<?php

/**

 * Twenty Fourteen Featured Content

 *

 * This module allows you to define a subset of posts to be displayed

 * in the theme's Featured Content area.

 *

 * For maximum compatibility with different methods of posting users

 * will designate a featured post tag to associate posts with. Since

 * this tag now has special meaning beyond that of a normal tags, users

 * will have the ability to hide it from the front-end of their site.

 */

class Featured_Content {

	/**

	 * The maximum number of posts a Featured Content area can contain.

	 *

	 * We define a default value here but themes can override

	 * this by defining a "max_posts" entry in the second parameter

	 * passed in the call to add_theme_support( 'featured-content' ).

	 *

	 * @see Featured_Content::init()

	 *

	 * @since Twenty Fourteen 1.0

	 *

	 * @static

	 * @access public

	 * @var int

	 */

	public static $max_posts = 15;

	/**

	 * Instantiate.

	 *

	 * All custom functionality will be hooked into the "init" action.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 */

	public static function setup() {

		add_action( 'init', array( __CLASS__, 'init' ), 30 );

	}

	/**

	 * Conditionally hook into WordPress.

	 *

	 * Theme must declare that they support this module by adding

	 * add_theme_support( 'featured-content' ); during after_setup_theme.

	 *

	 * If no theme support is found there is no need to hook into WordPress.

	 * We'll just return early instead.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 */

	public static function init() {

		$theme_support = get_theme_support( 'featured-content' );

		// Return early if theme does not support Featured Content.

		if ( ! $theme_support ) {

			return;

		}

		/*

		 * An array of named arguments must be passed as the second parameter

		 * of add_theme_support().

		 */

		if ( ! isset( $theme_support[0] ) ) {

			return;

		}

		// Return early if "featured_content_filter" has not been defined.

		if ( ! isset( $theme_support[0]['featured_content_filter'] ) ) {

			return;

		}

		$filter = $theme_support[0]['featured_content_filter'];

		// Theme can override the number of max posts.

		if ( isset( $theme_support[0]['max_posts'] ) ) {

			self::$max_posts = absint( $theme_support[0]['max_posts'] );

		}

		add_filter( $filter,                              array( __CLASS__, 'get_featured_posts' )    );

		add_action( 'customize_register',                 array( __CLASS__, 'customize_register' ), 9 );

		add_action( 'admin_init',                         array( __CLASS__, 'register_setting'   )    );

		add_action( 'switch_theme',                       array( __CLASS__, 'delete_transient'   )    );

		add_action( 'save_post',                          array( __CLASS__, 'delete_transient'   )    );

		add_action( 'delete_post_tag',                    array( __CLASS__, 'delete_post_tag'    )    );

		add_action( 'customize_controls_enqueue_scripts', array( __CLASS__, 'enqueue_scripts'    )    );

		add_action( 'pre_get_posts',                      array( __CLASS__, 'pre_get_posts'      )    );

		add_action( 'wp_loaded',                          array( __CLASS__, 'wp_loaded'          )    );

	}

	/**

	 * Hide "featured" tag from the front-end.

	 *

	 * Has to run on wp_loaded so that the preview filters of the Customizer

	 * have a chance to alter the value.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 */

	public static function wp_loaded() {

		if ( self::get_setting( 'hide-tag' ) ) {

			add_filter( 'get_terms',     array( __CLASS__, 'hide_featured_term'     ), 10, 3 );

			add_filter( 'get_the_terms', array( __CLASS__, 'hide_the_featured_term' ), 10, 3 );

		}

	}

	/**

	 * Get featured posts.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 *

	 * @return array Array of featured posts.

	 */

	public static function get_featured_posts() {

		$post_ids = self::get_featured_post_ids();

		// No need to query if there is are no featured posts.

		if ( empty( $post_ids ) ) {

			return array();

		}

		$featured_posts = get_posts( array(

			'include'        => $post_ids,

			'posts_per_page' => count( $post_ids ),

		) );

		return $featured_posts;

	}

	/**

	 * Get featured post IDs

	 *

	 * This function will return the an array containing the

	 * post IDs of all featured posts.

