<?php
/**
 * @package Duplicate_Widget
 * @author Scott Reilly
 * @version 1.0.2
 */
/*
Plugin Name: Duplicate Widget
Version: 1.0.2
Plugin URI: http://coffee2code.com/wp-plugins/duplicate-widget/
Author: Scott Reilly
Author URI: http://coffee2code.com/
Text Domain: duplicate-widget
Domain Path: /lang/
License: GPLv2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
Description: A widget that can act as a duplicate of another widget (for synchronized use in another sidebar)

Compatible with WordPress 3.1 through 3.4+.

=>> Read the accompanying readme.txt file for instructions and documentation.
=>> Also, visit the plugin's homepage for additional information and updates.
=>> Or visit: http://wordpress.org/extend/plugins/duplicate-widget/

TODO:
	* More dynamic updating via JS (maybe)
		* Add "[D]" and widget blurb (if not present) to widget after it is selected as the source widget for a duplicate
		* Remove "[D]" and widget blurb if final duplicate of widget is deleted
		* Immediately delete duplicates of a widget that gets deleted or deactivated
	* When clicking the dropdown, can check some JS flag that gets set when a widget gets activated/deactivated which causes the dropdown to be regenerated via AJAX (or simply always refresh it via AJAX)
	* Track down possible bug where source widget claims to have dupes, but it doesn't really anymore
	* Way to locate/highlight duplicates of a widget
*/

/*
	Copyright (c) 2010-2012 by Scott Reilly (aka coffee2code)

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

if ( ! class_exists( 'c2c_DuplicateWidget' ) ) :

class c2c_DuplicateWidget extends WP_Widget {

	private static $title          = '';
	private static $current        = null;
	private static $widget_id      = 'duplicate_widget';
	private static $input_name     = 'widget_to_duplicate';

	// For memoization
	private static $_duplicates    = array();
	private static $_sidebar_names = array();
	private static $_titles        = array();
	private static $_widgets       = array();

	/**
	 * Returns version of the plugin.
	 */
	public static function version() {
		return '1.0.2';
	}

	/**
	 * Initializes the widget.
	 */
	public static function init() {
		// Register the widget
		add_action( 'widgets_init',     array( __CLASS__, '__register' ) );
		// Output message at bottom of widgets that have been duplicated to make note of such
		add_action( 'in_widget_form',   array( __CLASS__, 'note_duplicates' ), 10, 3 );
		// Load localization
		add_action( 'admin_init',       array( __CLASS__, 'load_textdomain' ) );
		// Stuff to only do on the widgets admin page
		add_action( 'load-widgets.php', array( __CLASS__, 'widgets_page_actions' ) );
	}

	/**
	 * Registers the widget.
	 */
	public static function __register() {
		register_widget( __CLASS__ );
	}

	/**
	 * Loads the localization textdomain for the plugin.
	 *
	 * Translations go into 'lang' sub-directory.
	 *
	 * @return void
	 */
	public static function load_textdomain() {
		load_plugin_textdomain( 'duplicate-widget', false, basename( dirname( __FILE__ ) ) . DIRECTORY_SEPARATOR . 'lang' );
	}

	/**
	 * Triggers hooks intended to fire on admin widgets.php page.
	 */
	public static function widgets_page_actions() {
		// Enqueue JS to make an indicator in titlebar of duplicated widgets
		add_action( 'admin_enqueue_scripts', array( __CLASS__, 'enqueue_admin_js' ) );
		// Clean up any duplicates whose source widget is no longer active
		add_action( 'admin_init',            array( __CLASS__, 'delete_lame_dupes' ) );
	}

	/**
	 * Enqueues admin JS to make an indicator in titlebar of duplicated widgets.
	 */
	public static function enqueue_admin_js() {
		wp_enqueue_script( 'jquery' );
		wp_enqueue_script( self::$widget_id, plugins_url( 'js/admin.js', __FILE__ ), array( 'jquery' ), '0.1', true );
		$strings = array(
			'widget_is_duplicated' => __( 'This widget is duplicated elsewhere.', 'duplicate-widget' ),
			'notation'             => __( '[D]', 'duplicate-widget' )
		);
		wp_localize_script( self::$widget_id, self::$widget_id, $strings );
	}

