package flow

import (
	"context"
	"fmt"
	"gitee.com/os-lee/easy-paas/common"
	"strconv"
	"sync"
	"time"

	"github.com/go-redis/redis/v8"
)

// ReqCounterHandler 请求计算器
var (
	ReqCounterHandler *ReqCounter
)

func init() {
	ReqCounterHandler = newReqCounter()
}

type ReqCounter struct {
	// key:ServiceName val: *flow.ReqCounterItem
	ReqCounterMap sync.Map
}

func newReqCounter() *ReqCounter {
	return &ReqCounter{
		ReqCounterMap: sync.Map{},
	}
}

func (handler *ReqCounter) GetReqCounterItem(serviceName string, redisCli *redis.Client) *ReqCounterItem {
	if value, ok := handler.ReqCounterMap.Load(serviceName); ok {
		return value.(*ReqCounterItem)
	}
	reqCounterItem := newReqCounterItem(serviceName, redisCli)
	handler.ReqCounterMap.Store(serviceName, reqCounterItem)
	return reqCounterItem
}

// ReqCounterItem 结构体用于统计服务的请求
type ReqCounterItem struct {
	Client      *redis.Client
	ServiceName string // 服务名称
}

// newReqCounterItem 初始化ReqCounterItem实例
func newReqCounterItem(serviceName string, redisCli *redis.Client) *ReqCounterItem {
	return &ReqCounterItem{
		Client:      redisCli,
		ServiceName: serviceName,
	}
}

// RecordRequest 增加当前小时的请求计数
func (src *ReqCounterItem) RecordRequest(ctx context.Context) error {
	// TODO 每次请求都写入redis 优化
	now := time.Now()
	// dateKey = flow_ReqCounter_serviceName_2006-01-02
	dateKey := fmt.Sprintf("%s_%s_%s", common.ReqCounterByService, src.ServiceName, now.Format(common.DateFormat))
	hour := now.Hour()
	_, err := src.Client.HIncrBy(ctx, dateKey, strconv.Itoa(hour), 1).Result()
	return err
}

// GetHourlyCountsForDate 获取指定日期每小时的请求计数
func (src *ReqCounterItem) GetHourlyCountsForDate(ctx context.Context, date string) ([]int64, error) {
	fullKey := fmt.Sprintf("%s_%s_%s", common.ReqCounterByService, src.ServiceName, date)
	hashEntries, err := src.Client.HGetAll(ctx, fullKey).Result()
	if err != nil {
		return nil, err
	}

	counts := make([]int64, 24)
	for hourStr, countStr := range hashEntries {
		hour, err := strconv.Atoi(hourStr)
		if err != nil {
			continue
		}
		if hour >= 0 && hour < 24 {
			count, err := strconv.ParseInt(countStr, 10, 64)
			if err == nil {
				counts[hour] = count
			}
		}
	}

	return counts, nil
}

// CleanupOldData 清理指定服务的过期统计数据
func (src *ReqCounterItem) CleanupOldData(ctx context.Context, retentionDays int) (int64, error) {
	cutoff := time.Now().AddDate(0, 0, -retentionDays).Format(common.DateFormat)
	pattern := fmt.Sprintf("%s_%s_%s", common.ReqCounterByService, src.ServiceName, cutoff)
	keys, err := src.Client.Keys(ctx, pattern).Result()
	if err != nil {
		return 0, err
	}
	if len(keys) > 0 {
		deletedCount, err := src.Client.Del(ctx, keys...).Result()
		if err != nil {
			return 0, err
		}
		return deletedCount, nil
	}
	return 0, nil
}