Collage Extensions for Gazelle Music Trackers

Click on collage size = browse through this collage; Alt + click on collage name = remove from this collage

目前為 2020-12-16 提交的版本,檢視 最新版本

// ==UserScript==
// @name         Collage Extensions for Gazelle Music Trackers
// @version      1.20
// @description  Click on collage size = browse through this collage; Alt + click on collage name = remove from this collage
// @author       Anakunda
// @license      GPL-3.0-or-later
// @copyright    2020, Anakunda (https://openuserjs.org/users/Anakunda)
// @namespace    https://greasyfork.org/users/321857-anakunda
// @match        https://*/torrents.php?id=*
// @match        https://*/collages.php?*id=*
// @match        https://*/artist.php?*id=*
// @grant        GM_getValue
// @grant        GM_setValue
// ==/UserScript==

'use strict';

var auth = document.querySelector('input[name="auth"][value]');
if (auth != null) auth = auth.value; else {
	auth = document.querySelector('li#nav_logout > a');
	if (auth != null && /\b(?:auth)=(\w+)\b/.test(auth.search)) auth = RegExp.$1; else throw 'Auth not found';
}
let userId = document.querySelector('li#nav_userinfo > a.username');
if (userId != null) {
	userId = new URLSearchParams(userId.search);
	userId = parseInt(userId.get('id'));
}

const siteApiTimeframeStorageKey = document.location.hostname + ' API time frame';
const gazelleApiFrame = 10500;
try { var redacted_api_key = GM_getValue('redacted_api_key') } catch(e) { }

function queryAjaxAPI(action, params) {
	if (!action) return Promise.reject('Action missing');
	let retryCount = 0;
	return new Promise(function(resolve, reject) {
		params = new URLSearchParams(params || undefined);
		params.set('action', action);
		let url = '/ajax.php?' + params, xhr = new XMLHttpRequest;
		queryInternal();

		function queryInternal() {
			let now = Date.now();
			try { var apiTimeFrame = JSON.parse(window.localStorage[siteApiTimeframeStorageKey]) } catch(e) { apiTimeFrame = {} }
			if (!apiTimeFrame.timeStamp || now > apiTimeFrame.timeStamp + gazelleApiFrame) {
				apiTimeFrame.timeStamp = now;
				apiTimeFrame.requestCounter = 1;
			} else ++apiTimeFrame.requestCounter;
			window.localStorage[siteApiTimeframeStorageKey] = JSON.stringify(apiTimeFrame);
			if (apiTimeFrame.requestCounter <= 5) {
				xhr.open('GET', url, true);
				xhr.setRequestHeader('Accept', 'application/json');
				if (redacted_api_key) xhr.setRequestHeader('Authorization', redacted_api_key);
				xhr.responseType = 'json';
				//xhr.timeout = 5 * 60 * 1000;
				xhr.onload = function() {
					if (xhr.status == 404) return reject('not found');
					if (xhr.status < 200 || xhr.status >= 400) return reject(defaultErrorHandler(xhr));
					if (xhr.response.status == 'success') return resolve(xhr.response.response);
					if (xhr.response.error == 'not found') return reject(xhr.response.error);
					console.warn('queryAjaxAPI.queryInternal(...) response:', xhr, xhr.response);
					if (xhr.response.error == 'rate limit exceeded') {
						console.warn('queryAjaxAPI.queryInternal(...) ' + xhr.response.error + ':', apiTimeFrame, now, retryCount);
						if (retryCount++ <= 10) return setTimeout(queryInternal, apiTimeFrame.timeStamp + gazelleApiFrame - now);
					}
					reject('API ' + xhr.response.status + ': ' + xhr.response.error);
				};
				xhr.onerror = function() { reject(defaultErrorHandler(xhr)) };
				xhr.ontimeout = function() { reject(defaultTimeoutHandler(xhr)) };
				xhr.send();
			} else {
				setTimeout(queryInternal, apiTimeFrame.timeStamp + gazelleApiFrame - now);
				console.debug('AJAX API request quota exceeded: /ajax.php?action=' +
					action + ' (' + apiTimeFrame.requestCounter + ')');
			}
		}
	});
}

