<?php
/**
 * Link/Bookmark API
 *
 * @package WordPress
 * @subpackage Bookmark
 */

/**
 * Retrieves bookmark data.
 *
 * @since 2.1.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int|stdClass $bookmark
 * @param string       $output   Optional. The required return type. One of OBJECT, ARRAY_A, or ARRAY_N, which
 *                               correspond to an stdClass object, an associative array, or a numeric array,
 *                               respectively. Default OBJECT.
 * @param string       $filter   Optional. How to sanitize bookmark fields. Default 'raw'.
 * @return array|object|null Type returned depends on $output value.
 */
function get_bookmark( $bookmark, $output = OBJECT, $filter = 'raw' ) {
	global $wpdb;

	if ( empty( $bookmark ) ) {
		if ( isset( $GLOBALS['link'] ) ) {
			$_bookmark = & $GLOBALS['link'];
		} else {
			$_bookmark = null;
		}
	} elseif ( is_object( $bookmark ) ) {
		wp_cache_add( $bookmark->link_id, $bookmark, 'bookmark' );
		$_bookmark = $bookmark;
	} else {
		if ( isset( $GLOBALS['link'] ) && ( $GLOBALS['link']->link_id == $bookmark ) ) {
			$_bookmark = & $GLOBALS['link'];
		} else {
			$_bookmark = wp_cache_get( $bookmark, 'bookmark' );
			if ( ! $_bookmark ) {
				$_bookmark = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->links WHERE link_id = %d LIMIT 1", $bookmark ) );
				if ( $_bookmark ) {
					$_bookmark->link_category = array_unique( wp_get_object_terms( $_bookmark->link_id, 'link_category', array( 'fields' => 'ids' ) ) );
					wp_cache_add( $_bookmark->link_id, $_bookmark, 'bookmark' );
				}
			}
		}
	}

	if ( ! $_bookmark ) {
		return $_bookmark;
	}

	$_bookmark = sanitize_bookmark( $_bookmark, $filter );

	if ( OBJECT === $output ) {
		return $_bookmark;
	} elseif ( ARRAY_A === $output ) {
		return get_object_vars( $_bookmark );
	} elseif ( ARRAY_N === $output ) {
		return array_values( get_object_vars( $_bookmark ) );
	} else {
		return $_bookmark;
	}
}

/**
 * Retrieves single bookmark data item or field.
 *
 * @since 2.3.0
 *
 * @param string $field    The name of the data field to return.
 * @param int    $bookmark The bookmark ID to get field.
 * @param string $context  Optional. The context of how the field will be used. Default 'display'.
 * @return string|WP_Error
 */
function get_bookmark_field( $field, $bookmark, $context = 'display' ) {
	$bookmark = (int) $bookmark;
	$bookmark = get_bookmark( $bookmark );

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

	if ( ! is_object( $bookmark ) ) {
		return '';
	}

	if ( ! isset( $bookmark->$field ) ) {
		return '';
	}

	return sanitize_bookmark_field( $field, $bookmark->$field, $bookmark->link_id, $context );
}

/**
 * Retrieves the list of bookmarks.
 *
 * Attempts to retrieve from the cache first based on MD5 hash of arguments. If
 * that fails, then the query will be built from the arguments and executed. The
 * results will be stored to the cache.
 *
 * @since 2.1.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string|array $args {
 *     Optional. String or array of arguments to retrieve bookmarks.
 *
 *     @type string   $orderby        How to order the links by. Accepts 'id', 'link_id', 'name', 'link_name',
 *                                    'url', 'link_url', 'visible', 'link_visible', 'rating', 'link_rating',
 *                                    'owner', 'link_owner', 'updated', 'link_updated', 'notes', 'link_notes',
 *                                    'description', 'link_description', 'length' and 'rand'.
 *                                    When `$orderby` is 'length', orders by the character length of
 *                                    'link_name'. Default 'name'.
 *     @type string   $order          Whether to order bookmarks in ascending or descending order.
 *                                    Accepts 'ASC' (ascending) or 'DESC' (descending). Default 'ASC'.
 *     @type int      $limit          Amount of bookmarks to display. Accepts any positive number or
 *                                    -1 for all.  Default -1.
 *     @type string   $category       Comma-separated list of category IDs to include links from.
 *                                    Default empty.
 *     @type string   $category_name  Category to retrieve links for by name. Default empty.
 *     @type int|bool $hide_invisible Whether to show or hide links marked as 'invisible'. Accepts
 *                                    1|true or 0|false. Default 1|true.
 *     @type int|bool $show_updated   Whether to display the time the bookmark was last updated.
 *                                    Accepts 1|true or 0|false. Default 0|false.
 *     @type string   $include        Comma-separated list of bookmark IDs to include. Default empty.
 *     @type string   $exclude        Comma-separated list of bookmark IDs to exclude. Default empty.
 *     @type string   $search         Search terms. Will be SQL-formatted with wildcards before and after
 *                                    and searched in 'link_url', 'link_name' and 'link_description'.
 *                                    Default empty.
 * }
 * @return object[] List of bookmark row objects.
 */
function get_bookmarks( $args = '' ) {
	global $wpdb;

