// ==UserScript==
// @name         Sharty 'log Filter
// @namespace    https://soyjak.st/
// @version      1.0.0
// @description  Filters out everything related to your current filter. You can still view threads if you wish to do so.
// @match        *://soyjak.st/*/catalog.html*
// @match        *://*.soyjak.st/*/catalog.html*
// @run-at       document-end
// @grant        none
// ==/UserScript==

(function () {
	'use strict';

	const grid = document.getElementById('Grid');
	if (!grid) return;

	const STORAGE_KEY = 'postFilter';
	const PURGE_INTERVAL = 86400; // same first re-check delay post-filter.js uses
	const TYPE_LABELS = {
		name: 'Name',
		trip: 'Tripcode',
		sub: 'Subject',
		com: 'Comment',
		flag: 'Flag',
		filename: 'Filename',
		filehash: 'File hash',
	};

	const pageBoard = (typeof window.board_name === 'string' && window.board_name) ||
		location.pathname.split('/')[1];
	const apiData = new Map(); // "board/id" -> post data from catalog.json
	const domCache = new WeakMap();
	let apiFailed = false;

	/* ---------- storage ---------- */

	function now() {
		return Math.floor(Date.now() / 1000);
	}

	function readList() {
		const raw = localStorage.getItem(STORAGE_KEY);
		if (raw == null) {
			return { generalFilter: [], postFilter: {}, nextPurge: {}, lastPurge: now() };
		}
		const list = JSON.parse(raw);
		list.generalFilter = list.generalFilter || [];
		list.postFilter = list.postFilter || {};
		list.nextPurge = list.nextPurge || {};
		return list;
	}

	function setManual(mix, hide) {
		const key = tileKey(mix);
		if (!key) return;

		let list;
		try {
			list = readList();
		} catch (err) {
			alert('Catalog Filter: localStorage.postFilter could not be read, so nothing was changed.');
			return;
		}

		const threads = list.postFilter[key.board] || (list.postFilter[key.board] = {});
		const purge = list.nextPurge[key.board] || (list.nextPurge[key.board] = {});
		const entries = threads[key.id] || (threads[key.id] = []);
		const i = entries.findIndex(e => e && e.post != null && String(e.post) === key.id);

		if (hide && i < 0) {
			entries.push({ post: key.id, hideReplies: false });
			purge[key.id] = { timestamp: now(), interval: PURGE_INTERVAL };
		} else if (!hide && i >= 0) {
			entries.splice(i, 1);
		}

		if (!entries.length) {
			delete threads[key.id];
			delete purge[key.id];
		}
		if (!Object.keys(threads).length) delete list.postFilter[key.board];
		if (!Object.keys(purge).length) delete list.nextPurge[key.board];

		localStorage.setItem(STORAGE_KEY, JSON.stringify(list));
		refresh();
	}

	/* ---------- thread data ---------- */

	function tileKey(mix) {
		let id = mix.getAttribute('data-id');
		if (!id) {
			const link = mix.querySelector('a[href*="/res/"]');
			const m = link && link.getAttribute('href').match(/\/res\/(\d+)/);
			id = m && m[1];
		}
		if (!id) return null;

		// the catalog template renders the board as the thumbnail's first class
		const img = mix.querySelector('img.thread-image');
		const first = img && img.classList[0];
		const board = first && first !== 'thread-image' ? first : pageBoard;
		return { board, id: String(id) };
	}

	function bodyText(nodes) {
		return Array.from(nodes)
			.map(n => n.textContent)
			.filter(t => t !== '')
			.map(t => t.trim())
			.join(' ');
	}

	function htmlText(html) {
		return bodyText(new DOMParser().parseFromString(html, 'text/html').body.childNodes);
	}

	function domData(mix) {
		let d = domCache.get(mix);
		if (d) return d;

		const img = mix.querySelector('img.thread-image');
		const replies = mix.querySelector('.replies');
		let com = '';
		let sub = img ? img.getAttribute('data-subject') || '' : '';

		if (replies) {
			const kids = Array.from(replies.childNodes);
			let start = 0;
			for (let seen = 0; start < kids.length && seen < 2; start++) {
				if (kids[start].nodeType === 1) seen++;
			}
			com = bodyText(kids.slice(start));
			if (!sub) {
				const s = replies.querySelector('.subject');
				sub = s ? s.textContent.trim() : '';
			}
		}

		d = {
			name: img ? (img.getAttribute('data-name') || '').trim() : null,
			trip: '',
			sub,
			com,
			flag: '',
			uid: '',
			files: [],
		};
		domCache.set(mix, d);
		return d;
	}

	function toHex(value) {
		if (!value) return '';
		if (/^[0-9a-f]+$/i.test(value) && value.length % 2 === 0) return value.toLowerCase();
		try {
			return Array.from(atob(value), c => c.charCodeAt(0).toString(16).padStart(2, '0')).join('');
		} catch (err) {
			return '';
		}
	}

