const cheerio = require('cheerio');
const rp = require('request-promise');
const fs = require('fs');

const BASE_URL = "https://www.skroutz.gr";
const SHOP_URL = "/m.DasHome.10646.html";

const queue = [];
var _timer = null;
function exec () {
	if(!queue.length) {
		_timer = null;
		return;
	}

	var i = queue.shift();
	console.log("Performing Query", i[2].uri);
	rp(i[2]).then((d) => i[0](d)).catch((e) => i[1](e));
	setTimeout(exec, 1000);
}

function httpsGet(uri) {
	let options = {
		uri,
		headers: {
			'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36'
		},
		transform: (body) => cheerio.load(body) 
	};
	// return rp(options);
	return new Promise((res,rej) => {
		queue.push([res, rej, options]);
		if(!_timer) {
			_timer = setTimeout(exec, 100);
		}
	});
}

class Crawler {
	constructor() {
		this.baseURL = BASE_URL;
	}

	getCategories() { 
		return httpsGet(this.baseURL + SHOP_URL)
		.then(($) => {
			let categories = $(".super-categories .card:not(.manufacturer-card) h2 a").toArray();
			let quantity = $(".super-categories .card:not(.manufacturer-card) h2 a span").toArray();
			let links = $(".super-categories .card:not(.manufacturer-card) h2 a").toArray();
			categories    = categories.map((i) => $(i).attr('title'));
			quantity 	  = quantity.map((i) => $(i).text().replace('(','').replace(')','')); //remove parenthesis
			links		  = links.map((i) => $(i).attr('href'));
			
			let objects = categories.map((item, index) => {
				return {
					name: item,
					quantity: parseInt(quantity[index]),
					link: this.baseURL + links[index]
				};
			});

			return objects;
		})
		.catch((e) => console.log("ERROR:::::",e));

	}

	getProducts(url) {
		return httpsGet(url)
		.then(($) => {
			let cards = $("ol#sku-list li").toArray().map((item) => $(item).data('skuid'));
			const anchors = $("ol#sku-list li div.price a.js-sku-link").toArray();
			let links  = anchors.map((item) => $(item).attr('href'));
			let prices = anchors.map((item) => $(item).text());
			let titles = anchors.map((item) => $(item).attr('title'));

			let result = [];
			for (let i = 0; i < cards.length; i ++) {
				result.push({
					link : this.baseURL + links[i],
					sku  : cards[i],
					price: prices[i],
					title: titles[i] 
				});
			}
			return result;
		})
		.catch((er) => console.log("ERROR PRODUCT GET : " , er));
	}

	getAllProducts(url, total) {
		console.log(url);
		let pages = Math.ceil(total/48);
		let res = [];
		for(let j=1;j<=pages;j++) {
			res.push(
			 this.getProducts(url + "?page=" + j)
			)
		}
		return Promise.all(res).then((values) =>  {
			let a = [].concat.apply([], values);
			return a;
		})
		.catch((e) => console.log("ALL PRODUCTS ERROR:::::", url));
	}

	getCompanies(url) {
		console.log(url);
		return httpsGet(url)
		.then(($) => {
			let companies = $("ol#prices li").toArray();

			let names  = $("ol#prices li .shop .shop-name").toArray().map((i) => $(i).text());
			let prices = $("ol#prices li .price a.product-link").toArray().map((i) => parseFloat($(i).text().replace('€', '').replace(',','.')));			
			let res = [];
			for (let i=0;i<names.length;i++) {
				res.push({
					name: names[i],
					price: prices[i]
				});
			}
			return res;
		})
	}

	retrieve() {
		let result = {
			categories: [],
			skus: [],
			companies: []
		}
		return this.getCategories().then((categories) => {
			result.categories = categories;
			return Promise.all(categories.map((cat) => this.getAllProducts(cat.link, cat.quantity)));
		})
		.then((skus) => {
			result.skus = skus;
			return Promise.all(skus.map((sku) => this.getCompanies(sku.link)))
		})
		.then((companies) => {
			result.companies = companies;
			return result;
		})
	}
}



let crawler = new Crawler();
crawler.retrieve().then((data) => {
	fs.writeFileSync("data", JSON.stringify(data));
	console.log("SUCCESS123123");
	console.log(data);
	console.log("SUCCESS123123");

});


//crawler.getCategories();
// crawler.getAllProducts('/c/1158/kourtines/m/10646/Das-Home.html', 49);
// crawler.getCompanies('/s/12890875/Das-Home-%CE%A3%CE%B5%CF%84-Ninjago-Lego-5008-160x260.html');