package main

import (
	"encoding/json"
	"fmt"
	"html/template"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"
)

// 启动HTTP服务器
func StartHTTPServer(address string) error {
	http.HandleFunc("/", handleIndex)
	// 静态资源
	http.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir("static"))))

	http.HandleFunc("/api/data", handleGetData)
	http.HandleFunc("/api/latest", handleGetLatest)
	http.HandleFunc("/api/sensors", handleGetSensors)
	http.HandleFunc("/api/devices", handleGetDevices)
	fmt.Printf("HTTP服务器已启动，正在监听 %s\n", address)
	return http.ListenAndServe(address, nil)
}

// 处理主页
func handleIndex(w http.ResponseWriter, r *http.Request) {
	log.Printf("接收到主页请求: %s", r.URL.Path)

	templatePath := "templates/index.html"
	absPath, _ := filepath.Abs(templatePath)

	_, err := os.Stat(templatePath)
	if os.IsNotExist(err) {
		log.Printf("错误: 模板文件不存在: %s", absPath)
		http.Error(w, "模板文件不存在", http.StatusInternalServerError)
		return
	}

	tmpl, err := template.ParseFiles(templatePath)
	if err != nil {
		log.Printf("错误: 无法解析模板: %v", err)
		http.Error(w, "无法加载模板："+err.Error(), http.StatusInternalServerError)
		return
	}

	log.Printf("模板加载成功，开始渲染")
	err = tmpl.Execute(w, nil)
	if err != nil {
		log.Printf("错误: 渲染模板出错: %v", err)
		http.Error(w, "渲染模板出错："+err.Error(), http.StatusInternalServerError)
	}
	log.Printf("模板渲染完成")
}

// 处理获取传感器数据的API
func handleGetData(w http.ResponseWriter, r *http.Request) {
	log.Printf("接收到获取数据请求: %s", r.URL.String())

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

	deviceID := r.URL.Query().Get("device_id")
	sensorIDStr := r.URL.Query().Get("sensor_id")
	limitStr := r.URL.Query().Get("limit")
	startDateStr := r.URL.Query().Get("start_date")
	endDateStr := r.URL.Query().Get("end_date")

	limit := 500     // 默认限制为500条数据
	noLimit := false // 是否不限制数据条数

	var sensorID int
	var err error
	if sensorIDStr != "" && sensorIDStr != "all" {
		sensorID, err = strconv.Atoi(sensorIDStr)
		if err != nil {
			log.Printf("错误: 无效的传感器ID: %s", sensorIDStr)
			http.Error(w, "无效的传感器ID", http.StatusBadRequest)
			return
		}
	}

	if limitStr != "" {
		if limitStr == "all" {
			noLimit = true
			limit = 0 // 设置为0表示不使用LIMIT子句
		} else {
			limit, err = strconv.Atoi(limitStr)
			if err != nil || limit <= 0 {
				log.Printf("错误: 无效的记录数限制: %s", limitStr)
				http.Error(w, "无效的记录数限制", http.StatusBadRequest)
				return
			}
		}
	}

	// 使用北京时间解析前端传来的本地时间
	var startDate, endDate time.Time
	shLoc, _ := time.LoadLocation("Asia/Shanghai")
	if startDateStr != "" {
		startDate, err = time.ParseInLocation("2006-01-02T15:04", startDateStr, shLoc)
		if err != nil {
			log.Printf("错误: 无效的开始日期: %s, %v", startDateStr, err)
			http.Error(w, "无效的开始日期", http.StatusBadRequest)
			return
		}
	}

	if endDateStr != "" {
		endDate, err = time.ParseInLocation("2006-01-02T15:04", endDateStr, shLoc)
		if err != nil {
			log.Printf("错误: 无效的结束日期: %s, %v", endDateStr, err)
			http.Error(w, "无效的结束日期", http.StatusBadRequest)
			return
		}
	}

	// 业务要求：必须提供 device_id；在设备下可选指定探头
	if strings.TrimSpace(deviceID) == "" {
		http.Error(w, "必须提供 device_id", http.StatusBadRequest)
		return
	}

	var data []SensorData
	if sensorIDStr == "all" || sensorIDStr == "" {
		data, err = GetSensorDataByDevice(deviceID, limit, startDate, endDate)
		log.Printf("查询设备%s下所有传感器数据，limit=%d, 结果数量=%d", deviceID, limit, len(data))
	} else {
		data, err = GetSensorDataByDeviceAndSensor(deviceID, sensorID, limit, startDate, endDate)
		log.Printf("查询设备%s下传感器%d数据，limit=%d, 结果数量=%d", deviceID, sensorID, limit, len(data))
	}

	if err != nil {
		log.Printf("错误: 获取数据失败: %v", err)
		http.Error(w, "获取数据失败："+err.Error(), http.StatusInternalServerError)
		return
	}

