package main

import (
	"github.com/PuerkitoBio/goquery"
	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"
	"log"
	"net/http"
	"regexp"
	"strconv"
	"strings"
	"sync"
	"time"
)

type fetchData struct {
	Url   string `json:"url"`
	Title string `json:"title"`
	Desc  string `json:"desc"`
	Date  string `json:"date"`
}

type connChan struct {
	conn string
	msg  message
}
type dataChan struct {
	conn string
	item []fetchData
}

type fetchHandler struct {
	fetchUrl      string
	hadFetchData  []fetchData
	cronTime      map[string]time.Duration
	keyword       map[string]string
	hadFetchedMap map[string]int
	reloadCron    map[string]chan int
	isOff         chan int
	rMsgChan      chan connChan
	newFetchItem  chan dataChan
	connMap       map[string]*websocket.Conn
}

type setting struct {
	Keyword  string `json:"keyword"`
	TimeStep int    `json:"timeStep"`
}

type message struct {
	Status  bool
	Action  string
	Message string
	Data    interface{}
}

func setMap[T string | time.Duration | int](obj *mapXS[T], key string, v T) {
	obj.Lock()
	(*obj.mapX)[key] = v
	obj.Unlock()
}

type mapX[T string | int | time.Duration] map[string]T

type mapXS[T string | int | time.Duration] struct {
	*mapX[T]
	*sync.Mutex
}

func newFetchHandler(fetchUrl string) *fetchHandler {
	return &fetchHandler{
		fetchUrl:      fetchUrl,
		keyword:       make(map[string]string),
		hadFetchedMap: make(map[string]int),
		cronTime:      make(map[string]time.Duration),
		reloadCron:    make(map[string]chan int),
		isOff:         make(chan int),
		rMsgChan:      make(chan connChan, 10),
		newFetchItem:  make(chan dataChan, 10),
		connMap:       make(map[string]*websocket.Conn),
	}
}

func (f *fetchHandler) handle(conn string) {
	key := "纪检"
	if kk, ok := f.keyword[conn]; ok && kk != "" {
		key = kk
	}
	f.parsesDom(f.fetch(f.fetchUrl+key), conn)
}

func (f *fetchHandler) receiveMsg() {
	for {
		r := <-f.rMsgChan
		switch r.msg.Action {
		case "search":
			if t, ok := r.msg.Data.(*setting); ok {
				f.reloadCron[r.conn] <- t.TimeStep
				f.keyword[r.conn] = t.Keyword
				f.handle(r.conn)
			}
		}
	}
}

func (f *fetchHandler) fetch(url string) *http.Response {
	defer func() {
		if r := recover(); r != nil {
			log.Println(r)
		}
	}()
	client := http.Client{
		Transport:     nil,
		CheckRedirect: nil,
		Jar:           nil,
		Timeout:       10 * time.Second,
	}
	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9")
	req.Header.Add("accept-language", "zh-CN,zh;q=0.9")
	req.Header.Add("cache-control", "no-cache")
	req.Header.Add("connection", "keep-alive")
	req.Header.Add("cookie", "BIDUPSID=844E3DCAA2EEBF5C872DC99B967B6B7B; PSTM=1655872163; BAIDUID=844E3DCAA2EEBF5CB3E1D79750162204:FG=1; BD_UPN=123353; ORIGIN=2; ISSW=1; ISSW=1; BAIDUID_BFESS=844E3DCAA2EEBF5CB3E1D79750162204:FG=1; ZFY=jWFAySgO:AoQfb6emY9vnmEdptVao:Anj0FFkp028wFws:C; BD_HOME=1; delPer=0; BD_CK_SAM=1; PSINO=3; COOKIE_SESSION=42_0_2_2_3_0_1_0_2_0_0_0_18_0_51_0_1655888428_0_1655888377%7C3%230_0_1655888377%7C1; BAIDU_WISE_UID=wapp_1655902298617_702; ZD_ENTRY=google; channel=baidusearch; baikeVisitId=b3b23509-9330-4d33-82ae-b8eb37895917; BA_HECTOR=8k2g2g218ga40181ak1hbgg1n14; BDRCVFR[C0p6oIjvx-c]=mbxnW11j9Dfmh7GuZR8mvqV; BDSVRTM=1011; H_PS_PSSID=36550_36459_36673_36455_36453_36692_36165_36695_36697_36569_36075_36467_36316_36651")
	req.Header.Add("referer", "http://news.baidu.com/")
	req.Header.Add("sec-fetch-dest", "document")
	req.Header.Add("sec-fetch-mode", "navigate")
	req.Header.Add("sec-fetch-site", "cross-site")
	req.Header.Add("sec-fetch-user", "?1")
	req.Header.Add("upgrade-insecure-requests", "1")
	req.Header.Add("user-agent", "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36")
	req.Header.Add("#sec-ch-ua", "\".Not/A)Brand\";v=\"99\", \"Google Chrome\";v=\"103\", \"Chromium\";v=\"103\"")
	req.Header.Add("sec-ch-ua-mobile", "?0")
	req.Header.Add("sec-ch-ua-platform", "\"Linux\"")
	req.Header.Add("postman-token", "81407fbc-2b96-54a7-0193-f640156714ab")

