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

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

const dbUtils = global.dbUtils;

// 从数据库中查出还缺少的歌词，并进行爬取
async function fetchAll({ args = {} }) {
    console.log("start fetching lyrics ...");
    let whereClause = [
        args.min ? `song_id >  ${args.min}` : '1=1',
        args.max ? `song_id <= ${args.max}` : '1=1',
    ].join(' AND ');
    var sql = `
        SELECT song_id FROM song WHERE ${whereClause} AND song_id NOT IN ( SELECT song_id FROM lyric )
        ${args.limit ? `LIMIT ${args.limit}` : ''}
    `;
    console.log(sql);

    var songIds = await dbUtils.query(sql, []);
    songIds = songIds.map(song => song.song_id);
    for (let i = 0; i < songIds.length; i++) {
        await global.checkIsExit();
        const songId = songIds[i];
        console.log(`${i + 1}/${songIds.length} | lyric: ${songId} | ${args.min || "?"}-${args.max || "?"}`);
        try {
            await fetch({ songId: songId });
        } catch (err) {
            console.error(err);
        }
        await sleepUtils.sleep(global.sleepTime);
    }
}

// 获取歌词详情
async function fetch({ songId, debug = false }) {
    let result = await dbUtils.query('SELECT count(*) as count FROM lyric WHERE song_id = ?', [songId]);
    if (result[0].count > 0 && !debug) {
        // 这里暂时跳过，后期可能要考虑歌词version更新的问题
        console.log(`数据库中已有数据，跳过 songId: ${songId}`);
        return;
    }

    var url = `https://music.163.com/api/song/lyric?id=${songId}&lv=1`; // &kv=1&tv=-1
    try {
        // var json = fs.readFileSync(path.join(__dirname, "../../temp", `lyric-${songId}.json`), 'utf8');
        var json = await requestUtils.getApiResult(url);
        // fs.writeFileSync(path.join(__dirname, "../../temp", `lyric-${songId}.json`), json);
    } catch (errors) {
        console.error(errors);
        return;
    }

    try {
        var lyric = JSON.parse(json).lrc; // { version: xx, lyric: 'xxx' }
    } catch (error) {
        console.error(error);
        return;
    }

    if (typeof lyric == "undefined") {
        // 这首歌爬song的时候还在，但是现在不在了
        // 这里数据丢了不要紧，所以不加await
        dbUtils.query('INSERT IGNORE INTO lyric SET ?', {
            song_id: songId,
            lyric: '',
            version: -1,
        });
        return;
    }

    let lyricInfo = {
        songId: songId,
        lyric: lyric.lyric,
        version: lyric.version,
    };
    // console.log("lyricInfo", lyricInfo);
    // 这里数据丢了不要紧，所以不加await
    dbUtils.query('INSERT IGNORE INTO lyric SET ?', {
        song_id: lyricInfo.songId,
        lyric: lyricInfo.lyric,
        version: lyricInfo.version,
    });
    return lyricInfo;
}

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