	/**
	 * Returns a list of all active, non-duplicate widgets across all sidebars.
	 *
	 * Also incidentally stores a listing of all duplicate widgets.
	 *
	 * @return array Array of all widgets
	 */
	public static function get_widgets() {
		if ( ! empty( self::$_widgets ) ) // Return memoized result if it's there
			return self::$_widgets;

		// Note: wp_get_sidebars_widgets() is noted as being a private function.
		// I'd rather use it than to access data from globals and recreate logic
		$sidebars_with_widgets = wp_get_sidebars_widgets();
		$sidebars_widgets      = array();
		$duplicate_widgets     = array();

		foreach ( $sidebars_with_widgets as $sidebar => $widgets ) {
			if ( 'wp_inactive_widgets' == $sidebar || is_null( $widgets ) )
				continue;

			foreach ( $widgets as $widget ) {
				if ( strpos( $widget, self::$widget_id . '-' ) !== 0 )
					$sidebars_widgets[] = $widget;
				else // Record the duplicate widgets for possible other use
					$duplicate_widgets[] = $widget;
			}
		}

		self::$_duplicates = $duplicate_widgets;
		self::$_widgets    = $sidebars_widgets;
		return self::$_widgets;
	}

	/**
	 * Returns an array of all duplicate widgets.
	 *
	 * Note: get_widgets() actually obtains and stores all duplicate widgets,
	 * so this method defers to that one.
	 *
	 * @return array All duplicate widgets
	 */
	public static function get_duplicate_widgets() {
		self::get_widgets();
		return self::$_duplicates;
	}

	/**
	 * Returns the title for the specified active widget.
	 *
	 * @param string $widget_id The id of the widget
	 * @return string The title for the specified active widget
	 */
	public static function get_widget_title( $widget_id ) {
		global $wp_registered_widgets;

		if ( empty( $widget_id ) || ! isset( $wp_registered_widgets[$widget_id] ) )
			return;

		if ( isset( self::$_titles[$widget_id] ) )
			return self::$_titles[$widget_id];

		$widget_num = explode( '-', $widget_id );
		$widget_num = end( $widget_num );

		$instance = get_option( $wp_registered_widgets[$widget_id]['callback'][0]->option_name );

		if ( is_array( $instance ) && array_key_exists( $widget_num, $instance ) )
			$title = $instance[$widget_num]['title'];
		else
			$title = '';

		self::$_titles[$widget_id] = $title;
		return $title;
	}

	/**
	 * Returns the markup for the <select> HTML tag and its <option> tags to
	 * select from the active widgets to duplicate.
	 *
	 * @param array $widgets (optional) The widgets to list in the dropdown. If not provided, get_widgets() will be called to get all active widgets.
	 * @param string $value (optional) The current value selected
	 * @return string The HTML for the <select>
	 */
	public function get_widgets_dropdown( $widgets = array(), $value = '' ) {
		global $wp_registered_widgets;

		if ( empty( $widgets ) )
			$widgets = self::get_widgets();

		$opt        = self::$input_name;
		$input_id   = $this->get_field_id( $opt );
		$input_name = $this->get_field_name( $opt );

		$html = "<select name='$input_name' id='$input_id'>\n";
		$html .= '<option value="">&#8212; ' . __( 'Choose widget to duplicate', 'duplicate-widget' ) . ' &#8212;</option>';
		foreach ( $widgets as $widget ) {
			$label = $wp_registered_widgets[$widget]['name'];
			$title = self::get_widget_title( $widget );
			if ( ! empty( $title ) )
				$label .= ": $title";
			$label .= ' &#8212; ' . self::get_sidebar_name( self::find_sidebar_for_widget( $widget ) ) . '';
			$selected = $value == $widget ? " selected='selected'" : '';
			$html .= '<option value="' . $widget . '" ' . $selected . '">' . $label . "</option>\n";
		}
		$html .= "</select>\n";
		return $html;
	}

	/**
	 * Returns boolean indicating if the specified widget is active.
	 *
	 * @param string $widget_id The id of the widget
	 * @return bool True if the widget is active; false otherwise
	 */
	public static function is_widget_active( $widget_id ) {
		global $wp_registered_widgets;

		if ( ! isset( $wp_registered_widgets[$widget_id] ) )
			return false;

		return is_active_widget( $wp_registered_widgets[$widget_id]['callback'], $widget_id, false, false );
	}

