// ==UserScript==
// @name         MB Auto Track Lengths from CD TOC
// @version      1.09
// @match        https://musicbrainz.org/release/*
// @match        https://beta.musicbrainz.org/release/*
// @match        https://musicbrainz.org/cdtoc/*
// @match        https://beta.musicbrainz.org/cdtoc/*
// @run-at       document-end
// @author       Anakunda
// @namespace    https://greasyfork.org/users/321857
// @copyright    2024, Anakunda (https://greasyfork.org/users/321857)
// @license      GPL-3.0-or-later
// @description  Autoset track lengths from unique CD-TOC
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_registerMenuCommand
// @require      https://openuserjs.org/src/libs/Anakunda/xhrLib.min.js
// @downloadURL none
// ==/UserScript==

'use strict';

const loggedIn = document.body.querySelector('div.links-container > ul.menu > li.account') != null;
if (!loggedIn) console.warn('Not logged in: the script functionality is limited');
let autoSet = loggedIn && GM_getValue('auto_set', true);
const flashElement = elem => elem instanceof HTMLElement ? elem.animate([
	{ offset: 0.0, opacity: 1 },
	{ offset: 0.4, opacity: 1 },
	{ offset: 0.5, opacity: 0.1 },
	{ offset: 0.9, opacity: 0.1 },
], { duration: 600, iterations: Infinity }) : null;
const getTime = str => str ? str.split(':').reverse().reduce((t, v, n) => t + parseInt(v) * Math.pow(60, n), 0) : NaN;
if ('mbDiscIdStates' in sessionStorage) try {
	var discIdStates = JSON.parse(sessionStorage.getItem('mbDiscIdStates'));
} catch(e) { console.warn(e) }
if (typeof discIdStates != 'object') discIdStates = { };
const getEntity = url => /^\/(\w+)\/([\da-f]{8}-[\da-f]{4}-[\da-f]{4}-[\da-f]{4}-[\da-f]{12})(?=[\/\?]|$)/i.exec(url.pathname);

if (loggedIn) {
	const setMenu = oldId => GM_registerMenuCommand(`Switch to ${autoSet ? 'conservative' : 'full auto'} mode`, function(param) {
		GM_setValue('auto_set', autoSet = !autoSet);
		if (autoSet) document.location.reload(); else menuId = setMenu(menuId);
	}, { id: oldId, autoClose: false, title: `Operating in ${autoSet ? 'full auto' : 'conservative'} mode

Full auto mode: autoset times in background and report the status as style/tooltip
Conservative mode: evaluate status in background and autoset times on user click` });
	let menuId = setMenu();
}

const mbRequestRate = 1000, mbRequestsCache = new Map;
let mbLastRequest = null;

function apiRequest(endPoint, params) {
	if (!endPoint) throw 'Endpoint is missing';
	const url = new URL('/ws/2/' + endPoint.replace(/^\/+|\/+$/g, ''), 'https://musicbrainz.org');
	if (params) for (let key in params) url.searchParams.set(key, params[key]);
	url.searchParams.set('fmt', 'json');
	const cacheKey = url.pathname.slice(6) + url.search;
	if (mbRequestsCache.has(cacheKey)) return mbRequestsCache.get(cacheKey);
	const recoverableHttpErrors = [429, 500, 502, 503, 504, 520, /*521, */522, 523, 524, 525, /*526, */527, 530];
	const request = new Promise(function(resolve, reject) {
		function request() {
			if (mbLastRequest == Infinity) return setTimeout(request, 50);
			const availableAt = mbLastRequest + mbRequestRate, now = Date.now();
			if (now < availableAt) return setTimeout(request, availableAt - now); else mbLastRequest = Infinity;
			xhr.open('GET', url, true);
			xhr.setRequestHeader('Accept', 'application/json');
			xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
			xhr.send();
		}
		function errorHandler(response) {
			console.error('HTTP error:', response);
			let reason = 'HTTP error ' + response.status;
			if (response.status == 0) reason += '/' + response.readyState;
			let statusText = response.statusText;
			if (response.response) try {
				if (typeof response.response.error == 'string') statusText = response.response.error;
			} catch(e) { }
			if (statusText) reason += ' (' + statusText + ')';
			return reason;
		}

		let retryCounter = 0;
		const xhr = Object.assign(new XMLHttpRequest, {
			responseType: 'json',
			timeout: 60e3,
			onload: function() {
				mbLastRequest = Date.now();
				if (this.status >= 200 && this.status < 400) resolve(this.response);
				else if (recoverableHttpErrors.includes(this.status))
					if (++retryCounter < 60) setTimeout(request, 1000); else reject('Request retry limit exceeded');
				else reject(errorHandler(this));
			},
			onerror: function() { mbLastRequest = Date.now(); reject(errorHandler(this)); },
			ontimeout: function() {
				mbLastRequest = Date.now();
				console.error('HTTP timeout:', this);
				let reason = 'HTTP timeout';
				if (this.timeout) reason += ' (' + this.timeout + ')';
				reject(reason);
			},
		});
		request();
	});
	mbRequestsCache.set(cacheKey, request);
	return request;
}

