let baseUrl = 'https://wallhaven.cc/search?q='//earth&categories=111&purity=110&sorting=relevance&order=desc'
const path = require('path')
const cheerio = require('cheerio')
const fs = require('fs')
const request = require('request')
const readline = require('readline');
const imgDir = path.join(__dirname, 'img')

var search = ''
var allPage = 1
var allImg = []
var url = baseUrl + search + '&categories=111&purity=110&sorting=relevance&order=desc&page='

//创建img目录
fs.mkdir('./img', (error) => {
    if (error) {
        //console.log(error);
    } else {
        //console.log('ok');
    }
});

//获取总页数
function getAllPage(word) {
    let realUrl = baseUrl + word + '&categories=111&purity=110&sorting=relevance&order=desc'
    return new Promise((resolve, reject) => {
        //console.log('获取图片页数中...')
        //encodeURI防止用户输入中文搜索无法解析
        request(encodeURI(realUrl), function (err, res, body) {
            //console.log(realUrl)
            if (!err && res) {
                let $ = cheerio.load(body)
                var arr = $('h1').text().split(' ')
                //console.log(arr)
                if (parseInt(arr[0]) == 0) {
                    console.log('未搜索到图片')
                    return
                } else if (parseInt(arr[0].split(",").join("")) <= 24) {
                    allPage = 1
                    console.log('获取到' + allPage + '页图片')
                } else {
                    allPage = Math.ceil(parseInt(arr[0].split(",").join("")) / 24)
                    console.log('获取到' + allPage + '页图片，每页最多24张图片')
                    speakOne.question('大兄弟你要撸多少页：', (res) => {
                        if(!Number(res)){
                            console.log('请输入数字')
                            return
                        }else if(Number(res)>allPage){
                            console.log('输入的页数大于总页数')
                            return
                        }else{
                            resolve(res)
                        }
                        
                    });
                    //allPage = 10
                }
                //resolve(allPage)
            }
        })
    })

}

//获取当前页码图片列表
function getPageImgList(page, word) {
    return new Promise((resolve, reject) => {
        url = baseUrl + word + '&categories=111&purity=110&sorting=relevance&order=desc&page=' + page
        request(url, function (err, res, body) {
            if (!err && res) {
                let $ = cheerio.load(body)
                //allImg = []
                let imgList = []
                $('img').each(function (i, elem) {
                    var imgSrc = $(this).attr('src')
                    if (imgSrc) { }
                    //目标页面有懒加载程序，图片地址先写在data-src当中
                    let imgOriginalSrc = $(this).attr('data-src')
                    if (imgOriginalSrc) {
                        var imgDetail = {
                            title: imgOriginalSrc.split('/')[4],
                            name: imgOriginalSrc.split('/')[5].split('.')[0]
                        }
                        imgList.push(imgDetail)
                    }
                })
                resolve(imgList)
            }
        })
    })
}

//拼接所有图片列表并启动下载
async function getAllImgList(word) {
    let a = await getAllPage(word);
    //console.log(a)
    console.log('获取图片地址中...')
    for (let i = 1; i <= a; i++) {
        console.log('获取第' + i + '页图片地址')
        let b = await getPageImgList(i, word)
        allImg = [...allImg, ...b]
    }
    //console.log(allImg)
    console.log('准备下载中...')
    downloadImg(allImg)
}

//下载图片
function downloadImg(list) {
    //console.log(allImg)
    for (let i = 0; i < list.length; i++) {
        //在下载完一张图片后休息下，防被侦查到是爬虫从而引发反爬虫机制。
        setTimeout(function () {
            var imgUrl = 'https://w.wallhaven.cc/full/' + list[i].title + '/wallhaven-' + list[i].name + '.jpg'
            request(imgUrl, function (err, res, ) {
                console.log(res.statusCode)
                //这里判断图片后缀是否正确,默认为jpg,其他情况都是png等类型图片，无法做出具体判断
                if (res.statusCode == 404) {
                    /* var imgUrl1 = 'https://w.wallhaven.cc/full/' + list[i].title + '/wallhaven-' + list[i].name + '.png'
                    console.log(imgUrl1)
                    request(imgUrl1).pipe(fs.createWriteStream(path.join(imgDir, i + list[i].name + '.' + 'png'))) */
                    console.log('未知图片类型')
                } else {
                    var imgUrl2 = 'https://w.wallhaven.cc/full/' + list[i].title + '/wallhaven-' + list[i].name + '.jpg'
                    console.log(imgUrl2)
                    //写入jpg图片
                    request(imgUrl2).pipe(fs.createWriteStream(path.join(imgDir, i + list[i].name + '.' + 'jpg')))
                }
            })
        }, 3000 * i)
    }
}

//用户输入命令行
const speakOne = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
});

speakOne.question('请输入搜索关键字(只支持英文关键字，如girl、boy,英文不好去百度)：', (line) => {
    getAllImgList(line)
    //speakOne.close();
})