheck(ctx, repos.Node, healthChecker, logger, time.Duration(cfg.Scheduler.HealthCheckInterval)*time.Second)

	// 启动 API 服务器
	apiServer := NewAPIServer(cfg, repos, db, logger)
	go func() {
		if err := apiServer.Start(); err != nil && err != http.ErrServerClosed {
			logger.Error("API 服务器错误", zap.Error(err))
		}
	}()

	logger.Info("调度中心启动完成",
		zap.String("api", fmt.Sprintf("%s:%d", cfg.Server.Host, cfg.Server.Port)),
		zap.String("socks5", fmt.Sprintf("%s:%d", cfg.SOCKS5.Host, cfg.SOCKS5.Port)),
	)

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

	logger.Info("正在关闭服务器...")
	cancel()

	// 关闭 API 服务器
	ctx2, cancel2 := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel2()
	apiServer.Shutdown(ctx2)

	logger.Info("服务器已关闭")
}

// startInstallMode 启动安装模式
func startInstallMode(cfg *config.Config, logger *zap.Logger) {
	gin.SetMode("release")
	router := gin.New()
	router.Use(gin.Recovery())
	
	// 安装相关路由
	api := router.Group("/api/v1")
	{
		api.GET("/install/check", handler.CheckInstall())
		api.POST("/install", handler.DoInstall(logger))
		api.GET("/install/status", handler.GetInstallStatus(nil))
	}
	
	// 静态文件服务（前端）
	router.Static("/assets", "web/dist/assets")
	router.StaticFile("/", "web/dist/index.html")
	router.StaticFile("/favicon.ico", "web/dist/favicon.ico")
	
	// 前端路由回退
	router.NoRoute(func(c *gin.Context) {
		c.File("web/dist/index.html")
	})
	
	server := &http.Server{
		Addr:    fmt.Sprintf("%s:%d", cfg.Server.Host, cfg.Server.Port),
		Handler: router,
	}
	
	logger.Info("安装模式启动", zap.String("addr", server.Addr))
	
	// 等待中断信号
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	
	go func() {
		if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			logger.Error("服务器错误", zap.Error(err))
		}
	}()
	
	<-quit
	logger.Info("安装模式关闭")
}

// SimpleAuthenticator 简单认证器
type SimpleAuthenticator struct {
	userRepo *repository.UserRepository
}

func NewSimpleAuthenticator(userRepo *repository.UserRepository) *SimpleAuthenticator {
	return &SimpleAuthenticator{userRepo: userRepo}
}

func (a *SimpleAuthenticator) Authenticate(username, password string) (uint, bool) {
	user, err := a.userRepo.FindByUsername(username)
	if err != nil {
		return 0, false
	}

	// TODO: 实现密码验证
	// 这里简化处理，实际应该使用 bcrypt 验证
	if user.PasswordHash == password && user.Status == "active" {
		return user.ID, true
	}

	return 0, false
}

// BackendSelector 后端节点选择器
type BackendSelector struct {
	nodeRepo  *repository.NodeRepository
	selector  *scheduler.Selector
	logger    *zap.Logger
}

func NewBackendSelector(nodeRepo *repository.NodeRepository, selector *scheduler.Selector, logger *zap.Logger) *BackendSelector {
	return &BackendSelector{
		nodeRepo: nodeRepo,
		selector: selector,
		logger:   logger,
	}
}

func (s *BackendSelector) SelectBackend(ctx context.Context, targetHost string, targetPort int, services []string) (string, int, error) {
	node, err := s.selector.Select(ctx, targetHost, targetPort, services)
	if err != nil {
		return "", 0, err
	}

	return node.Host, node.Port, nil
}

func (s *BackendSelector) ReleaseBackend(host string, port int, bytesIn, bytesOut int64) {
	// TODO: 更新节点统计信息
	s.logger.Info("释放后端节点",
		zap.String("host", host),
		zap.Int("port", port),
		zap.Int64("bytes_in", bytesIn),
		zap.Int64("bytes_out", bytesOut),
	)
}

// MemoryNodeCache 内存节点缓存
type MemoryNodeCache struct {
	stats map[string]*models.NodeStats
	mu    sync.RWMutex
}

func NewMemoryNodeCache() *MemoryNodeCache {
	return &MemoryNodeCache{
		stats: make(map[string]*models.NodeStats),
	}
}

func (c *MemoryNodeCache) GetStats(nodeID string) (*models.NodeStats, bool) {
	c.mu.RLock()
	defer c.mu.RUnlock()
	stats, ok := c.stats[nodeID]
	return stats, ok
}

func (c *MemoryNodeCache) SetStats(nodeID string, stats *models.NodeStats) {
	c.mu.Lock()
	defer c.mu.Unlock()
	c.stats[nodeID] = stats
}

func (c *MemoryNodeCache) GetAllStats() map[string]*models.NodeStats {
	c.mu.RLock()
	defer c.mu.RUnlock()
	result := make(map[string]*models.NodeStats)
	for k, v := range c.stats {
		result[k] = v
	}
	return result
}

