<?php

/*
 * Copyright (C) 2016 Nicolas Grekas - p@tchwork.com
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the (at your option):
 * Apache License v2.0 (see provided LICENCE.ASL20 file), or
 * GNU General Public License v2.0 (see provided LICENCE.GPLv2 file).
 */

namespace Patchwork;

/*
*
* This class shrinks Javascript code
* (a process called minification nowadays)
*
* Should work with most valid Javascript code,
* even when semi-colons are missing.
*
* Features:
* - Removes comments and white spaces.
* - Renames every local vars, typically to a single character.
* - Renames also global vars, methods and properties, but only if they
*   are marked special by some naming convention. By default, special
*   var names begin with one or more "$", or with a single "_".
* - Renames also local/global vars found in strings,
*   but only if they are marked special.
* - Keep Microsoft's conditional comments.
* - Output is optimized for later HTTP compression.
*
* Notes:
* - Source code must be parse error free before processing.
* - In order to maximise later HTTP compression (deflate, gzip),
*   new variables names are chosen by considering closures,
*   variables' frequency and characters' frequency.
* - If you use with/eval then be careful.
*
* Bonus:
* - Replaces false/true by !1/!0
* - Replaces new Array/Object by []/{}
* - Merges consecutive "var" declarations with commas
* - Merges consecutive concatened strings
* - Fix a bug in Safari's parser (http://forums.asp.net/thread/1585609.aspx)
* - Can replace optional semi-colons by line feeds,
*   thus facilitating output debugging.
* - Keep important comments marked with /*!...
* - Treats three semi-colons ;;; like single-line comments
*   (http://dean.edwards.name/packer/2/usage/#triple-semi-colon).
* - Fix special catch scope across browsers
* - Work around buggy-handling of named function expressions in IE<=8
*
* TODO?
* - foo['bar'] => foo.bar
* - {'foo':'bar'} => {foo:'bar'}
* - Dead code removal (never used function)
* - Munge primitives: var WINDOW=window, etc.
*/

class JSqueeze
{
    const

    SPECIAL_VAR_PACKER = '(\$+[a-zA-Z_]|_[a-zA-Z0-9$])[a-zA-Z0-9_$]*';

    public

    $charFreq;

    protected

    $strings,
    $closures,
    $str0,
    $str1,
    $argFreq,
    $specialVarRx,
    $keepImportantComments,

    $varRx = '(?:[a-zA-Z_$])[a-zA-Z0-9_$]*',
    $reserved = array(
        // Literals
        'true','false','null',
        // ES6
        'break','case','class','catch','const','continue','debugger','default','delete','do','else','export','extends','finally','for','function','if','import','in','instanceof','new','return','super','switch','this','throw','try','typeof','var','void','while','with','yield',
        // Future
        'enum',
        // Strict mode
        'implements','package','protected','static','let','interface','private','public',
        // Module
        'await',
        // Older standards
        'abstract','boolean','byte','char','double','final','float','goto','int','long','native','short','synchronized','throws','transient','volatile',
    );

    public function __construct()
    {
        $this->reserved = array_flip($this->reserved);
        $this->charFreq = array_fill(0, 256, 0);
    }

    /**
     * Squeezes a JavaScript source code.
     *
     * Set $singleLine to false if you want optional
     * semi-colons to be replaced by line feeds.
     *
     * Set $keepImportantComments to false if you want /*! comments to be removed.
     *
     * $specialVarRx defines the regular expression of special variables names
     * for global vars, methods, properties and in string substitution.
     * Set it to false if you don't want any.
     *
     * If the analysed javascript source contains a single line comment like
     * this one, then the directive will overwrite $specialVarRx:
     *
     * // jsqueeze.specialVarRx = your_special_var_regexp_here
     *
     * Only the first directive is parsed, others are ignored. It is not possible
     * to redefine $specialVarRx in the middle of the javascript source.
     *
     * Example:
     * $parser = new JSqueeze;
     * $squeezed_js = $parser->squeeze($fat_js);
     */
    public function squeeze($code, $singleLine = true, $keepImportantComments = true, $specialVarRx = false)
    {
        $code = trim($code);
        if ('' === $code) {
            return '';
        }

        $this->argFreq = array(-1 => 0);
        $this->specialVarRx = $specialVarRx;
        $this->keepImportantComments = !!$keepImportantComments;

        if (preg_match("#//[ \t]*jsqueeze\.specialVarRx[ \t]*=[ \t]*([\"']?)(.*)\\1#i", $code, $key)) {
            if (!$key[1]) {
                $key[2] = trim($key[2]);
                $key[1] = strtolower($key[2]);
                $key[1] = $key[1] && $key[1] != 'false' && $key[1] != 'none' && $key[1] != 'off';
            }

