package handler

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net"
	"net/http"
	"os"
	"strings"
	"sync"
	"time"

	"linkmaster-node/internal/config"
	"linkmaster-node/internal/continuous"
	"linkmaster-node/internal/heartbeat"

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

var continuousTasks = make(map[string]*ContinuousTask)
var taskMutex sync.RWMutex
var backendURL string
var logger *zap.Logger

// 批量推送缓冲（每个任务一个缓冲）
var pushBuffers = make(map[string]*pushBuffer)
var bufferMutex sync.RWMutex

// pushBuffer 批量推送缓冲
type pushBuffer struct {
	taskID    string
	results   []map[string]interface{}
	mu        sync.Mutex
	lastPush  time.Time
	pushTimer *time.Timer
}

const (
	// 批量推送配置
	batchPushInterval = 1 * time.Second // 批量推送间隔：1秒
	batchPushMaxSize  = 10              // 批量推送最大数量：10个结果
)

func InitContinuousHandler(cfg *config.Config) {
	backendURL = cfg.Backend.URL
	
	// 根据配置创建logger
	var level zapcore.Level
	logLevel := cfg.Log.Level
	if logLevel == "" {
		if cfg.Debug {
			logLevel = "debug"
		} else {
			logLevel = "info"
		}
	}
	
	switch logLevel {
	case "debug":
		level = zapcore.DebugLevel
	case "info":
		level = zapcore.InfoLevel
	case "warn":
		level = zapcore.WarnLevel
	case "error":
		level = zapcore.ErrorLevel
	default:
		level = zapcore.InfoLevel
	}
	
	// 创建编码器配置
	encoderConfig := zap.NewProductionEncoderConfig()
	if cfg.Debug {
		encoderConfig = zap.NewDevelopmentEncoderConfig()
	}
	encoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
	encoderConfig.EncodeLevel = zapcore.CapitalLevelEncoder
	
	// 创建核心 - 输出到标准错误（日志文件由main.go统一管理，这里输出到stderr便于调试）
	core := zapcore.NewCore(
		zapcore.NewJSONEncoder(encoderConfig),
		zapcore.AddSync(os.Stderr),
		level,
	)
	
	// 创建logger
	logger = zap.New(core, zap.AddCaller(), zap.AddStacktrace(zapcore.ErrorLevel))
	
	logger.Info("持续测试处理器已初始化",
		zap.String("backend_url", backendURL),
		zap.String("log_level", logLevel))
}

type ContinuousTask struct {
	TaskID      string
	Type        string
	Target      string
	Interval    time.Duration
	MaxDuration time.Duration
	StartTime   time.Time
	LastRequest time.Time
	StopCh      chan struct{}
	IsRunning   bool
	pingTask    *continuous.PingTask
	tcpingTask  *continuous.TCPingTask
}

func HandleContinuousStart(c *gin.Context) {
	var req struct {
		Type        string `json:"type" binding:"required"`
		Target      string `json:"target" binding:"required"`
		Interval    int    `json:"interval"`     // 秒
		MaxDuration int    `json:"max_duration"` // 分钟
	}

	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	// 生成任务ID
	taskID := generateTaskID()

	// 设置默认值
	interval := 10 * time.Second
	if req.Interval > 0 {
		interval = time.Duration(req.Interval) * time.Second
	}

	maxDuration := 60 * time.Minute
	if req.MaxDuration > 0 {
		maxDuration = time.Duration(req.MaxDuration) * time.Minute
	}

	// 创建任务
	task := &ContinuousTask{
		TaskID:      taskID,
		Type:        req.Type,
		Target:      req.Target,
		Interval:    interval,
		MaxDuration: maxDuration,
		StartTime:   time.Now(),
		LastRequest: time.Now(),
		StopCh:      make(chan struct{}),
		IsRunning:   true,
	}

	// 根据类型创建对应的任务
	if req.Type == "ping" {
		pingTask := continuous.NewPingTask(taskID, req.Target, interval, maxDuration)
		task.pingTask = pingTask
	} else if req.Type == "tcping" {
		tcpingTask, err := continuous.NewTCPingTask(taskID, req.Target, interval, maxDuration)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		task.tcpingTask = tcpingTask
	} else {
		c.JSON(http.StatusBadRequest, gin.H{"error": "不支持的持续测试类型"})
		return
	}

	taskMutex.Lock()
	continuousTasks[taskID] = task
	taskMutex.Unlock()

	// 启动持续测试goroutine
	ctx := context.Background()
	if task.pingTask != nil {
		go task.pingTask.Start(ctx, func(result map[string]interface{}) {
			pushResultToBackend(taskID, result)
		})
	} else if task.tcpingTask != nil {
		go task.tcpingTask.Start(ctx, func(result map[string]interface{}) {
			pushResultToBackend(taskID, result)
		})
	}

	c.JSON(http.StatusOK, gin.H{
		"task_id": taskID,
	})
}

func HandleContinuousStop(c *gin.Context) {
	var req struct {
		TaskID string `json:"task_id" binding:"required"`
	}