function addToTorrentCollage(collageId, torrentGroupId) {
	return collageId ? torrentGroupId ? queryAjaxAPI('collage', { id: collageId }).then(
		collage => !collage.torrentGroupIDList.map(groupId => parseInt(groupId)).includes(torrentGroupId) ? collageId
			: Promise.reject('already in collage')
	).then(collageId => new Promise(function(resolve, reject) {
		let xhr = new XMLHttpRequest, formData = new URLSearchParams({
			action: 'add_torrent',
			collageid: collageId,
			groupid: torrentGroupId,
			url: document.location.origin.concat('/torrents.php?id=', torrentGroupId),
			auth: auth,
		});
		xhr.open('POST', '/collages.php', true);
		xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
		xhr.onreadystatechange = function() {
			if (xhr.readyState < XMLHttpRequest.HEADERS_RECEIVED) return;
			if (xhr.status >= 200 && xhr.status < 400) resolve(collageId); else reject(defaultErrorHandler(xhr));
			xhr.abort();
		};
		xhr.onerror = function() { reject(defaultErrorHandler(xhr)) };
		xhr.ontimeout = function() { reject(defaultTimeoutHandler(xhr)) };
		xhr.send(formData);
	})).then(collageId => queryAjaxAPI('collage', { id: collageId }).then(
		collage => collage.torrentGroupIDList.map(groupId => parseInt(groupId)).includes(torrentGroupId) ? collage
			: Promise.reject('Error: not added for unknown reason')
	)) : Promise.reject('torrent group id not defined') : Promise.reject('collage id not defined');
}

function removeFromTorrentCollage(collageId, torrentGroupId, question) {
	if (!confirm(question)) return Promise.reject('Cancelled');
	return new Promise(function(resolve, reject) {
		let xhr = new XMLHttpRequest, formData = new URLSearchParams({
			action: 'manage_handle',
			collageid: collageId,
			groupid: torrentGroupId,
			auth: auth,
			submit: 'Remove',
		});
		xhr.open('POST', '/collages.php', true);
		xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
		xhr.onreadystatechange = function() {
			if (xhr.readyState < XMLHttpRequest.HEADERS_RECEIVED) return;
			if (xhr.status >= 200 && xhr.status < 400) resolve(xhr.status); else reject(defaultErrorHandler(xhr));
			xhr.abort();
		};
		xhr.onerror = function() { reject(defaultErrorHandler(xhr)) };
		xhr.ontimeout = function() { reject(defaultTimeoutHandler(xhr)) };
		xhr.send(formData);
	});
}

function addToArtistCollage(collageId, artistId) {
	return collageId ? artistId ? queryAjaxAPI('collage', { id: collageId }).then(
		collage => !collage.artists.map(artist => parseInt(artist.id)).includes(artistId) ? collageId
			: Promise.reject('already in collage')
	).then(collageId => new Promise(function(resolve, reject) {
		let xhr = new XMLHttpRequest, formData = new URLSearchParams({
			action: 'add_artist',
			collageid: collageId,
			artistid: artistId,
			url: document.location.origin.concat('/artist.php?id=', artistId),
			auth: auth,
		});
		xhr.open('POST', '/collages.php', true);
		xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
		xhr.onreadystatechange = function() {
			if (xhr.readyState < XMLHttpRequest.HEADERS_RECEIVED) return;
			if (xhr.status >= 200 && xhr.status < 400) resolve(collageId); else reject(defaultErrorHandler(xhr));
			xhr.abort();
		};
		xhr.onerror = function() { reject(defaultErrorHandler(xhr)) };
		xhr.ontimeout = function() { reject(defaultTimeoutHandler(xhr)) };
		xhr.send(formData);
	})).then(collageId => queryAjaxAPI('collage', { id: collageId }).then(
		collage => collage.artists.map(artist => parseInt(artist.id)).includes(artistId) ? collage
			: Promise.reject('Error: not added for unknown reason')
	)) : Promise.reject('artist id not defined') : Promise.reject('collage id not defined');
}