            $this->specialVarRx = $key[1] ? $key[2] : false;
        }

        // Remove capturing parentheses
        $this->specialVarRx && $this->specialVarRx = preg_replace('/(?<!\\\\)((?:\\\\\\\\)*)\((?!\?)/', '(?:', $this->specialVarRx);

        false !== strpos($code, "\r") && $code = strtr(str_replace("\r\n", "\n", $code), "\r", "\n");
        false !== strpos($code, "\xC2\x85") && $code = str_replace("\xC2\x85", "\n", $code); // Next Line
        false !== strpos($code, "\xE2\x80\xA8") && $code = str_replace("\xE2\x80\xA8", "\n", $code); // Line Separator
        false !== strpos($code, "\xE2\x80\xA9") && $code = str_replace("\xE2\x80\xA9", "\n", $code); // Paragraph Separator

        list($code, $this->strings) = $this->extractStrings($code);
        list($code, $this->closures) = $this->extractClosures($code);

        $key = "//''\"\"#0'"; // This crap has a wonderful property: it can not happen in any valid javascript, even in strings
        $this->closures[$key] = &$code;

        $tree = array($key => array('parent' => false));
        $this->makeVars($code, $tree[$key], $key);
        $this->renameVars($tree[$key], true);

        $code = substr($tree[$key]['code'], 1);
        $code = preg_replace("'\breturn !'", 'return!', $code);
        $code = preg_replace("'\}(?=(else|while)[^\$.a-zA-Z0-9_])'", "}\r", $code);
        $code = str_replace(array_keys($this->strings), array_values($this->strings), $code);

        if ($singleLine) {
            $code = strtr($code, "\n", ';');
        } else {
            $code = str_replace("\n", ";\n", $code);
        }
        false !== strpos($code, "\r") && $code = strtr(trim($code), "\r", "\n");

        // Cleanup memory
        $this->charFreq = array_fill(0, 256, 0);
        $this->strings = $this->closures = $this->argFreq = array();
        $this->str0 = $this->str1 = '';

        return $code;
    }

    protected function extractStrings($f)
    {
        if ($cc_on = false !== strpos($f, '@cc_on')) {
            // Protect conditional comments from being removed
            $f = str_replace('#', '##', $f);
            $f = str_replace('/*@', '1#@', $f);
            $f = preg_replace("'//@([^\n]+)'", '2#@$1@#3', $f);
            $f = str_replace('@*/', '@#1', $f);
        }

        $len = strlen($f);
        $code = str_repeat(' ', $len);
        $j = 0;

        $strings = array();
        $K = 0;

        $instr = false;

        $q = array(
            "'", '"',
            "'" => 0,
            '"' => 0,
        );

        // Extract strings, removes comments
        for ($i = 0; $i < $len; ++$i) {
            if ($instr) {
                if ('//' == $instr) {
                    if ("\n" == $f[$i]) {
                        $f[$i--] = ' ';
                        $instr = false;
                    }
                } elseif ($f[$i] == $instr || ('/' == $f[$i] && "/'" == $instr)) {
                    if ('!' == $instr) {
                    } elseif ('*' == $instr) {
                        if ('/' == $f[$i + 1]) {
                            ++$i;
                            $instr = false;
                        }
                    } else {
                        if ("/'" == $instr) {
                            while (isset($f[$i + 1]) && false !== strpos('gmi', $f[$i + 1])) {
                                $s[] = $f[$i++];
                            }
                            $s[] = $f[$i];
                        }

                        $instr = false;
                    }
                } elseif ('*' == $instr) {
                } elseif ('!' == $instr) {
                    if ('*' == $f[$i] && '/' == $f[$i + 1]) {
                        $s[] = "*/\r";
                        ++$i;
                        $instr = false;
                    } elseif ("\n" == $f[$i]) {
                        $s[] = "\r";
                    } else {
                        $s[] = $f[$i];
                    }
                } elseif ('\\' == $f[$i]) {
                    ++$i;

                    if ("\n" != $f[$i]) {
                        isset($q[$f[$i]]) && ++$q[$f[$i]];
                        $s[] = '\\'.$f[$i];
                    }
                } elseif ('[' == $f[$i] && "/'" == $instr) {
                    $instr = '/[';
                    $s[] = '[';
                } elseif (']' == $f[$i] && '/[' == $instr) {
                    $instr = "/'";
                    $s[] = ']';
                } elseif ("'" == $f[$i] || '"' == $f[$i]) {
                    ++$q[$f[$i]];
                    $s[] = '\\'.$f[$i];
                } else {
                    $s[] = $f[$i];
                }
            } else {
                switch ($f[$i]) {
                case ';':
                    // Remove triple semi-colon
                    if ($i > 0 && ';' == $f[$i - 1] && $i + 1 < $len && ';' == $f[$i + 1]) {
                        $f[$i] = $f[$i + 1] = '/';
                    } else {
                        $code[++$j] = ';';
                        break;
                    }

                case '/':
                    if ('*' == $f[$i + 1]) {
                        ++$i;
                        $instr = '*';

