<?php
namespace W3TCL\Minify;
/**
 * Class Minify_ClosureCompiler
 * @package Minify
 */

/**
 * Compress Javascript using the Closure Compiler
 *
 * You must set $jarFile and $tempDir before calling the minify functions.
 * Also, depending on your shell's environment, you may need to specify
 * the full path to java in $javaExecutable or use putenv() to setup the
 * Java environment.
 *
 * <code>
 * Minify_ClosureCompiler::$jarFile = '/path/to/closure-compiler-20120123.jar';
 * Minify_ClosureCompiler::$tempDir = '/tmp';
 * $code = Minify_ClosureCompiler::minify(
 *   $code,
 *   array('compilation_level' => 'SIMPLE_OPTIMIZATIONS')
 * );
 *
 * --compilation_level WHITESPACE_ONLY, SIMPLE_OPTIMIZATIONS, ADVANCED_OPTIMIZATIONS
 *
 * </code>
 *
 * @todo unit tests, $options docs
 * @todo more options support (or should just passthru them all?)
 *
 * @package Minify
 * @author Stephen Clay <steve@mrclay.org>
 * @author Elan Ruusamäe <glen@delfi.ee>
 */
class Minify_ClosureCompiler {

	/**
	 * Filepath of the Closure Compiler jar file. This must be set before
	 * calling minifyJs().
	 *
	 * @var string
	 */
	public static $jarFile = null;

	/**
	 * Writable temp directory. This must be set before calling minifyJs().
	 *
	 * @var string
	 */
	public static $tempDir = null;

	/**
	 * Filepath of "java" executable (may be needed if not in shell's PATH)
	 *
	 * @var string
	 */
	public static $javaExecutable = 'java';

	/**
	 * Minify a Javascript string
	 *
	 * @param string $js
	 *
	 * @param array $options (verbose is ignored)
	 *
	 * @see https://code.google.com/p/closure-compiler/source/browse/trunk/README
	 *
	 * @return string
	 */
	public static function minify($js, $options = array())
	{
		self::_prepare();
		if (! ($tmpFile = tempnam(self::$tempDir, 'cc_'))) {
			throw new \Exception('Minify_ClosureCompiler : could not create temp file.');
		}
		file_put_contents($tmpFile, $js);
		exec(self::_getCmd($options, $tmpFile), $output, $result_code);
		unlink($tmpFile);
		if ($result_code != 0) {
			throw new \Exception('Minify_ClosureCompiler : Closure Compiler execution failed.');
		}
		return implode("\n", $output);
	}

	private static function _getCmd($userOptions, $tmpFile)
	{
		$o = array_merge(
			array(
				'charset' => 'utf-8',
				'compilation_level' => 'SIMPLE_OPTIMIZATIONS',
			),
			$userOptions
		);

		 $javaExecutable = self::$javaExecutable;

		if ( false !== strpos(trim($javaExecutable), ' ') ) {
			  $javaExecutable = '"'.$javaExecutable.'"';
		}

		$cmd = $javaExecutable . ' -jar ' . escapeshellarg(self::$jarFile)
			 . (preg_match('/^[\\da-zA-Z0-9\\-]+$/', $o['charset'])
				? " --charset {$o['charset']}"
				: '');

		foreach (array('compilation_level') as $opt) {
			if ($o[$opt]) {
				$cmd .= " --{$opt} ". escapeshellarg($o[$opt]);
			}
		}
		return $cmd . ' ' . escapeshellarg($tmpFile);
	}

	private static function _prepare()
	{
		if (! is_file(self::$jarFile)) {
			throw new \Exception('Minify_ClosureCompiler : $jarFile('.self::$jarFile.') is not a valid file.');
		}
		if (! is_readable(self::$jarFile)) {
			throw new \Exception('Minify_ClosureCompiler : $jarFile('.self::$jarFile.') is not readable.');
		}
		if (! is_dir(self::$tempDir)) {
			throw new \Exception('Minify_ClosureCompiler : $tempDir('.self::$tempDir.') is not a valid direcotry.');
		}
		if (! is_writable(self::$tempDir)) {
			throw new \Exception('Minify_ClosureCompiler : $tempDir('.self::$tempDir.') is not writable.');
		}
	}

	public static function test(&$error) {
		try {
			self::minify('alert("ok");');
			$error = 'OK';

			return true;
		} catch (\Exception $exception) {
			$error = $exception->getMessage();

			return false;
		}
	}
}

/* vim:ts=4:sw=4:et */