function removeFromArtistCollage(collageId, artistId, question) {
	if (!confirm(question)) return Promise.reject('Cancelled');
	return new Promise(function(resolve, reject) {
		let xhr = new XMLHttpRequest, formData = new URLSearchParams({
			action: 'manage_artists_handle',
			collageid: collageId,
			artistid: artistId,
			auth: auth,
			submit: 'Remove',
		});
		xhr.open('POST', '/collages.php', true);
		xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
		xhr.onreadystatechange = function() {
			if (xhr.readyState < XMLHttpRequest.HEADERS_RECEIVED) return;
			if (xhr.status >= 200 && xhr.status < 400) resolve(xhr.status); else reject(defaultErrorHandler(xhr));
			xhr.abort();
		};
		xhr.onerror = function() { reject(defaultErrorHandler(xhr)) };
		xhr.ontimeout = function() { reject(defaultTimeoutHandler(xhr)) };
		xhr.send(formData);
	});
}

function defaultErrorHandler(response) {
	console.error('HTTP error:', response);
	let e = 'HTTP error ' + response.status;
	if (response.statusText) e += ' (' + response.statusText + ')';
	if (response.error) e += ' (' + response.error + ')';
	return e;
}

function defaultTimeoutHandler(response) {
	console.error('HTTP timeout:', response);
	const e = 'HTTP timeout';
	return e;
}

function addQuickAddForm() {
	if (!userId || !torrentGroupId && !artistId) return; // User id missing
	let ref = document.querySelector('div.sidebar');
	if (ref == null) return; // Sidebar missing
	const addSuccess = 'Successfully added to collage.';
	const alreadyInCollage = 'Error: This ' +
		(torrentGroupId ? 'torrent group' : artistId ? 'artist' : null) + ' is already in this collage';
	new Promise(function(resolve, reject) {
		try {
			var categories = JSON.parse(GM_getValue(document.location.hostname + '-categories'));
			if (categories.length > 0) resolve(categories); else throw 'empty list cached';
		} catch(e) {
			let xhr = new XMLHttpRequest;
			xhr.open('GET', '/collages.php', true);
			xhr.responseType = 'document';
			xhr.onload = function() {
				if (xhr.status >= 200 && xhr.status < 400) {
					categories = [ ];
					xhr.response.querySelectorAll('tr#categories > td > label').forEach(function(label, index) {
						let input = xhr.response.querySelector('tr#categories > td > input#' + label.htmlFor);
						categories[input != null && /\[(\d+)\]/.test(input.name) ? parseInt(RegExp.$1) : index] = label.textContent.trim();
					});
					if (categories.length > 0) {
						GM_setValue(document.location.hostname + '-categories', JSON.stringify(categories));
						resolve(categories);
					} else reject('Site categories could not be extracted');
				} else reject(defaultErrorHandler(xhr));
			};
			xhr.onerror = function() { reject(defaultErrorHandler(xhr)) };
			xhr.ontimeout = function() { reject(defaultTimeoutHandler()) };
			xhr.send();
		}
	}).then(function(categories) {
		const artistsIndexes = categories
			.map((category, index) => /^(?:Artists)$/i.test(category) ? index : -1)
			.filter(index => index >= 0);
		if (artistId && artistsIndexes.length <= 0) throw 'Artists index not found';
		const isCompatibleCategory = categoryId => categoryId >= 0 && categoryId < categories.length
			&& (torrentGroupId && !artistsIndexes.includes(categoryId) || artistId && artistsIndexes.includes(categoryId));
		document.head.appendChild(document.createElement('style')).innerHTML = `
form#addtocollage optgroup { background-color: slategray; color: white; }
form#addtocollage option { background-color: white; color: black; max-width: 290pt; }
div.box_addtocollage > form { padding: 0px 10px; }
`;
		let elem = document.createElement('div');
		elem.className = 'box box_addtocollage';
		elem.style = 'padding: 0 0 10px;';
		elem.innerHTML = `
<div class="head" style="margin-bottom: 5px;"><strong>Add to Collage</strong></div>
<div id="ajax_message" class="hidden center" style="padding: 7px 0px;"></div>
<form id="searchcollages">
	<input id="searchforcollage" placeholder="Collage search" type="text" style="max-width: 10em;">
	<input id="searchforcollagebutton" value="Search" type="submit" style="max-width: 4em;">
</form>
<form id="addtocollage" class="add_form" name="addtocollage">
	<select name="collageid" id="matchedcollages" class="add_to_collage_select" style="width: 96%;">
	<input id="opencollage-btn" value="Open collage" type="button">
	<input id="addtocollage-btn" value="Add to collage" type="button">
</form>
`;
		ref.append(elem);
		let ajaxMessage = document.getElementById('ajax_message');
		let srchForm = document.getElementById('searchcollages');
		if (srchForm == null) throw new Error('#searchcollages missing');
		let searchText = document.getElementById('searchforcollage');
		if (searchText == null) throw new Error('#searchforcollage missing');
		let dropDown = document.getElementById('matchedcollages');
		if (dropDown == null) throw new Error('#matchedcollages missing');
		let doOpen = document.getElementById('opencollage-btn');
		let doAdd = document.getElementById('addtocollage-btn');
		if (doAdd == null) throw new Error('#addtocollage-btn missing');
		srchForm.onsubmit = searchSubmit;
		searchText.ondrop = evt => dataHandler(evt.target, evt.dataTransfer);
		searchText.onpaste = evt => dataHandler(evt.target, evt.clipboardData);
		if (doOpen != null) doOpen.onclick = openCollage;
		doAdd.onclick = addToCollage;
		let initTimeCap = GM_getValue('max_preload_time', 0); // max time in ms to preload the dropdown
		if (initTimeCap > 0) findCollages({ userid: userId, contrib: 1 }, initTimeCap);

