WordPress/wp-admin/themes.php

<?php
require_once('admin.php');

if ( isset($_GET['action']) ) {
	check_admin_referer('switch-theme_' . $_GET['template']);

	if ('activate' == $_GET['action']) {
		switch_theme($_GET['template'], $_GET['stylesheet']);
		wp_redirect('themes.php?activated=true');
		exit;
	}
}

$title = __('Manage Themes');
$parent_file = 'themes.php';

add_thickbox();
wp_enqueue_script( 'theme-preview' );

require_once('admin-header.php');
?>

<?php if ( ! validate_current_theme() ) : ?>
<div id="message1" class="updated fade"><p><?php _e('The active theme is broken.  Reverting to the default theme.'); ?></p></div>
<?php elseif ( isset($_GET['activated']) ) : ?>
<div id="message2" class="updated fade"><p><?php printf(__('New theme activated. <a href="%s">Visit site</a>'), get_bloginfo('url') . '/'); ?></p></div>
<?php endif; ?>

<?php
$themes = get_themes();
$ct = current_theme_info();

ksort( $themes );
$theme_total = count( $themes );
$per_page = 15;

if ( isset( $_GET['pagenum'] ) )
	$page = absint( $_GET['pagenum'] );

if ( empty($page) )
	$page = 1;

$start = $offset = ( $page - 1 ) * $per_page;

$page_links = paginate_links( array(
	'base' => add_query_arg( 'pagenum', '%#%' ) . '#themenav',
	'format' => '',
	'total' => ceil($theme_total / $per_page),
	'current' => $page
));

$themes = array_slice( $themes, $start, $per_page );

?>

<div class="wrap">
<h2><?php _e('Current Theme'); ?></h2>
<div id="current-theme">
<?php if ( $ct->screenshot ) : ?>
<img src="<?php echo get_option('siteurl') . '/' . $ct->stylesheet_dir . '/' . $ct->screenshot; ?>" alt="<?php _e('Current theme preview'); ?>" />
<?php endif; ?>
<h3><?php printf(_c('%1$s %2$s by %3$s|1: theme title, 2: theme version, 3: theme author'), $ct->title, $ct->version, $ct->author) ; ?></h3>
<p class="description"><?php echo $ct->description; ?></p>
<?php if ($ct->parent_theme) { ?>
	<p><?php printf(__('The template files are located in <code>%2$s</code>.  The stylesheet files are located in <code>%3$s</code>.  <strong>%4$s</strong> uses templates from <strong>%5$s</strong>.  Changes made to the templates will affect both themes.'), $ct->title, $ct->template_dir, $ct->stylesheet_dir, $ct->title, $ct->parent_theme); ?></p>
<?php } else { ?>
	<p><?php printf(__('All of this theme&#8217;s files are located in <code>%2$s</code>.'), $ct->title, $ct->template_dir, $ct->stylesheet_dir); ?></p>
<?php } ?>
<?php if ( $ct->tags ) : ?>
<p><?php _e('Tags:'); ?> <?php echo join(', ', $ct->tags); ?></p>
<?php endif; ?>
</div>

<h2><?php _e('Available Themes'); ?></h2>
<br class="clear" />

<?php if ( $page_links ) : ?>
<div class="tablenav">
<?php echo "<div class='tablenav-pages'>$page_links</div>"; ?>
<br class="clear" />
</div>
<br class="clear" />
<?php endif; ?>

<?php if ( 1 < $theme_total ) { ?>
<table id="availablethemes" cellspacing="0" cellpadding="0">
<?php
$style = '';

$theme_names = array_keys($themes);
natcasesort($theme_names);

$rows = ceil(count($theme_names) / 3);
for ( $row = 1; $row <= $rows; $row++ )
	for ( $col = 1; $col <= 3; $col++ )
		$table[$row][$col] = array_shift($theme_names);

