// 爬虫相关
package main

import (
	"bytes"
	"fmt"
	"sync"
	"time"

	"github.com/PuerkitoBio/goquery"
	"github.com/valyala/fasthttp"
	"github.com/valyala/fastjson"
)

type httpClient struct {
	client      *fasthttp.Client
	url         string
	body        []byte
	method      string
	cookies     []*fasthttp.Cookie
	userAgent   string
	contentType string
	referer     string
}

var defaultClient = &fasthttp.Client{
	MaxIdleConnDuration: 90 * time.Second,
	ReadTimeout:         10 * time.Second,
	WriteTimeout:        10 * time.Second,
}

var fetchRoomPool fastjson.ParserPool

// 直播间的数据结构
type liveRoom struct {
	name   string // 主播名字
	title  string // 直播间标题
	liveID string // 直播 ID
}

// liveRoom 的 map
var liveRooms struct {
	sync.RWMutex                   // rooms 的锁
	rooms        map[int]*liveRoom // 现在的 liveRoom
	newRooms     map[int]*liveRoom // 新的 liveRoom
}

// liveRoom 的 pool
var liveRoomPool = &sync.Pool{
	New: func() any {
		return new(liveRoom)
	},
}

// 获取主播的直播链接
func getURL(uid int) string {
	const livePage = "https://live.acfun.cn/live/%d"
	return fmt.Sprintf(livePage, uid)
}

// 获取主播的直播链接
func (s *streamer) getURL() string {
	return getURL(s.UID)
}

// http 请求，调用后需要 defer fasthttp.ReleaseResponse(resp)
func (c *httpClient) doRequest() (resp *fasthttp.Response, e error) {
	defer func() {
		if err := recover(); err != nil {
			lPrintErrf("Recovering from panic in doRequest(), the error is: %v", err)
			e = fmt.Errorf("请求 %s 时出错，错误为 %v", c.url, err)
			fasthttp.ReleaseResponse(resp)
		}
	}()

	if c.client == nil {
		c.client = defaultClient
	}

	req := fasthttp.AcquireRequest()
	defer fasthttp.ReleaseRequest(req)
	resp = fasthttp.AcquireResponse()

	if c.url != "" {
		req.SetRequestURI(c.url)
	} else {
		fasthttp.ReleaseResponse(resp)
		return nil, fmt.Errorf("请求的 url 不能为空")
	}

	if len(c.body) != 0 {
		req.SetBody(c.body)
	}

	if c.method != "" {
		req.Header.SetMethod(c.method)
	} else {
		// 默认为 GET
		req.Header.SetMethod(fasthttp.MethodGet)
	}

	if len(c.cookies) != 0 {
		for _, cookie := range c.cookies {
			req.Header.SetCookieBytesKV(cookie.Key(), cookie.Value())
		}
	}

	const userAgent = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36"

	if c.userAgent != "" {
		req.Header.SetUserAgent(c.userAgent)
	} else {
		req.Header.SetUserAgent(userAgent)
	}

	if c.contentType != "" {
		req.Header.SetContentType(c.contentType)
	}

	if c.referer != "" {
		req.Header.SetReferer(c.referer)
	}

	req.Header.SetCookie("_did", deviceID)

	req.Header.Set("Accept-Encoding", "gzip")

	err := c.client.Do(req, resp)
	checkErr(err)

	return resp, nil
}

// 获取响应 body
func getBody(resp *fasthttp.Response) []byte {
	if string(resp.Header.Peek("content-encoding")) == "gzip" || string(resp.Header.Peek("Content-Encoding")) == "gzip" {
		body, err := resp.BodyGunzip()
		if err == nil {
			return body
		}
	}

	return resp.Body()
}

// 获取全部 AcFun 直播间
func fetchAllRooms() bool {
	for count := 10000; count < 1e9; count *= 10 {
		rooms, all, err := fetchLiveRoom(count)
		if err != nil {
			lPrintErr(err)
			return false
		}
		if all {
			liveRooms.newRooms = rooms
			return true
		}
		if count == 1e8 {
			lPrintErr("获取正在直播的直播间列表失败")
		}
	}
	return false
}

// 获取指定数量的 AcFun 直播间列表
func fetchLiveRoom(count int) (rooms map[int]*liveRoom, all bool, e error) {
	defer func() {
		if err := recover(); err != nil {
			e = fmt.Errorf("fetchLiveRoom() error: %v", err)
		}
	}()

	const liveListURL = "https://live.acfun.cn/api/channel/list?count=%d&pcursor=0"

	client := &httpClient{
		url:    fmt.Sprintf(liveListURL, count),
		method: fasthttp.MethodGet,
	}
	resp, err := client.doRequest()
	checkErr(err)
	defer fasthttp.ReleaseResponse(resp)
	body := getBody(resp)

	p := fetchRoomPool.Get()
	defer fetchRoomPool.Put(p)
	v, err := p.ParseBytes(body)
	checkErr(err)
	v = v.Get("channelListData")
	if !v.Exists("result") || v.GetInt("result") != 0 {
		panic(fmt.Errorf("无法获取AcFun直播间列表，响应为：%s", string(body)))
	}

	if string(v.GetStringBytes("pcursor")) != "no_more" {
		return nil, false, nil
	}

	liveList := v.GetArray("liveList")
	rooms = make(map[int]*liveRoom, len(liveList))
	for _, live := range liveList {
		uid := live.GetInt("authorId")
		room := liveRoomPool.Get().(*liveRoom)
		room.name = string(live.GetStringBytes("user", "name"))
		room.title = string(live.GetStringBytes("title"))
		room.liveID = string(live.GetStringBytes("liveId"))
		rooms[uid] = room
	}

	return rooms, true, nil
}

// 根据 uid 获取主播的名字，可能需要检查返回是否为空
func getName(uid int) string {
	liveRooms.RLock()
	room, ok := liveRooms.rooms[uid]
	if ok {
		name := room.name
		liveRooms.RUnlock()
		return name
	}
	liveRooms.RUnlock()

