match.js

const request = require('./UnblockNeteaseMusic/src/request')
const find = require("./UnblockNeteaseMusic/src/provider/find")

const provider = {
    netease: require('./UnblockNeteaseMusic/src/provider/netease'),
    qq: require('./UnblockNeteaseMusic/src/provider/qq'),
    xiami: require('./UnblockNeteaseMusic/src/provider/xiami'),
    baidu: require('./UnblockNeteaseMusic/src/provider/baidu'),
    kugou: require('./UnblockNeteaseMusic/src/provider/kugou'),
    kuwo: require('./UnblockNeteaseMusic/src/provider/kuwo'),
    migu: require('./UnblockNeteaseMusic/src/provider/migu'),
    joox: require('./UnblockNeteaseMusic/src/provider/joox'),
    youtube: require('./UnblockNeteaseMusic/src/provider/youtube')
}

const match = (id, source) => {
    let meta = {}
    const candidate = (source || global.source || ['qq', 'kuwo', 'migu']).filter(name => name in provider)
    return find(id)
        .then(async info => {
            meta = info
            return Promise.all(candidate.map(name => provider[name].check(info).catch(() => {
            })))
        })
        .then(results => {
            results = results.filter(result => result && result.url)
            return Promise.all(results.map(result => check(result)))
        })
        .then(songs => {
            songs = songs.filter(song => song.url)
            if (!songs.length) return Promise.reject()
            return [meta, songs]
        })
}

const check = result => {
    const {url, info} = result
    const song = {size: 0, br: null, url: null, md5: null, info}
    return Promise.race([request('GET', url, {'range': 'bytes=0-8191'}), new Promise((_, reject) => setTimeout(() => reject(504), 5 * 1000))])
        .then(response => {
            if (!response.statusCode.toString().startsWith('2')) return Promise.reject()
            if (url.includes('qq.com'))
                song.md5 = response.headers['server-md5']
            else if (url.includes('xiami.net') || url.includes('qianqian.com'))
                song.md5 = response.headers['etag'].replace(/"/g, '').toLowerCase()
            song.size = parseInt((response.headers['content-range'] || '').split('/').pop() || response.headers['content-length']) || 0
            song.url = response.url.href
            return response.headers['content-length'] === '8192' ? response.body(true) : Promise.reject()
        })
        .then(data => {
            const bitrate = decode(data)
            song.br = (bitrate && !isNaN(bitrate)) ? bitrate * 1000 : null
        })
        .catch(() => {
        })
        .then(() => song)
}

const decode = buffer => {
    const map = {
        3: {
            3: ['free', 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, 'bad'],
            2: ['free', 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 'bad'],
            1: ['free', 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 'bad']
        },
        2: {
            3: ['free', 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 'bad'],
            2: ['free', 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 'bad']
        }
    }
    map[2][1] = map[2][2]
    map[0] = map[2]

    let pointer = 0
    if (buffer.slice(0, 4).toString() === 'fLaC') return 999
    if (buffer.slice(0, 3).toString() === 'ID3') {
        pointer = 6
        const size = buffer.slice(pointer, pointer + 4).reduce((summation, value, index) => summation + (value & 0x7f) << (7 * (3 - index)), 0)
        pointer = 10 + size
    }
    const header = buffer.slice(pointer, pointer + 4)

    // https://www.allegro.cc/forums/thread/591512/674023
    if (
        header.length === 4 &&
        header[0] === 0xff &&
        ((header[1] >> 5) & 0x7) === 0x7 &&
        ((header[1] >> 1) & 0x3) !== 0 &&
        ((header[2] >> 4) & 0xf) !== 0xf &&
        ((header[2] >> 2) & 0x3) !== 0x3
    ) {
        const version = (header[1] >> 3) & 0x3
        const layer = (header[1] >> 1) & 0x3
        const bitrate = header[2] >> 4
        return map[version][layer][bitrate]
    }
}

module.exports = match