var http = require('http');      // http 网路
var cheerio = require('cheerio');  // html 解析
var fs = require("fs");        // 流
var mkdirp = require('mkdirp');

// 设置被查询的目标网址
var queryHref = "http://www.haha.mx/topic/1/new/";
// 设置分页位置
var querySearch = 1;
var urls = [];
var dir = 'hahamx';
mkdirp(dir, function (err) {
	if (err) {
		console.log(err);
	}
});
/**
 * 根据url和参数获取分页内容
 * @param {String}： url
 * @param {int}： serach
 */
function getHtml(href, serach) {
	var pageData = "";
	var req = http.get(href + serach, function (res) {
		res.setEncoding('utf8');
		res.on('data', function (chunk) {
			pageData += chunk;
		});
		res.on('end', function () {
			$ = cheerio.load(pageData);
			var html = $(".joke-list-item .joke-main-content a img");
			for (var i = 0; i < html.length; i++) {
				var src = html[i].attribs.src;
				// 筛选部分广告，不是真的段子
				if (src.indexOf("http://image.haha.mx") > -1) {
					urls.push(html[i].attribs.src)
				}
			}
			if (serach == pagemax) {
				console.log("图片链接获取完毕！" + urls.length);
				console.log("链接总数量：" + urls.length);
				if (urls.length > 0) {
					downImg(urls.shift());
				} else {
					console.log("下载完毕");
				}
			}
		});
	});
}
/**
 * 下载图片
 * @param {String} imgurl：图片地址
 */
function downImg(imgurl) {
	// console.log(imgurl);
	var narr = imgurl.replace("http://image.haha.mx/", "").split("/")
	http.get(imgurl.replace("/small/", "/big/"), function (res) {
		var imgData = "";
		//一定要设置response的编码为binary否则会下载下来的图片打不开
		res.setEncoding("binary");
		res.on("data", function (chunk) {
			imgData += chunk;
		});
		res.on("end", function () {
			var savePath = "./" + dir + "/" + narr[0] + narr[1] + narr[2] + "_" + narr[4];
			fs.writeFile(savePath, imgData, "binary", function (err) {
				if (err) {
					console.log(err);
				} else {
					console.log(narr[0]  + narr[1] + narr[2] + "_" + narr[4]);
					if (urls.length > 0) {
						downImg(urls.shift());
					} else {
						console.log("下载完毕");
					}
				}
			});
		});
	});
}
var pagemax = 20;    // 获取10页的内容
function start() {
	console.log("开始获取图片连接");
	for (var i = 1; i <= pagemax; i++) {
		getHtml(queryHref, i);
	}
}
start();