	 *

	 * Sets the "featured_content_ids" transient.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 *

	 * @return array Array of post IDs.

	 */

	public static function get_featured_post_ids() {

		// Get array of cached results if they exist.

		$featured_ids = get_transient( 'featured_content_ids' );

		if ( false === $featured_ids ) {

			$settings = self::get_setting();

			$term     = get_term_by( 'name', $settings['tag-name'], 'post_tag' );

			if ( $term ) {

				// Query for featured posts.

				$featured_ids = get_posts( array(

					'fields'           => 'ids',

					'numberposts'      => self::$max_posts,

					'suppress_filters' => false,

					'tax_query'        => array(

						array(

							'field'    => 'term_id',

							'taxonomy' => 'post_tag',

							'terms'    => $term->term_id,

						),

					),

				) );

			}

			// Get sticky posts if no Featured Content exists.

			if ( ! $featured_ids ) {

				$featured_ids = self::get_sticky_posts();

			}

			set_transient( 'featured_content_ids', $featured_ids );

		}

		// Ensure correct format before return.

		return array_map( 'absint', $featured_ids );

	}

	/**

	 * Return an array with IDs of posts maked as sticky.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 *

	 * @return array Array of sticky posts.

	 */

	public static function get_sticky_posts() {

		return array_slice( get_option( 'sticky_posts', array() ), 0, self::$max_posts );

	}

	/**

	 * Delete featured content ids transient.

	 *

	 * Hooks in the "save_post" action.

	 *

	 * @see Featured_Content::validate_settings().

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 */

	public static function delete_transient() {

		delete_transient( 'featured_content_ids' );

	}

	/**

	 * Exclude featured posts from the home page blog query.

	 *

	 * Filter the home page posts, and remove any featured post ID's from it.

	 * Hooked onto the 'pre_get_posts' action, this changes the parameters of

	 * the query before it gets any posts.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 *

	 * @param WP_Query $query WP_Query object.

	 * @return WP_Query Possibly-modified WP_Query.

	 */

	public static function pre_get_posts( $query ) {

		// Bail if not home or not main query.

		if ( ! $query->is_home() || ! $query->is_main_query() ) {

			return;

		}

		// Bail if the blog page is not the front page.

		if ( 'posts' !== get_option( 'show_on_front' ) ) {

			return;

		}

		$featured = self::get_featured_post_ids();

		// Bail if no featured posts.

		if ( ! $featured ) {

			return;

		}

		// We need to respect post ids already in the blacklist.

		$post__not_in = $query->get( 'post__not_in' );

		if ( ! empty( $post__not_in ) ) {

			$featured = array_merge( (array) $post__not_in, $featured );

			$featured = array_unique( $featured );

		}

		$query->set( 'post__not_in', $featured );

	}

	/**

	 * Reset tag option when the saved tag is deleted.

	 *

	 * It's important to mention that the transient needs to be deleted,

	 * too. While it may not be obvious by looking at the function alone,

	 * the transient is deleted by Featured_Content::validate_settings().

	 *

	 * Hooks in the "delete_post_tag" action.

	 *

	 * @see Featured_Content::validate_settings().

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 *

	 * @param int $tag_id The term_id of the tag that has been deleted.

	 */

	public static function delete_post_tag( $tag_id ) {

		$settings = self::get_setting();

		if ( empty( $settings['tag-id'] ) || $tag_id != $settings['tag-id'] ) {

			return;

		}

		$settings['tag-id'] = 0;

		$settings = self::validate_settings( $settings );

		update_option( 'featured-content', $settings );

	}

	/**

	 * Hide featured tag from displaying when global terms are queried from the front-end.

	 *

	 * Hooks into the "get_terms" filter.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 *

	 * @param array $terms      List of term objects. This is the return value of get_terms().

	 * @param array $taxonomies An array of taxonomy slugs.

	 * @return array A filtered array of terms.

