<?php

/**
 * jsmin.php - PHP implementation of Douglas Crockford's JSMin.
 *
 * This is a direct port of jsmin.c to PHP with a few PHP performance tweaks and
 * modifications to preserve some comments (see below). Also, rather than using
 * stdin/stdout, JSMin::minify() accepts a string as input and returns another
 * string as output.
 *
 * Comments containing IE conditional compilation are preserved, as are multi-line
 * comments that begin with "/*!" (for documentation purposes). In the latter case
 * newlines are inserted around the comment to enhance readability.
 *
 * PHP 5 or higher is required.
 *
 * 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 Ryan Grove <ryan@wonko.com> (PHP port)
 * @author Steve Clay <steve@mrclay.org> (modifications + cleanup)
 * @author Andrea Giammarchi <http://www.3site.eu> (spaceBeforeRegExp)
 * @copyright 2002 Douglas Crockford <douglas@crockford.com> (jsmin.c)
 * @copyright 2008 Ryan Grove <ryan@wonko.com> (PHP port)
 * @license http://opensource.org/licenses/mit-license.php MIT License
 * @link http://code.google.com/p/jsmin-php/
 */
/**
 * This library is used as part of Casset.
 * @package    Casset
 * @version    v1.21
 * @author     Antony Male
 * @license    MIT License
 * @link       http://github.com/canton7/fuelphp-casset
 */

namespace Casset;

class Casset_JSMin {
	const ORD_LF = 10;
	const ORD_SPACE = 32;
	const ACTION_KEEP_A = 1;
	const ACTION_DELETE_A = 2;
	const ACTION_DELETE_A_B = 3;

	protected $a = "\n";
	protected $b = '';
	protected $input = '';
	protected $inputIndex = 0;
	protected $inputLength = 0;
	protected $lookAhead = null;
	protected $output = '';
	protected $lastByteOut = '';

	/**
	 * Minify Javascript.
	 *
	 * @param string $js Javascript to be minified
	 * @return string
	 */
	public static function minify($js) {
		$jsmin = new Casset_JSmin($js);
		return $jsmin->min();
	}

	/**
	 * @param string $input
	 */
	public function __construct($input) {
		$this->input = $input;
	}

	/**
	 * Perform minification, return result
	 */
	public function min() {
		if ($this->output !== '') { // min already run
			return $this->output;
		}

		$mbIntEnc = null;
		if (function_exists('mb_strlen') && ((int) ini_get('mbstring.func_overload') & 2)) {
			$mbIntEnc = mb_internal_encoding();
			mb_internal_encoding('8bit');
		}
		$this->input = str_replace("\r\n", "\n", $this->input);
		$this->inputLength = strlen($this->input);

		$this->action(self::ACTION_DELETE_A_B);

		while ($this->a !== null) {
			// determine next command
			$command = self::ACTION_KEEP_A; // default
			if ($this->a === ' ') {
				if (($this->lastByteOut === '+' || $this->lastByteOut === '-')
						&& ($this->b === $this->lastByteOut)) {
					// Don't delete this space. If we do, the addition/subtraction
					// could be parsed as a post-increment
				} elseif (!$this->isAlphaNum($this->b)) {
					$command = self::ACTION_DELETE_A;
				}
			} elseif ($this->a === "\n") {
				if ($this->b === ' ') {
					$command = self::ACTION_DELETE_A_B;
					// in case of mbstring.func_overload & 2, must check for null b,
					// otherwise mb_strpos will give WARNING
				} elseif ($this->b === null
						|| (false === strpos('{[(+-', $this->b)
						&& !$this->isAlphaNum($this->b))) {
					$command = self::ACTION_DELETE_A;
				}
			} elseif (!$this->isAlphaNum($this->a)) {
				if ($this->b === ' '
						|| ($this->b === "\n"
						&& (false === strpos('}])+-"\'', $this->a)))) {
					$command = self::ACTION_DELETE_A_B;
				}
			}
			$this->action($command);
		}
		$this->output = trim($this->output);

		if ($mbIntEnc !== null) {
			mb_internal_encoding($mbIntEnc);
		}
		return $this->output;
	}

	/**
	 * ACTION_KEEP_A = Output A. Copy B to A. Get the next B.
	 * ACTION_DELETE_A = Copy B to A. Get the next B.
	 * ACTION_DELETE_A_B = Get the next B.
	 */
	protected function action($command) {
		if ($command === self::ACTION_DELETE_A_B
				&& $this->b === ' '
				&& ($this->a === '+' || $this->a === '-')) {
			// Note: we're at an addition/substraction operator; the inputIndex
			// will certainly be a valid index
			if ($this->input[$this->inputIndex] === $this->a) {
				// This is "+ +" or "- -". Don't delete the space.
				$command = self::ACTION_KEEP_A;
			}
		}
		switch ($command) {
			case self::ACTION_KEEP_A:
				$this->output .= $this->a;
				$this->lastByteOut = $this->a;

			// fallthrough
			case self::ACTION_DELETE_A:
				$this->a = $this->b;
				if ($this->a === "'" || $this->a === '"') { // string literal
					$str = $this->a; // in case needed for exception
					while (true) {
						$this->output .= $this->a;
						$this->lastByteOut = $this->a;