                        if ($this->keepImportantComments && '!' == $f[$i + 1]) {
                            ++$i;
                            // no break here
                        } else {
                            break;
                        }
                    } elseif ('/' == $f[$i + 1]) {
                        ++$i;
                        $instr = '//';
                        break;
                    } else {
                        $a = $j && (' ' == $code[$j] || "\x7F" == $code[$j]) ? $code[$j - 1] : $code[$j];
                        if (false !== strpos('-!%&;<=>~:^+|,()*?[{} ', $a)
                            || (false !== strpos('oenfd', $a)
                            && preg_match(
                                "'(?<![\$.a-zA-Z0-9_])(do|else|return|typeof|yield[ \x7F]?\*?)[ \x7F]?$'",
                                substr($code, $j - 7, 8)
                            ))
                        ) {
                            if (')' === $a && $j > 1) {
                                $a = 1;
                                $k = $j - (' ' == $code[$j] || "\x7F" == $code[$j]) - 1;
                                while ($k >= 0 && $a) {
                                    if ('(' === $code[$k]) {
                                        --$a;
                                    } elseif (')' === $code[$k]) {
                                        ++$a;
                                    }
                                    --$k;
                                }
                                if (!preg_match("'(?<![\$.a-zA-Z0-9_])(if|for|while)[ \x7F]?$'", substr($code, 0, $k + 1))) {
                                    $code[++$j] = '/';
                                    break;
                                }
                            }

                            $key = "//''\"\"".$K++.$instr = "/'";
                            $a = $j;
                            $code .= $key;
                            while (isset($key[++$j - $a - 1])) {
                                $code[$j] = $key[$j - $a - 1];
                            }
                            --$j;
                            isset($s) && ($s = implode('', $s)) && $cc_on && $this->restoreCc($s);
                            $strings[$key] = array('/');
                            $s = &$strings[$key];
                        } else {
                            $code[++$j] = '/';
                        }

                        break;
                    }

                case "'":
                case '"':
                    $instr = $f[$i];
                    $key = "//''\"\"".$K++.('!' == $instr ? ']' : "'");
                    $a = $j;
                    $code .= $key;
                    while (isset($key[++$j - $a - 1])) {
                        $code[$j] = $key[$j - $a - 1];
                    }
                    --$j;
                    isset($s) && ($s = implode('', $s)) && $cc_on && $this->restoreCc($s);
                    $strings[$key] = array();
                    $s = &$strings[$key];
                    '!' == $instr && $s[] = "\r/*!";

                    break;

                case "\n":
                    if ($j > 3) {
                        if (' ' == $code[$j] || "\x7F" == $code[$j]) {
                            --$j;
                        }

                        $code[++$j] =
                            false !== strpos('kend+-', $code[$j - 1])
                                && preg_match(
                                    "'(?:\+\+|--|(?<![\$.a-zA-Z0-9_])(break|continue|return|yield[ \x7F]?\*?))[ \x7F]?$'",
                                    substr($code, $j - 8, 9)
                                )
                            ? ';' : "\x7F";

                        break;
                    }

                case "\t": $f[$i] = ' ';
                case ' ':
                    if (!$j || ' ' == $code[$j] || "\x7F" == $code[$j]) {
                        break;
                    }

                default:
                    $code[++$j] = $f[$i];
                }
            }
        }

        isset($s) && ($s = implode('', $s)) && $cc_on && $this->restoreCc($s);
        unset($s);

        $code = substr($code, 0, $j + 1);
        $cc_on && $this->restoreCc($code, false);

        // Protect wanted spaces and remove unwanted ones
        $code = strtr($code, "\x7F", ' ');
        $code = str_replace('- -', "-\x7F-", $code);
        $code = str_replace('+ +', "+\x7F+", $code);
        $code = preg_replace("'(\d)\s+\.\s*([a-zA-Z\$_[(])'", "$1\x7F.$2", $code);
        $code = preg_replace("# ([-!%&;<=>~:.^+|,()*?[\]{}/']+)#", '$1', $code);
        $code = preg_replace("#([-!%&;<=>~:.^+|,()*?[\]{}/]+) #", '$1', $code);
        $cc_on && $code = preg_replace_callback("'//[^\'].*?@#3'", function ($m) { return strtr($m[0], ' ', "\x7F"); }, $code);

