const request = require('node-superfetch');
const cheerio = require('cheerio');
const fs = require('fs');
const { parser } = require('stream-json');
const { pick } = require('stream-json/filters/Pick');
const { streamArray } = require('stream-json/streamers/StreamArray');
const path = require('path');
const { checkFileExists } = require('../util/Util');
const rounds = ['jeopardy_round', 'double_jeopardy_round', 'final_jeopardy_round'];

const STATE_DIR = process.env.XIAO_STATE_DIR
	? path.resolve(process.env.XIAO_STATE_DIR)
	: path.join(__dirname, '..');

function resolveStatePath(fileName) {
	return path.join(STATE_DIR, fileName);
}

module.exports = class JeopardyScrape {
	constructor(client) {
		Object.defineProperty(this, 'client', { value: client });

		this.clues = [];
		this.gameIDs = null;
		this.seasons = null;
		this.imported = false;
	}

	async fetchSeasons() {
		const { text } = await request.get(`https://j-archive.com/listseasons.php`);
		const $ = cheerio.load(text);
		const seasons = [];
		$('table td a').each((j, elem) => {
			const href = $(elem).attr('href');
			seasons.push(href.split('season=')[1]);
		});
		return seasons.reverse();
	}

	async fetchSeason(season) {
		const { text } = await request.get(`https://j-archive.com/showseason.php`)
			.query({ season });
		const $ = cheerio.load(text);
		const gameIDs = [];
		$('table td a').each((j, elem) => {
			const href = $(elem).attr('href');
			gameIDs.push(href.split('id=')[1]);
		});
		return gameIDs;
	}

	async fetchClues(id) {
		const { text } = await request.get('http://www.j-archive.com/showgame.php')
			.query({ game_id: id });
		const $ = cheerio.load(text);
		const clues = [];
		for (const round of rounds) {
			const questions = $(`#${round} .clue`);
			const categories = $(`#${round} .category_name`);
			const categoryArr = [];
			categories.each((i, elem) => categoryArr.push($(elem).text().toLowerCase()));
			questions.each((i, elem) => {
				let value = $(elem).find('td[class="clue_value"]').text();
				if (!value) value = $(elem).find('td[class="clue_value_daily_double"]').text();
				const question = $(elem).find('td[class="clue_text"]').first().text();
				const answer = $(elem).find('em[class="correct_response"]').text();
				if (!question || !answer) return;
				clues.push({
					question,
					answer,
					category: categoryArr[i % 6],
					value: value ? value.match(/[0-9]+/)[0] : '0',
					gameID: id
				});
			});
		}
		return clues;
	}

	async importData() {
		const read = await fs.promises.readFile(resolveStatePath('jeopardy.json'), { encoding: 'utf8' });
		const { seasons, gameIDs } = JSON.parse(read);
		this.gameIDs = Array.isArray(gameIDs) ? gameIDs : [];
		this.seasons = Array.isArray(seasons) ? seasons : [];
		this.clues = await this.importClues();
		this.imported = true;
		return this;
	}

	importClues() {
		const pipeline = fs.createReadStream(resolveStatePath('jeopardy.json'), { encoding: 'utf8' })
			.pipe(parser())
			.pipe(pick({ filter: 'clues' }))
			.pipe(streamArray());
		pipeline.on('data', ({ value }) => this.clues.push(value));
		return new Promise(res => {
			pipeline.on('end', () => res(this.clues));
		});
	}

	exportData() {
		const buf = Buffer.from(JSON.stringify({
			clues: this.clues,
			gameIDs: this.gameIDs,
			seasons: this.seasons
		}));
		fs.mkdirSync(STATE_DIR, { recursive: true });
		fs.writeFileSync(resolveStatePath('jeopardy.json'), buf, { encoding: 'utf8' });
		return buf;
	}

	async checkForUpdates() {
		if (!this.imported) {
			const fileExists = await checkFileExists(resolveStatePath('jeopardy.json'));
			if (fileExists) {
				this.client.logger.info('[JEOPARDY] Importing from file...');
				await this.importData();
				this.client.logger.info('[JEOPARDY] Import complete!');
			} else {
				this.client.logger.warn('[JEOPARDY] No jeopardy.json found. Skipping update for now.');
				this.clues = [];
				this.gameIDs = [];
				this.seasons = [];
				this.imported = true;
				this.exportData();
				return 0;
			}
		}
		if (!Array.isArray(this.clues)) this.clues = [];
		if (!Array.isArray(this.gameIDs)) this.gameIDs = [];
		if (!Array.isArray(this.seasons)) this.seasons = [];
		if (!this.seasons.length) {
			this.client.logger.warn('[JEOPARDY] No seasons loaded. Skipping update.');
			return 0;
		}
		const cluesBefore = this.clues.length;
		const latestSeason = this.seasons[this.seasons.length - 1];
		const seasons = await this.fetchSeasons();
		for (const season of seasons) {
			if (this.seasons.includes(season) && latestSeason !== season) continue;
			if (latestSeason !== season) this.seasons.push(season);
			const games = await this.fetchSeason(season);
			for (const gameID of games) {
				if (this.gameIDs.includes(gameID)) continue;
				this.gameIDs.push(gameID);
				const clues = await this.fetchClues(gameID);
				this.clues.push(...clues);
			}
		}
		this.exportData();
		this.imported = true;
		return this.clues.length - cluesBefore;
	}
};