package core

import (
	"ZhenTuLocalPassiveAdapter/api"
	"ZhenTuLocalPassiveAdapter/config"
	"ZhenTuLocalPassiveAdapter/dto"
	"ZhenTuLocalPassiveAdapter/fs"
	"ZhenTuLocalPassiveAdapter/logger"
	"ZhenTuLocalPassiveAdapter/util"
	"context"
	"fmt"
	"path"
	"sort"
	"time"

	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/codes"
	"go.uber.org/zap"
)

var continuityTracer = otel.Tracer("continuity")

const (
	// 检查间隔：5分钟
	checkInterval = 5 * time.Minute
	// 检查起点：前12分钟
	rangeStartMinutes = 12
	// 检查终点：前2分钟
	rangeEndMinutes = 2
	// 间隔阈值：超过2秒视为断开
	gapThresholdSeconds = 2.0
	// 检查时间窗口：9点到18点
	checkStartHour = 9
	checkEndHour   = 18
)

// RunContinuityCheckLoop 启动连续性检查循环
func RunContinuityCheckLoop(ctx context.Context) {
	ticker := time.NewTicker(checkInterval)
	defer ticker.Stop()

	logger.Info("连续性检查循环已启动",
		zap.Duration("interval", checkInterval),
		zap.Int("rangeStartMinutes", rangeStartMinutes),
		zap.Int("rangeEndMinutes", rangeEndMinutes),
		zap.Int("checkStartHour", checkStartHour),
		zap.Int("checkEndHour", checkEndHour))

	for {
		select {
		case <-ctx.Done():
			logger.Info("连续性检查循环已停止")
			return
		case <-ticker.C:
			now := time.Now()

			// 只在9点到18点之间执行检查
			currentHour := now.Hour()
			if currentHour < checkStartHour || currentHour >= checkEndHour {
				continue
			}

			startTime := now.Add(-time.Duration(rangeStartMinutes) * time.Minute)
			endTime := now.Add(-time.Duration(rangeEndMinutes) * time.Minute)

			results := CheckAllDevicesContinuity(ctx, startTime, endTime)

			// 上报结果
			if len(results) > 0 {
				if err := api.ReportContinuityCheck(ctx, results); err != nil {
					logger.Error("上报连续性检查结果失败", zap.Error(err))
				}
			}
		}
	}
}

// CheckAllDevicesContinuity 检查所有设备的连续性
func CheckAllDevicesContinuity(ctx context.Context, startTime, endTime time.Time) []dto.ContinuityCheckResult {
	subCtx, span := continuityTracer.Start(ctx, "CheckAllDevicesContinuity")
	defer span.End()

	span.SetAttributes(
		attribute.String("range.start", startTime.Format("2006-01-02 15:04:05")),
		attribute.String("range.end", endTime.Format("2006-01-02 15:04:05")),
		attribute.Int("devices.count", len(config.Config.Devices)),
	)

	var results []dto.ContinuityCheckResult

	for _, device := range config.Config.Devices {
		result := CheckDeviceContinuity(subCtx, device, startTime, endTime)
		results = append(results, result)

		if !result.IsContinuous {
			logger.Warn("设备视频片段不连续",
				zap.String("deviceNo", device.DeviceNo),
				zap.String("deviceName", device.Name),
				zap.Int("gapCount", len(result.Gaps)),
				zap.String("errorMessage", result.ErrorMessage))
		}
	}

	span.SetAttributes(attribute.Int("results.count", len(results)))
	span.SetStatus(codes.Ok, "检查完成")
	return results
}

// CheckDeviceContinuity 检查单个设备的连续性
func CheckDeviceContinuity(ctx context.Context, device config.DeviceMapping, startTime, endTime time.Time) dto.ContinuityCheckResult {
	subCtx, span := continuityTracer.Start(ctx, "CheckDeviceContinuity")
	defer span.End()

	span.SetAttributes(
		attribute.String("device.no", device.DeviceNo),
		attribute.String("device.name", device.Name),
	)

	result := dto.ContinuityCheckResult{
		DeviceNo:     device.DeviceNo,
		DeviceName:   device.Name,
		CheckTime:    time.Now(),
		RangeStart:   startTime,
		RangeEnd:     endTime,
		IsContinuous: true,
	}

	adapter := fs.GetAdapter()

	// 获取文件列表（处理跨天跨小时）
	fileList, err := getFileListForCheck(subCtx, adapter, device, startTime, endTime)
	if err != nil {
		span.SetStatus(codes.Error, "获取文件列表失败")
		result.IsContinuous = false
		result.ErrorMessage = fmt.Sprintf("获取文件列表失败: %v", err)
		return result
	}

	// 过滤和排序
	files := util.FilterAndSortFiles(subCtx, fileList, startTime, endTime)
	result.FileCount = len(files)

	if len(files) == 0 {
		span.SetStatus(codes.Error, "时间范围内无文件")
		result.IsContinuous = false
		result.ErrorMessage = "时间范围内无视频文件"
		return result
	}

	// 记录实际覆盖范围
	coverageStart := files[0].StartTime
	coverageEnd := files[len(files)-1].EndTime
	result.CoverageStart = &coverageStart
	result.CoverageEnd = &coverageEnd

