/**

 * Web Worker for AutoWikiBrowser script. Used to run certain tasks on a parallel process to be able to terminate it.

 * Idea from https://stackoverflow.com/a/66162733/1256925. Dirty hack workaround due to https://stackoverflow.com/q/66188950/1256925.

 * See /info/en/?search=User:Joeytje50/JWB.js for the full script, as well as licensing.

 * Licensed under GNU GPL 2. http://www.gnu.org/copyleft/gpl.html

 */



JWB.worker.function = function() {

	var ret = {};

	

	function regexMatch(str, pattern, flags, callback) {

		var re, result;

		try {

			re = new RegExp(pattern, flags);

			result = str.match(re);

		} catch(e) {

			// catch and propagate invalid regexes etc.

			callback(undefined, e);

		}

		callback(result, undefined);

	}

	ret.match = regexMatch;

	

	function regexReplace(str, pattern, flags, rWith, callback) {

		var re, result;

		try {

			re = new RegExp(pattern, flags);

			result = str.replace(re, rWith);

		} catch(e) {

			// catch and propagate invalid regexes etc.

			callback(undefined, e);

		}

		callback(result, undefined);

	}

	ret.replace = regexReplace;

	

	//function to *only* replace the parsed wikitext

	//It excludes comments (<!-- -->), and nowiki, math, source, syntaxhighlight, pre, code, gallery and timeline tags)

	//Based on http://stackoverflow.com/a/23589204/1256925

	function unparsedReplace(str, pattern, flags, rWith, callback) {

		var exclude = '(<!--[\\s\\S]*?-->|<(nowiki|math|source|syntaxhighlight|pre|gallery|timeline)[^>]*?>[\\s\\S]*?<\\/\\2>)';

		//add /i flag, to exclude the correct tags regardless of casing.

		//This won't matter for the actual replacing, as the specified flags are used there.

		var replacements = 0;

		var global = flags.indexOf('g') !== -1;

		// build regex with exclusion list.

		// This re will be case insensitive, but the actual replacement done will still be case sensitive if the 'i' flag is not given.

		// This re will also be executed globally on the string, but the separate tracker will only allow one replacement to be done if 'g' is not given.

		try {

			var re = new RegExp(exclude + '|(' + pattern + ')', flags.replace(/i|$/, 'i').replace(/g|$/, 'g'));

			str = str.replace(re, function(match, g1, g2, g3) {

				if (!global && replacements > 0) { // a replacement has already been made in non-global mode

					return match;

				} else if (g3 !== undefined) { //continue to perform replacement if the match is the group that's supposed to be the match

					replacements++; // keep track of the amount of replacements made.

					return match.replace(new RegExp(pattern, flags), rWith);

				} else { //do nothing if the match is one of the excluded groups

					return match;

				}

			});

		} catch(e) {

			// catch and propagate invalid regexes etc.

			callback(undefined, e);

		}

		callback(str, undefined);

	}

	ret.unparsedreplace = unparsedReplace;

	

	onmessage = function(e) {

		let data = e.data;

		console.log('worker message', data);

		let callback = (result, err) => postMessage({cmd: data.cmd, result: result, err: err});

		switch (data.cmd) {

			case 'match':

				regexMatch(data.str, data.pattern, data.flags, callback);

				break;

			case 'replace':

				regexReplace(data.str, data.pattern, data.flags, data.rWith, callback);

				break;

			case 'unparsedreplace':

				unparsedReplace(data.str, data.pattern, data.flags, data.rWith, callback);

				break;

			default:

				postMessage({err: 'Unknown command: ' + data.cmd});

		}

	};

	

	return ret; // return object containing synchronous functions as a fallback.

};