<?php
define ( '__ABSPATH__', dirname ( __FILE__ ) . '/' );
define ( '__CSSPATH__', 'css/' );
define ( '__JSPATH__', 'js/' );
define ( '__LENGTH__', 60 * 60 * 24 * 14 );

class Resources
{
    private $packages = array ( );

    public function __construct ( )
    {
        $xml = simplexml_load_file("package-config.xml");

        foreach ( $xml -> package as $pckg )
        {
            $type = (string) $pckg [ 'type' ];
            $name = (string) $pckg [ 'name' ];

            $minify = $pckg [ 'minify' ];

            foreach ( $pckg -> file as $file )
            {
                $this -> packages [ $type ] [ $name ] [ 'files' ] [ ] = $file [ 'url' ];
            }

            $this -> packages [ $type ] [ $name ] [ 'minify' ] = $minify;
        }
    }

    public function load_package ( $key, $cache = true )
    {
        if ( ! preg_match ( "/^(\w+\.(?:css|js))$/", $key ) )
        {
            show_404 ( );
        }

        $key_bits = explode ( ".", $key );
        $pckg = $key_bits [ 0 ];
        $type = $key_bits [ 1 ];

        if ( ! isset ( $this -> packages [ $type ] [ $pckg ] )
            ||
            ! is_array ( $this -> packages [ $type ] [ $pckg ] ) )
        {
            show_404 ( );
        }

        $content = array ( );

        foreach ( $this -> packages [ $type ] [ $pckg ] [ 'files' ] as $file )
        {
            $file_path = ( ( $type == 'css' ) ? __CSSPATH__ : __JSPATH__ ) . $file;

            if ( ! file_exists ( $file_path ) )
            {
                show_404();
            }

            $content [ ] = file_get_contents ( $file_path );
        }

        if ( $this -> packages [ $type ] [ $pckg ] [ 'minify' ] == 'true' )
        {
            switch ($type)
            {
                case 'css':
                    foreach ( $content as $k => $v )
                    {
                        $content [ $k ] = $this -> minify_css ( $v );
                    }
                break;
                case 'js':
                    foreach ( $content as $k => $v )
                    {
                        $content [ $k ] = $this -> minify_js ( $v );
                    }
                break;
            }
        }

        $this -> dump_output (
            implode ( ' ', $content ),
            get_mime_by_extension ( $type ),
            $cache
        );
    }

    function dump_output ( $output, $mime, $cache = true )
    {
        header ( 'Content-Type: ' . $mime );

        if ( $cache === true )
        {
            header ( 'Pragma: public' );
            header ( 'Cache-Control: maxage=' . __LENGTH__ );
            header ( 'Expires: ' . gmdate ( 'D, d M Y H:i:s', time ( ) + __LENGTH__ ) . ' GMT' );
        }

        die ( $output );
    }

    public function minify_css ( $css )
    {
        // Compress whitespace.
        $css = preg_replace ( '/\s+/', '', $css );

        // Remove comments.
        $css = preg_replace ( '/\/\*.*?\*\//', '', $css );

        return trim ( $css );
    }

    public function minify_js ( $js )
    {
        require_once ( "jsmin.php" );

        return ( JSMin :: minify ( $js ) );
    }
}

function show_404 ( )
{
    header ( 'HTTP/1.0 404 Not Found' );
    die ( "404, Not found" );
}

function get_mime_by_extension ( $ext )
{
    $mimes = array (
        'js'  => 'application/x-javascript',
        'css' => 'text/css',
    );

    return ( ( isset ( $mimes [ $ext ] ) ) ? $mimes [ $ext ] : false );
}
?>