        // Replace new Array/Object by []/{}
        false !== strpos($code, 'new Array') && $code = preg_replace("'new Array(?:\(\)|([;\])},:]))'", '[]$1', $code);
        false !== strpos($code, 'new Object') && $code = preg_replace("'new Object(?:\(\)|([;\])},:]))'", '{}$1', $code);

        // Add missing semi-colons after curly braces
        // This adds more semi-colons than strictly needed,
        // but it seems that later gzipping is favorable to the repetition of "};"
        $code = preg_replace("'\}(?![:,;.()\[\]}\|&]|(else|catch|finally|while)[^\$.a-zA-Z0-9_])'", '};', $code);

        // Tag possible empty instruction for easy detection
        $code = preg_replace("'(?<![\$.a-zA-Z0-9_])if\('", '1#(', $code);
        $code = preg_replace("'(?<![\$.a-zA-Z0-9_])for\('", '2#(', $code);
        $code = preg_replace("'(?<![\$.a-zA-Z0-9_])while\('", '3#(', $code);

        $forPool = array();
        $instrPool = array();
        $s = 0;

        $f = array();
        $j = -1;

        // Remove as much semi-colon as possible
        $len = strlen($code);
        for ($i = 0; $i < $len; ++$i) {
            switch ($code[$i]) {
            case '(':
                if ($j >= 0 && "\n" == $f[$j]) {
                    $f[$j] = ';';
                }

                ++$s;

                if ($i && '#' == $code[$i - 1]) {
                    $instrPool[$s - 1] = 1;
                    if ('2' == $code[$i - 2]) {
                        $forPool[$s] = 1;
                    }
                }

                $f[++$j] = '(';
                break;

            case ']':
            case ')':
                if ($i + 1 < $len && !isset($forPool[$s]) && !isset($instrPool[$s - 1]) && preg_match("'[a-zA-Z0-9_\$]'", $code[$i + 1])) {
                    $f[$j] .= $code[$i];
                    $f[++$j] = "\n";
                } else {
                    $f[++$j] = $code[$i];
                }

                if (')' == $code[$i]) {
                    unset($forPool[$s]);
                    --$s;
                }

                continue 2;

            case '}':
                if ("\n" == $f[$j]) {
                    $f[$j] = '}';
                } else {
                    $f[++$j] = '}';
                }
                break;

            case ';':
                if (isset($forPool[$s]) || isset($instrPool[$s])) {
                    $f[++$j] = ';';
                } elseif ($j >= 0 && "\n" != $f[$j] && ';' != $f[$j]) {
                    $f[++$j] = "\n";
                }

                break;

            case '#':
                switch ($f[$j]) {
                case '1': $f[$j] = 'if';    break 2;
                case '2': $f[$j] = 'for';   break 2;
                case '3': $f[$j] = 'while'; break 2;
                }

            case '[';
                if ($j >= 0 && "\n" == $f[$j]) {
                    $f[$j] = ';';
                }

            default: $f[++$j] = $code[$i];
            }

            unset($instrPool[$s]);
        }

        $f = implode('', $f);
        $cc_on && $f = str_replace('@#3', "\r", $f);

        // Fix "else ;" empty instructions
        $f = preg_replace("'(?<![\$.a-zA-Z0-9_])else\n'", "\n", $f);

        $r1 = array( // keywords with a direct object
            'case','delete','do','else','function','in','instanceof','of','break',
            'new','return','throw','typeof','var','void','yield','let','if',
            'const','get','set',
        );

        $r2 = array( // keywords with a subject
            'in','instanceof','of',
        );

        // Fix missing semi-colons
        $f = preg_replace("'(?<!(?<![a-zA-Z0-9_\$])".implode(')(?<!(?<![a-zA-Z0-9_\$])', $r1).') (?!('.implode('|', $r2).")(?![a-zA-Z0-9_\$]))'", "\n", $f);
        $f = preg_replace("'(?<!(?<![a-zA-Z0-9_\$])do)(?<!(?<![a-zA-Z0-9_\$])else) if\('", "\nif(", $f);
        $f = preg_replace("'(?<=--|\+\+)(?<![a-zA-Z0-9_\$])(".implode('|', $r1).")(?![a-zA-Z0-9_\$])'", "\n$1", $f);
        $f = preg_replace("'(?<![a-zA-Z0-9_\$])for\neach\('", 'for each(', $f);
        $f = preg_replace("'(?<![a-zA-Z0-9_\$])\n(".implode('|', $r2).")(?![a-zA-Z0-9_\$])'", '$1', $f);