function saveDiscIdStates(releaseId, states) {
	if (states) discIdStates[releaseId] = states; else delete discIdStates[releaseId];
	sessionStorage.setItem('mbDiscIdStates', JSON.stringify(discIdStates));
}

function getRequestparams(link) {
	console.assert(link instanceof HTMLAnchorElement);
	if (!(link instanceof HTMLAnchorElement)) throw 'Invalid argument';
	const params = { discId: /^\/cdtoc\/([\w\_\.\-]+)\/set-durations$/i.exec(link.pathname) };
	if (params.discId != null) params.discId = params.discId[1]; else return null;
	const query = new URLSearchParams(link.search);
	if (!query.has('medium')) return null;
	console.assert(link.textContent.trim() == 'Set track lengths', link);
	params.mediumId = parseInt(query.get('medium'));
	console.assert(params.mediumId > 0, link.href);
	return params.mediumId >= 0 ? params : null;
}

function tooltipFromState(state) {
	if (state <= -0x1000) return 'Unhandled error occured (see browser console for more details)';
	if (state <= -0x40) return 'Suspicious disc ID assigned (severe timing differences)';
	if (state <= -0x20) return 'Suspicious disc ID assigned (considerable timing differences)';
	if (state <= -0x10) return 'Ambiguity: multiple suspicious disc IDs attached';
	if (state === null) return 'No disc IDs attached';
	if (state === 0) return 'Track times already match CD TOC';
	if (state >= 0x180) return 'TOC lengths successfully applied on tracks';
	if (state >= 0x100) return 'Unique CD TOC available to apply';
	if (state >= 0x10) return 'Ambiguity: multiple disc IDs attached';
	return `Unknown status 0x${state.toString(16).toUpperCase()}`;
}

function styleByState(element, state) {
	console.assert(element instanceof HTMLElement);
	if (!(element instanceof HTMLElement)) throw 'Invalid argument';
	if (state <= -0x1000) element.style = 'color: white; background-color: red;';
	else if (state <= -0x40) element.style = 'color: #f00; background-color: #f003;';
	else if (state <= -0x20) element.style = 'color: #d20;';
	else if (state <= -0x10) element.style = 'color: #b40;';
	else if ((state & 0x18) == 0x10) element.style = 'color: #960;';
	else if ((state & 0x18) == 0x18) element.style = 'color: #780';
	if (state == 0x100 && loggedIn) element.style.fontWeight = 'bold';
	element.title = tooltipFromState(state);
}


function computeDifferenceState(deltas, considerable, severe) {
	if (!Array.isArray(deltas) || typeof considerable != 'function' || typeof severe != 'function')
		throw 'Invalid argument';
	[considerable, severe] = [considerable, severe].map(fn => deltas.filter(fn).length);
	deltas = deltas.filter(delta => !isNaN(delta)).length;
	let state = 0;
	if (deltas > 0 && severe * 2 >= deltas) state |= 0x100;
	if (deltas > 0 && considerable * 2 >= deltas) state |= 0x80;
	if (severe > 0) state |= 0x40;
	if (considerable > 0) state |= 0x20;
	return -state;
}

const getSetLink = row => Array.prototype.find.call(row.querySelectorAll('td a'), a => getRequestparams(a) != null) || null;

