<?php

/**
 * A class to rapid develop meta boxes for custom & built in content types
 * Piggybacks on WordPress
 *
 * @author  Tran Ngoc Tuan Anh <rilwis@gmail.com>
 * @license GNU GPL2+
 * @package Meta Box
 */
class RW_Meta_Box
{
	/**
	 * @var array Meta box information
	 */
	public $meta_box;

	/**
	 * @var array Fields information
	 */
	public $fields;

	/**
	 * @var array Contains all field types of current meta box
	 */
	public $types;

	/**
	 * @var bool Used to prevent duplicated calls like revisions, manual hook to wp_insert_post, etc.
	 */
	public $saved = false;

	/**
	 * Create meta box based on given data
	 * @param array $meta_box Meta box definition
	 */
	function __construct( $meta_box )
	{
		// Run script only in admin area
		if ( ! is_admin() )
			return;

		$meta_box           = self::normalize( $meta_box );
		$meta_box['fields'] = self::normalize_fields( $meta_box['fields'] );

		$this->meta_box = $meta_box;
		$this->fields   = &$this->meta_box['fields'];

		// Allow users to show/hide meta box
		// 1st action applies to all meta boxes
		// 2nd action applies to only current meta box
		$show = true;
		$show = apply_filters( 'rwmb_show', $show, $this->meta_box );
		$show = apply_filters( "rwmb_show_{$this->meta_box['id']}", $show, $this->meta_box );
		if ( ! $show )
			return;

		// Enqueue common styles and scripts
		add_action( 'admin_enqueue_scripts', array( $this, 'admin_enqueue_scripts' ) );

		// Add additional actions for fields
		$fields = self::get_fields( $this->fields );
		foreach ( $fields as $field )
		{
			call_user_func( array( self::get_class_name( $field ), 'add_actions' ) );
		}

		// Add meta box
		add_action( 'add_meta_boxes', array( $this, 'add_meta_boxes' ) );

		// Hide meta box if it's set 'default_hidden'
		add_filter( 'default_hidden_meta_boxes', array( $this, 'hide' ), 10, 2 );

		// Save post meta
		foreach ( $this->meta_box['post_types'] as $post_type )
		{
			if ( 'attachment' === $post_type )
			{
				// Attachment uses other hooks
				// @see wp_update_post(), wp_insert_attachment()
				add_action( 'edit_attachment', array( $this, 'save_post' ) );
				add_action( 'add_attachment', array( $this, 'save_post' ) );
			}
			else
			{
				add_action( "save_post_{$post_type}", array( $this, 'save_post' ) );
			}
		}
	}

	/**
	 * Enqueue common styles
	 *
	 * @return void
	 */
	function admin_enqueue_scripts()
	{
		if ( ! $this->is_edit_screen() )
			return;

		wp_enqueue_style( 'rwmb', RWMB_CSS_URL . 'style.css', array(), RWMB_VER );
		if( is_rtl() )
			wp_enqueue_style( 'rwmb-rtl', RWMB_CSS_URL . 'style-rtl.css', array(), RWMB_VER );

		// Load clone script conditionally
		$fields = self::get_fields( $this->fields );
		foreach ( $fields as $field )
		{
			if ( $field['clone'] )
			{
				wp_enqueue_script( 'rwmb-clone', RWMB_JS_URL . 'clone.js', array( 'jquery-ui-sortable' ), RWMB_VER, true );
				break;
			}
		}

		// Enqueue scripts and styles for fields
		foreach ( $fields as $field )
		{
			call_user_func( array( self::get_class_name( $field ), 'admin_enqueue_scripts' ) );
		}

		// Auto save
		if ( $this->meta_box['autosave'] )
			wp_enqueue_script( 'rwmb-autosave', RWMB_JS_URL . 'autosave.js', array( 'jquery' ), RWMB_VER, true );

		/**
		 * Allow developers to enqueue more scripts and styles
		 *
		 * @param RW_Meta_Box $object Meta Box object
		 */
		do_action( 'rwmb_enqueue_scripts', $this );
	}

