"use strict";

const Promise = require("bluebird");
const bhttp = require("bhttp");
const url = require("url");
const cheerio = require("cheerio");
const defaultValue = require("default-value");

const mergeUrl = require("../merge-url");
const partialData = require("../partial-data");

function ensureValidResponse(response) {
	if (response.statusCode !== 200) {
		throw new Error(`Encountered non-200 response`);
	}
}

let sessionIdRegex = /\/SID-[0-9A-F]{8}-[0-9A-F]{8}\//;

function resolveFromRoot(path) {
	return url.resolve("https://www.lidl-service.com/", path);
}

function parseSku(text) {
	return text.match(/IAN: ([0-9]+)/)[1];
}

function parseType(text) {
	let trimmedText = trimText(text);

	if (trimmedText === "Bedienungsanleitung") {
		return "manual";
	} else if (trimmedText === "Treiber") {
		return "driver";
	} else if (trimmedText === "Sonstiges") {
		/* "Miscellaneous" */
		return null;
	} else {
		throw new Error(`Unrecognized download type: ${trimmedText}`);
	}
}

function trimText(text) {
	if (text == null) {
		return null;
	} else {
		return text.trim();
	}
}

function pageNumberForUrl(targetUrl) {
	let parsedUrl = url.parse(targetUrl, { parseQueryString: true });
	let pageNumber = parseInt(defaultValue(parsedUrl.query.page, 1));

	return pageNumber;
}

module.exports = function createLidlServiceScraper(options) {
	let session = bhttp.session({
		headers: {
			"User-Agent": "Manual scraper (contact/problems: admin@cryto.net)"
		}
	});

	let currentSessionId;

	return {
		name: "Lidl-Service.com",
		initialize: function () {
			return Promise.try(() => {
				return session.get("https://www.lidl-service.com/");
			}).then((response) => {
				ensureValidResponse(response);

				let $ = cheerio.load(response.body);
				let targetUrl = $("a.de").attr("href");
				
				let sessionId = sessionIdRegex.exec(targetUrl);

				if (sessionId == null) {
					throw new Error("Did not find expected session ID in URL");
				} else {
					currentSessionId = sessionId[0];
					return resolveFromRoot(targetUrl);
				}
			});
		},
		handlers: [
			[/&searchType=/, "category", (targetUrl, {description, metadata}) => {
				return Promise.try(() => {
					return session.get(targetUrl);
				}).then((response) => {
					ensureValidResponse(response);

					/* TODO: Explain this conditional. */
					if (metadata.isCategoryIndex) {
						return {
							urls: [{
								description: `${description} - Page 1`,
								url: mergeUrl(targetUrl, {
									query: {
										action: "search",
										searchType: "search2",
										searchRefresh: "chgPage",
										rdeLocaleAttr: "de",
										page: "1"
									}
								})
							}]
						};
					} else {
						let $ = cheerio.load(response.body);
	
						let items = $("#product-search-results tbody tr").get().map((row) => {
							let item = $(row);
	
							return {
								url: resolveFromRoot(item.find("h3 a").attr("href")),
								picture: resolveFromRoot(item.find("img").attr("src")),
								title: trimText(item.find("h3 a").text()),
								sku: parseSku(trimText(item.find(".ian").text())),
								description: partialData(trimText(item.find(".col2 ul").html()))
							};
						});
	
						let currentPageNumber = pageNumberForUrl(targetUrl);
	
						let nextPageButton = $(".page-navigation a.next");
						let nextPageUrl;
	
						if (nextPageButton.length > 0) {
							nextPageUrl = resolveFromRoot(nextPageButton.attr("href"));
						}
	
						let urls = items.map((item) => {
							return {
								url: item.url,
								description: item.title
							};
						});
	
						if (nextPageUrl != null) {
							urls = urls.concat([{
								url: nextPageUrl,
								description: description.replace(/- Page [0-9]+/, `- Page ${currentPageNumber + 1}`),
								sameDepth: true
							}]);
						}
	
						return {
							urls: urls,
							items: items
						};
					}
				});
			}],
			[/\?rdeLocaleAttr=/, "index", (targetUrl) => {
				return Promise.try(() => {
					return session.get(targetUrl);
				}).then((response) => {
					ensureValidResponse(response);

					let $ = cheerio.load(response.body);

					let categories = $("#select-product-categories option")
						.get()
						.map((item) => $(item).attr("value"));

					return {
						items: [],
						urls: categories.map((categoryQuery) => {
							return {
								description: categoryQuery,
								url: mergeUrl(targetUrl, {
									query: {
										action: "search",
										searchType: "search2",
										searchText: categoryQuery,
										x: 37,
										y: 3
									}
								}),
								metadata: {
									isCategoryIndex: true
								}
							};
						})
					};
				})
			}],
			[/\/product.html/, "product", (targetUrl) => {
				/* Product page */

				return Promise.try(() => {
					return session.get(targetUrl);
				}).then((response) => {
					ensureValidResponse(response);

					let $ = cheerio.load(response.body);

					return {
						items: [{
							title: trimText($(".description h1").text()),
							sku: parseSku(trimText($(".description .ian").text())),
							description: trimText($(".description > ul").html()),
							brand: trimText($(".brand-image img").attr("alt")),
							downloads: $(".description table a").get().map((element) => {
								let link = $(element);
								let flagTag = link.closest("table").prev(".table-flag-tag").find("span");

								let column = link.closest("td").index();
								let typeHeading = link.closest("tbody").prev("thead").find("th").eq(column);

								return {
									language: flagTag.attr("class"),
									type: parseType(typeHeading.text()),
									description: link.text(),
									url: resolveFromRoot(link.attr("href")),
								};
							})
						}]
					}
				});
			}]
		],
		updateUrl: function (oldUrl) {
			return oldUrl.replace(sessionIdRegex, currentSessionId);
		}
	}
};