<?php
/**
 * Plugin Name: WP Downloader
 * Plugin URI: http://szalkiewicz.pl/
 * Description: This plugin allows you to download other plugins and themes installed on your site as a zip package, ready to install on another site.
 * Version: 2.0
 * Author: Wojtek Szałkiewicz
 * Author URI: http://szalkiewicz.pl/
 * Requires at least: 3.5
 * Tested up to: 4.1
 */
add_action('plugins_loaded', 'wpd_load');

/**
 * Hooks some actions and filters,
 * Handles the download link
 *
 * @return  void
 */
function wpd_load(){
	// Hook for the plugin action links
	add_filter('plugin_action_links', 'wpd_plugin_action_links', 10, 4);
	// Hook for the theme action links in wordpress <3.8
	add_filter('theme_action_links', 'wpd_theme_action_links', 10, 2);
	// Hook for adding javasctript on the themes page
	add_action('admin_footer-themes.php', 'wpd_scripts', 99);

	// Check, if there is a 'wpd' Get param, and there is a proper nonce set...
	if(isset($_GET['wpd']) && wp_verify_nonce($_GET['_wpnonce'], 'wpd-download')){
		// ...yup, perform downloading
		wpd_download();
	}
}

/**
 * Displays "download" link on the plugins page
 *
 * @param   array  list of action links
 * @param   string plugin file name
 * @param   array  An array of plugin data.
 * @param   string The plugin context.
 * @return  array
 */
function wpd_plugin_action_links($links, $file, $plugin_data, $context){
	if('dropins' === $context)
		return $links;
	if('mustuse' === $context)
		$what = 'muplugin';
	else
		$what = 'plugin';

	$dowload_query = build_query(array('wpd' => $what, 'object' => $file));
	$download_link = sprintf('<a href="%s">%s</a>',
		wp_nonce_url(admin_url('?' . $dowload_query), 'wpd-download'),
		__('Download')
	);
		
	array_push($links, $download_link); 
	return $links;
}

/**
 * Displays "download" link on the themes page in wordpress <3.8
 *
 * @param   array  list of action links
 * @param   string theme name
 * @return  array
 */
function wpd_theme_action_links($links, $theme){
	$dowload_query = build_query(array('wpd' => 'theme', 'object' => $theme->get_stylesheet()));
	$download_link = sprintf('<a href="%s">%s</a>',
		wp_nonce_url(admin_url('?' . $dowload_query), 'wpd-download'),
		__('Download')
	);
	
	array_push($links, $download_link); 
	return $links;
}

/**
 * Displays javascript code in the footer of themes.php
 *
 * @return  void
 */
function wpd_scripts(){
	// Download url
	$query = build_query(array('wpd' => 'theme', 'object' => '_obj_'));
	$url = wp_nonce_url(admin_url('?' . $query), 'wpd-download');
	// Label used for download links
	$label = __('Download');
	// Current theme
	$current_theme = get_stylesheet();

	$script_template = '<script type="text/javascript" id="wp-downloader">
		(function($){
			var url = "%s",
				label = "%s",
				current = "%s",
				button = \'<a class="button button-primary download hide-if-no-js" href="\' + url + \'">\' + label + \'</a>\';
			
			
			$(window).load(function(){			
				// For current theme in wordpress <3.8
				$("#current-theme .theme-options").after(\'<div class="theme-options"><a href="\' + url.replace("_obj_", current) + \'">\' + label + \'</a></div>\');

				// Add download button for each theme on the themes page
				$("#wpbody .theme .theme-actions .load-customize").each(function(i, e){
					var btn = $(button),
						$e = $(e),
						href = $e.prop("href");

					btn.prop("href", url.replace("_obj_", href.replace(/.*theme=(.*)(&|$)/, "$1")));

					$e.parent().append(btn);
				});
			});

			// Modify single theme template to add the download button
			var d = $("#tmpl-theme-single").html(),
			   	ar = new RegExp(\'(<div class="active-theme">)(([\n\t]*(<#|<a).*[\n\t]*)*)(</div>)\', "mi");
			   	ir = new RegExp(\'(<div class="inactive-theme">)(([\n\t]*(<#|<a).*[\n\t]*)*)(</div>)\', "mi");

			d = d.replace(ar, "$1$2" + button + "$5");
			d = d.replace(ir, "$1$2" + button + "$5");

			$("#tmpl-theme-single").html(d);

			$(document).on("click", "a.button.download", function(e){
				e.preventDefault();
				var $this = $(this),
					href = $(this).parent().find(".load-customize").attr("href"),
					theme;

				theme = href.replace(/.*theme=(.*)(&|$)/, "$1");
				href = url.replace("_obj_", theme).replace(new RegExp("&amp;", "g"), "&");
				
				window.location = href;
			});
		}(jQuery))
	</script>';
	
	// Print javascript
	printf($script_template, $url, $label, $current_theme);
}

/**
 * Handles the download
 *
 * @return  array
 */
function wpd_download(){
	if(!class_exists('PclZip')){
		// Load class file if it's not loaded yet
		include ABSPATH . 'wp-admin/includes/class-pclzip.php';
	}

	// Kind of object we download (theme or plugin)
	$what = $_GET['wpd'];
	// The name of object
	$object = $_GET['object'];

	// Prepare object name and root path for given object type
	switch($what){
		case 'plugin':
			if(strpos($object, '/')){
				$object = dirname($object);
			}
			$root = WP_PLUGIN_DIR;
			break;
		case 'muplugin':
			if(strpos($object, '/')){
				$object = dirname($object);
			}
			$root = WPMU_PLUGIN_DIR;
			break;
		case 'theme':
			$root = get_theme_root($object);
			break;
		default:
			// bad URL
			wp_die('Cheatin&#8217; uh?');
	}
	
	$object = sanitize_file_name($object);
	if(empty($object))
		// No object name
		wp_die('Cheatin&#8217; uh?');

	// Prepare full path do the desired object
	$path = $root . '/' . $object;
	// Filename for a zip package
	$fileName = $object . '.zip';
	
	// Temporary file name in upload dir
	$upload_dir = wp_upload_dir();
	$tmpFile = trailingslashit($upload_dir['path']) . $fileName;

	// Create new archive
	$archive = new PclZip($tmpFile);
	// Add entire folder to the archive
	$archive->add($path, PCLZIP_OPT_REMOVE_PATH, $root);

	// Set headers for the zip archive
	header('Content-type: application/zip');
	header('Content-Disposition: attachment; filename="'.$fileName.'"');
	
	// Read file content directly
	readfile($tmpFile);
	// Remove zip file
	unlink($tmpFile);

	// Exit. No wp_die(), it produces HTML
	exit;
}