#!/usr/bin/env node

var
	app,
	json = require('../src/apps.json');

for ( app in json.apps ) {
	['headers', 'html', 'env', 'meta', 'script'].forEach(function(type) {
		var
			key,
			patterns = json.apps[app][type];

		if ( patterns !== undefined ) {
			patterns = typeof patterns === 'string' ? [patterns] : patterns;

			if ( !( patterns instanceof Array ) ) {
				patterns = [];

				for ( key in json.apps[app][type] ) {
					patterns.push(json.apps[app][type][key]);
				}
			}

			patterns.forEach(function(pattern) {
				var
					attrs = pattern.split('\\;'),
					regex = '/' + attrs.shift().replace('/', '\/') + '/',
					version = attrs.find( function (attr){
						return attr.indexOf('version:')===0;
						} ),
					amountOfCaptureGroups,
					captureGroupsNeeded,
					amountOfCaptureGroupsNeeded,
					highestBackReference;

				//Check if the pattern is a valid RegExp
				//Note: unlike when used in Wappalyzer, the modifier i isn't added here
				new RegExp(regex);

				//Actual amount of capture groups
				amountOfCaptureGroups = ''.match(new RegExp('(?:'+pattern+')?')).length - 1;

				//Capture groups of which the result is used
				captureGroupsNeeded = version ? (version.match(/\\\d/g) || []).filter( function(value, index, self){
					return self.indexOf(value) === index;
				}).map( function(value){//Because Math.max needs the integers only
					return parseInt(value.charAt(1), 10);//Will only work if backreferences cannot be any longer than a single digit
				}) : [];

				//Amount of capture groups needed
				amountOfCaptureGroupsNeeded = captureGroupsNeeded.length;

				//Highest back reference number used
				highestBackReference = Math.max.apply(null, captureGroupsNeeded);

				//Report error
				if(amountOfCaptureGroups > amountOfCaptureGroupsNeeded) {
					throw new Error('The pattern uses more capture groups than needed. Use non-capturing groups where appropriate.\n' + app + ': ' + type + ': ' + pattern);
				}else if(amountOfCaptureGroups < amountOfCaptureGroupsNeeded){
					throw new Error('The version string references more capture groups than there are in the pattern! Remove any incorrect back references from the version string and/or add the missing capture groups to the pattern.\n' + app + ': ' + type + ': ' + pattern);
				} else if(highestBackReference > amountOfCaptureGroups){
					throw new Error('The version string references one or more capture groups whose index is higher than the amount of capture groups in the pattern. Please use the correct index instead of \\\\'+highestBackReference+'.\n' + app + ': ' + type + ': ' + pattern);
				}

				if ( /^\/(?:\^\$|\.\+|\.\*)\/$/.test(regex) )  {
					throw new Error('Pattern should be replaced with empty string.\n' + app + ': ' + type + ': ' + pattern);
				}

				if ( type === 'html' ) {
					if ( /\.(?:\+|\*)/.test(regex) )  {
						throw new Error('Avoid ".+" and ".*" in HTML patterns. Consider using "[^>]+" or "[^<]+" instead.\n' + app + ': ' + type + ': ' + pattern);
					}

					if ( !/[<>]/.test(regex) )  {
						throw new Error('HTML patterns must contain "<" or ">".\n' + app + ': ' + type + ': ' + pattern);
					}
				}
			});
		}
	});

	if ( !/^https?:\/\//i.test(json.apps[app].website) ) {
		throw new Error('Invalid website URL\n' + app + ': ' + json.apps[app].website);
	}
}