        // Merge strings
        if ($q["'"] > $q['"']) {
            $q = array($q[1], $q[0]);
        }
        $f = preg_replace("#//''\"\"[0-9]+'#", $q[0].'$0'.$q[0], $f);
        strpos($f, $q[0].'+'.$q[0]) && $f = str_replace($q[0].'+'.$q[0], '', $f);
        $len = count($strings);
        foreach ($strings as $r1 => &$r2) {
            $r2 = "/'" == substr($r1, -2)
                ? str_replace(array("\\'", '\\"'), array("'", '"'), $r2)
                : str_replace('\\'.$q[1], $q[1], $r2);
        }

        // Restore wanted spaces
        $f = strtr($f, "\x7F", ' ');

        return array($f, $strings);
    }

    protected function extractClosures($code)
    {
        $code = ';'.$code;

        $this->argFreq[-1] += substr_count($code, '}catch(');

        if ($this->argFreq[-1]) {
            // Special catch scope handling

            // FIXME: this implementation doesn't work with nested catch scopes who need
            // access to their parent's caught variable (but who needs that?).

            $f = preg_split("@}catch\(({$this->varRx})@", $code, -1, PREG_SPLIT_DELIM_CAPTURE);

            $code = 'catch$scope$var'.mt_rand();
            $this->specialVarRx = $this->specialVarRx ? '(?:'.$this->specialVarRx.'|'.preg_quote($code).')' : preg_quote($code);
            $i = count($f) - 1;

            while ($i) {
                $c = 1;
                $j = 0;
                $l = strlen($f[$i]);

                while ($c && $j < $l) {
                    $s = $f[$i][$j++];
                    $c += '(' == $s ? 1 : (')' == $s ? -1 : 0);
                }

                if (!$c) {
                    do {
                        $s = $f[$i][$j++];
                        $c += '{' == $s ? 1 : ('}' == $s ? -1 : 0);
                    } while ($c && $j < $l);
                }

                $c = preg_quote($f[$i - 1], '#');
                $f[$i - 2] .= '}catch('.preg_replace("#([.,{]?)(?<![a-zA-Z0-9_\$@]){$c}\\b#", '$1'.$code, $f[$i - 1].substr($f[$i], 0, $j)).substr($f[$i], $j);

                unset($f[$i--], $f[$i--]);
            }

            $code = $f[0];
        }

        $f = preg_split("'(?<![a-zA-Z0-9_\$])((?:function[ (]|get |set ).*?\{)'", $code, -1, PREG_SPLIT_DELIM_CAPTURE);
        $i = count($f) - 1;
        $closures = array();

        while ($i) {
            $c = 1;
            $j = 0;
            $l = strlen($f[$i]);

            while ($c && $j < $l) {
                $s = $f[$i][$j++];
                $c += '{' == $s ? 1 : ('}' == $s ? -1 : 0);
            }

            switch (substr($f[$i - 2], -1)) {
            default:
                if (false !== $c = strpos($f[$i - 1], ' ', 8)) {
                    break;
                }
            case false: case "\n": case ';': case '{': case '}': case ')': case ']':
                $c = strpos($f[$i - 1], '(', 4);
            }

            $l = "//''\"\"#$i'";
            $code = substr($f[$i - 1], $c);
            $closures[$l] = $code.substr($f[$i], 0, $j);
            $f[$i - 2] .= substr($f[$i - 1], 0, $c).$l.substr($f[$i], $j);

            if ('(){' !== $code) {
                $j = substr_count($code, ',');
                do {
                    isset($this->argFreq[$j]) ? ++$this->argFreq[$j] : $this->argFreq[$j] = 1;
                } while ($j--);
            }

            $i -= 2;
        }

        return array($f[0], $closures);
    }

    protected function makeVars($closure, &$tree, $key)
    {
        $tree['code'] = &$closure;
        $tree['nfe'] = false;
        $tree['used'] = array();
        $tree['local'] = array();

        // Replace multiple "var" declarations by a single one
        $closure = preg_replace_callback("'(?<=[\n\{\}])var [^\n\{\};]+(?:\nvar [^\n\{\};]+)+'", array($this, 'mergeVarDeclarations'), $closure);

        // Get all local vars (functions, arguments and "var" prefixed)

