MusicBrainz UserScript: play on ListenBrainz

lb_play.user.js

// ==UserScript==
// @name           Show "play on ListenBrainz" button on MusicBrainz pages
// @description    Add a button on some MusicBrainz pages to open ListenBrainz with a ready-to-play playlist (supported pages: Recording, Release, Release Group, Collection)
// @version        2022.12.19.0
// @namespace      https://listenbrainz.org/
// @downloadURL    https://gist.github.com/MonkeyDo/6b919302e97dc979f8277b9c71ff82ab
// @updateURL      https://gist.github.com/MonkeyDo/6b919302e97dc979f8277b9c71ff82ab
// @include        /musicbrainz.org\/(release|release-group|recording|collection)/
// @require        https://cdnjs.cloudflare.com/ajax/libs/cash/8.1.2/cash.min.js
// @icon           https://github.com/metabrainz/metabrainz-logos/raw/master/logos/ListenBrainz/PNG/ListenBrainz_logo_no_text.png
// @grant          none
// @run-at         document-start
// ==/UserScript==


// MBID regular expression
var MBIDRegexp = "[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}";

var regexp = new RegExp(`musicbrainz.org/(release|release-group|recording|collection)/(${MBIDRegexp})`, 'i');
var regexpResults = window.location.href.match(regexp);
// Bail early if we don't support this page
if(!regexpResults || !regexpResults.length){
  return;
}

// This function gathers the recording MBIDs from a collection
function getCollectionRecordingMBIDs(){
  var matches = $('#content table > tbody > tr > td:nth-child(2) > a')
  .map(function(){
    var recordingLinkRegexp = `^/recording/(${MBIDRegexp})`;
    var match = $(this).attr("href").match(recordingLinkRegexp);
    return match && match[1] || null;
  })
  return Array.from(matches);
}

// This function gathers the MBID of the first Release in from a Release Group page
function getFirstReleaseMBID(){
  var releaseLinkRegexp = `^/release/(${MBIDRegexp})`;
  var firstMatch = $('#content table > tbody > tr > td:nth-child(2) > a')
  .first();
  var mbidMatch = firstMatch.attr("href").match(releaseLinkRegexp);
    return mbidMatch && mbidMatch[1] || null;
}

$(document).ready(function () {

  var logoURL = "https://raw.githubusercontent.com/metabrainz/metabrainz-logos/master/logos/ListenBrainz/SVG/ListenBrainz_logo_icon.svg"
  // Get the entity type and MBID from the URL
  var entityType = regexpResults[1];
  var entityMBID = regexpResults[2];
  var LBLink;
  // Depending on the entity type we need to hit different LB endpoints
  switch(entityType){
    case 'release':
      LBLink = `//listenbrainz.org/player/release/${entityMBID}`;
    break;
    case 'release-group':
      var releaseMBID = getFirstReleaseMBID();
      LBLink = `//listenbrainz.org/player/release/${releaseMBID}`;
    break;
    case 'recording':
      LBLink = `//listenbrainz.org/player?recording_mbids=${entityMBID}`;
    break;
    case 'collection':
      var recordingMBIDs = getCollectionRecordingMBIDs();
      // getCollectionRecordingMBIDs will return an empty array if no matches
      if(recordingMBIDs.length){
        LBLink = `//listenbrainz.org/player?recording_mbids=${recordingMBIDs.join(",")}`;
      }
    break;
  }
  // We couldn't construct a link to play on LB so don't show a button
  if(!LBLink){
    return;
  }
  $('#sidebar').prepend(
    `<a class="styled-button" style="margin-bottom: 0.5rem; display: block; text-align: center;"
    target="_blank"
    href="${LBLink}">
    <img src="${logoURL}" style="vertical-align: bottom; height: 16px;"> Play on ListenBrainz
    </a>
    `)
});