function processRelease(param, autoSet = true, setParams) {
	if (param instanceof HTMLDocument) {
		function getDiscIds(row) {
			console.assert(row instanceof HTMLElement);
			const discIds = [ ], isDiscIdRow = row => row instanceof HTMLElement && ['odd', 'even']
				.some(cls => row.classList.contains(cls));
			while (isDiscIdRow(row = row.nextElementSibling)) discIds.push(getSetLink(row));
			return discIds;
		}
		function processTrackLengths(link, autoSet = true) {
			console.assert(link instanceof HTMLAnchorElement);
			if (!(link instanceof HTMLAnchorElement)) throw 'Invalid argument';
			if (loggedIn && autoSet && visible) link.disabled = true;
			const animation = visible ? flashElement(link) : null;
			return localXHR(link).then(function(document) {
				const deltas = Array.from(document.body.querySelectorAll('div#page > table.wrap-block.details'), function(track) {
					const times = ['old', 'new'].map(function(cls) {
						if ((cls = track.querySelector('td.' + cls)) != null) cls = cls.textContent; else return NaN;
						return getTime(cls);
					});
					return Math.abs(times[1] - times[0]);
				});
				return Promise[deltas.some(delta => delta > 5) ? 'reject' : 'resolve'](deltas);
			}).then(function(deltas) {
				if (!loggedIn || !autoSet) {
					if (animation) animation.cancel();
					link.disabled = false;
					if (visible) styleByState(link, 0x100);
					return 0x100;
				}
				const postData = new URLSearchParams({ 'confirm.edit_note': GM_getValue('edit_note', '') });
				if (GM_getValue('make_votable', false)) postData.set('confirm.make_votable', 1);
				return localXHR(link, { responseType: null }, postData).then(function(statusCode) {
					let title = `Status code: ${statusCode}`;
					if (deltas.length > 0) title = `Deltas: ${deltas}\n${title}`;
					if (visible) link.replaceWith(Object.assign(document.createElement('span'), {
						textContent: 'Track lengths successfully set',
						style: 'color: green;',
						title: title,
					}));
					return 0x180;
				});
			}).catch(function(reason) {
				if (animation) animation.cancel();
				link.disabled = false;
				if (Array.isArray(reason)) {
					const state = computeDifferenceState(reason, delta => delta > 5, delta => delta > 30);
					if (visible) styleByState(link, state);
					return state;
				} else {
					if (visible) styleByState(link, -0x1000);
					return -0x1000;
				}
			});
		}
		function processMedium(medium) {
			function clickHandler(evt) {
				const link = evt.currentTarget;
				if (!link.disabled) processTrackLengths(link, true)
					.then(state => { if (state < 0x180) document.location.assign(link) });
				return false;
			}

			console.assert(medium instanceof HTMLElement);
			if (!(medium instanceof HTMLElement)) throw 'Invalid argument';
			const discIds = getDiscIds(medium);
			if (discIds.length <= 0) return Promise.resolve(null);
			const settable = discIds.filter(Boolean);
			if (discIds.length > 1) {
				const state = 0x10 | (settable.length < discIds.length ? 0 : 8);
				if (loggedIn && visible) for (let link of settable) {
					link.onclick = clickHandler;
					processTrackLengths(link, false).then(status => { if (status >= 0) styleByState(link, state) });
				}
				return Promise.resolve(state);
			} else if (settable.length <= 0) return Promise.resolve(0x00); else {
				if (loggedIn && visible) settable[0].onclick = autoSet ? evt => !evt.currentTarget.disabled : clickHandler;
				return processTrackLengths(settable[0], autoSet);
			}
		}

		const visible = param == window.document;
		const media = param.body.querySelectorAll('table.tbl > tbody > tr.subh');
		if (media.length <= 0) return Promise.reject('No media found');
		else if (setParams && typeof setParams == 'object') {
			const medium = Array.prototype.find.call(media, medium => getDiscIds(medium).some(function(link) {
				if (link == null) return false;
				const requestParams = getRequestparams(link);
				return requestParams != null && (requestParams.discId == setParams.discId)
					&& (requestParams.mediumId == setParams.mediumId);
			}));
			console.assert(medium, setParams, media);
			return medium ? processMedium(medium) : Promise.reject('Medium not found');
		} else return Promise.all(Array.from(media, processMedium));
	} else if (param)	{
		const url = `/release/${param}/discids`;
		if (setParams) return localXHR(url).then(document => processRelease(document, autoSet, setParams));
		return (param in discIdStates ? Promise.resolve(discIdStates[param]) : (function getDisdIdStates() {
			return apiRequest('release/' + param, { inc: 'recordings+discids'}).then(function(release) {
				const states = release.media.map(function(medium, mediumIndex) {
					if (!medium.discs || medium.discs.length <= 0) return null;
					const discIdStates = medium.discs.map(function(discId, tocIndex) {
						const grpLabel = `Medium ${mediumIndex + 1} / Disc ID ${tocIndex + 1}`;
						console.groupCollapsed(grpLabel);
						const deltas = medium.tracks.map(function lengthsEqual(track, index, tracks) {
							const trackLength = 'length' in track ? typeof track.length == 'number' ? track.length / 1000
								: typeof track.length == 'string' ? getTime(track.length) : NaN : NaN;
							const hiOffset = (index + 1) in discId.offsets ? discId.offsets[index + 1] : discId.sectors;
							const tocLength = (hiOffset - discId.offsets[index]) / 75;
							const delta = Math.abs(tocLength - trackLength);
							console.debug('[%02d] Track length: %.3f (%s), TOC length: %.4f, Delta: %.4f',
								index + 1, trackLength, track.length, tocLength, delta);
							return delta;
						});
						console.groupEnd(grpLabel);
						if (medium.tracks.every(function lengthsEqual(track, index, tracks) {
							if (typeof track.length != 'number') return false;
							const hiOffset = (index + 1) in discId.offsets ? discId.offsets[index + 1] : discId.sectors;
							return track.length == Math.floor((hiOffset - discId.offsets[index]) * 1000 / 75);
						})) return 0;