        $vars = &$tree['local'];

        if (preg_match("'^( [^(]*)?\((.*?)\)\{'", $closure, $v)) {
            if ($v[1]) {
                $vars[$tree['nfe'] = substr($v[1], 1)] = -1;
                $tree['parent']['local'][';'.$key] = &$vars[$tree['nfe']];
            }

            if ($v[2]) {
                $i = 0;
                $v = explode(',', $v[2]);
                foreach ($v as $w) {
                    $vars[$w] = $this->argFreq[$i++] - 1; // Give a bonus to argument variables
                }
            }
        }

        $v = preg_split("'(?<![\$.a-zA-Z0-9_])var '", $closure);
        if ($i = count($v) - 1) {
            $w = array();

            while ($i) {
                $j = $c = 0;
                $l = strlen($v[$i]);

                while ($j < $l) {
                    switch ($v[$i][$j]) {
                    case '(': case '[': case '{':
                        ++$c;
                        break;

                    case ')': case ']': case '}':
                        if ($c-- <= 0) {
                            break 2;
                        }
                        break;

                    case ';': case "\n":
                        if (!$c) {
                            break 2;
                        }

                    default:
                        $c || $w[] = $v[$i][$j];
                    }

                    ++$j;
                }

                $w[] = ',';
                --$i;
            }

            $v = explode(',', implode('', $w));
            foreach ($v as $w) {
                if (preg_match("'^{$this->varRx}'", $w, $v)) {
                    isset($vars[$v[0]]) || $vars[$v[0]] = 0;
                }
            }
        }

        if (preg_match_all("@function ({$this->varRx})//''\"\"#@", $closure, $v)) {
            foreach ($v[1] as $w) {
                isset($vars[$w]) || $vars[$w] = 0;
            }
        }

        if ($this->argFreq[-1] && preg_match_all("@}catch\(({$this->varRx})@", $closure, $v)) {
            $v[0] = array();
            foreach ($v[1] as $w) {
                isset($v[0][$w]) ? ++$v[0][$w] : $v[0][$w] = 1;
            }
            foreach ($v[0] as $w => $v) {
                $vars[$w] = $this->argFreq[-1] - $v;
            }
        }

        // Get all used vars, local and non-local

        $vars = &$tree['used'];

        if (preg_match_all("#([.,{]?(?:[gs]et )?)(?<![a-zA-Z0-9_\$])({$this->varRx})(:?)#", $closure, $w, PREG_SET_ORDER)) {
            foreach ($w as $k) {
                if (isset($k[1][0]) && (',' === $k[1][0] || '{' === $k[1][0])) {
                    if (':' === $k[3]) {
                        $k = '.'.$k[2];
                    } elseif ('get ' === substr($k[1], 1, 4) || 'set ' === substr($k[1], 1, 4)) {
                        ++$this->charFreq[ord($k[1][1])]; // "g" or "s"
                        ++$this->charFreq[101]; // "e"
                        ++$this->charFreq[116]; // "t"
                        $k = '.'.$k[2];
                    } else {
                        $k = $k[2];
                    }
                } else {
                    $k = $k[1].$k[2];
                }

                isset($vars[$k]) ? ++$vars[$k] : $vars[$k] = 1;
            }
        }

        if (preg_match_all("#//''\"\"[0-9]+(?:['!]|/')#", $closure, $w)) {
            foreach ($w[0] as $a) {
                $v = "'" === substr($a, -1) && "/'" !== substr($a, -2) && $this->specialVarRx
                    ? preg_split("#([.,{]?(?:[gs]et )?(?<![a-zA-Z0-9_\$@]){$this->specialVarRx}:?)#", $this->strings[$a], -1, PREG_SPLIT_DELIM_CAPTURE)
                    : array($this->strings[$a]);
                $a = count($v);

                for ($i = 0; $i < $a; ++$i) {
                    $k = $v[$i];

                    if (1 === $i % 2) {
                        if (',' === $k[0] || '{' === $k[0]) {
                            if (':' === substr($k, -1)) {
                                $k = '.'.substr($k, 1, -1);
                            } elseif ('get ' === substr($k, 1, 4) || 'set ' === substr($k, 1, 4)) {
                                ++$this->charFreq[ord($k[1])]; // "g" or "s"
                                ++$this->charFreq[101]; // "e"
                                ++$this->charFreq[116]; // "t"
                                $k = '.'.substr($k, 5);
                            } else {
                                $k = substr($k, 1);
                            }
                        } elseif (':' === substr($k, -1)) {
                            $k = substr($k, 0, -1);
                        }

                        $w = &$tree;

                        while (isset($w['parent']) && !(isset($w['used'][$k]) || isset($w['local'][$k]))) {
                            $w = &$w['parent'];
                        }

                        (isset($w['used'][$k]) || isset($w['local'][$k])) && (isset($vars[$k]) ? ++$vars[$k] : $vars[$k] = 1);