		function clearList() {
			while (dropDown.childElementCount > 0) dropDown.removeChild(dropDown.firstElementChild);
		}

		function findCollages(query, maxSearchTime) {
			return typeof query == 'object' ? new Promise(function(resolve, reject) {
				let start = Date.now();
				searchFormEnable(false);
				clearList();
				elem = document.createElement('option');
				elem.text = 'Searching...';
				dropDown.add(elem);
				dropDown.selectedIndex = 0;
				let retryCount = 0, options = [ ];
				searchInternal();

				function searchInternal(page) {
					if (maxSearchTime > 0 && Date.now() - start > maxSearchTime) {
						reject('Time limit exceeded');
						return;
					}
					let xhr = new XMLHttpRequest, _query = new URLSearchParams(query);
					if (!page) page = 1;
					_query.set('page', page);
					xhr.open('GET', '/collages.php?' + _query, true);
					xhr.responseType = 'document';
					xhr.onload = function() {
						if (xhr.status < 200 || xhr.status >= 400) throw defaultErrorHandler(xhr);
						xhr.response.querySelectorAll('table.collage_table > tbody > tr[class^="row"]').forEach(function(tr, rowNdx) {
							if ((ref = tr.querySelector(':scope > td:nth-of-type(1) > a')) == null) {
								console.warn('Page parsing error');
								return;
							}
							elem = document.createElement('option');
							if ((elem.category = categories.findIndex(category => category.toLowerCase() == ref.textContent.toLowerCase())) < 0
									&& /\b(?:cats)\[(\d+)\]/i.test(ref.search)) elem.category = parseInt(RegExp.$1); // unsafe due to site bug
							if ((ref = tr.querySelector(':scope > td:nth-of-type(2) > a')) == null || !/\b(?:id)=(\d+)\b/i.test(ref.search)) {
								console.warn(`Unknown collage id (${xhr.responseURL}/${rowNdx})`);
								return;
							}
							elem.value = elem.collageId = parseInt(RegExp.$1);
							elem.text = elem.title = ref.textContent.trim();
							if ((ref = tr.querySelector(':scope > td:nth-of-type(3)')) != null) elem.size = parseInt(ref.textContent);
							if ((ref = tr.querySelector(':scope > td:nth-of-type(4)')) != null) elem.subscribers = parseInt(ref.textContent);
							if ((ref = tr.querySelector(':scope > td:nth-of-type(6) > a')) != null
									&& /\b(?:id)=(\d+)\b/i.test(ref.search)) elem.author = parseInt(RegExp.$1);
							if (isCompatibleCategory(elem.category) && (elem.category != 0 || elem.author == userId)) options.push(elem);
						});
						if (xhr.response.querySelector('div.linkbox > a.pager_next') != null) searchInternal(page + 1); else {
							if (!Object.keys(query).includes('order'))
								options.sort((a, b) => (b.size || 0) - (a.size || 0)/*a.title.localeCompare(b.title)*/);
							resolve(options);
						}
					};
					xhr.onerror = function() {
						if (xhr.status == 0 && retryCount++ <= 10) setTimeout(function() { searchInternal(page) }, 200);
						else reject(defaultErrorHandler(xhr));
					};
					xhr.ontimeout = function() { reject(defaultTimeoutHandler()) };
					xhr.send();
				}
			}).then(function(options) {
				clearList();
				categories.forEach(function(category, ndx) {
					let _category = options.filter(option => option.category == ndx);
					if (_category.length <= 0) return;
					elem = document.createElement('optgroup');
					elem.label = category;
					elem.append(..._category);
					dropDown.add(elem);
				});
				dropDown.selectedIndex = 0;
				searchFormEnable(true);
				return options;
			}).catch(function(reason) {
				clearList();
				searchFormEnable(true);
				console.warn(reason);
			}) : Promise.reject('Invalid parameter');
		}

