package main

import (
	"bufio"
	"fmt"
	"github.com/antchfx/htmlquery"
	"io/ioutil"
	"net/http"
	"os"
	"strconv"
	"time"
)

func getResponse(url string ) *http.Response {

	client := &http.Client{}
	//生成要访问的url
	//提交请求
	request, err := http.NewRequest("GET", url, nil)

	//增加header选项
	request.Header.Add("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36")
	request.Header.Add("Referer", "https://www.cnblogs.com/brady-wang/default.html?page=167")

	if err != nil {
		panic(err)
	}
	//处理返回结果
	resp, _ := client.Do(request)

	return resp
}

func main() {

		var url string = "https://www.cnblogs.com/brady-wang/default.html?page="
		pages := 167
		for i:=1;i<=pages;i++{
			newUrl := url + strconv.Itoa(i)
			fmt.Printf("crawl page %s\n",newUrl)
			urlList := getUrls(newUrl)
			if len(urlList) > 0{
				for _,detailUrl := range urlList{
					//fmt.Printf("crawl 详情页面 %s\n",detailUrl)
					title := getDetail(detailUrl)
					fmt.Printf("%s\n",title)
					time.Sleep(time.Microsecond*3000)
				}
			}
		}

}

func getDetail(url string) string  {
	response := getResponse(url)
	defer response.Body.Close()
	doc,err := htmlquery.Parse(response.Body)

	if err !=nil{
		return ""
	}

	titleNodes := htmlquery.Find(doc,"//*[@id='cb_post_title_url']/span")
	if len(titleNodes) >0{
		title := htmlquery.InnerText(titleNodes[0])
		return title
	} else {
		return ""
	}


}

func getUrls(url string )[]string  {
	response := getResponse(url)
	defer response.Body.Close()

	doc,_ := htmlquery.Parse(response.Body)
	list := htmlquery.Find(doc,"//*[@id='mainContent']//div[@class='postTitle']/a")
	var urls = make([]string,0)
	for _,item := range list{
		url := htmlquery.SelectAttr(item,"href")
		urls = append(urls, url)
	}
	return urls
}

func downloadXiaoshuo(url string)  {
	response := getResponse(url)
	defer response.Body.Close()
	body,err := ioutil.ReadAll(response.Body)
	if err != nil{
		fmt.Println(err)
	}
	writeToFile(string(body))
}

func writeToFile(str string )  {
	filePath := "./a.txt"
	file, err := os.OpenFile(filePath, os.O_WRONLY | os.O_CREATE, 0666)
	if err != nil {
		fmt.Printf("open file err=%v\n", err)
		return
	}
	//及时关闭file句柄
	defer file.Close()
	//写入时，使用带缓存的 *Writer
	writer := bufio.NewWriter(file)
	for i := 0; i < 5; i++ {
		writer.WriteString(str)
	}

}