From 4747050b60b2a6c35253123c8bcd106ed478c677 Mon Sep 17 00:00:00 2001
From: Sem Visscher <semvisscher10@gmail.com>
Date: Fri, 19 Mar 2021 21:32:33 +0100
Subject: [PATCH] Added working lastfm support

currently only played songs are added
---
 config/defaults.js      |   6 ++
 package.json            |   3 +
 plugins/discord/back.js |   5 +-
 plugins/last-fm/back.js | 135 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 145 insertions(+), 4 deletions(-)
 create mode 100644 plugins/last-fm/back.js

diff --git a/config/defaults.js b/config/defaults.js
index 6238e114..b81d1d2e 100644
--- a/config/defaults.js
+++ b/config/defaults.js
@@ -35,6 +35,12 @@ const defaultConfig = {
 			ffmpegArgs: [], // e.g. ["-b:a", "192k"] for an audio bitrate of 192kb/s
 			downloadFolder: undefined, // Custom download folder (absolute path)
 		},
+		"last-fm": {
+			enabled: false,
+			api_root: "http://ws.audioscrobbler.com/2.0/",
+			api_key: "04d76faaac8726e60988e14c105d421a", // api key registered by @semvis123
+			secret: "a5d2a36fdf64819290f6982481eaffa2",
+		}
 	},
 };
 
diff --git a/package.json b/package.json
index f5524a37..df4725e1 100644
--- a/package.json
+++ b/package.json
@@ -66,6 +66,7 @@
 		"@ffmpeg/core": "^0.8.5",
 		"@ffmpeg/ffmpeg": "^0.9.7",
 		"YoutubeNonStop": "git://github.com/lawfx/YoutubeNonStop.git#v0.8.1",
+		"axios": "^0.21.1",
 		"browser-id3-writer": "^4.4.0",
 		"discord-rpc": "^3.2.0",
 		"downloads-folder": "^3.0.1",
@@ -76,7 +77,9 @@
 		"electron-unhandled": "^3.0.2",
 		"electron-updater": "^4.3.6",
 		"filenamify": "^4.2.0",
+		"md5": "^2.3.0",
 		"node-fetch": "^2.6.1",
+		"open": "^8.0.3",
 		"ytdl-core": "^4.4.5"
 	},
 	"devDependencies": {
diff --git a/plugins/discord/back.js b/plugins/discord/back.js
index 5c53193b..1d7e8e21 100644
--- a/plugins/discord/back.js
+++ b/plugins/discord/back.js
@@ -45,9 +45,6 @@ module.exports = (win) => {
 		});
 
 		// Startup the rpc client
-		rpc.login({
-				clientId,
-			})
-			.catch(console.error);
+		rpc.login({ clientId }).catch(console.error);
 	});
 };
diff --git a/plugins/last-fm/back.js b/plugins/last-fm/back.js
new file mode 100644
index 00000000..9a88d4fb
--- /dev/null
+++ b/plugins/last-fm/back.js
@@ -0,0 +1,135 @@
+const fetch = require('node-fetch');
+const md5 = require('md5');
+const open = require("open");
+const axios = require('axios');
+const { setOptions } = require('../../config/plugins');
+const getSongInfo = require('../../providers/song-info');
+
+const createFormData = (params) => {
+	// creates the body for in the post request
+	let formData = new URLSearchParams();
+	for (key in params) {
+		formData.append(key, params[key]);
+	}
+	return formData;
+}
+const createQueryString = (params, api_sig) => {
+	// creates a querystring
+	const queryData = []
+	params.api_sig = api_sig
+	for (key in params) {
+		queryData.push(`${key}=${params[key]}`)
+	}
+	return '?'+queryData.join('&')
+}
+
+const createApiSig = (params, secret) => { 
+	// this function creates the api signature, see: https://www.last.fm/api/authspec
+	let keys = [];
+	for (key in params){
+		keys.push(key);
+	}
+	keys.sort();
+	let sig = '';
+	for (key of keys) {
+		if (String(key) === 'format')
+			continue
+		sig += `${key}${params[key]}`
+	}
+	sig += secret
+	sig = md5(sig)
+	return sig
+}
+
+const createToken = async ({api_key, api_root, secret}) => {
+	// creates an auth token
+	data = {
+		method: 'auth.gettoken',
+		api_key: api_key,
+		format: 'json'
+	}
+	let api_sig = createApiSig(data, secret);
+	let response = await fetch(`${api_root}${createQueryString(data, api_sig)}`);
+	response = await response.json();
+	return response?.token;
+}
+
+const authenticate = async (config) => {
+	// asks user for authentication
+	config.token = await createToken(config);
+	setOptions('last-fm', config);
+	open(`https://www.last.fm/api/auth/?api_key=${config.api_key}&token=${config.token}`);
+	return config
+}
+
+const getAndSetSessionKey = async (config) => {
+	// get and set the session key
+	data = {
+		api_key: config.api_key,
+		format: 'json',
+		method: 'auth.getsession',
+		token: config.token,
+	}
+	api_sig = createApiSig(data, config.secret);
+	res = await fetch(`${config.api_root}${createQueryString(data, api_sig)}`);
+	res = await res.json();
+	if (res.error)
+		await authenticate(config);
+	config.session_key = res?.session?.key;
+	setOptions('last-fm', config);
+	return config
+}
+
+
+const addScrobble = async (songInfo, config) => {
+	// this adds one scrobbled song
+	if (!config.session_key)
+		await getAndSetSessionKey(config);
+	data = {
+		track: songInfo.title,
+		artist: songInfo.artist,
+		api_key: config.api_key,
+		sk: config.session_key,
+		format: 'json',
+		method: 'track.scrobble',
+		timestamp: ~~((Date.now() - songInfo.elapsedSeconds)/1000),
+		duration: songInfo.songDuration,
+	}
+	data.api_sig = createApiSig(data, config.secret)
+	axios.post('https://ws.audioscrobbler.com/2.0/', createFormData(data))
+		.then(res => res.data.scrobbles)
+		.catch(res => {
+			if (res.response.data.error == 9){
+				// session key is invalid
+				config.session_key = undefined;
+				setOptions('last-fm', config);
+				authenticate(config);
+			}
+		});
+}
+
+// this will store the timeout that will trigger addScrobble
+let scrobbleTimer = undefined;
+
+const lastfm = async (win, config) => {
+	const registerCallback = getSongInfo(win);
+	
+	if (!config.session_key) {
+		// not authenticated
+		config = await getAndSetSessionKey(config);
+	}
+
+	registerCallback((songInfo)=> {
+		clearTimeout(scrobbleTimer);
+		if (!songInfo.isPaused) {
+			let scrobbleTime = Math.min(Math.ceil(songInfo.songDuration/2), 4*60);
+			if (scrobbleTime > songInfo.elapsedSeconds) {
+				// scrobble still needs to happen
+				timeToWait = (scrobbleTime-songInfo.elapsedSeconds)*1000;
+				scrobbleTimer = setTimeout(addScrobble, timeToWait, songInfo, config);
+			}
+		}
+	})
+}
+
+module.exports = lastfm;
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