		function searchFormEnable(enabled) {
			for (let i = 0; i < srchForm.length; ++i) srchForm[i].disabled = !enabled;
		}

		function searchSubmit(evt) {
			let searchTerm = searchText.value.trim();
			if (searchTerm.length <= 0) return false;
			let query = {
				action: 'search',
				search: searchTerm,
				type: 'c.name',
				order: 'Updated',
				sort: 'desc',
				order_way: 'Descending',
			};
			categories.map((category, index) => 'cats[' + index + ']')
				.filter((category, index) => isCompatibleCategory(index))
				.forEach(index => { query[index] = 1 });
			findCollages(query);
			return false;
		}

		function addToCollage(evt) {
			(function() {
				evt.target.disabled = true;
				if (ajaxMessage != null) ajaxMessage.classList.add('hidden');
				let collageId = parseInt(dropDown.value);
				if (!collageId) return Promise.reject('No collage selected');
/*
				if (Array.from(document.querySelectorAll('table.collage_table > tbody > tr:not([class="colhead"]) > td > a'))
						.map(node => /\b(?:id)=(\d+)\b/i.test(node.search) && parseInt(RegExp.$1)).includes(collageId))
					return Promise.reject(alreadyInCollage);
*/
				if (torrentGroupId) return addToTorrentCollage(collageId, torrentGroupId);
				if (artistId) return addToArtistCollage(collageId, artistId);
				return Promise.reject('munknown page class');
			})().then(function(collage) {
				if (ajaxMessage != null) {
					ajaxMessage.innerHTML = '<span style="color: #0A0;">' + addSuccess + '</span>';
					ajaxMessage.classList.remove('hidden');
				}
				evt.target.disabled = false;
				let mainColumn = document.querySelector('div.main_column');
				if (mainColumn == null) return collage;
				let tableName = collage.collageCategoryID != 0 ? 'collages' : 'personal_collages'
				let tbody = mainColumn.querySelector('table#' + tableName + ' > tbody');
				if (tbody == null) {
					tbody = document.createElement('tbody');
					tbody.innerHTML = '<tr class="colhead"><td width="85%"><a href="#">↑</a>&nbsp;</td><td># torrents</td></tr>';
					elem = document.createElement('table');
					elem.id = tableName;
					elem.className = 'collage_table';
					elem.append(tbody);
					mainColumn.insertBefore(elem, [
						'table#personal_collages', 'table#vote_matches', 'div.torrent_description',
						'div#similar_artist_map', 'div#artist_information',
					].reduce((acc, selector) => acc || document.querySelector(selector), null));
				}
				tableName = '\xA0This ' + (artistsIndexes.includes(collage.collageCategoryID) ? 'artist' : 'album') + ' is in ' +
					tbody.childElementCount + ' ' + (collage.collageCategoryID != 0 ? 'collage' : 'personal collage');
				if (tbody.childElementCount > 1) tableName += 's';
				tbody.firstElementChild.firstElementChild.childNodes[1].data = tableName;
				elem = document.createElement('tr');
				elem.className = 'collage_rows';
				if (tbody.querySelector('tr.collage_rows.hidden') != null) elem.classList.add('hidden');
				elem.innerHTML = '<td><a href="/collages.php?id=' + collage.id + '">' + collage.name + '</a></td><td class="number_column">' +
					collage[artistsIndexes.includes(collage.collageCategoryID) ? 'artists' : 'torrentgroups'].length + '</td>';
				tbody.append(elem);
				return collage;
			}).catch(function(reason) {
				evt.target.disabled = false;
				if (ajaxMessage == null) return;
				ajaxMessage.innerHTML = '<span style="color: #A00;">' + reason.toString() + '</span>';
				ajaxMessage.classList.remove('hidden');
			});
		}

