<?php

class VideoPressHQPlaylist {
	public const TAXONOMY_NAME = 'vp-playlist';

	public const META_ITEMS_ORDER = 'vp_playlist_items_order';

	public const VISIBILITY_UNPUBLISHED = 0;
	public const VISIBILITY_PUBLIC      = 1;
	public const VISIBILITY_PROTECTED   = 2;

	/**
	 * @var WP_Term|null
	 */
	public $term = null;

	public static function register_hooks() {
		add_action( 'set_object_terms', array( __CLASS__, 'set_object_terms' ), 10, 6 );
		add_action( 'delete_term_relationships', array( __CLASS__, 'delete_term_relationships' ), 10, 3 );
		add_filter( 'comment_reply_link', array( __CLASS__, 'comment_reply_link' ), 10, 4 );
		add_filter( 'comment_post_redirect', array( __CLASS__, 'comment_post_redirect' ), 10, 2 );
	}

	private static function unregister_hooks() {
		remove_action( 'set_object_terms', array( __CLASS__, 'set_object_terms' ), 10 );
		remove_action( 'delete_term_relationships', array( __CLASS__, 'delete_term_relationships' ), 10 );
		remove_filter( 'comment_reply_link', array( __CLASS__, 'comment_reply_link' ), 10 );
		remove_filter( 'comment_post_redirect', array( __CLASS__, 'comment_post_redirect' ), 10 );
	}

	public static function register_taxonomy() {
		register_taxonomy(
			self::TAXONOMY_NAME,
			array( 'vp_video' ),
			array(
				'hierarchical' => false,
				'labels'       => array(
					'name'          => __( 'Video Playlists', 'videopress-hq' ),
					'singular_name' => __( 'Video Playlist', 'videopress-hq' ),
					'search_items'  => __( 'Search Playlists', 'videopress-hq' ),
					'all_items'     => __( 'All Playlists', 'videopress-hq' ),
					'edit_item'     => __( 'Edit Playlist', 'videopress-hq' ),
					'update_item'   => __( 'Update Playlist', 'videopress-hq' ),
					'add_new_item'  => __( 'Add New Playlist', 'videopress-hq' ),
					'new_item_name' => __( 'New Playlist Name', 'videopress-hq' ),
					'menu_name'     => __( 'Playlists', 'videopress-hq' ),
				),
				'show_ui'      => true,
				'show_in_rest' => true,
				'query_var'    => true,
				'rewrite'      => array( 'slug' => 'playlist' ),
			)
		);
	}

	public static function comment_reply_link( $link, $args, $comment, $post ) {
		if ( ! $post || 'vp_video' !== $post->post_type ) {
			return $link;
		}

		$playlist_slug = get_query_var( self::TAXONOMY_NAME );
		if ( ! $playlist_slug ) {
			return $link;
		}
		$playlist_slug = sanitize_text_field( $playlist_slug );

		$playlist = self::get_by_slug( $playlist_slug );
		if ( ! $playlist ) {
			return $link;
		}

		if ( ! preg_match( '/href="([^"]*)"/', $link, $matches ) && ! preg_match( "/href='([^']*)'/", $link, $matches ) ) {
			return $link;
		}

		$query = parse_url( $matches[1] );
		if ( ! $query ) {
			return $link;
		}

		$url = add_query_arg( self::TAXONOMY_NAME, $playlist->term->slug, $matches[1] );

		return str_replace( $matches[1], esc_attr( $url ), $link );
	}

	public static function comment_post_redirect( $location, $comment ) {
		$referrer = wp_get_referer();
		if ( ! $referrer ) {
			return $location;
		}

		$referrer_query = parse_url( $referrer, PHP_URL_QUERY );
		if ( ! $referrer_query ) {
			return $location;
		}

		$referrer_query = wp_parse_args( $referrer_query );
		if ( ! isset( $referrer_query[ self::TAXONOMY_NAME ] ) ) {
			return $location;
		}

		$playlist_slug = sanitize_text_field( $referrer_query[ self::TAXONOMY_NAME ] );

		$playlist = self::get_by_slug( $playlist_slug );
		if ( ! $playlist ) {
			return $location;
		}

		return add_query_arg( self::TAXONOMY_NAME, $playlist->term->slug, $location );
	}

	public static function is_valid_visibility( $visibility ) {
		return in_array(
			$visibility,
			array(
				self::VISIBILITY_PUBLIC,
				self::VISIBILITY_PROTECTED,
				self::VISIBILITY_UNPUBLISHED,
			),
			true
		);
	}

	public static function delete_term_relationships( $object_id, $tt_ids, $taxonomy ) {
		if ( self::TAXONOMY_NAME !== $taxonomy ) {
			return;
		}

		$post = get_post( $object_id );
		if ( ! $post || 'vp_video' !== $post->post_type ) {
			return;
		}

		foreach ( $tt_ids as $term_id ) {
			delete_post_meta( $object_id, self::get_order_meta_key( $term_id ) );
		}
	}

	public static function set_object_terms( $object_id, $terms, $tt_ids, $taxonomy, $append, $old_tt_ids ) {
		if ( self::TAXONOMY_NAME !== $taxonomy ) {
			return;
		}

		$post = get_post( $object_id );
		if ( ! $post || 'vp_video' !== $post->post_type ) {
			return;
		}