	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	taskMutex.Lock()
	task, exists := continuousTasks[req.TaskID]
	if exists {
		task.IsRunning = false
		if task.pingTask != nil {
			task.pingTask.Stop()
		}
		if task.tcpingTask != nil {
			task.tcpingTask.Stop()
		}
		
		// 关闭停止通道
		select {
		case <-task.StopCh:
			// 已经关闭
		default:
			close(task.StopCh)
		}
		
		delete(continuousTasks, req.TaskID)
	}
	taskMutex.Unlock()

	if !exists {
		c.JSON(http.StatusNotFound, gin.H{"error": "任务不存在"})
		return
	}

	// 清理推送缓冲
	bufferMutex.Lock()
	if buffer, exists := pushBuffers[req.TaskID]; exists {
		if buffer.pushTimer != nil {
			buffer.pushTimer.Stop()
		}
		delete(pushBuffers, req.TaskID)
		logger.Debug("已清理任务推送缓冲", zap.String("task_id", req.TaskID))
	}
	bufferMutex.Unlock()

	c.JSON(http.StatusOK, gin.H{"message": "任务已停止"})
}

func HandleContinuousStatus(c *gin.Context) {
	taskID := c.Query("task_id")
	if taskID == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "task_id参数缺失"})
		return
	}

	taskMutex.RLock()
	task, exists := continuousTasks[taskID]
	if exists {
		// 更新LastRequest时间
		task.LastRequest = time.Now()
		if task.pingTask != nil {
			task.pingTask.UpdateLastRequest()
		}
		if task.tcpingTask != nil {
			task.tcpingTask.UpdateLastRequest()
		}
	}
	taskMutex.RUnlock()

	if !exists {
		c.JSON(http.StatusNotFound, gin.H{"error": "任务不存在"})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"task_id":      task.TaskID,
		"is_running":   task.IsRunning,
		"start_time":   task.StartTime,
		"last_request": task.LastRequest,
	})
}

func pushResultToBackend(taskID string, result map[string]interface{}) {
	// 确保result包含必要的字段
	if result["timestamp"] == nil {
		result["timestamp"] = time.Now().Unix()
	}
	if result["latency"] == nil {
		result["latency"] = 0.0
	}
	if result["success"] == nil {
		result["success"] = true
	}
	if result["packet_loss"] == nil {
		result["packet_loss"] = false
	}

	// 优先使用心跳返回的节点信息
	nodeID := heartbeat.GetNodeID()
	nodeIP := heartbeat.GetNodeIP()
	
	// 如果心跳还没有返回节点信息，使用本地IP作为后备
	if nodeIP == "" {
		nodeIP = getLocalIP()
		logger.Debug("使用本地IP作为后备", zap.String("node_ip", nodeIP))
	}
	
	// 确保已经获取到 node_id，避免发送无效数据包
	if nodeID == 0 {
		logger.Warn("节点ID未获取，跳过推送结果",
			zap.String("task_id", taskID),
			zap.String("node_ip", nodeIP),
			zap.String("hint", "等待心跳返回node_id后再推送"),
			zap.Any("result", result))
		return
	}
	
	// 确保已经获取到 node_ip
	if nodeIP == "" {
		logger.Warn("节点IP未获取，跳过推送结果",
			zap.String("task_id", taskID),
			zap.Uint("node_id", nodeID),
			zap.String("hint", "等待心跳返回node_ip后再推送"),
			zap.Any("result", result))
		return
	}
	
	// 记录调试信息
	logger.Debug("准备推送结果到后端",
		zap.String("task_id", taskID),
		zap.Uint("node_id", nodeID),
		zap.String("node_ip", nodeIP),
		zap.Any("result", result))
	
	// 添加到批量推送缓冲
	addToPushBuffer(taskID, nodeID, nodeIP, result)
}

// addToPushBuffer 添加结果到批量推送缓冲
func addToPushBuffer(taskID string, nodeID uint, nodeIP string, result map[string]interface{}) {
	bufferMutex.Lock()
	buffer, exists := pushBuffers[taskID]
	if !exists {
		buffer = &pushBuffer{
			taskID:   taskID,
			results:  make([]map[string]interface{}, 0, batchPushMaxSize),
			lastPush: time.Now(),
		}
		pushBuffers[taskID] = buffer
	}
	bufferMutex.Unlock()
	
	buffer.mu.Lock()
	
	// 添加结果到缓冲
	buffer.results = append(buffer.results, result)
	