		function openCollage(evt) {
			let collageId = parseInt(dropDown.value);
			if (collageId <= 0) return false;
			let win = window.open('/collages.php?id=' + collageId, '_blank');
			win.focus();
		}

		function dataHandler(target, data) {
			var text = data.getData('text/plain');
			if (!text) return true;
			target.value = text;
			srchForm.onsubmit();
			return false;
		}
	});
}

switch (document.location.pathname) {
	case '/torrents.php': {
		var torrentGroupId = new URLSearchParams(document.location.search).get('id'), collages;
		if (torrentGroupId) torrentGroupId = parseInt(torrentGroupId); else break; // Unexpected URL format
		const searchforcollage = document.getElementById('searchforcollage');
		if (searchforcollage != null) {
			if (typeof SearchCollage == 'function') SearchCollage = () => {
				const searchTerm = $('#searchforcollage').val(),
							personalCollages = $('#personalcollages');
				ajax.get(`ajax.php?action=collages&search=${encodeURIComponent(searchTerm)}`, responseText => {
					const { response, status } = JSON.parse(responseText);
					if (status !== 'success') return;
					const categories = response.reduce((accumulator, item) => {
						const { collageCategoryName } = item;
						accumulator[collageCategoryName] = (accumulator[collageCategoryName] || []).concat(item);
						return accumulator;
					}, {});
					personalCollages.children().remove();
					Object.entries(categories).forEach(([category, collages]) => {
						console.log(collages);
						personalCollages.append(`
<optgroup label="${category}">
${collages.reduce((accumulator, { id, name }) =>
	`${accumulator}<option value="${id}">${name}</option>`
	,'')}
</optgroup>
		`);
					});
				});
			};

			function inputHandler(evt, key) {
				const data = evt[key].getData('text/plain').trim();
				if (!data) return true;
				evt.target.value = data;
				SearchCollage();
				setTimeout(function() {
					const add_to_collage_select = document.querySelector('select.add_to_collage_select');
					if (add_to_collage_select != null && add_to_collage_select.options.length > 1) {
						// TODO: expand
					}
				}, 3000);
				return false;
			}
			searchforcollage.onpaste = evt => inputHandler(evt, 'clipboardData');
			searchforcollage.ondrop = evt => inputHandler(evt, 'dataTransfer');
			searchforcollage.onkeypress = evt => { if (evt.key == 'Enter') SearchCollage() };
		} else addQuickAddForm();

		try { collages = JSON.parse(window.sessionStorage.collages) } catch(e) { collages = { } }
		if (!collages[document.domain]) collages[document.domain] = { };

		document.querySelectorAll('table[id$="collages"] > tbody > tr > td > a').forEach(function(link) {
			if (!link.pathname.startsWith('/collages.php') || !/\b(?:id)=(\d+)\b/.test(link.search)) return;
			let collageId = parseInt(RegExp.$1), toggle, navLinks = [],
					numberColumn = link.parentNode.parentNode.querySelector('td.number_column');
			link.onclick = function(evt) {
				return evt.button == 0 && evt.altKey ? removeFromTorrentCollage(collageId, torrentGroupId,
						'Are you sure to remove this group from collage "' + link.textContent.trim() + '"?')
					.then(status => { link.parentNode.parentNode.remove() }) : true;
			};
			link.title = 'Use Alt + left click to remove from this collage';
			if (numberColumn != null) {
				numberColumn.style.cursor = 'pointer';
				numberColumn.onclick = loadCollage;
				numberColumn.title = collages[document.domain][collageId] ? 'Refresh' : 'Load collage for direct browsing';
			}
			if (collages[document.domain][collageId]) {
				expandSection();
				addCollageLinks(collages[document.domain][collageId]);
			}

