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

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

const dbUtils = global.dbUtils;

// refer:
// https://neteasecloudmusicapi-docs.4everland.app/
// https://github.com/Binaryify/NeteaseCloudMusicApi
const { playlist_catlist, playlist_hot, playlist_detail } = require('NeteaseCloudMusicApi');

async function fetchAll({ args }) {
    console.log("start fetching playlists ...");
    console.log("playlist 需要一口气爬完，中途不能停止，否则下次又要重头爬（歌单不会重复爬取，但是分页列表会）")

    // 从数据库中查出所有的网易云分类
    let result = await dbUtils.query(`SELECT title FROM category WHERE netease_group_chinese IS NOT NULL`);
    cate = result.map(cate => cate.title);
    cate.unshift('全部'); // 插入第一个
    console.log(cate);
    for (let i = 0; i < cate.length; i++) {
        const categoryName = cate[i];
        try {
            await fetchCategory({ categoryName: categoryName, progress: `${i + 1}/${cate.length}` });
        } catch (err) {
            console.error(err);
        }
    }
}

async function fetchCategory({ categoryName, progress }) {
    // 首先去网易云音乐首页获得歌单 (每一首音乐右侧都会有几个包含该音乐的歌单)
    let haveNext = true;
    let perPage = 35;
    let offset = 0;
    while (haveNext) {
        let url = `https://music.163.com/discover/playlist?cat=${encodeURIComponent(categoryName)}&limit=${perPage}&offset=${offset}`;
        try {
            // var html = fs.readFileSync(path.join(__dirname, "../../temp", `discover-playlist.html`), 'utf8');
            var html = await requestUtils.getApiResult(url);
            // fs.writeFileSync(path.join(__dirname, "../../temp", `discover-playlist.html`), html);

            var matcher = html.matchAll(/"\/playlist\?id=(\d{1,20})"/g);
            var m = matcher.next();
            var a = new Set(); // 因为每个歌单id会出现两次，所以使用Set去重
            while (!m.done) {
                a.add(Number(m.value[1]));
                m = matcher.next();
            }
            var playlistIds = Array.from(a).sort();
        } catch (errors) {
            console.error(errors);
            return;
        }

        // 从数据库查出已爬取的歌单ids，并从 playlistIds 中排除这部分歌单
        var exceptPlaylistIds = await dbUtils.query(`
            SELECT playlist_id FROM playlist WHERE playlist_id IN ?
        `, [[playlistIds]]);
        exceptPlaylistIds = exceptPlaylistIds.map(playlist => playlist.playlist_id);

        var finalPlaylistIds = playlistIds.filter(playlistId => exceptPlaylistIds.indexOf(playlistId) == -1);

        // console.log("playlistIds", playlistIds);
        // console.log("exceptPlaylistIds", exceptPlaylistIds);
        // console.log("finalPlaylistIds", finalPlaylistIds);
        console.log("finalPlaylistIds.length", finalPlaylistIds.length);

        for (let i = 0; i < finalPlaylistIds.length; i++) {
            await global.checkIsExit();
            const playlistId = finalPlaylistIds[i];
            // console.log(offset, i, finalPlaylistIds.length);
            console.log(`分类: ${progress} | 歌单: ${offset + i + 1}/${offset + finalPlaylistIds.length} | playlist: ${playlistId}`);
            try {
                await fetch({ playlistId: playlistId });
            } catch (err) {
                console.error(err);
            }
            await sleepUtils.sleep(global.sleepTime);
        }

        // 最有一页判断标识
        if (html.indexOf(`class="zbtn znxt js-disabled">下一页</a>`) > -1) haveNext = false;
        offset += perPage;
    }
}

// 获取歌词详情
async function fetch({ playlistId, debug = false }) {
    let result = await dbUtils.query('SELECT count(*) as count FROM playlist WHERE playlist_id = ?', [playlistId]);
    if (result[0].count > 0 && !debug) {
        console.log(`数据库中已有数据，跳过 playlistId: ${playlistId}`);
        return;
    }

    // https://neteasecloudmusicapi-docs.4everland.app/#/?id=%e6%ad%8c%e5%8d%95%e5%88%86%e7%b1%bb
    try {
        // 获取歌单分类
        // var playlistResult = await playlist_catlist({});
        // var playlistResult = await playlist_hot({});
        var playlistResult = await playlist_detail({
            id: playlistId,
        });
        // fs.writeFileSync(path.join(__dirname, "../../temp", `playlist-${playlistId}.json`), JSON.stringify(playlistResult));
    } catch (errors) {
        console.error(errors);
        return;
    }

    let playlist = playlistResult.body.playlist;
    // console.log("playlist", playlist);

    let playlistInfo = {
        playlist_id: playlist.id,
        title: playlist.name,
        english_title: playlist.englishTitle,
        description: playlist.description,
        user_id: playlist.userId,
        tags: JSON.stringify(playlist.tags),
        alg_tags: JSON.stringify(playlist.algTags),
        playlist_create_time: playlist.createTime,
        playlist_update_time: playlist.updateTime,
        track_count: playlist.trackCount,
        play_count: playlist.playCount,
        subscribed_count: playlist.subscribedCount,
        share_count: playlist.shareCount,
        comment_count: playlist.commentCount,
        cover_image: playlist.coverImgUrl ? /^https?:\/\/p.\.music\.126\.net\/(.*?)$/.exec(playlist.coverImgUrl)[1] : '',
        title_image: playlist.titleImageUrl ? /^https?:\/\/p.\.music\.126\.net\/(.*?)$/.exec(playlist.titleImageUrl)[1] : '',
        background_cover: playlist.backgroundCoverUrl ? /^https?:\/\/p.\.music\.126\.net\/(.*?)$/.exec(playlist.backgroundCoverUrl)[1] : '',
        ordered: playlist.ordered,
        copied: playlist.copied,
        status: playlist.status,
        privacy: playlist.privacy,
        ad_type: playlist.adType,
        special_type: playlist.specialType,
        official_playlist_type: playlist.officialPlaylistType,
        op_recommend: playlist.opRecommend,
        high_quality: playlist.highQuality,
        new_imported: playlist.newImported,
        update_frequency: playlist.updateFrequency,
        grade_status: playlist.gradeStatus,
        score: playlist.score,
        creator: JSON.stringify(playlist.creator),
        video_ids: JSON.stringify(playlist.videoIds),
        videos: JSON.stringify(playlist.videos),
        banned_track_ids: JSON.stringify(playlist.bannedTrackIds),
        remix_video: JSON.stringify(playlist.remixVideo),
    };
    // console.log("playlistInfo", playlistInfo);

    if (playlist.bannedTrackIds) {
        console.log("bannedTrackIds", playlist.bannedTrackIds);
        process.exit(0);

    }
    let trackIds = playlist.trackIds.map(track => [track.id, playlist.id, track.alg, track.rcmdReason]);
    if (trackIds.length > 0)
        await dbUtils.query('INSERT IGNORE INTO song_playlist_relation (song_id, playlist_id, alg, rcmd_reason) VALUES ?', [trackIds]);
    await dbUtils.query(`
        INSERT INTO playlist ( ${Object.keys(playlistInfo).map(field => `\`${field}\``).join(",")} ) VALUES ?
        ON DUPLICATE KEY UPDATE ${Object.keys(playlistInfo).map(field => `${field}=VALUES(${field})`).join(", ")}
    `, [[Object.values(playlistInfo)]]);
    return playlistInfo;
}

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