	function apiPostData(t) {
		const files = [t].concat(t.extra_files || [])
			.filter(f => f.filename != null || f.md5 || f.pdq)
			.map(f => ({
				name: f.filename != null ? f.filename + (f.ext || '') : '',
				hashes: [toHex(f.pdq), toHex(f.md5)].filter(Boolean),
			}));

		return {
			name: t.name != null ? String(t.name).trim() : null,
			trip: t.trip || '',
			sub: t.sub || '',
			com: htmlText(t.com || ''),
			flag: t.country_name || '',
			uid: t.id != null ? String(t.id) : '',
			files,
		};
	}

	async function loadApi() {
		const url = location.pathname.replace(/catalog\.html$/, 'catalog.json');
		try {
			const res = await fetch(url, { credentials: 'same-origin', cache: 'no-cache' });
			if (!res.ok) throw new Error('HTTP ' + res.status);
			for (const page of await res.json()) {
				for (const t of page.threads || []) {
					apiData.set((t.board || pageBoard) + '/' + t.no, apiPostData(t));
				}
			}
		} catch (err) {
			apiFailed = true;
			console.warn('[Catalog Filter] could not load ' + url + ':', err);
		}
		refresh();
	}

	/* ---------- matching (mirrors js/post-filter.js) ---------- */

	function safeRegExp(source) {
		try {
			return new RegExp(source);
		} catch (err) {
			return null;
		}
	}

	function compileRules(list) {
		return list.generalFilter.filter(Boolean).map(rule => {
			const value = String(rule.value == null ? '' : rule.value);
			let test;
			if (rule.regex) {
				const re = safeRegExp(value);
				test = re ? s => re.test(s) : () => false;
			} else if (rule.type === 'sub' || rule.type === 'com' || rule.type === 'flag') {
				// post-filter.js wraps plain sub/com/flag rules in word boundaries
				const re = safeRegExp('\\b' + value + '\\b') ||
					new RegExp('\\b' + value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&') + '\\b');
				test = s => re.test(s);
			} else {
				test = s => s === value;
			}
			return { rule, test };
		});
	}

	function matches({ rule, test }, d) {
		switch (rule.type) {
			case 'name': return d.name != null && test(d.name);
			case 'trip': return d.trip !== '' && test(d.trip);
			case 'sub': return d.sub !== '' && test(d.sub);
			case 'com': return test(d.com);
			case 'flag': return d.flag !== '' && test(d.flag);
			case 'filename': return d.files.some(f => f.name !== '' && test(f.name));
			case 'filehash': return d.files.some(f => f.hashes.some(test));
		}
		return false;
	}

	function shorten(text, max) {
		return text.length > max ? text.slice(0, max - 1) + '…' : text;
	}

	function describe(rule) {
		const value = String(rule.value);
		const shown = rule.type === 'filehash' && !rule.regex ? shorten(value, 13) : shorten(value, 40);
		return (TYPE_LABELS[rule.type] || rule.type) + ': ' + (rule.regex ? '/' + shown + '/' : shown);
	}

	function statusOf(mix, list, compiled) {
		const key = tileKey(mix);
		if (!key) return null;

		const d = apiData.get(key.board + '/' + key.id) || domData(mix);
		const entries = (list.postFilter[key.board] || {})[key.id] || [];
		const manual = entries.some(e => e && e.post != null && String(e.post) === key.id);
		const reasons = [];

		if (manual) reasons.push('Hidden by you');
		if (d.uid && entries.some(e => e && e.uid != null && String(e.uid) === d.uid)) {
			reasons.push('Poster ID: ' + d.uid);
		}
		for (const c of compiled) {
			if (matches(c, d)) reasons.push(describe(c.rule));
		}
		return { manual, reasons };
	}

	/* ---------- UI ---------- */

	function el(tag, className, text) {
		const node = document.createElement(tag);
		if (className) node.className = className;
		if (text != null) node.textContent = text;
		return node;
	}

	function action(name, text) {
		const a = el('a', null, text);
		a.href = '#';
		a.dataset.sjcf = name;
		return a;
	}

	function render(mix, st) {
		const hidden = !!st && st.reasons.length > 0;
		const host = mix.querySelector('.thread') || mix;
		let label = host.querySelector(':scope > .sjcf-label');

		mix.classList.toggle('sjcf-hidden', hidden);
		if (!hidden) {
			if (label) label.remove();
			return;
		}

		if (!label) {
			label = el('div', 'sjcf-label');
			host.prepend(label);
		}
		label.title = st.manual
			? 'Shift+click to unhide'
			: 'Matches your filters (Options → Filters on a board or thread page)';
		label.replaceChildren(
			el('span', 'sjcf-tag', 'Hidden'),
			el('span', 'sjcf-why', st.reasons.join(' · '))
		);
		if (st.manual) label.append(action('unhide', 'unhide'));
	}