                        unset($w);
                    }

                    if (0 === $i % 2 || !isset($vars[$k])) {
                        foreach (count_chars($v[$i], 1) as $k => $w) {
                            $this->charFreq[$k] += $w;
                        }
                    }
                }
            }
        }

        // Propagate the usage number to parents

        foreach ($vars as $w => $a) {
            $k = &$tree;
            $chain = array();
            do {
                $vars = &$k['local'];
                $chain[] = &$k;
                if (isset($vars[$w])) {
                    unset($k['used'][$w]);
                    if (isset($vars[$w])) {
                        $vars[$w] += $a;
                    } else {
                        $vars[$w] = $a;
                    }
                    $a = false;
                    break;
                }
            } while ($k['parent'] && $k = &$k['parent']);

            if ($a && !$k['parent']) {
                if (isset($vars[$w])) {
                    $vars[$w] += $a;
                } else {
                    $vars[$w] = $a;
                }
            }

            if (isset($tree['used'][$w]) && isset($vars[$w])) {
                foreach ($chain as &$b) {
                    isset($b['local'][$w]) || $b['used'][$w] = &$vars[$w];
                }
            }
        }

        // Analyse childs

        $tree['childs'] = array();
        $vars = &$tree['childs'];

        if (preg_match_all("@//''\"\"#[0-9]+'@", $closure, $w)) {
            foreach ($w[0] as $a) {
                $vars[$a] = array('parent' => &$tree);
                $this->makeVars($this->closures[$a], $vars[$a], $a);
            }
        }
    }

    protected function mergeVarDeclarations($m)
    {
        return str_replace("\nvar ", ',', $m[0]);
    }

    protected function renameVars(&$tree, $root)
    {
        if ($root) {
            $tree['local'] += $tree['used'];
            $tree['used'] = array();

            foreach ($tree['local'] as $k => $v) {
                if ('.' == $k[0]) {
                    $k = substr($k, 1);
                }

                if ('true' === $k) {
                    $this->charFreq[48] += $v;
                } elseif ('false' === $k) {
                    $this->charFreq[49] += $v;
                } elseif (!$this->specialVarRx || !preg_match("#^{$this->specialVarRx}$#", $k)) {
                    foreach (count_chars($k, 1) as $k => $w) {
                        $this->charFreq[$k] += $w * $v;
                    }
                } elseif (2 == strlen($k)) {
                    $tree['used'][] = $k[1];
                }
            }

            $this->charFreq = $this->rsort($this->charFreq);

            $this->str0 = '';
            $this->str1 = '';

            foreach ($this->charFreq as $k => $v) {
                if (!$v) {
                    break;
                }

                $v = chr($k);

                if ((64 < $k && $k < 91) || (96 < $k && $k < 123)) { // A-Z a-z
                    $this->str0 .= $v;
                    $this->str1 .= $v;
                } elseif (47 < $k && $k < 58) { // 0-9
                    $this->str1 .= $v;
                }
            }

            if ('' === $this->str0) {
                $this->str0 = 'claspemitdbfrugnjvhowkxqyzCLASPEMITDBFRUGNJVHOWKXQYZ';
                $this->str1 = $this->str0.'0123456789';
            }

            foreach ($tree['local'] as $var => $root) {
                if ('.' != substr($var, 0, 1) && isset($tree['local'][".{$var}"])) {
                    $tree['local'][$var] += $tree['local'][".{$var}"];
                }
            }

            foreach ($tree['local'] as $var => $root) {
                if ('.' == substr($var, 0, 1) && isset($tree['local'][substr($var, 1)])) {
                    $tree['local'][$var] = $tree['local'][substr($var, 1)];
                }
            }

            $tree['local'] = $this->rsort($tree['local']);

            foreach ($tree['local'] as $var => $root) {
                switch (substr($var, 0, 1)) {
                case '.':
                    if (!isset($tree['local'][substr($var, 1)])) {
                        $tree['local'][$var] = '#'.($this->specialVarRx && 3 < strlen($var) && preg_match("'^\.{$this->specialVarRx}$'", $var) ? $this->getNextName($tree).'$' : substr($var, 1));
                    }
                    break;

                case ';': $tree['local'][$var] = 0 === $root ? '' : $this->getNextName($tree);
                case '#': break;

                default:
                    $root = $this->specialVarRx && 2 < strlen($var) && preg_match("'^{$this->specialVarRx}$'", $var) ? $this->getNextName($tree).'$' : $var;
                    $tree['local'][$var] = $root;
                    if (isset($tree['local'][".{$var}"])) {
                        $tree['local'][".{$var}"] = '#'.$root;
                    }
                }
            }

            foreach ($tree['local'] as $var => $root) {
                $tree['local'][$var] = preg_replace("'^#'", '.', $tree['local'][$var]);
            }
        } else {
            $tree['local'] = $this->rsort($tree['local']);
            if (false !== $tree['nfe']) {
                $tree['used'][] = $tree['local'][$tree['nfe']];
            }

            foreach ($tree['local'] as $var => $root) {
                if ($tree['nfe'] !== $var) {
                    $tree['local'][$var] = 0 === $root ? '' : $this->getNextName($tree);
                }
            }
        }