		$diff_add = array_diff( $tt_ids, $old_tt_ids );
		$diff_rm  = array_diff( $old_tt_ids, $tt_ids );
		if ( empty( $diff_add ) && empty( $diff_rm ) ) {
			return;
		}

		if ( ! $append && ! empty( $diff_rm ) ) {
			foreach ( $diff_rm as $term_id ) {
				delete_post_meta( $object_id, self::get_order_meta_key( $term_id ) );
			}
		}

		if ( ! empty( $diff_add ) ) {
			$terms_to_add = get_terms( array( 'include' => $diff_add ) );
			if ( empty( $terms_to_add ) || is_wp_error( $terms_to_add ) ) {
				return;
			}

			foreach ( $terms_to_add as $term_id ) {
				$term = get_term( $term_id, self::TAXONOMY_NAME );
				if ( ! $term || is_wp_error( $term ) ) {
					continue;
				}

				update_post_meta( $object_id, self::get_order_meta_key( $term_id ), $term->count + 1 );
			}
		}
	}

	public static function from_terms( array $terms ) {
		$result = array();
		if ( empty( $terms ) ) {
			return $result;
		}

		/**
		 * @var WP_Term $term
		 */
		foreach ( $terms as $term ) {
			$instance = self::from_term( $term );
			if ( null === $instance ) {
				continue;
			}
			$result[] = $instance;
		}

		return $result;
	}

	public static function from_term( $term ) {
		if ( ! $term || self::TAXONOMY_NAME !== $term->taxonomy ) {
			return null;
		}

		$instance       = new VideoPressHQPlaylist();
		$instance->term = $term;

		return $instance;
	}

	public static function get_by_slug( $slug ) {
		$term = get_term_by( 'slug', $slug, self::TAXONOMY_NAME );
		if ( ! $term ) {
			return null;
		}

		return self::from_term( $term );
	}

	public static function get_order_meta_key( $term_id ) {
		return self::META_ITEMS_ORDER . '-' . $term_id;
	}

	public function is_visible_to_current_user( $include_unpublished = true ) {
		if ( self::VISIBILITY_PUBLIC === $this->term->term_group ) {
			return true;
		}

		if ( ! is_user_logged_in() ) {
			return false;
		}

		if ( self::VISIBILITY_PROTECTED === $this->term->term_group ) {
			return true;
		}

		return $include_unpublished && current_user_can( VideoPressHQCaps::CAP_READ_PRIVATE_PLAYLISTS );
	}

	public function set_items( array $items ) {
		self::unregister_hooks();

		$all_items_query = $this->get_posts_query(
			array(
				'post_status' => 'any',
				'fields'      => 'ids',
			)
		);

		$all_item_ids = $all_items_query->get_posts();
		foreach ( $all_item_ids as $item_id ) {
			wp_remove_object_terms( $item_id, $this->term->term_id, self::TAXONOMY_NAME );
			delete_post_meta( $item_id, self::get_order_meta_key( $this->term->term_id ) );
		}

		$order = 1;
		foreach ( $items as $item_id ) {
			if ( ! is_numeric( $item_id ) ) {
				continue;
			}

			wp_add_object_terms( $item_id, $this->term->term_id, self::TAXONOMY_NAME );
			update_post_meta( $item_id, self::get_order_meta_key( $this->term->term_id ), $order );
			$order++;
		}

		self::register_hooks();
	}

	/**
	 * @return array|WP_Error|bool
	 */
	public function update() {
		if ( ! $this->term ) {
			return false;
		}

		$update_result = wp_update_term(
			$this->term->term_id,
			self::TAXONOMY_NAME,
			array(
				'name'        => $this->term->name,
				'slug'        => $this->term->slug,
				'description' => $this->term->description,
				'term_group'  => $this->term->term_group ?? self::VISIBILITY_UNPUBLISHED,
			)
		);

		return is_wp_error( $update_result ) ? $update_result : true;
	}

	public static function create( $name, $description = '' ) {
		$term = wp_insert_term(
			$name,
			self::TAXONOMY_NAME,
			array(
				'description' => $description,
			)
		);

		if ( is_wp_error( $term ) ) {
			return $term;
		}

		$term = get_term( $term['term_id'], self::TAXONOMY_NAME );

		return self::from_term( $term );
	}

	public function get_post_permalink( $post_id ) {
		$permalink = get_permalink( $post_id );
		if ( ! $permalink ) {
			return '';
		}

		$permalink = add_query_arg( self::TAXONOMY_NAME, $this->term->slug, $permalink );

		return $permalink;
	}

	public function get_posts_query_params() {
		$order_meta_key = self::get_order_meta_key( $this->term->term_id );
		return array(
			'post_type'      => 'vp_video',
			'posts_per_page' => -1,
			'meta_query'     => array(
				'relation' => 'OR',
				array(
					'key'     => $order_meta_key,
					'compare' => 'EXISTS',
				),
				array(
					'key'     => $order_meta_key,
					'compare' => 'NOT EXISTS',
				),
			),
			'orderby'        => 'meta_value_num',
			'order'          => 'ASC',
			'tax_query'      => array(
				array(
					'taxonomy' => self::TAXONOMY_NAME,
					'field'    => 'term_id',
					'terms'    => $this->term->term_id,
				),
			),
		);
	}

	public function get_posts_query( array $query_params = array() ) {
		$query_params += $this->get_posts_query_params();

		return new WP_Query( $query_params );
	}

	public static function delete( $term ) {
		if ( ! $term || self::TAXONOMY_NAME !== $term->taxonomy ) {
			return new WP_Error( 'invalid_term', __( 'Invalid playlist', 'videopress-hq' ) );
		}

		return wp_delete_term( $term->term_id, self::TAXONOMY_NAME );
	}

}