foreach ( $table as $row => $cols ) {
?>
<tr>
<?php
foreach ( $cols as $col => $theme_name ) {
	$class = array('available-theme');
	if ( $row == 1 ) $class[] = 'top';
	if ( $col == 1 ) $class[] = 'left';
	if ( $row == $rows ) $class[] = 'bottom';
	if ( $col == 3 ) $class[] = 'right';
?>
	<td class="<?php echo join(' ', $class); ?>">
<?php if ( !empty($theme_name) ) :
	$template = $themes[$theme_name]['Template'];
	$stylesheet = $themes[$theme_name]['Stylesheet'];
	$title = $themes[$theme_name]['Title'];
	$version = $themes[$theme_name]['Version'];
	$description = $themes[$theme_name]['Description'];
	$author = $themes[$theme_name]['Author'];
	$screenshot = $themes[$theme_name]['Screenshot'];
	$stylesheet_dir = $themes[$theme_name]['Stylesheet Dir'];
	$preview_link = clean_url( get_option('home') . '/');
	$preview_link = add_query_arg( array('preview' => 1, 'template' => $template, 'stylesheet' => $stylesheet, 'TB_iframe' => 'true', 'width' => 600, 'height' => 400 ), $preview_link );
	$preview_text = attribute_escape( sprintf( __('Preview of "%s"'), $title ) );
	$tags = $themes[$theme_name]['Tags'];
	$thickbox_class = 'thickbox';
	$activate_link = wp_nonce_url("themes.php?action=activate&amp;template=".urlencode($template)."&amp;stylesheet=".urlencode($stylesheet), 'switch-theme_' . $template);
	$activate_text = attribute_escape( sprintf( __('Activate "%s"'), $title ) );
?>
		<a href="<?php echo $activate_link; ?>" class="<?php echo $thickbox_class; ?> screenshot">
<?php if ( $screenshot ) : ?>
			<img src="<?php echo ( $tpage == 'stage' ) ? $screenshot : get_option('siteurl') . '/' . $stylesheet_dir . '/' . $screenshot; ?>" alt="" />
<?php endif; ?>
		</a>
		<h3><a class="<?php echo $thickbox_class; ?>" href="<?php echo $activate_link; ?>"><?php echo $title; ?></a></h3>
		<p><?php echo $description; ?></p>
<?php if ( $tags ) : ?>
		<p><?php _e('Tags:'); ?> <?php echo join(', ', $tags); ?></p>
		<noscript><p class="themeactions"><a href="<?php echo $preview_link; ?>" title="<?php echo $preview_text; ?>"><?php _e('Preview'); ?></a> <a href="<?php echo $activate_link; ?>" title="<?php echo $activate_text; ?>"><?php _e('Activate'); ?></a></p></noscript>
<?php endif; ?>
		<div style="display:none;"><a class="previewlink" href="<?php echo $preview_link; ?>"><?php echo $preview_text; ?></a> <a class="activatelink" href="<?php echo $activate_link; ?>"><?php echo $activate_text; ?></a></div>
<?php endif; // end if not empty theme_name ?>
	</td>
<?php } // end foreach $cols ?>
</tr>
<?php } // end foreach $table ?>
</table>
<?php } ?>

<br class="clear" />

<?php if ( $page_links ) : ?>
<div class="tablenav">
<?php echo "<div class='tablenav-pages'>$page_links</div>"; ?>
<br class="clear" />
</div>
<?php endif; ?>

<br class="clear" />

<?php
// List broken themes, if any.
$broken_themes = get_broken_themes();
if ( count($broken_themes) ) {
?>

<h2><?php _e('Broken Themes'); ?></h2>
<p><?php _e('The following themes are installed but incomplete.  Themes must have a stylesheet and a template.'); ?></p>

<table width="100%" cellpadding="3" cellspacing="3">
	<tr>
		<th><?php _e('Name'); ?></th>
		<th><?php _e('Description'); ?></th>
	</tr>
<?php
	$theme = '';

	$theme_names = array_keys($broken_themes);
	natcasesort($theme_names);

	foreach ($theme_names as $theme_name) {
		$title = $broken_themes[$theme_name]['Title'];
		$description = $broken_themes[$theme_name]['Description'];

		$theme = ('class="alternate"' == $theme) ? '' : 'class="alternate"';
		echo "
		<tr $theme>
			 <td>$title</td>
			 <td>$description</td>
		</tr>";
	}
?>
</table>
<?php
}
?>

<h2><?php _e('Get More Themes'); ?></h2>
<p><?php _e('You can find additional themes for your site in the <a href="http://wordpress.org/extend/themes/">WordPress theme directory</a>. To install a theme you generally just need to upload the theme folder into your <code>wp-content/themes</code> directory. Once a theme is uploaded, you should see it on this page.'); ?></p>

</div>

<?php require('admin-footer.php'); ?>