// startHealthCheck 启动健康检查
func startHealthCheck(ctx context.Context, nodeRepo *repository.NodeRepository, checker *scheduler.HealthChecker, logger *zap.Logger, interval time.Duration) {
	ticker := time.NewTicker(interval)
	defer ticker.Stop()

	for {
		select {
		case <-ctx.Done():
			return
		case <-ticker.C:
			nodes, err := nodeRepo.ListOnline()
			if err != nil {
				logger.Error("获取节点列表失败", zap.Error(err))
				continue
			}

			for _, node := range nodes {
				if err := checker.Check(ctx, &node); err != nil {
					logger.Warn("节点健康检查失败",
						zap.String("node_id", node.NodeID),
						zap.Error(err),
					)
				}
			}
		}
	}
}

// APIServer API 服务器
type APIServer struct {
	cfg    *config.Config
	repos  *repository.Repositories
	db     *gorm.DB
	logger *zap.Logger
	server *http.Server
	router *gin.Engine
}

func NewAPIServer(cfg *config.Config, repos *repository.Repositories, db *gorm.DB, logger *zap.Logger) *APIServer {
	gin.SetMode(cfg.Server.Mode)
	router := gin.New()

	server := &APIServer{
		cfg:    cfg,
		repos:  repos,
		db:     db,
		logger: logger,
		router: router,
		server: &http.Server{
			Addr:    fmt.Sprintf("%s:%d", cfg.Server.Host, cfg.Server.Port),
			Handler: router,
		},
	}

	// 注册路由
	server.setupRoutes()

	return server
}

func (s *APIServer) setupRoutes() {
	// 健康检查
	s.router.GET("/health", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"status": "ok"})
	})

	// API 路由组
	api := s.router.Group("/api/v1")
	{
		// 安装相关
		install := api.Group("/install")
		{
			install.GET("/check", handler.CheckInstall())
			install.GET("/status", handler.GetInstallStatus(s.db))
		}
		
		// 用户相关
		users := api.Group("/users")
		{
			users.GET("", handler.ListUsers(s.repos.User))
			users.POST("", handler.CreateUser(s.repos.User))
			users.GET("/:id", handler.GetUser(s.repos.User))
			users.PUT("/:id", handler.UpdateUser(s.repos.User))
			users.DELETE("/:id", handler.DeleteUser(s.repos.User))
		}

		// 节点相关
		nodes := api.Group("/nodes")
		{
			nodes.GET("", handler.ListNodes(s.repos.Node))
			nodes.POST("", handler.CreateNode(s.repos.Node))
			nodes.GET("/:id", handler.GetNode(s.repos.Node))
			nodes.PUT("/:id", handler.UpdateNode(s.repos.Node))
			nodes.DELETE("/:id", handler.DeleteNode(s.repos.Node))
			nodes.POST("/:id/refresh-ip", handler.RefreshNodeIP(s.repos.Node, s.logger))
		}

		// Agent 相关
		agent := api.Group("/agent")
		{
			agent.POST("/heartbeat", handler.AgentHeartbeat(s.repos.Node, s.logger))
			agent.POST("/unlock/report", handler.ReportUnlockStatus(s.repos.UnlockStatus, s.logger))
			agent.POST("/ip/change/result", handler.ReportIPChange(s.repos.Node, s.repos.IPChangeLog, s.logger))
		}

		// 规则相关
		rules := api.Group("/rules")
		{
			rules.GET("", handler.ListRules(s.repos.IPRefreshRule))
			rules.POST("", handler.CreateRule(s.repos.IPRefreshRule))
			rules.GET("/:id", handler.GetRule(s.repos.IPRefreshRule))
			rules.PUT("/:id", handler.UpdateRule(s.repos.IPRefreshRule))
			rules.DELETE("/:id", handler.DeleteRule(s.repos.IPRefreshRule))
		}

		// 统计相关
		stats := api.Group("/stats")
		{
			stats.GET("/overview", handler.GetOverview(s.repos))
			stats.GET("/traffic", handler.GetTrafficStats(s.repos.ConnectionLog))
		}
	}
}

func (s *APIServer) Start() error {
	return s.server.ListenAndServe()
}

func (s *APIServer) Shutdown(ctx context.Context) {
	s.server.Shutdown(ctx)
}