	// 输出最新数据的详细信息（当limit=1时）
	if limit == 1 && len(data) > 0 {
		latest := data[0]
		log.Printf("返回最新数据: ID=%d, SensorID=%d, X=%.3f, Y=%.3f, Z=%.3f, Temperature=%.1f, Timestamp=%s",
			latest.ID, latest.SensorID, latest.X, latest.Y, latest.Z, latest.Temperature, latest.Timestamp.Format("2006-01-02 15:04:05"))
	}

	if noLimit {
		log.Printf("成功获取到所有数据记录（%d条）", len(data))
	} else {
		log.Printf("成功获取到 %d 条数据记录（限制：%d条）", len(data), limit)
	}

	if err := json.NewEncoder(w).Encode(data); err != nil {
		log.Printf("错误: 编码JSON失败: %v", err)
		http.Error(w, "编码JSON失败："+err.Error(), http.StatusInternalServerError)
	}
}

// 处理获取所有传感器ID的API
func handleGetSensors(w http.ResponseWriter, r *http.Request) {
	log.Printf("接收到获取传感器列表请求")

	w.Header().Set("Content-Type", "application/json")
	deviceID := r.URL.Query().Get("device_id")
	var (
		sensorIDs []int
		err       error
	)
	if strings.TrimSpace(deviceID) != "" {
		sensorIDs, err = GetSensorIDsByDevice(deviceID)
	} else {
		sensorIDs, err = GetAllSensorIDs()
	}
	if err != nil {
		log.Printf("错误: 获取传感器ID失败: %v", err)
		http.Error(w, "获取传感器ID失败："+err.Error(), http.StatusInternalServerError)
		return
	}

	log.Printf("成功获取到 %d 个传感器ID", len(sensorIDs))

	if err := json.NewEncoder(w).Encode(sensorIDs); err != nil {
		log.Printf("错误: 编码JSON失败: %v", err)
		http.Error(w, "编码JSON失败："+err.Error(), http.StatusInternalServerError)
	}
}

// 已移除 /api/clients，在线统计改由 /api/devices 提供（3小时窗口）

// 处理获取设备列表及统计的API
func handleGetDevices(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	list, err := GetDevicesWithStats()
	if err != nil {
		log.Printf("错误: 获取设备列表失败: %v", err)
		http.Error(w, "获取设备列表失败："+err.Error(), http.StatusInternalServerError)
		return
	}

	// 构造响应，计算是否在线（3小时内有上报）
	type deviceResp struct {
		ID          int        `json:"id"`
		DeviceID    string     `json:"device_id"`
		SensorCount int        `json:"sensor_count"`
		LastSeen    *time.Time `json:"last_seen"`
		Online      bool       `json:"online"`
	}

	shLoc, _ := time.LoadLocation("Asia/Shanghai")
	resp := make([]deviceResp, 0, len(list))
	now := time.Now().In(shLoc)
	for _, d := range list {
		var lsPtr *time.Time
		online := false
		if d.LastSeen.Valid {
			ls := d.LastSeen.Time.In(shLoc)
			lsPtr = &ls
			if now.Sub(ls) <= 3*time.Hour {
				online = true
			}
		}
		resp = append(resp, deviceResp{
			ID:          d.ID,
			DeviceID:    d.DeviceID,
			SensorCount: d.SensorCount,
			LastSeen:    lsPtr,
			Online:      online,
		})
	}

	if err := json.NewEncoder(w).Encode(resp); err != nil {
		log.Printf("错误: 编码设备列表JSON失败: %v", err)
		http.Error(w, "编码JSON失败："+err.Error(), http.StatusInternalServerError)
	}
}

// 处理获取最新传感器数据的API
func handleGetLatest(w http.ResponseWriter, r *http.Request) {
	log.Printf("接收到获取最新数据请求")

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

	// 获取最新的一条数据
	data, err := GetAllSensorData(1, time.Time{}, time.Time{})
	if err != nil {
		log.Printf("错误: 获取最新数据失败: %v", err)
		http.Error(w, "获取最新数据失败："+err.Error(), http.StatusInternalServerError)
		return
	}

	log.Printf("查询最新数据结果数量: %d", len(data))

	if len(data) == 0 {
		log.Printf("数据库中没有任何数据")
		// 返回空数组而不是错误
		if err := json.NewEncoder(w).Encode([]SensorData{}); err != nil {
			log.Printf("错误: 编码空数据JSON失败: %v", err)
			http.Error(w, "编码JSON失败："+err.Error(), http.StatusInternalServerError)
		}
		return
	}

	// 输出最新数据的详细信息
	latest := data[0]
	log.Printf("返回最新数据: ID=%d, SensorID=%d, X=%.3f, Y=%.3f, Z=%.3f, Temperature=%.1f, Timestamp=%s",
		latest.ID, latest.SensorID, latest.X, latest.Y, latest.Z, latest.Temperature, latest.Timestamp.Format("2006-01-02 15:04:05"))

	if err := json.NewEncoder(w).Encode(data); err != nil {
		log.Printf("错误: 编码最新数据JSON失败: %v", err)
		http.Error(w, "编码JSON失败："+err.Error(), http.StatusInternalServerError)
	}
}