modelRT/handler/real_time_data_pull.go

// Package handler provides HTTP handlers for various endpoints.
package handler

import (
	"context"
	"fmt"
	"net/http"
	"time"

	"modelRT/logger"
	"modelRT/network"

	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"
)

var pullUpgrader = websocket.Upgrader{
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
	CheckOrigin: func(_ *http.Request) bool {
		return true
	},
}

// PullRealTimeDataHandler define real time data pull API
// @Summary 实时数据拉取 websocket api
// @Description 根据用户输入的clientID拉取对应的实时数据
// @Tags RealTime Component Websocket
// @Router /monitors/data/realtime/stream/:clientID [get]
func PullRealTimeDataHandler(c *gin.Context) {
	clientID := c.Param("clientID")
	if clientID == "" {
		err := fmt.Errorf("clientID is missing from the path")
		logger.Error(c, "query clientID from path failed", "error", err, "url", c.Request.RequestURI)
		c.JSON(http.StatusOK, network.FailureResponse{
			Code: http.StatusBadRequest,
			Msg:  err.Error(),
		})
		return
	}

	conn, err := pullUpgrader.Upgrade(c.Writer, c.Request, nil)
	if err != nil {
		logger.Error(c, "upgrade http protocol to websocket protocal failed", "error", err)
		c.JSON(http.StatusOK, network.FailureResponse{
			Code: http.StatusBadRequest,
			Msg:  err.Error(),
		})
		return
	}
	defer conn.Close()

	ctx, cancel := context.WithCancel(c.Request.Context())
	defer cancel()
	fanInChan := make(chan []float64)
	go processTargetPolling(ctx, globalMonitorState, clientID, fanInChan)

	// 主循环：负责接收客户端消息（如心跳包、停止拉取命令等）
	go readClientMessages(ctx, conn, clientID)

	for {
		select {
		case value, ok := <-fanInChan:
			// 从扇入通道拿去数据后，将数据写入websocket 返回流中
			sendRealTimeDataStream(conn, clientID)
			fmt.Println(value, ok)
		default:
			fmt.Println("default")
		}
	}
}

// readClientMessages 负责持续监听客户端发送的消息（例如 Ping/Pong, Close Frame, 或控制命令）
func readClientMessages(ctx context.Context, conn *websocket.Conn, clientID string) {
	// conn.SetReadLimit(512)
	for {
		msgType, _, err := conn.ReadMessage()
		if err != nil {
			// **【核心逻辑】判断是否为客户端主动正常关闭**
			if websocket.IsCloseError(err, websocket.CloseNormalClosure) {
				fmt.Printf("客户端 %s 主动正常关闭连接 (Code 1000)。\n", clientID)
				// 客户端主动发起的正常关闭，这是最清晰的主动退出信号。
			} else if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
				// 这是您代码中已有的逻辑，用于处理非正常或服务器离开的关闭（如网络中断、浏览器关闭 Tab 但未发送关闭帧）。
				logger.Error(ctx, "clientID: %s 读取时发生错误: %v", clientID, err)
			} else {
				// 处理其他读取错误（如 I/O 错误）
				logger.Error(ctx, "clientID: %s 读取时发生错误: %v", clientID, err)
				fmt.Printf("客户端 %s 读取时发生未知错误: %v\n", clientID, err)
			}

			break // 退出循环，断开连接
		}

		// 客户端发送关闭帧时，msgType 可能是 websocket.CloseMessage，但通常在 ReadMessage 中被转换为错误。
		// 如果客户端主动发送了数据（非关闭帧），在这里继续处理
		if msgType == websocket.TextMessage || msgType == websocket.BinaryMessage {
			fmt.Println(msgType)
			// ... 处理正常接收到的消息 ...
		}
	}
}

// sendRealTimeDataStream 负责持续向客户端推送实时数据
func sendRealTimeDataStream(conn *websocket.Conn, clientID string) {
	fmt.Println(conn, clientID)
	// ⚠️ 这是一个模拟的推送逻辑，您需要替换为您的实际数据源

	// 模拟数据源
	// dataChannel := globalMonitorState.GetDataChannel(clientID)

	// 持续监听数据，并写入 WebSocket
	// for data := range dataChannel {
	//     err := conn.WriteJSON(data) // 使用 WriteJSON 发送结构化数据
	//     if err != nil {
	//         log.Printf("clientID: %s 写入数据失败: %v", clientID, err)
	//         break // 写入失败，断开连接
	//     }
	// }
}

// processTargetPolling define function to process target in monitor map and data is continuously retrieved from redis based on the target
func processTargetPolling(ctx context.Context, s *SharedMonitorState, clientID string, fanInChan chan []float64) {
	stopChanMap := make(map[string]chan struct{})
	s.mutex.RLock()

	config, confExist := s.monitorMap[clientID]
	if !confExist {
		logger.Error(ctx, "can not found config into local stored map by clientID", "clientID", clientID)
		return
	}

	for interval, componentItems := range config.components {
		fmt.Println(componentItems)
		for _, target := range componentItems.targets {
			dataSize, exist := componentItems.targetParam[target]
			if !exist {
				logger.Error(ctx, "can not found subscription node param into param map", "target", target)
				continue
			}

			stopChan := make(chan struct{})
			// store stop channel with target into map
			stopChanMap[target] = stopChan
			go realTimeDataQueryFromRedis(ctx, interval, dataSize, fanInChan, stopChan)
		}
	}
	s.mutex.RUnlock()

	// TODO 持续监听noticeChannel
	for {
		select {
		case noticeValue, ok := <-config.noticeChan:
			if !ok {
				logger.Error(ctx, "notice channel was closed unexpectedly", "clientID", clientID)
				stopAllPolling(ctx, stopChanMap)
				return
			}
			// TODO 判断传递数据类型，决定是调用新增函数或者移除函数
			fmt.Println(noticeValue, ok)
		case <-ctx.Done():
			logger.Info(ctx, fmt.Sprintf("stop all data retrieval goroutines under this clientID:%s", clientID))
			stopAllPolling(ctx, stopChanMap)
			return
		}
	}
}

func stopAllPolling(ctx context.Context, stopChanMap map[string]chan struct{}) {
	for target, stopChan := range stopChanMap {
		logger.Info(ctx, fmt.Sprintf("stop the data fetching behavior for the corresponding target:%s", target))
		close(stopChan)
	}
	clear(stopChanMap)
	return
}

// TODO 根据Measure表 datasource 字段从 redis 查询信息
func realTimeDataQueryFromRedis(ctx context.Context, interval string, dataSize int, fanInChan chan []float64, stopChan chan struct{}) {
	duration, err := time.ParseDuration(interval)
	if err != nil {
		logger.Error(ctx, "failed to parse the time string", "interval", interval, "error", err)
		return
	}
	ticker := time.NewTicker(duration * time.Second)
	defer ticker.Stop()

	for {
		select {
		case <-ticker.C:
			// TODO 添加 redis 查询逻辑
			result := make([]float64, dataSize)
			select {
			case fanInChan <- result:
			default:
				// TODO 考虑如果 fanInChan 阻塞，避免阻塞查询循环，可以丢弃数据或记录日志
				// logger.Warning("Fan-in channel is full, skipping data push.")
			}

		case <-stopChan:
			// TODO 优化日志输出
			logger.Info(ctx, "redis query goroutine have stopped")
			return
		}
	}
}