						$this->a = $this->get();
						if ($this->a === $this->b) { // end quote
							break;
						}
						if (ord($this->a) <= self::ORD_LF) {
							throw new JSMin_UnterminatedStringException(
									"JSMin: Unterminated String at byte "
									. $this->inputIndex . ": {$str}");
						}
						$str .= $this->a;
						if ($this->a === '\\') {
							$this->output .= $this->a;
							$this->lastByteOut = $this->a;

							$this->a = $this->get();
							$str .= $this->a;
						}
					}
				}
			// fallthrough
			case self::ACTION_DELETE_A_B:
				$this->b = $this->next();
				if ($this->b === '/' && $this->isRegexpLiteral()) { // RegExp literal
					$this->output .= $this->a . $this->b;
					$pattern = '/'; // in case needed for exception
					while (true) {
						$this->a = $this->get();
						$pattern .= $this->a;
						if ($this->a === '/') { // end pattern
							break; // while (true)
						} elseif ($this->a === '\\') {
							$this->output .= $this->a;
							$this->a = $this->get();
							$pattern .= $this->a;
						} elseif (ord($this->a) <= self::ORD_LF) {
							throw new JSMin_UnterminatedRegExpException(
									"JSMin: Unterminated RegExp at byte "
									. $this->inputIndex . ": {$pattern}");
						}
						$this->output .= $this->a;
						$this->lastByteOut = $this->a;
					}
					$this->b = $this->next();
				}
			// end case ACTION_DELETE_A_B
		}
	}

	protected function isRegexpLiteral() {
		if (false !== strpos("\n{;(,=:[!&|?", $this->a)) { // we aren't dividing
			return true;
		}
		if (' ' === $this->a) {
			$length = strlen($this->output);
			if ($length < 2) { // weird edge case
				return true;
			}
			// you can't divide a keyword
			if (preg_match('/(?:case|else|in|return|typeof)$/', $this->output, $m)) {
				if ($this->output === $m[0]) { // odd but could happen
					return true;
				}
				// make sure it's a keyword, not end of an identifier
				$charBeforeKeyword = substr($this->output, $length - strlen($m[0]) - 1, 1);
				if (!$this->isAlphaNum($charBeforeKeyword)) {
					return true;
				}
			}
		}
		return false;
	}

	/**
	 * Get next char. Convert ctrl char to space.
	 */
	protected function get() {
		$c = $this->lookAhead;
		$this->lookAhead = null;
		if ($c === null) {
			if ($this->inputIndex < $this->inputLength) {
				$c = $this->input[$this->inputIndex];
				$this->inputIndex += 1;
			} else {
				return null;
			}
		}
		if ($c === "\r" || $c === "\n") {
			return "\n";
		}
		if (ord($c) < self::ORD_SPACE) { // control char
			return ' ';
		}
		return $c;
	}

	/**
	 * Get next char. If is ctrl character, translate to a space or newline.
	 */
	protected function peek() {
		$this->lookAhead = $this->get();
		return $this->lookAhead;
	}

	/**
	 * Is $c a letter, digit, underscore, dollar sign, escape, or non-ASCII?
	 */
	protected function isAlphaNum($c) {
		return (preg_match('/^[0-9a-zA-Z_\\$\\\\]$/', $c) || ord($c) > 126);
	}

	protected function singleLineComment() {
		$comment = '';
		while (true) {
			$get = $this->get();
			$comment .= $get;
			if (ord($get) <= self::ORD_LF) { // EOL reached
				// if IE conditional comment
				if (preg_match('/^\\/@(?:cc_on|if|elif|else|end)\\b/', $comment)) {
					return "/{$comment}";
				}
				return $get;
			}
		}
	}

	protected function multipleLineComment() {
		$this->get();
		$comment = '';
		while (true) {
			$get = $this->get();
			if ($get === '*') {
				if ($this->peek() === '/') { // end of comment reached
					$this->get();
					// if comment preserved by YUI Compressor
					if (0 === strpos($comment, '!')) {
						return "\n/*!" . substr($comment, 1) . "*/\n";
					}
					// if IE conditional comment
					if (preg_match('/^@(?:cc_on|if|elif|else|end)\\b/', $comment)) {
						return "/*{$comment}*/";
					}
					return ' ';
				}
			} elseif ($get === null) {
				throw new JSMin_UnterminatedCommentException(
						"JSMin: Unterminated comment at byte "
						. $this->inputIndex . ": /*{$comment}");
			}
			$comment .= $get;
		}
	}

	/**
	 * Get the next character, skipping over comments.
	 * Some comments may be preserved.
	 */
	protected function next() {
		$get = $this->get();
		if ($get !== '/') {
			return $get;
		}
		switch ($this->peek()) {
			case '/': return $this->singleLineComment();
			case '*': return $this->multipleLineComment();
			default: return $get;
		}
	}
}

class JSMin_UnterminatedStringException extends Casset_Exception {
}

class JSMin_UnterminatedCommentException extends Casset_Exception {
}

class JSMin_UnterminatedRegExpException extends Casset_Exception {
}
