import Handlebars from "handlebars/runtime";
import URI from "urijs";

module.exports = function(text) {
	text = Handlebars.Utils.escapeExpression(text);
	text = colors(text);
	text = channels(text);
	text = uri(text);
	return text;
};

function uri(text) {
	return URI.withinString(text, function(url) {
		if (url.indexOf("javascript:") === 0) {
			return url;
		}
		var split = url.split("<");
		url = "<a href='" + split[0].replace(/^www/, "http://www") + "' target='_blank' rel='noopener'>" + split[0] + "</a>";
		if (split.length > 1) {
			url += "<" + split.slice(1).join("<");
		}
		return url;
	});
}

/**
 * Channels names are strings of length up to fifty (50) characters.
 * The only restriction on a channel name is that it SHALL NOT contain
 * any spaces (' '), a control G (^G or ASCII 7), a comma (',').
 * Channel prefix '&' is handled as '&amp;' because this parser is executed
 * after entities in the message have been escaped. This prevents a couple of bugs.
 */
function channels(text) {
	return text.replace(
		/(^|\s|\x07|,)((?:#|&amp;)[^\x07\s,]{1,49})/g,
		'$1<span class="inline-channel" role="button" tabindex="0" data-chan="$2">$2</span>'
	);
}

/**
 * MIRC compliant colour and style parser
 * Unfortuanately this is a non trivial operation
 * See this branch for source and tests
 * https://github.com/megawac/irc-style-parser/tree/shout
 */
var styleCheck_Re = /[\x00-\x1F]/,
	back_re = /^([0-9]{1,2})(,([0-9]{1,2}))?/,
	colourKey = "\x03",
	// breaks all open styles ^O (\x0F)
	styleBreak = "\x0F";

function styleTemplate(settings) {
	return "<span class='" + settings.style + "'>" + settings.text + "</span>";
}

var styles = [
	["normal", "\x00", ""], ["underline", "\x1F"],
	["bold", "\x02"], ["italic", "\x1D"]
].map(function(style) {
	var escaped = encodeURI(style[1]).replace("%", "\\x");
	return {
		name: style[0],
		style: style[2] ? style[2] : "irc-" + style[0],
		key: style[1],
		keyregex: new RegExp(escaped + "(.*?)(" + escaped + "|$)")
	};
});

function colors(line) {
	// http://www.mirc.com/colors.html
	// http://www.aviran.org/stripremove-irc-client-control-characters/
	// https://github.com/perl6/mu/blob/master/examples/rules/Grammar-IRC.pm
	// regexs are cruel to parse this thing

	// already done?
	if (!styleCheck_Re.test(line)) {
		return line;
	}

	// split up by the irc style break character ^O
	if (line.indexOf(styleBreak) >= 0) {
		return line.split(styleBreak).map(colors).join("");
	}

	var result = line;
	var parseArr = result.split(colourKey);
	var text, match, colour, background = "";
	for (var i = 0; i < parseArr.length; i++) {
		text = parseArr[i];
		match = text.match(back_re);
		if (!match) {
			// ^C (no colour) ending. Escape current colour and carry on
			background = "";
			continue;
		}
		colour = "irc-fg" + +match[1];
		// set the background colour
		if (match[3]) {
			background = " irc-bg" + +match[3];
		}
		// update the parsed text result
		result = result.replace(colourKey + text, styleTemplate({
			style: colour + background,
			text: text.slice(match[0].length)
		}));
	}

	// Matching styles (italics/bold/underline)
	// if only colours were this easy...
	styles.forEach(function(style) {
		if (result.indexOf(style.key) < 0) {
			return;
		}

		result = result.replace(style.keyregex, function(matchedTrash, matchedText) {
			return styleTemplate({
				style: style.style,
				text: matchedText
			});
		});
	});

	return result;
}