						const state = computeDifferenceState(deltas, delta => delta >= 5.5, delta => delta >= 30.5);
						return state == 0 ? 0x100 : state;
					});
					if (discIdStates.length == 1) return discIdStates[0];
					let state = 0x10;
					if (!discIdStates.some(state => state == 0)) state |= 8;
					if (!discIdStates.some(state => state < 0)) state |= 4;
					return discIdStates.some(state => state > 0) ? state : -state;
				});
				saveDiscIdStates(param, states);
				return states;
			}).catch(reason => { console.warn('Disc ID states query failed:', reason, '; falling back to scraping HTML') });
		})()).then(function(states) {
			if (states && !(autoSet && states.some(state => state >= 0x100))) return states;
			return localXHR(url).then(processRelease);
		});
	} else throw 'Invalid argument';
}

if (document.location.pathname.startsWith('/release/')) {
	function currentPageStates(states) {
		saveDiscIdStates(release[2], states.every(state => [0x00, null].includes(state)) ? states : undefined);
		return states;
	}

	const release = getEntity(document.location);
	console.assert(release != null && release[1] == 'release', document.location.pathname);
	if (release == null) throw 'Failed to identify entity from page url';
	let tabLinks = document.body.querySelectorAll('div#page ul.tabs > li a');
	tabLinks = Array.prototype.filter.call(tabLinks, a => a.pathname.endsWith('/discids'));
	console.assert(tabLinks.length == 1, tabLinks);
	if (tabLinks.length != 1) throw 'Assertion failed: Disc ID tab links mismatch';
	const tabLink = tabLinks[0], li = tabLink.closest('li');
	console.assert(li != null);
	if (document.location.pathname.endsWith('/discids') || li.classList.contains('sel'))
		return processRelease(document, autoSet).then(currentPageStates);
	else if (li.classList.contains('disabled')) return Promise.reject('Release has no disc IDs attached');
	const animation = flashElement(tabLink);
	processRelease(release[2], autoSet).then(function(states) {
		console.debug('Media disc ID states:', states);
		saveDiscIdStates(release[2], states.some(state => state <= -0x1000) ? undefined
			: states.map(state => state == 0x180 ? 0 : state));
		if (states.some(state => state <= -0x1000)) li.style = 'color: white; background-color: red;';
		else if (states.some(state => state <= -0x40)) li.style.backgroundColor = '#f004';
		else if (states.some(state => state <= -0x20)) li.style.backgroundColor = '#f002';
		else if (states.some(state => state == 0x180)) li.style.backgroundColor = '#0f02';
		if (states.some(state => state == 0x100)) li.style.fontWeight = 'bold';
		if (animation) animation.cancel();
		li.title = states.map(tooltipFromState).map((state, index) => `Medium ${index + 1}: ${state}`).join('\n');
	}, function(reason) {
		if (animation) animation.cancel();
		[li.style, li.title] = ['color: white; background-color: red;', 'Something went wrong: ' + reason];
	});
} else if (document.location.pathname.startsWith('/cdtoc/'))
	document.body.querySelectorAll('table.tbl > tbody > tr').forEach(function(medium, index) {
		function processLink(userClick) {
			setLink.disabled = true;
			const animation = flashElement(setLink);
			processRelease(release[2], userClick || autoSet, setparams).then(function(state) {
				saveDiscIdStates(release[2]);
				if (state == 0x180) setLink.replaceWith(Object.assign(document.createElement('span'), {
					textContent: 'Track lengths successfully set',
					style: 'color: green;',
				})); else {
					if (animation) animation.cancel();
					styleByState(setLink, state);
					if (state < 0x100) {
						const ambiguous = (Math.abs(state) & 0x10) != 0;
						const redirect = `/release/${release[2]}/discids`;
						if (userClick) document.location.assign(ambiguous ? redirect : setLink);
						else if (ambiguous) setLink.href = redirect;
					}
					setLink.disabled = false;
				}
			}, function(reason) {
				setLink.style = 'color: white; background-color: red;';
				setLink.disabled = false;
				if (animation) animation.cancel();
				setLink.title = reason;
			});
		}

		let release = Array.prototype.find.call(medium.querySelectorAll(':scope > td a'),
			a => (a = getEntity(a)) != null && a[1] == 'release');
		console.assert(release, medium);
		if (release) release.pathname += '/discids';
		const setLink = getSetLink(medium);
		if (setLink != null && release) release = getEntity(release); else return;
		console.assert(release != null, medium);
		const setparams = getRequestparams(setLink);
		console.assert(setparams != null, setLink);
		if (loggedIn) setLink.onclick = autoSet ? evt => !evt.currentTarget.disabled : function(evt) {
			if (!evt.currentTarget.disabled) processLink(true);
			return false;
		};
		processLink(false);
	});