			function addCollageLinks(collage) {
				var index = collage.torrentgroups.findIndex(group => group.id == torrentGroupId);
				if (index < 0) {
					console.warn('Assertion failed: torrent', torrentGroupId, 'not found in the collage', collage);
					return false;
				}
				link.style.color = 'white';
				link.parentNode.parentNode.style = 'color:white; background-color: darkgoldenrod;';
				var stats = document.createElement('span');
				stats.textContent = `${index + 1} / ${collage.torrentgroups.length}`;
				stats.style = 'font-size: 8pt; color: antiquewhite; font-weight: 100; margin-left: 10px;';
				navLinks.push(stats);
				link.parentNode.append(stats);
				if (collage.torrentgroups[index - 1]) {
					var a = document.createElement('a');
					a.href = '/torrents.php?id=' + collage.torrentgroups[index - 1].id;
					a.textContent = '[\xA0<\xA0]';
					a.title = getTitle(index - 1);
					a.style = 'color: chartreuse; margin-right: 10px;';
					navLinks.push(a);
					link.parentNode.prepend(a);
					a = document.createElement('a');
					a.href = '/torrents.php?id=' + collage.torrentgroups[0].id;
					a.textContent = '[\xA0<<\xA0]';
					a.title = getTitle(0);
					a.style = 'color: chartreuse; margin-right: 5px;';
					navLinks.push(a);
					link.parentNode.prepend(a);
				}
				if (collage.torrentgroups[index + 1]) {
					a = document.createElement('a');
					a.href = '/torrents.php?id=' + collage.torrentgroups[index + 1].id;
					a.textContent = '[\xA0>\xA0]';
					a.title = getTitle(index + 1);
					a.style = 'color: chartreuse; margin-left: 10px;';
					navLinks.push(a);
					link.parentNode.append(a);
					a = document.createElement('a');
					a.href = '/torrents.php?id=' + collage.torrentgroups[collage.torrentgroups.length - 1].id;
					a.textContent = '[\xA0>>\xA0]';
					a.title = getTitle(collage.torrentgroups.length - 1);
					a.style = 'color: chartreuse; margin-left: 5px;';
					navLinks.push(a);
					link.parentNode.append(a);
				}
				return true;

				function getTitle(index) {
					if (typeof index != 'number' || index < 0 || index >= collage.torrentgroups.length) return undefined;
					let title = collage.torrentgroups[index].musicInfo && Array.isArray(collage.torrentgroups[index].musicInfo.artists) ?
						collage.torrentgroups[index].musicInfo.artists.map(artist => artist.name).join(', ') + ' - ' : '';
					if (collage.torrentgroups[index].name) title += collage.torrentgroups[index].name;
					if (collage.torrentgroups[index].year) title += ' (' + collage.torrentgroups[index].year + ')';
					return title;
				}
			}

			function expandSection() {
				if (toggle === undefined) toggle = link.parentNode.parentNode.parentNode.querySelector('td > a[href="#"][onclick]');
				if (toggle === null || toggle.dataset.expanded) return false;
				toggle.dataset.expanded = true;
				toggle.click();
				return true;
			}

			function loadCollage(evt) {
				evt.target.disabled = true;
				navLinks.forEach(a => { a.remove() });
				navLinks = [];
				var span = document.createElement('span');
				span.textContent = '[\xA0loading...\xA0]';
				span.style = 'color: red; background-color: white; margin-left: 10px;';
				link.parentNode.append(span);
				queryAjaxAPI('collage', { id: collageId }).then(function(collage) {
					span.remove();
					cacheCollage(collage);
					addCollageLinks(collage);
					evt.target.disabled = false;
				}, function(reason) {
					span.remove();
					evt.target.disabled = false;
				});
				return false;
			}
		});