	/**
	 * Returns the id of the sidebar containing the specified widget.
	 *
	 * @param int $widget_id Id of the widget
	 * @return int|null The sidebar id, if one was found to contain widget_id; otherwise null
	 */
	public static function find_sidebar_for_widget( $widget_id ) {
		$sidebars = wp_get_sidebars_widgets(); // NOTE: This is a private method

		foreach ( $sidebars as $sidebar => $widgets ) {
			if ( 'wp_inactive_widgets' == $sidebar )
				continue;

			if ( in_array( $widget_id, $widgets ) )
				return $sidebar;
		}
		return null;
	}

	/**
	 * Returns the name of the specified sidebar.
	 *
	 * @param int $sidebar_id ID of the sidebar
	 * @return string The name of the sidebar
	 */
	public static function get_sidebar_name( $sidebar_id ) {
		global $wp_registered_sidebars;
		if ( isset( self::$_sidebar_names[$sidebar_id] ) )
			$name = self::$_sidebar_names[$sidebar_id];
		elseif ( isset( $wp_registered_sidebars[$sidebar_id] ) )
			$name = self::$_sidebar_names[$sidebar_id] = $wp_registered_sidebars[$sidebar_id]['name'];
		else
			$name = '';
		return $name;
	}

	/**
	 * Deletes a widget.
	 *
	 * @param string $widget_id The id of the widget to delete
	 */
	public static function delete_widget( $widget_id ) {
		global $wp_registered_widgets;
		if ( ! isset( $wp_registered_widgets[$widget_id] ) )
			return false;
		$sidebars   = wp_get_sidebars_widgets();
		$sidebar_id = self::find_sidebar_for_widget( $widget_id );
		$sidebar    = isset( $sidebars[$sidebar_id] ) ? $sidebars[$sidebar_id] : array();
		$sidebar    = array_diff( $sidebar, array( $widget_id ) );
		$sidebars[$sidebar_id] = $sidebar;
		wp_set_sidebars_widgets( $sidebars );
		return true;
	}

	/**
	 * Deletes duplicates whose source widgets have been deactivated or deleted.
	 *
	 * Technically there isn't any harm in leaving lame dupes in place. Their
	 * dropdowns will indicate they need a value set since the source isn't
	 * active. Also, the front-end won't show lame dupes. I think it's
	 * nicer to clean things up though, even at the cost of a little time for
	 * processing.
	 */
	public static function delete_lame_dupes() {
		$duplicates = get_option( 'widget_' . self::$widget_id );
		foreach ( $duplicates as $num => $settings ) {
			if ( isset( $settings[self::$input_name] ) && ! self::is_widget_active( $settings[self::$input_name] ) ) {
				self::delete_widget( self::$widget_id . '-' . $num );
			}
		}
	}

	/**
	 * Outputs a source widget.
	 *
	 * The approach used here abides by the before_title, after_title,
	 * before_widget, and after_widget of the duplicate widget's sidebar
	 * (and therefore not those settings for the source widget)
	 *
	 * @param string $source_widget_id The id of the widget being duplicated
	 * @param string $widget_id The id of the duplicate widget
	 * @param array $args The settings for the target sidebar
	 */
	public static function output_widget( $source_widget_id, $widget_id, $args ) {
		global $wp_registered_widgets;

		if ( ! self::is_widget_active( $source_widget_id ) ) {
			self::delete_widget( $widget_id );
			return;
		}

		$callback = $wp_registered_widgets[$source_widget_id]['callback'];

		$parts = explode( '-', $source_widget_id );
		$num = end( $parts );

		// Add some class information that pertains to the source widget (its
		// id and general type are added as additional classes)
		if ( isset( $args['before_widget'] ) ) {
			$more_class = implode( ' ', array( $source_widget_id, $wp_registered_widgets[$source_widget_id]['classname'] ) );
			$args['before_widget'] = preg_replace( '/(class=[\'\"])/', '${1} ' . $more_class . ' ', $args['before_widget'] );
		}

		if ( is_callable( $callback ) )
			call_user_func_array( $callback, array( $args, $num ) );
	}

	/**
	 * Returns a count of the number of duplicates of the specified widget.
	 *
	 * @param string $widget_id The id of the widget
	 * @return integer The number of duplicates of the widget
	 */
	public static function count_duplicates( $widget_id ) {
		$count = 0;