	/**
	 * Get all fields of a meta box, recursively
	 *
	 * @param array $fields
	 *
	 * @return array
	 */
	static function get_fields( $fields )
	{
		$all_fields = array();
		foreach ( $fields as $field )
		{
			$all_fields[] = $field;
			if ( isset( $field['fields'] ) )
				$all_fields = array_merge( $all_fields, self::get_fields( $field['fields'] ) );
		}

		return $all_fields;
	}

	/**************************************************
	 * SHOW META BOX
	 **************************************************/

	/**
	 * Add meta box for multiple post types
	 *
	 * @return void
	 */
	function add_meta_boxes()
	{
		foreach ( $this->meta_box['post_types'] as $post_type )
		{
			add_meta_box(
				$this->meta_box['id'],
				$this->meta_box['title'],
				array( $this, 'show' ),
				$post_type,
				$this->meta_box['context'],
				$this->meta_box['priority']
			);
		}
	}

	/**
	 * Hide meta box if it's set 'default_hidden'
	 *
	 * @param array  $hidden Array of default hidden meta boxes
	 * @param object $screen Current screen information
	 *
	 * @return array
	 */
	function hide( $hidden, $screen )
	{
		if ( $this->is_edit_screen( $screen ) && $this->meta_box['default_hidden'] )
		{
			$hidden[] = $this->meta_box['id'];
		}

		return $hidden;
	}

	/**
	 * Callback function to show fields in meta box
	 *
	 * @return void
	 */
	function show()
	{
		$saved = $this->is_saved();

		// Container
		printf(
			'<div class="rwmb-meta-box" data-autosave="%s">',
			$this->meta_box['autosave'] ? 'true' : 'false'
		);

		wp_nonce_field( "rwmb-save-{$this->meta_box['id']}", "nonce_{$this->meta_box['id']}" );

		// Allow users to add custom code before meta box content
		// 1st action applies to all meta boxes
		// 2nd action applies to only current meta box
		do_action( 'rwmb_before', $this );
		do_action( "rwmb_before_{$this->meta_box['id']}", $this );

		foreach ( $this->fields as $field )
		{
			call_user_func( array( self::get_class_name( $field ), 'show' ), $field, $saved );
		}

		// Allow users to add custom code after meta box content
		// 1st action applies to all meta boxes
		// 2nd action applies to only current meta box
		do_action( 'rwmb_after', $this );
		do_action( "rwmb_after_{$this->meta_box['id']}", $this );

		// End container
		echo '</div>';
	}

	/**************************************************
	 * SAVE META BOX
	 **************************************************/

	/**
	 * Save data from meta box
	 *
	 * @param int $post_id Post ID
	 */
	function save_post( $post_id )
	{
		// Check if this function is called to prevent duplicated calls like revisions, manual hook to wp_insert_post, etc.
		if ( true === $this->saved )
			return;
		$this->saved = true;

		// Check whether form is submitted properly
		$nonce = (string) filter_input( INPUT_POST, "nonce_{$this->meta_box['id']}" );
		if ( ! wp_verify_nonce( $nonce, "rwmb-save-{$this->meta_box['id']}" ) )
			return;

		// Autosave
		if ( defined( 'DOING_AUTOSAVE' ) && ! $this->meta_box['autosave'] )
			return;

		// Make sure meta is added to the post, not a revision
		if ( $the_post = wp_is_post_revision( $post_id ) )
			$post_id = $the_post;

		// Before save action
		do_action( 'rwmb_before_save_post', $post_id );
		do_action( "rwmb_{$this->meta_box['id']}_before_save_post", $post_id );

		foreach ( $this->fields as $field )
		{
			$name   = $field['id'];
			$single = $field['clone'] || ! $field['multiple'];
			$old    = get_post_meta( $post_id, $name, $single );
			$new    = isset( $_POST[$name] ) ? $_POST[$name] : ( $single ? '' : array() );

			// Allow field class change the value
			$new = call_user_func( array( self::get_class_name( $field ), 'value' ), $new, $old, $post_id, $field );
			$new = RWMB_Core::filter( 'value', $new, $field, $old );