	 *

	 * @uses Featured_Content::get_setting()

	 */

	public static function hide_featured_term( $terms, $taxonomies, $args ) {

		// This filter is only appropriate on the front-end.

		if ( is_admin() ) {

			return $terms;

		}

		// We only want to hide the featured tag.

		if ( ! in_array( 'post_tag', $taxonomies ) ) {

			return $terms;

		}

		// Bail if no terms were returned.

		if ( empty( $terms ) ) {

			return $terms;

		}

		// Bail if term objects are unavailable.

		if ( 'all' != $args['fields'] ) {

			return $terms;

		}

		$settings = self::get_setting();

		foreach ( $terms as $order => $term ) {

			if ( ( $settings['tag-id'] === $term->term_id || $settings['tag-name'] === $term->name ) && 'post_tag' === $term->taxonomy ) {

				unset( $terms[ $order ] );

			}

		}

		return $terms;

	}

	/**

	 * Hide featured tag from display when terms associated with a post object

	 * are queried from the front-end.

	 *

	 * Hooks into the "get_the_terms" filter.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 *

	 * @param array $terms    A list of term objects. This is the return value of get_the_terms().

	 * @param int   $id       The ID field for the post object that terms are associated with.

	 * @param array $taxonomy An array of taxonomy slugs.

	 * @return array Filtered array of terms.

	 *

	 * @uses Featured_Content::get_setting()

	 */

	public static function hide_the_featured_term( $terms, $id, $taxonomy ) {

		// This filter is only appropriate on the front-end.

		if ( is_admin() ) {

			return $terms;

		}

		// Make sure we are in the correct taxonomy.

		if ( 'post_tag' != $taxonomy ) {

			return $terms;

		}

		// No terms? Return early!

		if ( empty( $terms ) ) {

			return $terms;

		}

		$settings = self::get_setting();

		foreach ( $terms as $order => $term ) {

			if ( ( $settings['tag-id'] === $term->term_id || $settings['tag-name'] === $term->name ) && 'post_tag' === $term->taxonomy ) {

				unset( $terms[ $term->term_id ] );

			}

		}

		return $terms;

	}

	/**

	 * Register custom setting on the Settings -> Reading screen.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 */

	public static function register_setting() {

		register_setting( 'featured-content', 'featured-content', array( __CLASS__, 'validate_settings' ) );

	}

	/**

	 * Add settings to the Customizer.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 *

	 * @param WP_Customize_Manager $wp_customize Customizer object.

	 */

	public static function customize_register( $wp_customize ) {

		$wp_customize->add_section( 'featured_content', array(

			'title'          => __( 'Featured Content', 'twentyfourteen' ),

			'description'    => sprintf( __( 'Use a <a href="%1$s">tag</a> to feature your posts. If no posts match the tag, <a href="%2$s">sticky posts</a> will be displayed instead.', 'twentyfourteen' ),

				esc_url( add_query_arg( 'tag', _x( 'featured', 'featured content default tag slug', 'twentyfourteen' ), admin_url( 'edit.php' ) ) ),

				admin_url( 'edit.php?show_sticky=1' )

			),

			'priority'       => 130,

			'theme_supports' => 'featured-content',

		) );

		// Add Featured Content settings.

		$wp_customize->add_setting( 'featured-content[tag-name]', array(

			'default'              => _x( 'featured', 'featured content default tag slug', 'twentyfourteen' ),

			'type'                 => 'option',

			'sanitize_js_callback' => array( __CLASS__, 'delete_transient' ),

		) );

		$wp_customize->add_setting( 'featured-content[hide-tag]', array(

			'default'              => true,

			'type'                 => 'option',

			'sanitize_js_callback' => array( __CLASS__, 'delete_transient' ),

		) );

		// Add Featured Content controls.

		$wp_customize->add_control( 'featured-content[tag-name]', array(

			'label'    => __( 'Tag Name', 'twentyfourteen' ),

			'section'  => 'featured_content',

			'priority' => 20,

		) );

		$wp_customize->add_control( 'featured-content[hide-tag]', array(

			'label'    => __( 'Don’t display tag on front end.', 'twentyfourteen' ),

			'section'  => 'featured_content',

			'type'     => 'checkbox',

			'priority' => 30,

		) );

	}

	/**

	 * Enqueue the tag suggestion script.

	 *

	 * @static

	 * @access public

	 * @since Twenty Fourteen 1.0

	 */

	public static function enqueue_scripts() {