	// 如果缓冲已满，立即推送
	shouldFlush := len(buffer.results) >= batchPushMaxSize
	
	if shouldFlush {
		// 复制结果列表
		results := make([]map[string]interface{}, len(buffer.results))
		copy(results, buffer.results)
		buffer.results = buffer.results[:0] // 清空缓冲
		
		// 停止定时器
		if buffer.pushTimer != nil {
			buffer.pushTimer.Stop()
			buffer.pushTimer = nil
		}
		
		buffer.lastPush = time.Now()
		buffer.mu.Unlock()
		
		// 批量推送结果
		for _, r := range results {
			pushSingleResult(taskID, nodeID, nodeIP, r)
		}
		return
	}
	
	// 如果距离上次推送超过间隔时间，启动定时器推送
	if buffer.pushTimer == nil {
		buffer.pushTimer = time.AfterFunc(batchPushInterval, func() {
			flushPushBuffer(taskID, nodeID, nodeIP)
		})
	}
	
	buffer.mu.Unlock()
}

// flushPushBuffer 刷新并推送缓冲中的结果
func flushPushBuffer(taskID string, nodeID uint, nodeIP string) {
	bufferMutex.RLock()
	buffer, exists := pushBuffers[taskID]
	bufferMutex.RUnlock()
	
	if !exists {
		return
	}
	
	buffer.mu.Lock()
	if len(buffer.results) == 0 {
		buffer.mu.Unlock()
		return
	}
	
	// 复制结果列表
	results := make([]map[string]interface{}, len(buffer.results))
	copy(results, buffer.results)
	buffer.results = buffer.results[:0] // 清空缓冲
	
	// 停止定时器
	if buffer.pushTimer != nil {
		buffer.pushTimer.Stop()
		buffer.pushTimer = nil
	}
	
	buffer.lastPush = time.Now()
	buffer.mu.Unlock()
	
	// 批量推送结果（目前后端只支持单个结果，所以逐个推送）
	// 但可以减少HTTP请求的频率
	for _, result := range results {
		pushSingleResult(taskID, nodeID, nodeIP, result)
	}
}

// pushSingleResult 推送单个结果到后端
func pushSingleResult(taskID string, nodeID uint, nodeIP string, result map[string]interface{}) {
	// 推送结果到后端
	url := fmt.Sprintf("%s/api/public/node/continuous/result", backendURL)
	
	// 获取节点位置信息
	country, province, city, isp := heartbeat.GetNodeLocation()
	
	// 发送 node_id、node_ip 和位置信息，后端可以通过这些信息精准匹配
	data := map[string]interface{}{
		"task_id": taskID,
		"node_id": nodeID,
		"node_ip": nodeIP,
		"result":  result,
	}
	
	// 添加位置信息（如果存在）
	if country != "" {
		data["country"] = country
	}
	if province != "" {
		data["province"] = province
	}
	if city != "" {
		data["city"] = city
	}
	if isp != "" {
		data["isp"] = isp
	}

	jsonData, err := json.Marshal(data)
	if err != nil {
		logger.Error("序列化结果失败", 
			zap.Error(err), 
			zap.String("task_id", taskID),
			zap.Uint("node_id", nodeID),
			zap.String("node_ip", nodeIP),
			zap.Any("data", data))
		return
	}

	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		logger.Error("创建请求失败", 
			zap.Error(err), 
			zap.String("task_id", taskID),
			zap.String("url", url))
		return
	}

	req.Header.Set("Content-Type", "application/json")

	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		logger.Warn("推送结果失败，继续运行", 
			zap.Error(err), 
			zap.String("task_id", taskID),
			zap.String("url", url),
			zap.Uint("node_id", nodeID),
			zap.String("node_ip", nodeIP))
		// 推送失败不停止任务，继续运行
		return
	}
	defer resp.Body.Close()
	
	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		bodyStr := string(body)
		
		// 检查是否是任务不存在的错误
		if containsTaskNotFoundError(bodyStr) {
			logger.Warn("后端任务不存在，停止节点端任务", 
				zap.String("task_id", taskID),
				zap.String("response", bodyStr),
				zap.Uint("node_id", nodeID),
				zap.String("node_ip", nodeIP))
			// 停止对应的持续测试任务
			stopTaskByTaskID(taskID)
			return
		}
		
		logger.Warn("推送结果失败，继续运行", 
			zap.Int("status", resp.StatusCode),
			zap.String("task_id", taskID),
			zap.String("url", url),
			zap.String("response", bodyStr),
			zap.Uint("node_id", nodeID),
			zap.String("node_ip", nodeIP))
		// 其他错误不停止任务，继续运行
		return
	}

	logger.Debug("推送结果成功", 
		zap.String("task_id", taskID),
		zap.Uint("node_id", nodeID),
		zap.String("node_ip", nodeIP),
		zap.Any("result", result))
}