	// 按开始时间排序（FilterAndSortFiles已排序，但确保顺序正确）
	sort.Slice(files, func(i, j int) bool {
		return files[i].StartTime.Before(files[j].StartTime)
	})

	// 计算总时长（毫秒）
	var totalDurationMs int64
	for _, file := range files {
		duration := file.EndTime.Sub(file.StartTime).Milliseconds()
		if duration > 0 {
			totalDurationMs += duration
		}
	}
	result.TotalDurationMs = totalDurationMs

	// 检查首个文件是否覆盖检查范围起点
	if files[0].StartTime.After(startTime) {
		gap := files[0].StartTime.Sub(startTime).Seconds()
		if gap > gapThresholdSeconds {
			result.IsContinuous = false
			result.Gaps = append(result.Gaps, dto.GapInfo{
				PreviousFileName: "(检查范围起点)",
				PreviousEndTime:  startTime,
				NextFileName:     files[0].Name,
				NextStartTime:    files[0].StartTime,
				GapSeconds:       gap,
			})
		}
	}

	// 检查文件间隔
	if len(files) > 1 {
		var lastFile *dto.File
		for i := range files {
			file := &files[i]
			if lastFile == nil {
				lastFile = file
				continue
			}

			gap := file.StartTime.Sub(lastFile.EndTime).Seconds()
			if gap > gapThresholdSeconds {
				result.IsContinuous = false
				result.Gaps = append(result.Gaps, dto.GapInfo{
					PreviousFileName: lastFile.Name,
					PreviousEndTime:  lastFile.EndTime,
					NextFileName:     file.Name,
					NextStartTime:    file.StartTime,
					GapSeconds:       gap,
				})
			}
			lastFile = file
		}
	}

	// 检查末个文件是否覆盖检查范围终点
	if files[len(files)-1].EndTime.Before(endTime) {
		gap := endTime.Sub(files[len(files)-1].EndTime).Seconds()
		if gap > gapThresholdSeconds {
			result.IsContinuous = false
			result.Gaps = append(result.Gaps, dto.GapInfo{
				PreviousFileName: files[len(files)-1].Name,
				PreviousEndTime:  files[len(files)-1].EndTime,
				NextFileName:     "(检查范围终点)",
				NextStartTime:    endTime,
				GapSeconds:       gap,
			})
		}
	}

	if result.IsContinuous {
		span.SetStatus(codes.Ok, "连续")
	} else {
		span.SetStatus(codes.Error, "不连续")
		span.SetAttributes(attribute.Int("gaps.count", len(result.Gaps)))
	}

	return result
}

// getFileListForCheck 获取用于检查的文件列表（处理跨天、跨小时）
func getFileListForCheck(ctx context.Context, adapter fs.Adapter, device config.DeviceMapping, startTime, endTime time.Time) ([]dto.File, error) {
	_, span := continuityTracer.Start(ctx, "getFileListForCheck")
	defer span.End()

	var allFiles []dto.File
	seen := make(map[string]struct{})

	storageType := config.Config.Record.Storage.Type

	// 处理跨天情况：遍历从 startTime 到 endTime 涉及的每一天
	currentDate := startTime
	for !currentDate.After(endTime) {
		dateDirPath := path.Join(device.Name,
			currentDate.Format("2006"+config.Config.FileName.DateSeparator+"01"+config.Config.FileName.DateSeparator+"02"))

		// 确定当天需要查询的小时范围
		dayStartHour := 0
		dayEndHour := 23

		if isSameDate(currentDate, startTime) {
			dayStartHour = startTime.Hour()
		}
		if isSameDate(currentDate, endTime) {
			dayEndHour = endTime.Hour()
		}

		// 对于 S3/OSS，按小时前缀查询更高效
		if storageType == "s3" || storageType == "alioss" {
			for hour := dayStartHour; hour <= dayEndHour; hour++ {
				hourPrefix := fmt.Sprintf("%02d", hour)
				dirPathWithHour := path.Join(dateDirPath, hourPrefix)
				files, err := adapter.GetFileList(ctx, dirPathWithHour, currentDate)
				if err != nil {
					// 某个小时目录不存在时跳过，不视为错误
					continue
				}
				for _, f := range files {
					key := f.Path + "/" + f.Name
					if _, ok := seen[key]; !ok {
						seen[key] = struct{}{}
						allFiles = append(allFiles, f)
					}
				}
			}
		} else {
			// 本地存储直接按天目录获取
			files, err := adapter.GetFileList(ctx, dateDirPath, currentDate)
			if err != nil {
				span.SetAttributes(attribute.String("error", err.Error()))
				// 某天目录不存在时继续检查其他天
			} else {
				for _, f := range files {
					key := f.Path + "/" + f.Name
					if _, ok := seen[key]; !ok {
						seen[key] = struct{}{}
						allFiles = append(allFiles, f)
					}
				}
			}
		}

		// 移到下一天
		currentDate = currentDate.AddDate(0, 0, 1)
		currentDate = time.Date(currentDate.Year(), currentDate.Month(), currentDate.Day(),
			0, 0, 0, 0, currentDate.Location())
	}

	return allFiles, nil
}