const fs = require('fs');
const path = require('path');

const requestUtils = require('../../../utils/requestUtils');
const sleepUtils = require('../../../utils/sleepUtils');

const dbUtils = global.dbUtils;

// 从数据库中查询
async function getFromDatabase({ artistId }) {
    // 查询出专辑
    let infoResultSet = await dbUtils.query('SELECT * FROM artist WHERE artist_id = ?', [artistId]);
    if (infoResultSet.length == 0) return {};

    // 查出专辑与歌曲对应关系
    let relationResultSet = await dbUtils.query('SELECT * FROM song_artist_relation WHERE artist_id = ?', [artistId]);

    // 拼装
    let artistInfo = JSON.parse(JSON.stringify(infoResultSet[0]));
    artistInfo.songIds = relationResultSet.map(song => song.song_id);
    return artistInfo;
}

// 从数据库中查出还缺少的歌手，并进行爬取
async function fetchAll() {
    console.log("start fetching artists ...")
    var artistIds = await dbUtils.query(`
        SELECT DISTINCT artist_id FROM song_artist_relation WHERE artist_id NOT IN ( SELECT DISTINCT artist_id FROM artist )
    `, []);
    artistIds = artistIds.map(item => item.artist_id);
    for (let i = 0; i < artistIds.length; i++) {
        await global.checkIsExit();
        const artistId = artistIds[i];
        console.log(`${i}/${artistIds.length} | artist: ${artistId}`);
        try {
            await fetch({ artistId: artistId });
        } catch (err) {
            console.error(err);
        }
        await sleepUtils.sleep(global.sleepTime);
    }
}

// 获取音乐人详情
async function fetch({ artistId, debug = false }) {
    let result = await dbUtils.query('SELECT count(*) as count FROM artist WHERE artist_id = ?', [artistId]);
    if (result[0].count > 0 && !debug) {
        console.log(`数据库中已有数据，跳过 artistId: ${artistId}`);
        return;
    }

    let url = `https://music.163.com/artist?id=${artistId}`;
    try {
        // var html = fs.readFileSync(path.join(__dirname, "../../temp", `artist-${artistId}.html`), 'utf8');
        var html = await requestUtils.getApiResult(url);
        // fs.writeFileSync(path.join(__dirname, "../../temp", `artist-${artistId}.html`), html);
    } catch (errors) {
        console.error(errors);
        return;
    }

    if (html.includes(`<p class="note s-fc3">很抱歉，你要查找的网页找不到</p>`)) {
        // TODO 最后统一来处理这里 demo: artistId == 30084536
        return;
    }

    // 正则匹配
    let regExResult = /\<script type\=\"application\/ld\+json\"\>([\S\s]*?)\<\/script\>/.exec(html);
    let artistInfoJSONString = regExResult[1];
    let artistInfoDict = JSON.parse(artistInfoJSONString);
    // console.log(artistInfoDict);

    let image = /<meta property="og:image" content="http:\/\/p.\.music\.126\.net\/(.*?)" \/>/.exec(html)[1];
    let songListJSONString = /<textarea id="song-list-pre-data" style="display:none;">(.*?)<\/textarea>/.exec(html)[1];
    let songList = JSON.parse(songListJSONString);
    let songIds = songList.map(song => song.id);

    let artistInfo = {
        artistId: artistId,
        title: artistInfoDict.title,
        image: image,
        description: artistInfoDict.description,
        pubDate: artistInfoDict.pubDate,
        songIds: songIds,
    };
    // console.log("artistInfo", artistInfo);
    dbUtils.query('INSERT IGNORE INTO artist SET ?', {
        artist_id: artistInfo.artistId,
        title: artistInfo.title,
        description: artistInfo.description,
        image: artistInfo.image,
        pub_date: artistInfo.pubDate,
    });
    songIds.forEach(function (songId) {
        if (isNaN(Number(songId)) || Number(songId) === 0 || isNaN(Number(artistId)) || Number(artistId) === 0)
            return;
        dbUtils.query('INSERT IGNORE INTO song_artist_relation SET ?', {
            song_id: songId,
            artist_id: artistId,
        });
    });
    return artistInfo;
}

module.exports = {
    getFromDatabase: getFromDatabase,
    fetch: fetch,
    fetchAll: fetchAll,
}