// ==UserScript==
// @name        dzunlock
// @namespace   io.github.uhwot.dzunlock
// @description enables deezer hifi features lol
// @author      uh wot
// @version     1.0.1
// @homepageURL https://git.freezer.life/uhwot/dzunlock
// @downloadURL https://git.freezer.life/uhwot/dzunlock/raw/branch/master/dzunlock.user.js
// @icon        https://cdns-files.dzcdn.net/cache/images/common/favicon/favicon-96x96.852baf648e79894b668670e115e4a375.png
// @include     /^https:\/\/www\.deezer\.com\/[a-z]{2}\/($|track|album|artist|playlist|episode|show|profile|channels)/
// @match       https://www.deezer.com/search/*
// @match       https://www.deezer.com/account/*
// @require     https://cdnjs.cloudflare.com/ajax/libs/aes-js/3.1.2/index.min.js
// @require     https://cdnjs.cloudflare.com/ajax/libs/spark-md5/3.0.0/spark-md5.min.js
// @grant GM_getValue
// @grant GM_setValue
// ==/UserScript==

const debug = false

function log(...args) {
    if (debug) {
        return console.log(...args)
    }
}

// https://github.com/werk85/fetch-intercept/blob/develop/src/attach.js modified for browser support
let interceptors = [];

function interceptor(fetch, ...args) {
    const reversedInterceptors = interceptors.reduce((array, interceptor) => [interceptor].concat(array), []);
    let promise = Promise.resolve(args);

    // Register request interceptors
    reversedInterceptors.forEach(({ request, requestError }) => {
        if (request || requestError) {
            promise = promise.then(args => request(...args), requestError);
        }
    });

    // Register fetch call
    promise = promise.then(args => {
        const request = new Request(...args);
        return fetch(request).then(response => {
            response.request = request;
            return response;
        }).catch(error => {
            error.request = request;
            return Promise.reject(error);
        });
    });

    // Register response interceptors
    reversedInterceptors.forEach(({ response, responseError }) => {
        if (response || responseError) {
            promise = promise.then(response, responseError);
        }
    });

    return promise;
}

unsafeWindow.fetch = (function (fetch) {
    return function (...args) {
        return interceptor(fetch, ...args);
    };
})(unsafeWindow.fetch);

fetchIntercept = {
    register: function (interceptor) {
        interceptors.push(interceptor);
        return () => {
            const index = interceptors.indexOf(interceptor);
            if (index >= 0) {
                interceptors.splice(index, 1);
            }
        };
    },
    clear: function () {
        interceptors = [];
    }
};

// main code starts here

const clientId = '119915'
const clientSecret = '2f5b4c9785ddc367975b83d90dc46f5c'
const playerTokenKey = [102, 228, 95, 242, 215, 50, 122, 26, 57, 216, 206, 38, 164, 237, 200, 85]
const trackCDNKey = [106, 111, 54, 97, 101, 121, 54, 104, 97, 105, 100, 50, 84, 101, 105, 104]

const qualityToFormat = {
    'standard': '128',
    'high': '320',
    'lossless': 'flac'
}

const formatToNum = {
    '128': 1,
    '320': 3,
    'flac': 9
}

let dataTemplate = {
    data: [
        {
            media: [
                {
                    cipher: { type: "BF_CBC_STRIPE" },
                    exp: 694208008135,
                    format: "",
                    media_type: "FULL",
                    nbf: 694208008135,
                    sources: [
                        {
                            provider: "ak",
                            url: "",
                        },
                        {
                            provider: "ec",
                            url: "",
                        },
                    ],
                },
            ],
        },
    ],
};

function str2bin(str) {
    return Array.from(str).map(function (item) {
        return item.charCodeAt(0);
    })
}

function decryptHex(hex, key) {
    hex = aesjs.utils.hex.toBytes(hex)
    let aesEcb = new aesjs.ModeOfOperation.ecb(key)
    return aesjs.utils.utf8.fromBytes(aesEcb.decrypt(hex)).replace(/\0+$/, '')     // removes zero-padding
}

function encryptHex(str, key) {
    // zero-padding
    if (str.length % 16) {
        str += '\x00'.repeat(16 - str.length % 16)
    }

    let aesEcb = new aesjs.ModeOfOperation.ecb(key)
    return aesjs.utils.hex.fromBytes(aesEcb.encrypt(str2bin(str)))
}

function playerTokenPatch(playerToken) {
    playerToken = JSON.parse(decryptHex(playerToken, playerTokenKey))

