/* cgit.js: javacript functions for cgit
 *
 * Copyright (C) 2006-2018 cgit Development Team <cgit@lists.zx2c4.com>
 *
 * Licensed under GNU General Public License v2
 *   (see LICENSE.txt for full license text)
 */

(function () {

/* This follows the logic and suffixes used in ui-shared.c */

var age_classes = [ "age-mins", "age-hours", "age-days",    "age-weeks",    "age-months",    "age-years" ];
var age_suffix =  [ "min.",     "hours",     "days",        "weeks",        "months",        "years",         "years" ];
var age_next =    [ 60,         3600,        24 * 3600,     7 * 24 * 3600,  30 * 24 * 3600,  365 * 24 * 3600, 365 * 24 * 3600 ];
var age_limit =   [ 7200,       24 * 7200,   7 * 24 * 7200, 30 * 24 * 7200, 365 * 25 * 7200, 365 * 25 * 7200 ];
var update_next = [ 10,         5 * 60,      1800,          24 * 3600,      24 * 3600,       24 * 3600,       24 * 3600 ];

function render_age(e, age) {
	var t, n;

	for (n = 0; n < age_classes.length; n++)
		if (age < age_limit[n])
			break;

	t = Math.round(age / age_next[n]) + " " + age_suffix[n];

	if (e.textContent != t) {
		e.textContent = t;
		if (n == age_classes.length)
			n--;
		if (e.className != age_classes[n])
			e.className = age_classes[n];
	}
}

function aging() {
	var n, next = 24 * 3600,
	    now_ut = Math.round((new Date().getTime() / 1000));

	for (n = 0; n < age_classes.length; n++) {
		var m, elems = document.getElementsByClassName(age_classes[n]);

		if (elems.length && update_next[n] < next)
			next = update_next[n];

		for (m = 0; m < elems.length; m++) {
			var age = now_ut - elems[m].getAttribute("data-ut");

			/* A commit dated ahead of the viewer's clock would
			 * otherwise render as a negative age; ui-shared.c
			 * clamps the same way. */
			if (age < 0)
				age = 0;

			render_age(elems[m], age);
		}
	}

	/*
	 * We only need to come back when the age might have changed.
	 * Eg, if everything is counted in hours already, once per
	 * 5 minutes is accurate enough.
	 */

	window.setTimeout(aging, next * 1000);
}

document.addEventListener("DOMContentLoaded", function() {
	/* we can do the aging on DOM content load since no layout dependency */
	aging();
}, false);

})();

/* Selects marked data-autosubmit reload the page with the new setting.
 * Wired here instead of inline onchange handlers, which a strict
 * Content-Security-Policy blocks. Without scripting the forms keep
 * their noscript reload button. */

(function () {

document.addEventListener("DOMContentLoaded", function () {
	var i, els = document.querySelectorAll("select[data-autosubmit]");

	for (i = 0; i < els.length; i++)
		els[i].addEventListener("change", function () {
			this.form.submit();
		});
}, false);

})();

/* Wash a faded highlight over the source line targeted by the URL
 * fragment, #n231, or over a range like #n5-n12. The line anchors live
 * in the number gutter, so this measures the anchor and lays a
 * full-width bar across the code at the same height. Without JS the
 * CSS :target rule still tints the line number itself. */

(function () {

var bar = null;

function place() {
	var m, a, b, table, box, ra, rb, top, bottom;

	if (bar) {
		bar.remove();
		bar = null;
	}
	m = /^#n(\d+)(?:-n?(\d+))?$/.exec(location.hash);
	if (!m)
		return;
	a = document.getElementById("n" + m[1]);
	if (!a)
		return;
	b = (m[2] && document.getElementById("n" + m[2])) || a;
	table = a.closest("table");
	if (!table)
		return;
	box = table.getBoundingClientRect();
	ra = a.getBoundingClientRect();
	rb = b.getBoundingClientRect();
	top = Math.min(ra.top, rb.top) - box.top;
	bottom = Math.max(ra.bottom, rb.bottom) - box.top;
	bar = document.createElement("div");
	bar.className = "line-hl";
	bar.style.top = top + "px";
	bar.style.height = (bottom - top) + "px";
	table.appendChild(bar);
	/* The browser only scrolls to fragments that name a real id, so
	 * bring ranges into view ourselves. */
	if (m[2])
		a.scrollIntoView({ block: "center" });
}

document.addEventListener("DOMContentLoaded", place, false);
window.addEventListener("hashchange", place, false);

})();

/* Colour theme toggle: cycles auto -> light -> dark and remembers the
 * choice. "auto" leaves the page following the system preference via CSS. */