			// Call defined method to save meta value, if there's no methods, call common one
			call_user_func( array( self::get_class_name( $field ), 'save' ), $new, $old, $post_id, $field );
		}

		// After save action
		do_action( 'rwmb_after_save_post', $post_id );
		do_action( "rwmb_{$this->meta_box['id']}_after_save_post", $post_id );
	}

	/**************************************************
	 * HELPER FUNCTIONS
	 **************************************************/

	/**
	 * Normalize parameters for meta box
	 *
	 * @param array $meta_box Meta box definition
	 *
	 * @return array $meta_box Normalized meta box
	 */
	static function normalize( $meta_box )
	{
		// Set default values for meta box
		$meta_box = wp_parse_args( $meta_box, array(
			'id'             => sanitize_title( $meta_box['title'] ),
			'context'        => 'normal',
			'priority'       => 'high',
			'post_types'     => 'post',
			'autosave'       => false,
			'default_hidden' => false,
		) );

		/**
		 * Use 'post_types' for better understanding and fallback to 'pages' for previous versions
		 * @since 4.4.1
		 */
		if ( ! empty( $meta_box['pages'] ) )
		{
			$meta_box['post_types'] = $meta_box['pages'];
		}

		// Allow to set 'post_types' param by string
		if ( is_string( $meta_box['post_types'] ) )
		{
			$meta_box['post_types'] = array( $meta_box['post_types'] );
		}

		// Allow to add default values for meta box
		$meta_box = apply_filters( 'rwmb_normalize_meta_box', $meta_box );
		$meta_box = apply_filters( "rwmb_normalize_{$meta_box['id']}_meta_box", $meta_box );

		return $meta_box;
	}

	/**
	 * Normalize an array of fields
	 *
	 * @param array $fields Array of fields
	 *
	 * @return array $fields Normalized fields
	 */
	static function normalize_fields( $fields )
	{
		foreach ( $fields as $k => $field )
		{
			$class = self::get_class_name( $field );

			// Make sure field has correct 'type', ignore warning error when users forget to set field type or set incorrect one
			if ( false === $class )
			{
				unset( $fields[$k] );
				continue;
			}

			// Allow field class add/change default field values
			$field = call_user_func( array( $class, 'normalize' ), $field );

			if ( isset( $field['fields'] ) )
				$field['fields'] = self::normalize_fields( $field['fields'] );

			// Allow to add default values for fields
			$field = apply_filters( 'rwmb_normalize_field', $field );
			$field = apply_filters( "rwmb_normalize_{$field['type']}_field", $field );
			$field = apply_filters( "rwmb_normalize_{$field['id']}_field", $field );

			$fields[$k] = $field;
		}

		return $fields;
	}

	/**
	 * Get field class name
	 *
	 * @param array $field Field array
	 * @return string Field class name
	 */
	static function get_class_name( $field )
	{
		$type  = str_replace( array( '-', '_' ), ' ', $field['type'] );
		$class = 'RWMB_' . ucwords( $type ) . '_Field';
		$class = str_replace( ' ', '_', $class );
		return $class;
	}

	/**
	 * Check if meta box is saved before.
	 * This helps saving empty value in meta fields (for text box, check box, etc.) and set the correct default values.
	 *
	 * @return bool
	 */
	public function is_saved()
	{
		$post = get_post();

		foreach ( $this->fields as $field )
		{
			if ( empty( $field['id'] ) )
			{
				continue;
			}
			$value = get_post_meta( $post->ID, $field['id'], ! $field['multiple'] );
			if (
				( ! $field['multiple'] && '' !== $value )
				|| ( $field['multiple'] && array() !== $value )
			)
			{
				return true;
			}
		}

		return false;
	}

	/**
	 * Check if we're on the right edit screen.
	 *
	 * @param WP_Screen $screen Screen object. Optional. Use current screen object by default.
	 *
	 * @return bool
	 */
	function is_edit_screen( $screen = null )
	{
		if ( ! ( $screen instanceof WP_Screen ) )
		{
			$screen = get_current_screen();
		}
		return 'post' == $screen->base && in_array( $screen->post_type, $this->meta_box['post_types'] );
	}
}