	function flash(mix) {
		mix.classList.remove('sjcf-flash');
		void mix.offsetWidth;
		mix.classList.add('sjcf-flash');
		setTimeout(() => mix.classList.remove('sjcf-flash'), 700);
	}

	let revealed = false;
	const showButton = el('button');
	showButton.type = 'button';
	showButton.id = 'sjcf-show';
	showButton.addEventListener('click', () => {
		revealed = !revealed;
		document.body.classList.toggle('sjcf-reveal', revealed);
		refresh();
	});

	const sizeSelect = document.getElementById('image_size');
	if (sizeSelect) sizeSelect.after(showButton);
	else grid.before(showButton);

	function refresh() {
		let list;
		try {
			list = readList();
		} catch (err) {
			console.warn('[Catalog Filter] localStorage.postFilter is not valid JSON:', err);
			return;
		}

		const compiled = compileRules(list);
		let hidden = 0;
		for (const mix of grid.querySelectorAll('.mix')) {
			const st = statusOf(mix, list, compiled);
			render(mix, st);
			if (st && st.reasons.length) hidden++;
		}

		showButton.textContent = (revealed ? 'Hide again' : 'Show anyways') + ' (' + hidden + ')';
		showButton.disabled = !revealed && hidden === 0;
		showButton.title = apiFailed
			? "catalog.json didn't load, so tripcode, flag, poster ID, filename and file hash filters can't be checked."
			: '';
	}

	let queued = false;
	function scheduleRefresh() {
		if (queued) return;
		queued = true;
		setTimeout(() => {
			queued = false;
			refresh();
		}, 0);
	}

	/* ---------- events ---------- */

	window.addEventListener('click', e => {
		const target = e.target instanceof Element ? e.target : null;
		if (!target) return;

		const unhide = target.closest('.sjcf-label [data-sjcf="unhide"]');
		if (unhide && !e.shiftKey) {
			e.preventDefault();
			e.stopPropagation();
			setManual(unhide.closest('.mix'), false);
			return;
		}

		if (!e.shiftKey || e.button !== 0 || e.ctrlKey || e.metaKey || e.altKey) return;
		const mix = target.closest('.mix');
		if (!mix || !grid.contains(mix)) return;

		e.preventDefault();
		e.stopImmediatePropagation();

		let st;
		try {
			const list = readList();
			st = statusOf(mix, list, compileRules(list));
		} catch (err) {
			alert('Catalog Filter: localStorage.postFilter could not be read, so nothing was changed.');
			return;
		}
		if (!st) return;

		if (st.manual) setManual(mix, false);
		else if (st.reasons.length) flash(mix); // hidden by a filter rule; edit that in Options -> Filters
		else setManual(mix, true);
	}, true);

	window.addEventListener('mousedown', e => {
		if (e.shiftKey && e.button === 0 && e.target instanceof Element && e.target.closest('#Grid .mix')) {
			e.preventDefault();
		}
	}, true);

	window.addEventListener('storage', e => {
		if (e.key === STORAGE_KEY || e.key === null) scheduleRefresh();
	});

	new MutationObserver(records => {
		let dirty = false;
		for (const r of records) {
			for (const node of r.removedNodes) {
				if (node.nodeType !== 1 || node.isConnected || !node.classList.contains('sjcf-hidden')) continue;
				const next = r.nextSibling && r.nextSibling.parentNode === r.target ? r.nextSibling : null;
				r.target.insertBefore(node, next);
				dirty = true;
			}
			for (const node of r.addedNodes) {
				if (node.nodeType === 1 && node.classList.contains('mix')) dirty = true;
			}
		}
		if (dirty) scheduleRefresh();
	}).observe(grid, { childList: true });

	/* ---------- styles ---------- */

	const style = el('style', null, `
		body:not(.sjcf-reveal) .mix.sjcf-hidden { display: none !important; }
		.sjcf-label { display: none; }
		body.sjcf-reveal .mix.sjcf-hidden .sjcf-label {
			display: flex; flex-wrap: wrap; justify-content: center; gap: 0 6px;
			margin-bottom: 4px; padding: 2px 4px; border: 1px dashed currentColor; border-radius: 3px;
			font-size: 11px; line-height: 1.35;
		}
		body.sjcf-reveal .mix.sjcf-hidden .thread > :not(.sjcf-label) { opacity: 0.6; }
		.sjcf-label .sjcf-tag { font-weight: bold; letter-spacing: 0.08em; text-transform: uppercase; }
		.sjcf-label .sjcf-why { opacity: 0.85; overflow-wrap: anywhere; }
		.mix.sjcf-flash .sjcf-label { outline: 2px solid currentColor; }
		#sjcf-show { margin-left: 8px; }
	`);
	document.head.append(style);

	refresh();
	loadApi();
})();