    // enables 320/flac quality selection
    playerToken.audio_qualities.wifi_streaming = ['low', 'standard', 'high', 'lossless']
    // disables previews
    playerToken.streaming = true

    log(playerToken)

    return encryptHex(JSON.stringify(playerToken), playerTokenKey)
}

function trackCDNGen(md5_origin, format, id, media_version) {
    result = [md5_origin, format, id, media_version].join('\xa4')
    log(result)

    result = SparkMD5.hashBinary(result) + '\xa4' + result + '\xa4'
    log(result)
    return encryptHex(result, trackCDNKey)
}

async function renewAccessToken() {
    let url = `https://connect.deezer.com/oauth/access_token.php?grant_type=client_credentials&client_id=${clientId}&client_secret=${clientSecret}&output=json`
    let resp = await fetch(url)
    let json = await resp.json()
    access_token = json['access_token']

    // cache access token
    GM_setValue('access_token', access_token)
    GM_setValue('access_token_expiry', Math.floor(Date.now() / 1000) + Number(json['expires']))
    return access_token
}

unsafeWindow.dzPlayer.setTrackList = (function (old) {
    return function (...args) {
        // needed for player to accept flac url responses
        for (let i = args[0].data; i < args[0].data.length; i++) {
            args[0].data[i].FILESIZE_FLAC = "1"
        }

        log(args)

        return old(...args)
    };
})(unsafeWindow.dzPlayer.setTrackList);

fetchIntercept.register({
    request: function (url, config) {
        // Modify the url or config here

        return [url, config];
    },

    requestError: function (error) {
        // Called when an error occured during another 'request' interceptor call

        return Promise.reject(error);
    },

    response: async function (response) {
        // Modify the response object

        if (response.url.startsWith('https://www.deezer.com/ajax/gw-light.php?method=deezer.getUserData')) {
            const json = await response.json()

            // removes upgrade popup stuff
            json.results.USER.ENTRYPOINTS = {}
            // needed to play premium-restricted albums like https://www.deezer.com/album/801279
            json.results.OFFER_ID = 600
            // disables ads
            json.results.USER.OPTIONS.ads_display = false
            json.results.USER.OPTIONS.ads_audio = false

            json.results.PLAYER_TOKEN = playerTokenPatch(json.results.PLAYER_TOKEN)

            log(json)

            return new Response(JSON.stringify(json))
        }

        if (response.url.startsWith('https://www.deezer.com/ajax/gw-light.php?method=log.listen')) {
            const json = await response.json()

            if (typeof json.results === 'string') {
                json.results = playerTokenPatch(json.results)
            }

            return new Response(JSON.stringify(json))
        }

        if (response.url === 'https://media.deezer.com/v1/get_url') {
            const id = Number(unsafeWindow.dzPlayer.getSongId())
            const quality = unsafeWindow.dzPlayer.control.getAudioQuality()
            log(id, quality)

            // check if account is allowed to get quality, if so use the server's response instead
            const orig = await response.json()
            if (id < 0 /* user-upped track */ || (unsafeWindow.dzPlayer.user_status.audio_qualities.wifi_download.includes(quality) && orig.data && orig.data[0].media && orig.data[0].media[0])) {
                return new Response(JSON.stringify(orig))
            }

            let access_token = GM_getValue('access_token', false)
            const expiry = GM_getValue('access_token_expiry', 0)
            if (!access_token || Math.floor(Date.now() / 1000) >= expiry) {
                access_token = await renewAccessToken()
            }

            url = `https://api.deezer.com/track/${id}?access_token=${access_token}`
            resp = await fetch(url)
            let json = await resp.json()

            // renew access token if token is invalid
            if (json.error && json.error.code === 300) {
                access_token = await renewAccessToken()
                url = `https://api.deezer.com/track/${id}?access_token=${access_token}`
                resp = await fetch(url)
                json = await resp.json()
            }

            const md5_origin = json['md5_origin']
            const media_version = json['media_version']

            const formats = Object.values(qualityToFormat)
            let format = qualityToFormat[quality]
            while (format !== '128') {
                if (json['filesize_' + format] !== "0") {
                    break
                }
                format = formats[formats.indexOf(format) - 1]
            }
            format_num = formatToNum[format]

            const trackCDNPath = trackCDNGen(md5_origin, format_num, id, media_version)

            if (format === 'flac') {
                dataTemplate.data[0].media[0].format = 'FLAC'
            } else {
                dataTemplate.data[0].media[0].format = 'MP3_128'    // doesn't matter whether it's 128 or 320
            }

            dataTemplate.data[0].media[0].sources[0].url = `https://cdns-proxy-${md5_origin[0]}.dzcdn.net/mobile/1/${trackCDNPath}`
            dataTemplate.data[0].media[0].sources[1].url = `https://e-cdns-proxy-${md5_origin[0]}.dzcdn.net/mobile/1/${trackCDNPath}`

            log(dataTemplate)

            return new Response(JSON.stringify(dataTemplate))
        }

        return response;
    },

    responseError: function (error) {
        // Handle an fetch error

        return Promise.reject(error);
    }
});