(function () {

var KEY = "cgit-theme";
var ORDER = [ "auto", "light", "dark" ];
var ICONS = {
	auto:  '<svg viewBox="0 0 24 24"><circle cx="12" cy="12" r="9"/><path d="M12 3a9 9 0 0 0 0 18z" fill="currentColor" stroke="none"/></svg>',
	light: '<svg viewBox="0 0 24 24"><circle cx="12" cy="12" r="5"/><path d="M12 1v3M12 20v3M4.2 4.2l2.1 2.1M17.7 17.7l2.1 2.1M1 12h3M20 12h3M4.2 19.8l2.1-2.1M17.7 6.3l2.1-2.1"/></svg>',
	dark:  '<svg viewBox="0 0 24 24"><path d="M21 12.8A9 9 0 1 1 11.2 3 7 7 0 0 0 21 12.8z"/></svg>'
};

function saved() {
	try { return localStorage.getItem(KEY); } catch (e) { return null; }
}

function persist(value) {
	try { localStorage.setItem(KEY, value); } catch (e) { }
}

function apply(theme, root, btn) {
	if (theme === "auto")
		root.removeAttribute("data-theme");
	else
		root.setAttribute("data-theme", theme);
	/* Keep the standalone page background in sync with the choice. */
	document.documentElement.style.colorScheme = (theme === "auto") ? "" : theme;
	if (btn) {
		btn.innerHTML = ICONS[theme];
		btn.title = "Colour theme: " + theme;
	}
}

document.addEventListener("DOMContentLoaded", function () {
	var root = document.getElementById("cgit");
	if (!root)
		return;
	var btn = root.querySelector(".theme-toggle");
	var theme = saved();
	if (ORDER.indexOf(theme) < 0)
		theme = "auto";

	apply(theme, root, btn);
	if (!btn)
		return;
	btn.hidden = false;
	btn.addEventListener("click", function () {
		theme = ORDER[(ORDER.indexOf(theme) + 1) % ORDER.length];
		persist(theme);
		apply(theme, root, btn);
	});
}, false);

})();

/* Built-in Markdown rendering for the about page. When no about-filter is
 * configured, cgit escapes a markdown readme into a data-markdown container
 * (see cgit_print_repo_readme) and this renders a deliberately small, safe
 * subset client-side: headings, lists, blockquotes, rules, fenced and inline
 * code, pipe tables, links, images and emphasis. Every run of text is escaped
 * before any markup is added, and link and image URLs are restricted to http,
 * https, mailto and relative targets, so a hostile readme cannot inject markup
 * or scripts. Fenced code carries its language in data-lang as a styling
 * hook. Without JavaScript the escaped source stays readable as plain text.
 *
 * This is intentionally a subset, not CommonMark: no reference links, raw HTML
 * passthrough, nested lists or setext headings. Configure an about-filter to
 * replace it, or set enable-markdown=0 to turn it off. */

(function () {

var MAX_BYTES = 400000;

function esc(s) {
	return s.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
}

function escAttr(s) {
	return esc(s).replace(/"/g, "&quot;").replace(/'/g, "&#39;");
}

/* Return the url if its scheme is safe, else "". Whitespace and control bytes
 * are stripped before the scheme is read because browsers ignore them when
 * resolving it, so "java\nscript:..." must still be caught as javascript. */
function safeUrl(url) {
	url = (url || "").replace(/[\u0000-\u0020]+/g, "");
	var scheme = /^([a-z][a-z0-9+.\-]*):/i.exec(url);
	if (scheme && !/^(https?|mailto)$/i.test(scheme[1]))
		return "";
	return url;
}

function link(text, url, image) {
	var u = safeUrl(url);
	if (!u)
		return image ? esc("![" + text + "]") : inline(text);
	if (image)
		return "<img src='" + escAttr(u) + "' alt='" + escAttr(text) + "'/>";
	return "<a href='" + escAttr(u) + "'>" + inline(text) + "</a>";
}

/* Inline rendering over one block of text. Scans to the next marker character
 * and bulk-escapes the plain text in between, so it stays roughly linear. */
function inline(s) {
	var out = "", i = 0, n = s.length, marker = /[`!\[*_]/g, m, rest;
	while (i < n) {
		marker.lastIndex = i;
		m = marker.exec(s);
		if (!m) { out += esc(s.slice(i)); break; }
		if (m.index > i) { out += esc(s.slice(i, m.index)); i = m.index; }
		rest = s.slice(i);
		if ((m = /^`([^`]+)`/.exec(rest)))
			out += "<code>" + esc(m[1]) + "</code>";
		else if ((m = /^!\[([^\]]*)\]\(\s*([^)\s]+)[^)]*\)/.exec(rest)))
			out += link(m[1], m[2], true);
		else if ((m = /^\[([^\]]*)\]\(\s*([^)\s]+)[^)]*\)/.exec(rest)))
			out += link(m[1], m[2], false);
		else if ((m = /^(\*\*|__)([\s\S]+?)\1/.exec(rest)))
			out += "<strong>" + inline(m[2]) + "</strong>";
		else if ((m = /^(\*|_)([^\s][\s\S]*?)\1/.exec(rest)))
			out += "<em>" + inline(m[2]) + "</em>";
		else { out += esc(s.charAt(i)); i++; continue; }
		i += m[0].length;
	}
	return out;
}