	_, room, err := tryFetchLiveInfo(uid)
	if err != nil {
		return ""
	}
	defer liveRoomPool.Put(room)
	return room.name
}

// 根据 uid 获取主播直播间的标题
func getTitle(uid int) string {
	liveRooms.RLock()
	room, ok := liveRooms.rooms[uid]
	if ok {
		title := room.title
		liveRooms.RUnlock()
		return title
	}
	liveRooms.RUnlock()

	if isLive, room, err := tryFetchLiveInfo(uid); err == nil {
		defer liveRoomPool.Put(room)
		if isLive {
			return room.title
		}
	}
	return ""
}

// 根据 uid 获取 liveID，结果准确，可能需要检查返回是否为空
func getLiveID(uid int) string {
	if isLive, room, err := tryFetchLiveInfo(uid); err == nil {
		defer liveRoomPool.Put(room)
		if isLive {
			return room.liveID
		}
	}
	return ""
}

// 根据 uid 查看主播是否正在直播
func isLiveOn(uid int) bool {
	liveRooms.RLock()
	_, ok := liveRooms.rooms[uid]
	liveRooms.RUnlock()
	if ok {
		return true
	}

	if isLive, room, err := tryFetchLiveInfo(uid); err == nil {
		defer liveRoomPool.Put(room)
		return isLive
	}
	return false
}

// 获取主播直播间的标题
func (s *streamer) getTitle() string {
	return getTitle(s.UID)
}

// 获取 liveID，由于 AcFun 的 bug，结果不一定准确，可能需要检查返回是否为空
func (s *streamer) getLiveID() string {
	liveRooms.RLock()
	defer liveRooms.RUnlock()
	room, ok := liveRooms.rooms[s.UID]
	if ok {
		return room.liveID
	}
	return ""
}

// 查看主播是否在直播，由于 AcFun 的 bug，结果不一定准确
func (s *streamer) isLiveOn() bool {
	liveRooms.RLock()
	defer liveRooms.RUnlock()
	_, ok := liveRooms.rooms[s.UID]
	return ok
}

// 获取用户直播相关信息，可能要将 room 放回 liveRoomPool
func fetchLiveInfo(uid int) (isLive bool, room *liveRoom, e error) {
	defer func() {
		if err := recover(); err != nil {
			e = fmt.Errorf("fetchLiveInfo() error: %v", err)
		}
	}()

	const acLiveInfo = "https://live.acfun.cn/api/live/info?authorId=%d"

	client := &httpClient{
		url:    fmt.Sprintf(acLiveInfo, uid),
		method: fasthttp.MethodGet,
	}
	resp, err := client.doRequest()
	checkErr(err)
	defer fasthttp.ReleaseResponse(resp)
	body := getBody(resp)

	p := fetchRoomPool.Get()
	defer fetchRoomPool.Put(p)
	v, err := p.ParseBytes(body)
	checkErr(err)
	if !v.Exists("result") || v.GetInt("result") != 0 {
		return false, nil, fmt.Errorf("无法获取uid为%d的主播的直播信息，响应为：%s", uid, string(body))
	}

	room = liveRoomPool.Get().(*liveRoom)
	if v.Exists("liveId") {
		isLive = true
		room.title = string(v.GetStringBytes("title"))
		room.liveID = string(v.GetStringBytes("liveId"))
	} else {
		isLive = false
		room.title = ""
		room.liveID = ""
	}

	room.name = string(v.GetStringBytes("user", "name"))

	return isLive, room, nil
}

// 获取用户直播相关信息，可能要将 room 放回 liveRoomPool
func tryFetchLiveInfo(uid int) (isLive bool, room *liveRoom, err error) {
	err = runThrice(func() (err error) {
		isLive, room, err = fetchLiveInfo(uid)
		return err
	})
	return isLive, room, err
}

// 通过 wap 版网页查看主播是否在直播
func (s *streamer) isLiveOnByPage() (isLive bool) {
	defer func() {
		if err := recover(); err != nil {
			lPrintErr("Recovering from panic in isLiveOnByPage(), the error is:", err)
			lPrintErr("获取" + s.longID() + "的直播页面时出错")
		}
	}()

	const acLivePage = "https://m.acfun.cn/live/detail/%d"
	const mobileUserAgent = "Mozilla/5.0 (iPad; CPU iPhone OS 13_2_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0.3 Mobile/15E148 Safari/604.1"

	client := &httpClient{
		url:       fmt.Sprintf(acLivePage, s.UID),
		method:    fasthttp.MethodGet,
		userAgent: mobileUserAgent,
	}
	resp, err := client.doRequest()
	checkErr(err)
	defer fasthttp.ReleaseResponse(resp)
	body := getBody(resp)

	doc, err := goquery.NewDocumentFromReader(bytes.NewReader(body))
	checkErr(err)
	return doc.Find("p.closed-tip").Text() != "直播已结束"
}