// containsTaskNotFoundError 检查响应中是否包含任务不存在的错误
func containsTaskNotFoundError(responseBody string) bool {
	// 检查常见的任务不存在错误消息
	errorKeywords := []string{
		"找不到对应的后端任务",
		"任务不存在",
		"task not found",
		"找不到对应的任务",
	}
	
	responseLower := strings.ToLower(responseBody)
	for _, keyword := range errorKeywords {
		if strings.Contains(responseLower, strings.ToLower(keyword)) {
			return true
		}
	}
	
	// 尝试解析 JSON 响应，检查错误消息
	var resp struct {
		Code int    `json:"code"`
		Msg  string `json:"msg"`
	}
	if err := json.Unmarshal([]byte(responseBody), &resp); err == nil {
		msgLower := strings.ToLower(resp.Msg)
		for _, keyword := range errorKeywords {
			if strings.Contains(msgLower, strings.ToLower(keyword)) {
				return true
			}
		}
	}
	
	return false
}

// stopTaskByTaskID 根据 taskID 停止对应的持续测试任务
func stopTaskByTaskID(taskID string) {
	taskMutex.Lock()
	defer taskMutex.Unlock()
	
	task, exists := continuousTasks[taskID]
	if !exists {
		logger.Debug("任务不存在，无需停止", zap.String("task_id", taskID))
		return
	}
	
	logger.Info("停止持续测试任务", zap.String("task_id", taskID))
	
	// 停止任务
	task.IsRunning = false
	if task.pingTask != nil {
		task.pingTask.Stop()
	}
	if task.tcpingTask != nil {
		task.tcpingTask.Stop()
	}
	
	// 关闭停止通道
	select {
	case <-task.StopCh:
		// 已经关闭
	default:
		close(task.StopCh)
	}
	
	// 删除任务
	delete(continuousTasks, taskID)
	
	// 清理推送缓冲
	bufferMutex.Lock()
	if buffer, exists := pushBuffers[taskID]; exists {
		if buffer.pushTimer != nil {
			buffer.pushTimer.Stop()
		}
		delete(pushBuffers, taskID)
	}
	bufferMutex.Unlock()
	
	logger.Info("持续测试任务已停止", zap.String("task_id", taskID))
}

func getLocalIP() string {
	// 简化实现：返回第一个非回环IP
	// 实际应该获取外网IP
	addrs, err := net.InterfaceAddrs()
	if err != nil {
		return "127.0.0.1"
	}
	
	for _, addr := range addrs {
		if ipNet, ok := addr.(*net.IPNet); ok && !ipNet.IP.IsLoopback() {
			if ipNet.IP.To4() != nil {
				return ipNet.IP.String()
			}
		}
	}
	
	return "127.0.0.1"
}

func generateTaskID() string {
	return fmt.Sprintf("task_%d", time.Now().UnixNano())
}

// 定期清理超时任务
func StartTaskCleanup() {
	ticker := time.NewTicker(1 * time.Minute)
	go func() {
		for range ticker.C {
			now := time.Now()
			taskMutex.Lock()
			var tasksToDelete []string
			for taskID, task := range continuousTasks {
				shouldDelete := false
				// 检查最大运行时长
				if now.Sub(task.StartTime) > task.MaxDuration {
					logger.Info("任务达到最大运行时长，自动停止", zap.String("task_id", taskID))
					shouldDelete = true
				} else if now.Sub(task.LastRequest) > 30*time.Minute {
					// 检查无客户端连接（30分钟无请求）
					logger.Info("任务无客户端连接，自动停止", zap.String("task_id", taskID))
					shouldDelete = true
				}
				
				if shouldDelete {
					task.IsRunning = false
					if task.pingTask != nil {
						task.pingTask.Stop()
					}
					if task.tcpingTask != nil {
						task.tcpingTask.Stop()
					}
					
					// 关闭停止通道
					select {
					case <-task.StopCh:
						// 已经关闭
					default:
						close(task.StopCh)
					}
					
					tasksToDelete = append(tasksToDelete, taskID)
				}
			}
			taskMutex.Unlock()
			
			// 清理任务和推送缓冲
			if len(tasksToDelete) > 0 {
				taskMutex.Lock()
				for _, taskID := range tasksToDelete {
					delete(continuousTasks, taskID)
				}
				taskMutex.Unlock()
				
				// 清理推送缓冲
				bufferMutex.Lock()
				for _, taskID := range tasksToDelete {
					if buffer, exists := pushBuffers[taskID]; exists {
						if buffer.pushTimer != nil {
							buffer.pushTimer.Stop()
						}
						delete(pushBuffers, taskID)
						logger.Debug("已清理任务推送缓冲", zap.String("task_id", taskID))
					}
				}
				bufferMutex.Unlock()
			}
		}
	}()
}