package utils

import (
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"math/rand"
	"regexp"
	"sort"
	"strings"
	"time"
)

func toHexDigest(str string) string {
	h := md5.New()
	h.Write([]byte(str))

	return hex.EncodeToString(h.Sum(nil))
}

/* contributor: https://github.com/Azure99/GenshinPlayerQuery/issues/20 @lulu666lulu */
func GetDS(url, data string) (t, v, ds string) {
	// 5: mobile web
	const appType = "5"
	const apiSalt = "xV8v4Qu54lUKrEYFZkJhB8cuOh9Asafs"
	const appVersion = "2.11.1"
	rand.Seed(time.Now().UnixNano())

	// unix timestamp
	i := time.Now().Unix()
	// random number 100k - 200k
	r := rand.Intn(100000) + 100000
	// body
	b := data
	// query
	q := func() string {
		urlParts := strings.Split(url, "?")
		if len(urlParts) == 2 {
			querys := strings.Split(urlParts[1], "&")
			sort.Strings(querys)
			return strings.Join(querys, "&")
		}
		return ""
	}()
	c := toHexDigest(fmt.Sprintf("salt=%s&t=%d&r=%d&b=%s&q=%s", apiSalt, i, r, b, q))
	ds = fmt.Sprintf("%d,%d,%s", i, r, c)

	return appType, appVersion, ds
}

/*
 * t1, t2: string, HH:MM
 * t1 > t2 return 1
 * t1 = t2 return 0
 * t1 < t2 return -1
 */
func timeCmp(t1, t2 string) int {
	hh1, mm1, hh2, mm2 := 0, 0, 0, 0
	fmt.Sscanf(t1, "%d:%d", &hh1, &mm1)
	fmt.Sscanf(t2, "%d:%d", &hh2, &mm2)

	switch {
	case hh1 > hh2:
		return 1
	case hh2 > hh1:
		return -1
	case mm1 > mm2:
		return 1
	case mm1 < mm2:
		return -1
	default:
		return 0
	}
}

/*
 * 判断当前时刻是否在某个事件段内, 分钟级
 * timeRangeStr: string, HH:MM-HH:MM
 * 返回true or false， 若结果true，第二个返回值为距离结束时间段结束的时间，否则返回0
 * 如果timeRangeStr格式错误，返回false, 0
 */
func NowInTimeRange(timeRangeStr string) (bool, time.Duration) {
	rc := regexp.MustCompile("^((0?[0-9]|1[0-9]|2[0-3]):(0?[0-9]|[1-5][0-9])) *- *((0?[0-9]|1[0-9]|2[0-3]):(0?[0-9]|[1-5][0-9]))$")
	if timeRangeStr == "" || !rc.Match([]byte(timeRangeStr)) {
		/* 无效的时间段 */
		return false, 0
	}
	waitTime := func(now, end time.Time) time.Duration {
		return time.Duration((end.Unix() - now.Unix())) * time.Second
	}
	timeRange := regexp.MustCompile("((0?[0-9]|1[0-9]|2[0-3]):([1-5][0-9]|0?[0-9]))").FindAllString(timeRangeStr, 2)
	now := time.Now()
	end, _ := time.ParseInLocation("2006-01-02 15:04", fmt.Sprintf("%d-%02d-%02d %s", now.Year(), now.Month(), now.Day(), timeRange[1]), time.Local)
	nowHHMM := fmt.Sprint(now.Hour(), ":", now.Minute())
	if timeCmp(timeRange[0], timeRange[1]) > 0 {
		/* 时间范围跨过0点 */
		if timeCmp(nowHHMM, timeRange[0]) >= 0 && timeCmp(nowHHMM, "23:59") <= 0 {
			/* 0点前 */
			return true, waitTime(now, end.AddDate(0, 0, 1))
		}
		if timeCmp(nowHHMM, "00:00") >= 0 && timeCmp(nowHHMM, timeRange[1]) < 0 {
			return true, waitTime(now, end)
		}
	} else {
		if timeCmp(nowHHMM, timeRange[0]) >= 0 && timeCmp(nowHHMM, timeRange[1]) < 0 {
			return true, waitTime(now, end)
		}
	}

	return false, 0
}