const { createProxyMiddleware } = require('http-proxy-middleware');
let axios = require('axios')
let qs = require('querystring')

// The authorization token to use with the Spotify API.
// Will need to be refreshed once in a while.
var authToken: string | null = null;

async function updateToken(clientId: string, clientSecret: string) {
    if (authToken) { return; }

    let buf = Buffer.from(clientId + ':' + clientSecret)
    let encoded = buf.toString('base64');

    let response = await axios.post(
        'https://accounts.spotify.com/api/token',
        qs.stringify({ 'grant_type': 'client_credentials' }),
        {
            'headers': {
                'Authorization': 'Basic ' + encoded,
                'Content-Type': 'application/x-www-form-urlencoded'
            }
        }
    );

    authToken = (await response).data.access_token;
}

let onProxyReq = (proxyReq: any, req: any, res: any) => {
    proxyReq.setHeader("Authorization", "Bearer " + req._access_token)

    console.log("Proxying request",
        {
            'path': req.path,
            'originalUrl': req.originalUrl,
            'baseUrl': req.baseUrl,
        },
        {
            'path': proxyReq.path,
            'originalUrl': proxyReq.originalUrl,
            'baseUrl': req.baseUrl,
        },
    );
}

export function useSpotifyClientCreds(app: any) {
    // First add a layer which creates a token and saves it in the request.
    app.use((req: any, res: any, next: any) => {
        updateToken('c3e5e605e7814cdf94cd86eeba6f4c4f', '5d870c84a3c34aa3a4cf803aa95cb96a')
            .then(() => {
                req._access_token = authToken;
                next();
            })
    })
    app.use(
        '/spotifycc',
        createProxyMiddleware({
            target: 'https://api.spotify.com/',
            changeOrigin: true,
            onProxyReq: onProxyReq,
            logLevel: 'debug',
            pathRewrite: { '^/spotifycc': '' },
        })
    )
}