<?php

namespace JchOptimize;

/**
 * This is a regular expressions based implementation of the JSMin algorithim as decsribed on 
 * Douglas Crockford's page at http://www.crockford.com/javascript/jsmin.html in PHP and also 
 * guided by the PHP port written by  Ryan Grove <ryan@wonko.com>
 * 
 * This was written to provide a PHP tool to minify javascript but with an emphasis on speed, 
 * in particular for tools that want to minify javascript on the fly such as http://www.jch-optimize.net. 
 * Based on independent comparison tests, this library consistently returns the same results as JSMin.php 
 * but on an average of 200 times faster.
 * 
 * Permission is hereby granted to use this version of the library under the
 * same terms as jsmin.c, which has the following license:
 * 
 *  -- 
 * Copyright (c) 2002 Douglas Crockford  (www.crockford.com)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * The Software shall be used for Good, not Evil.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 * --
 * 
 * @author Samuel Marshall <sdmarshall73@gmail.com>
 * @copyright (c) 2002, Douglas Crockford <douglas@crockford.com> (jsmin.c)
 * @copyright (c) 2014, Samuel Marshall <sdmarshall73@gmail.com> (JS_Optimize.php)
 * @license http://opensource.org/licenses/mit-license.php MIT License
 * 
 */
class JS_Optimize
{

        protected $options = array();

        public static function minify($js, $options = array())
        {
                $oMinifyJs = new JS_Optimize($options);
                return $oMinifyJs->process($js);
        }

        private function __construct($options)
        {
                $this->options = $options;
        }

        protected function process($js)
        {
                //regex for double quoted strings
                $s1 = '"(?>(?:\\\\.)?[^\\\\"]*+)+?"';

                //regex for single quoted string
                $s2 = "'(?>(?:\\\\.)?[^\\\\']*+)+?'";

                //regex for block comments
                $b = '/\*(?>[^/\*]++|//|\*(?!/)|(?<!\*)/)*+\*/';

                //regex for line comments
                $c = '//[^\r\n]*+';

                //We have to do some manipulating with regexp literals; Their pattern is a little 'irregular' but 
                //they need to be escaped
                //
                //characters that can precede a regexp literal
                $x1 = '[(.<>%,=:[!&|?+\-~*{;\r\n^]';
                //keywords that can precede a regex literal
                $x2 = '\breturn|\bthrow|\btypeof|\bcase|\bdelete|\bdo|\belse|\bin|\binstanceof|\bnew|\bvoid';
                //actual regexp literal
                $x3 = '/(?![/*])(?>(?(?=\\\\)\\\\.|\[(?>(?:\\\\.)?[^\]\r\n]*+)+?\])?[^\\\\/\r\n\[]*+)+?/';
                //ambiguous characters
                $x4 = '[)}]';
                //methods and properties
                $x5 = 'compile|exec|test|toString|constructor|global|ignoreCase|lastIndex|multiline|source';

                //regex for complete regexp literal
                $x = "(?:(?<={$x1}|$x2)(?<!\+\+|--){$x3}"
                        . "|(?<={$x4}){$x3}(?=\.(?:{$x5})))";

                //control characters excluding \r, \n and space
                $ws = '\x00-\x09\x0B\x0C\x0E-\x1F\x7F';        
                
                //Remove spaces before regexp literals
                $js = preg_replace(
                        "#(?>\s*+[^'\"/$ws ]*+(?>$s1|$s2|$b|$c|$x|/)?)*?\K"
                        . "(?>(?<=$x1|$x2)[$ws ]++($x3)|(?<=$x4)[$ws ]++($x3)(?=\.(?:$x5))|$)#si", '$1$2', $js
                );
          
                //replace line comments with line feed
                $js = preg_replace("#(?>[^'\"/]*+(?>{$s1}|{$s2}|{$x}|{$b}|/(?![*/]))?)*?\K(?>{$c}|$)#si", "\n", $js);

                //replace block comments with single space
                $js = preg_replace("#(?>[^'\"/]*+(?>{$s1}|{$s2}|{$x}|/(?![*/]))?)*?\K(?>{$b}|$)#si", ' ', $js);

                //convert carriage returns to line feeds
                $js = preg_replace("#(?>[^'\"/\\r]*+(?>$s1|$s2|$x|/)?)*?\K(?>\\r\\n?|$)#si", "\n", $js); 
                
                //convert all other control characters to space
                $js = preg_replace("#(?>[^'\"/$ws]*+(?>$s1|$s2|$x|/)?)*?\K(?>[$ws]++|$)#si", ' ', $js);

                //replace runs of whitespace with single space or linefeed
                $js = preg_replace("#(?>[^'\"/\\n ]*+(?>{$s1}|{$s2}|{$x}|[ \\n](?![ \\n])|/)?)*?\K(?:[ ]++(?=\\n)|\\n\K\s++|[ ]\K[ ]++|$)#si", '', $js);

                //if regex literal ends line (without modifiers) insert semicolon
                $js = preg_replace("#(?>[/]?[^'\"/]*+(?>$s1|$s2|$x(?!\\n))?)*?(?:$x\K\\n(?![!\#%&`*./,:;<=>?@\^|~}\])\"'])|\K$)#si", ';', $js);

                //clean up
                $js = preg_replace('#.+\K;$#s', '', $js);
                
                //regex for removing spaces
                //remove space except when a space is preceded and followed by a non-ASCII character or by an ASCII letter or digit, 
                //or by one of these characters \ $ _  ...ie., all ASCII characters except those listed.
                $c = '["\'!\#%&`()*./,:;<=>?@\[\]\^{}|~+\-]';
                $sp = "(?<=$c) | (?=$c)";

                //Non-ASCII characters
                $na = '[^\x00-\x7F]';
                
                //spaces to keep
                $k1 = "(?<=[\$_a-z0-9\\\\]|$na) (?=[\$_a-z0-9\\\\]|$na)|(?<=\+) (?=\+)|(?<=-) (?=-)";

                //regex for removing linefeeds
                //remove linefeeds except if it precedes a non-ASCII character or an ASCII letter or digit or one of these 
                //characters: \ $ _ [ ( { + - and if it follows a non-ASCII character or an ASCII letter or digit or one of these 
                //characters: \ $ _ ] ) } + - " ' ...ie., all ASCII characters except those listed respectively
                $ln = '(?<=[!\#%&`*./,:;<=>?@\^|~{\[(])\n|\n(?=[!\#%&`*./,:;<=>?@\^|~}\])"\'])';

                //line feeds to keep
                $k2 = "(?<=[\$_a-z0-9\\\\\])}+\-\"']|$na)\n(?=[\$_a-z0-9\\\\\[({+\-]|$na)";

                //remove unnecessary linefeeds and spaces
                $js = preg_replace(
                        "#(?>[^'\"/\\n ]*+(?>$s1|$s2|$x|/|$k1|$k2)?)*?\K(?>$sp|$ln|$)#si", '', $js
                );

                $js = trim($js);

                return $js;
        }

}