        $this->local_tree = &$tree['local'];
        $this->used_tree = &$tree['used'];

        $tree['code'] = preg_replace_callback("#[.,{ ]?(?:[gs]et )?(?<![a-zA-Z0-9_\$@]){$this->varRx}:?#", array($this, 'getNewName'), $tree['code']);

        if ($this->specialVarRx && preg_match_all("#//''\"\"[0-9]+'#", $tree['code'], $b)) {
            foreach ($b[0] as $a) {
                $this->strings[$a] = preg_replace_callback(
                    "#[.,{]?(?:[gs]et )?(?<![a-zA-Z0-9_\$@]){$this->specialVarRx}:?#",
                    array($this, 'getNewName'),
                    $this->strings[$a]
                );
            }
        }

        foreach ($tree['childs'] as $a => &$b) {
            $this->renameVars($b, false);
            $tree['code'] = str_replace($a, $b['code'], $tree['code']);
            unset($tree['childs'][$a]);
        }
    }

    protected function getNewName($m)
    {
        $m = $m[0];

        $pre = '.' === $m[0] ? '.' : '';
        $post = '';

        if (',' === $m[0] || '{' === $m[0] || ' ' === $m[0]) {
            $pre = $m[0];

            if (':' === substr($m, -1)) {
                $post = ':';
                $m = (' ' !== $m[0] ? '.' : '').substr($m, 1, -1);
            } elseif ('get ' === substr($m, 1, 4) || 'set ' === substr($m, 1, 4)) {
                $pre .= substr($m, 1, 4);
                $m = '.'.substr($m, 5);
            } else {
                $m = substr($m, 1);
            }
        } elseif (':' === substr($m, -1)) {
            $post = ':';
            $m = substr($m, 0, -1);
        }

        $post = (isset($this->reserved[$m])
            ? ('true' === $m ? '!0' : ('false' === $m ? '!1' : $m))
            : (
                  isset($this->local_tree[$m])
                ? $this->local_tree[$m]
                : (
                      isset($this->used_tree[$m])
                    ? $this->used_tree[$m]
                    : $m
                )
            )
        ).$post;

        return '' === $post ? '' : ($pre.('.' === $post[0] ? substr($post, 1) : $post));
    }

    protected function getNextName(&$tree = array(), &$counter = false)
    {
        if (false === $counter) {
            $counter = &$tree['counter'];
            isset($counter) || $counter = -1;
            $exclude = array_flip($tree['used']);
        } else {
            $exclude = $tree;
        }

        ++$counter;

        $len0 = strlen($this->str0);
        $len1 = strlen($this->str0);

        $name = $this->str0[$counter % $len0];

        $i = intval($counter / $len0) - 1;
        while ($i >= 0) {
            $name .= $this->str1[ $i % $len1 ];
            $i = intval($i / $len1) - 1;
        }

        return !(isset($this->reserved[$name]) || isset($exclude[$name])) ? $name : $this->getNextName($exclude, $counter);
    }

    protected function restoreCc(&$s, $lf = true)
    {
        $lf && $s = str_replace('@#3', '', $s);

        $s = str_replace('@#1', '@*/', $s);
        $s = str_replace('2#@', '//@', $s);
        $s = str_replace('1#@', '/*@', $s);
        $s = str_replace('##', '#', $s);
    }

    private function rsort($array)
    {
        if (!$array) {
            return $array;
        }

        $i = 0;
        $tuples = array();
        foreach ($array as $k => &$v) {
            $tuples[] = array(++$i, $k, &$v);
        }

        usort($tuples, function ($a, $b) {
            if ($b[2] > $a[2]) {
                return 1;
            }
            if ($b[2] < $a[2]) {
                return -1;
            }
            if ($b[0] > $a[0]) {
                return -1;
            }
            if ($b[0] < $a[0]) {
                return 1;
            }

            return 0;
        });

        $array = array();

        foreach ($tuples as $t) {
            $array[$t[1]] = &$t[2];
        }

        return $array;
    }
}
