package utils

import (
	"strconv"

	"github.com/TeaOSLab/EdgeCommon/pkg/iplibrary"
	teaconst "github.com/TeaOSLab/EdgeNode/internal/const"
	"github.com/TeaOSLab/EdgeNode/internal/utils/agents"
	"github.com/TeaOSLab/EdgeNode/internal/utils/cachehits"
	"github.com/TeaOSLab/EdgeNode/internal/utils/fasttime"
	"github.com/TeaOSLab/EdgeNode/internal/utils/re"
	"github.com/TeaOSLab/EdgeNode/internal/utils/ttlcache"
	"github.com/TeaOSLab/EdgeNode/internal/waf/requests"
	"github.com/cespare/xxhash/v2"
	"github.com/iwind/TeaGo/types"
	stringutil "github.com/iwind/TeaGo/utils/string"
)

var SharedCache = ttlcache.NewCache[int8]()
var cacheHits *cachehits.Stat

func init() {
	if !teaconst.IsMain {
		return
	}
	cacheHits = cachehits.NewStat(5)
}

const (
	MaxCacheDataSize = 1024
)

type CacheLife = int64

const (
	CacheDisabled   CacheLife = 0
	CacheShortLife  CacheLife = 600
	CacheMiddleLife CacheLife = 1800
	CacheLongLife   CacheLife = 7200
)

// MatchStringCache 正则表达式匹配字符串，并缓存结果
func MatchStringCache(regex *re.Regexp, s string, cacheLife CacheLife) bool {
	if regex == nil {
		return false
	}

	var regIdString = regex.IdString()

	// 如果长度超过一定数量，大概率是不能重用的
	if cacheLife <= 0 || len(s) > MaxCacheDataSize || !cacheHits.IsGood(regIdString) {
		return regex.MatchString(s)
	}

	var hash = xxhash.Sum64String(s)
	var key = regIdString + "@" + strconv.FormatUint(hash, 10)
	var item = SharedCache.Read(key)
	if item != nil {
		cacheHits.IncreaseHit(regIdString)
		return item.Value == 1
	}
	var b = regex.MatchString(s)
	if b {
		SharedCache.Write(key, 1, fasttime.Now().Unix()+cacheLife)
	} else {
		SharedCache.Write(key, 0, fasttime.Now().Unix()+cacheLife)
	}
	cacheHits.IncreaseCached(regIdString)
	return b
}

// MatchBytesCache 正则表达式匹配字节slice，并缓存结果
func MatchBytesCache(regex *re.Regexp, byteSlice []byte, cacheLife CacheLife) bool {
	if regex == nil {
		return false
	}

	var regIdString = regex.IdString()

	// 如果长度超过一定数量，大概率是不能重用的
	if cacheLife <= 0 || len(byteSlice) > MaxCacheDataSize || !cacheHits.IsGood(regIdString) {
		return regex.Match(byteSlice)
	}

	var hash = xxhash.Sum64(byteSlice)
	var key = regIdString + "@" + strconv.FormatUint(hash, 10)
	var item = SharedCache.Read(key)
	if item != nil {
		cacheHits.IncreaseHit(regIdString)
		return item.Value == 1
	}
	var b = regex.Match(byteSlice)
	if b {
		SharedCache.Write(key, 1, fasttime.Now().Unix()+cacheLife)
	} else {
		SharedCache.Write(key, 0, fasttime.Now().Unix()+cacheLife)
	}
	cacheHits.IncreaseCached(regIdString)
	return b
}

// ComposeIPType 组合IP类型
func ComposeIPType(setId int64, req requests.Request) string {
	return "set:" + types.String(setId) + "@" + stringutil.Md5(req.WAFRaw().UserAgent())
}

var searchEngineProviderMap = map[string]bool{
	"谷歌":       true,
	"雅虎":       true,
	"脸书":       true,
	"百度":       true,
	"Facebook": true,
	"Yandex":   true,
}

// CheckSearchEngine check if ip is from search engines
func CheckSearchEngine(ip string) bool {
	if len(ip) == 0 {
		return false
	}

	if agents.SharedManager.ContainsIP(ip) {
		return true
	}

	var result = iplibrary.LookupIP(ip)
	if result == nil {
		return false
	}

	return searchEngineProviderMap[result.ProviderName()]
}