		$duplicates = get_option( 'widget_' . self::$widget_id );
		foreach ( (array) $duplicates as $num => $settings ) {
			if ( isset( $settings[self::$input_name] ) && $settings[self::$input_name] == $widget_id )
				$count += 1;
		}

		return $count;
	}

	/**
	 * Adds a note to widgets that have duplicates.
	 */
	public static function note_duplicates( $obj, $return, $instance ) {
		// Don't do anything if the widget doesn't have any duplicates
		if ( ( $n = self::count_duplicates( $obj->id ) ) == 0 )
			return;

		echo '<p style="font-style:italic;">';
		echo sprintf( _n(
			'<strong>NOTE:</strong> This widget has <strong>%s</strong> duplicate.',
			'<strong>NOTE:</strong> This widget has <strong>%s</strong> duplicates.',
			$n,
			'duplicate-widget' ), $n
		);
		echo ' ';
		echo _n(
			'If you deactivate or delete this widget, that duplicate will be deleted.',
			'If you deactivate or delete this widget, those duplicates will be deleted.',
			$n,
			'duplicate-widget'
		);
		// Output hidden markup that JS will use to insert into the titlebar of duplicated widgets
		echo '<span class="widget_is_duplicated" style="display:none;">[ D(n) ]</span>';
		echo '</p>';
	}


	/* =====================================================================================
	 *
	 * START OF INSTANCE METHODS
	 *
	 * ===================================================================================== */


	/**
	 * Constructor to create widget.
	 */
	public function __construct() {
		self::$title = __( 'Duplicate', 'duplicate-widget' );
		$widget_ops = array(
			'classname'   => 'widget_' . self::$widget_id,
			'description' => __( 'Exact duplicate of any other widget.', 'duplicate-widget' ) . ' ' .
							 __( '(If the source widget gets deactivated or deleted, its duplicate(s) disappear.)', 'duplicate-widget' )
		);
		$control_ops = array( 'width' => '300' );
		parent::__construct( self::$widget_id, self::$title, $widget_ops, $control_ops );
	}

	/**
	 * Outputs the widget on the front-end.
	 *
	 * @param array $args Array of arguments
	 * @param array $instance Array of instance settings
	 */
	public function widget( $args, $instance ) {
		// Show nothing if the widget doesn't have any saved settings
		if ( ! isset( $instance[self::$input_name] ) )
			return;

		do_action( 'c2c_before_duplicate_widget', $instance, $args );

		self::output_widget( $instance[self::$input_name], $this->id, $args );

		do_action( 'c2c_after_duplicate_widget', $instance, $args );
	}

	/**
	 * Validates the widget before changes get saved.
	 *
	 * Namely, this ensures the widget being duplicated is active.
	 *
	 * @param array $new_instance Array of new setting values
	 * @param array $old_instance Array of old setting values
	 * @return array|false If the settings are valid, the array is returned; otherwise false is returned
	 */
	public function update( $new_instance, $old_instance ) {
		$widget_id = $new_instance[self::$input_name];

		if ( ! empty( $old_instance ) && ! self::is_widget_active( $widget_id ) )
			return false;

		// Save the title as the title of the source widget
		$new_instance['title'] = strip_tags( self::get_widget_title( $widget_id ) );

		return $new_instance;
	}

	/**
	 * Outputs configuration form for the widget.
	 *
	 * @param array $instance Array of instance settings
	 */
	public function form( $instance ) {
		$value = ( isset( $instance[self::$input_name] ) ? $instance[self::$input_name] : '' );
		$title = ( empty( $value ) ? '' : esc_attr( $instance['title'] ) );

		echo "<div class='duplicate_widget_form'>";

		do_action( 'c2c_before_duplicate_widget_form', $instance );

		echo '<input type="hidden" id="' . $this->get_field_id( 'title' ) . '"name="' . $this->get_field_name( 'title' ). '" value="' . $title . '" />';
		echo $this->get_widgets_dropdown( null, $value );

		echo '<p class="description">';
		_e( 'Each dropdown item specifies the name/title of the original widget followed by the name of the sidebar containing that widget.' );
		echo '</p>';
		do_action( 'c2c_after_duplicate_widget_form', $instance );

		echo "</div>";
	}
}

c2c_DuplicateWidget::init();

endif;