function cells(row) {
	return row.trim().replace(/^\|/, "").replace(/\|$/, "").split("|").map(function (c) {
		return c.trim();
	});
}

function render(src) {
	var lines = src.replace(/\r\n?/g, "\n").split("\n");
	var out = "", i = 0, n = lines.length, line, m, k;
	while (i < n) {
		line = lines[i];
		if (/^\s*$/.test(line)) { i++; continue; }
		if ((m = /^\s*(`{3,}|~{3,})\s*([\w.+#-]*)/.exec(line))) {
			var fence = m[1].charAt(0) === "`" ? /^\s*`{3,}\s*$/ : /^\s*~{3,}\s*$/;
			var lang = m[2], code = "";
			for (i++; i < n && !fence.test(lines[i]); i++)
				code += lines[i] + "\n";
			i++;
			out += "<pre><code" + (lang ? " data-lang='" + escAttr(lang) + "'" : "") +
				">" + esc(code) + "</code></pre>";
			continue;
		}
		if ((m = /^(#{1,6})\s+(.*?)\s*#*\s*$/.exec(line))) {
			k = m[1].length;
			out += "<h" + k + ">" + inline(m[2]) + "</h" + k + ">";
			i++; continue;
		}
		if (/^\s*([-*_])(\s*\1){2,}\s*$/.test(line)) { out += "<hr/>"; i++; continue; }
		if (/^\s*>/.test(line)) {
			var q = "";
			for (; i < n && /^\s*>/.test(lines[i]); i++)
				q += lines[i].replace(/^\s*>\s?/, "") + "\n";
			out += "<blockquote>" + render(q) + "</blockquote>";
			continue;
		}
		if (line.indexOf("|") >= 0 && i + 1 < n &&
		    /^\s*\|?(\s*:?-+:?\s*\|)+\s*:?-+:?\s*\|?\s*$/.test(lines[i + 1])) {
			var head = cells(line), t = "<table><thead><tr>";
			for (k = 0; k < head.length; k++)
				t += "<th>" + inline(head[k]) + "</th>";
			t += "</tr></thead><tbody>";
			for (i += 2; i < n && lines[i].indexOf("|") >= 0 && !/^\s*$/.test(lines[i]); i++) {
				var row = cells(lines[i]);
				t += "<tr>";
				for (k = 0; k < row.length; k++)
					t += "<td>" + inline(row[k]) + "</td>";
				t += "</tr>";
			}
			out += t + "</tbody></table>";
			continue;
		}
		if (/^\s*([-*+]|\d+[.)])\s+/.test(line)) {
			var ordered = /^\s*\d/.test(line), tag = ordered ? "ol" : "ul";
			out += "<" + tag + ">";
			for (; i < n && (m = /^\s*([-*+]|\d+[.)])\s+(.*)$/.exec(lines[i])); i++) {
				if ((/\d/.test(m[1])) !== ordered) break;
				out += "<li>" + inline(m[2]) + "</li>";
			}
			out += "</" + tag + ">";
			continue;
		}
		/* Always consume the current line so i advances even when it
		 * matched none of the block branches above. */
		var para = lines[i++];
		for (; i < n && !/^\s*$/.test(lines[i]) &&
		       !/^\s*(#{1,6}\s|>|`{3,}|~{3,}|([-*+]|\d+[.)])\s)/.test(lines[i]); i++)
			para += "\n" + lines[i];
		out += "<p>" + inline(para).replace(/\n/g, "<br/>") + "</p>";
	}
	return out;
}

document.addEventListener("DOMContentLoaded", function () {
	var nodes = document.querySelectorAll("div#cgit [data-markdown]"), i, el, text;
	for (i = 0; i < nodes.length; i++) {
		el = nodes[i];
		text = el.textContent;
		if (!text || text.length > MAX_BYTES)
			continue;
		try {
			el.innerHTML = render(text);
			/* The attribute doubles as the style hook for the
			 * unrendered source, so drop it once rendered. */
			el.removeAttribute("data-markdown");
		} catch (e) {
			/* leave the escaped source in place on any failure */
		}
	}
}, false);

})();