	response, err := client.Do(req)

	if err != nil {
		panic(err)
	}
	return response
}

func (f *fetchHandler) parsesDom(html *http.Response, conn string) {
	defer func() {
		if r := recover(); r != nil {
			log.Println(r)
		}
	}()
	doc, err := goquery.NewDocumentFromReader(html.Body)
	if err != nil {
		panic(err)
	}
	var newFetch []fetchData
	ti := time.Now()
	log.Println(ti.Format("2006-01-02 15:04:05"))
	compile := regexp.MustCompile(`(\d+)`)

	doc.Find("div[class=\"result-op c-container xpath-log new-pmd\"]").Each(func(i int, selection *goquery.Selection) {
		data := fetchData{}
		data.Url, _ = selection.Attr("mu")
		t := selection.Find(".news-title-font_1xS-F").First()
		data.Title = t.Text()
		data.Desc = selection.Find(".c-row .c-color-text").First().Text()
		data.Date = selection.Find("span[class=\"c-color-gray2 c-font-normal c-gap-right-xsmall\"]").First().Text()
		n := compile.FindAllStringSubmatch(data.Date, -1)
		if nil != n {
			nn, _ := strconv.Atoi(n[0][0])
			if strings.Contains(data.Date, "小时") {
				data.Date = ti.Add(-time.Duration(nn) * time.Hour).Format("2006-01-02 15:04")
			}
			if strings.Contains(data.Date, "分钟") {
				data.Date = ti.Add(-time.Duration(nn) * time.Minute).Format("2006-01-02 15:04")
			}
		}

		k := conn + "_" + data.Url + "_" + data.Title
		if _, ok := f.hadFetchedMap[k]; !ok {
			f.hadFetchData = append(f.hadFetchData, data)
			f.hadFetchedMap[k] = 1
			newFetch = append(newFetch, data)
		}
	})
	if len(newFetch) > 0 {
		f.newFetchItem <- dataChan{
			conn: conn,
			item: newFetch,
		}
	}
	err = html.Body.Close()
	if err != nil {
		panic(err)
	}
}

func (f *fetchHandler) sendFetchData() {
	for {
		data := <-f.newFetchItem

		err := f.connMap[data.conn].WriteJSON(message{
			Status:  true,
			Action:  "newData",
			Message: "",
			Data:    data.item,
		})
		if err != nil {
			log.Println(err)
		}
	}
}

func (f *fetchHandler) cronFetch(conn string, c chan int) {
	step, ok := f.cronTime[conn]
	if !ok {
		step = time.Second * 60
	}
	t := time.NewTicker(step)
	if _, ok := f.cronTime[conn]; !ok {
		f.reloadCron[conn] = make(chan int)
	}
	defer t.Stop()
	for {
		select {
		case <-t.C:
			f.handle(conn)
		case tt := <-f.reloadCron[conn]:
			f.cronTime[conn] = time.Duration(tt) * time.Second
			go f.cronFetch(conn, c)
			return
		case <-c:
			close(c)
			return
		}
	}
}

func main() {
	h := newFetchHandler("https://www.baidu.com/s?rtt=1&bsst=1&cl=2&tn=news&rsv_dl=ns_pc&word=")
	router := gin.Default()
	var upgrader = websocket.Upgrader{
		CheckOrigin: func(r *http.Request) bool {
			return true
		},
	}
	go h.sendFetchData()
	go h.receiveMsg()
	router.LoadHTMLGlob("templates/*")
	//router.LoadHTMLFiles("templates/template1.html", "templates/template2.html")
	router.GET("/index", func(c *gin.Context) {
		c.HTML(http.StatusOK, "index.gohtml", gin.H{
			"title": "爬虫",
		})
	})
	router.GET("ws", func(c *gin.Context) {
		conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
		if err != nil {
			c.JSON(201, message{
				Status:  false,
				Message: err.Error(),
				Data:    nil,
				Action:  "upgradeWs",
			})
			log.Println(err)
			return
		}
		remote := conn.RemoteAddr().String()
		if _, ok := h.connMap[remote]; !ok {
			h.connMap[remote] = conn
		}
		cc := make(chan int)
		go h.cronFetch(remote, cc)
		go func() {
			msg := connChan{
				conn: remote,
				msg: message{
					Data: &setting{},
				},
			}
			for {
				err := conn.ReadJSON(&msg.msg)
				if err != nil {
					if _, ok := h.connMap[remote]; ok && !websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway) {
						delete(h.connMap, remote)
						cc <- 1
						return
					}
					log.Println(err)
				} else {
					h.rMsgChan <- msg
				}
			}
		}()
	})
	err := router.Run(":8080")
	if err != nil {
		panic(err)
	}
}