		function cacheCollage(collage) {
			collages[document.domain][collage.id] = {
				id: collage.id,
				name: collage.name,
				torrentgroups: collage.torrentgroups.map(group => ({
					id: group.id,
					musicInfo: group.musicInfo ? {
						artists: Array.isArray(group.musicInfo.artists) ?
						group.musicInfo.artists.map(artist => ({ name: artist.name })) : undefined,
					} : undefined,
					name: group.name,
					year: group.year,
				})),
			};
			window.sessionStorage.collages = JSON.stringify(collages);
		}

		break;
	}
	case '/artist.php': {
		var artistId = new URLSearchParams(document.location.search).get('id');
		if (artistId) artistId = parseInt(artistId); else break; // Unexpected URL format
		addQuickAddForm();
		break;
	}
	case '/collages.php': {
		var collageId = new URLSearchParams(document.location.search).get('id');
		if (collageId) collageId = parseInt(collageId); else break; // Collage id missing
		let category = document.querySelector('div.box_category > div.pad > a');
		category = category != null ? category.textContent : undefined;

		function scanPage() {
			if (category != 'Artists') {
				var sel = [
					'tr.group > td[colspan] > strong > a[href^="torrents.php?id="]',
					'ul.collage_images > li > a[href^="torrents.php?id="]',
				]
				document.querySelectorAll(sel.join(', ')).forEach(function(a) {
					a.onclick = function(evt) {
						if (evt.button != 0 || !evt.altKey) return true;
						let torrentGroupId = new URLSearchParams(a.search);
						torrentGroupId = torrentGroupId.get('id');
						if (torrentGroupId) torrentGroupId = parseInt(torrentGroupId); else {
							console.warn('Assertion failed: no id', a);
							throw 'no id';
						}
						removeFromTorrentCollage(collageId, torrentGroupId, 'Are you sure to remove selected group from this collage?').then(function(status) {
							document.querySelectorAll(sel.join(', ')).forEach(function(a) {
								if (parseInt(new URLSearchParams(a.search).get('id')) == torrentGroupId) switch (a.parentNode.nodeName) {
									case 'STRONG': a.parentNode.parentNode.parentNode.remove(); break;
									case 'LI': a.parentNode.remove(); break;
								}
							});
						});
					};
				});
			} else {
				sel = [
					'table#discog_table > tbody > tr > td > a[href^="artist.php?id="]',
					'ul.collage_images > li > a[href^="artist.php?id="]',
				];
				document.querySelectorAll(sel.join(', ')).forEach(function(a) {
					a.onclick = function(evt) {
						if (evt.button != 0 || !evt.altKey) return true;
						let artistId = new URLSearchParams(a.search);
						artistId = artistId.get('id');
						if (artistId) artistId = parseInt(artistId); else {
							console.warn('Assertion failed: no id', a);
							throw 'no id';
						}
						removeFromArtistCollage(collageId, artistId, 'Are you sure to remove selected artist from this collage?').then(function(status) {
							document.querySelectorAll(sel.join(', ')).forEach(function(a) {
								if (parseInt(new URLSearchParams(a.search).get('id')) == artistId) switch (a.parentNode.nodeName) {
									case 'TD': a.parentNode.parentNode.remove(); break;
									case 'LI': a.parentNode.remove(); break;
								}
							});
						});
					};
				});
				let artistLink = document.querySelector('form.add_form[name="artist"] input#artist');
				if (artistLink != null) {
					let ref = document.querySelector('form.add_form[name="artist"] > div.submit_div');
					let searchBtn = document.createElement('input');
					searchBtn.value = 'Look up';
					searchBtn.type = 'button';
					searchBtn.onclick = function(evt) {
						let xhr = new XMLHttpRequest;
						xhr.open('HEAD', '/artist.php?artistname=' + encodeURIComponent(artistLink.value.trim()), true);
						xhr.onreadystatechange = function() {
							if (xhr.readyState < XMLHttpRequest.HEADERS_RECEIVED) return;
							artistLink.value = xhr.responseURL.includes('/artist.php?id=') ? xhr.responseURL : '';
						};
						xhr.send();
					};
					ref.append(searchBtn);
				}
			}
		}

		scanPage();
		document.querySelectorAll('div#pageslinksdiv > span > a.pageslink')
			.forEach(a => { a.addEventListener('click', evt => { setTimeout(scanPage, 1000) }) });
		break;
	}
}