	$defaults = array(
		'orderby'        => 'name',
		'order'          => 'ASC',
		'limit'          => -1,
		'category'       => '',
		'category_name'  => '',
		'hide_invisible' => 1,
		'show_updated'   => 0,
		'include'        => '',
		'exclude'        => '',
		'search'         => '',
	);

	$parsed_args = wp_parse_args( $args, $defaults );

	$key   = md5( serialize( $parsed_args ) );
	$cache = wp_cache_get( 'get_bookmarks', 'bookmark' );

	if ( 'rand' !== $parsed_args['orderby'] && $cache ) {
		if ( is_array( $cache ) && isset( $cache[ $key ] ) ) {
			$bookmarks = $cache[ $key ];
			/**
			 * Filters the returned list of bookmarks.
			 *
			 * The first time the hook is evaluated in this file, it returns the cached
			 * bookmarks list. The second evaluation returns a cached bookmarks list if the
			 * link category is passed but does not exist. The third evaluation returns
			 * the full cached results.
			 *
			 * @since 2.1.0
			 *
			 * @see get_bookmarks()
			 *
			 * @param array $bookmarks   List of the cached bookmarks.
			 * @param array $parsed_args An array of bookmark query arguments.
			 */
			return apply_filters( 'get_bookmarks', $bookmarks, $parsed_args );
		}
	}

	if ( ! is_array( $cache ) ) {
		$cache = array();
	}

	$inclusions = '';
	if ( ! empty( $parsed_args['include'] ) ) {
		$parsed_args['exclude']       = '';  // Ignore exclude, category, and category_name params if using include.
		$parsed_args['category']      = '';
		$parsed_args['category_name'] = '';

		$inclinks = wp_parse_id_list( $parsed_args['include'] );
		if ( count( $inclinks ) ) {
			foreach ( $inclinks as $inclink ) {
				if ( empty( $inclusions ) ) {
					$inclusions = ' AND ( link_id = ' . $inclink . ' ';
				} else {
					$inclusions .= ' OR link_id = ' . $inclink . ' ';
				}
			}
		}
	}
	if ( ! empty( $inclusions ) ) {
		$inclusions .= ')';
	}

	$exclusions = '';
	if ( ! empty( $parsed_args['exclude'] ) ) {
		$exlinks = wp_parse_id_list( $parsed_args['exclude'] );
		if ( count( $exlinks ) ) {
			foreach ( $exlinks as $exlink ) {
				if ( empty( $exclusions ) ) {
					$exclusions = ' AND ( link_id <> ' . $exlink . ' ';
				} else {
					$exclusions .= ' AND link_id <> ' . $exlink . ' ';
				}
			}
		}
	}
	if ( ! empty( $exclusions ) ) {
		$exclusions .= ')';
	}

	if ( ! empty( $parsed_args['category_name'] ) ) {
		$parsed_args['category'] = get_term_by( 'name', $parsed_args['category_name'], 'link_category' );
		if ( $parsed_args['category'] ) {
			$parsed_args['category'] = $parsed_args['category']->term_id;
		} else {
			$cache[ $key ] = array();
			wp_cache_set( 'get_bookmarks', $cache, 'bookmark' );
			/** This filter is documented in wp-includes/bookmark.php */
			return apply_filters( 'get_bookmarks', array(), $parsed_args );
		}
	}

	$search = '';
	if ( ! empty( $parsed_args['search'] ) ) {
		$like   = '%' . $wpdb->esc_like( $parsed_args['search'] ) . '%';
		$search = $wpdb->prepare( ' AND ( (link_url LIKE %s) OR (link_name LIKE %s) OR (link_description LIKE %s) ) ', $like, $like, $like );
	}

	$category_query = '';
	$join           = '';
	if ( ! empty( $parsed_args['category'] ) ) {
		$incategories = wp_parse_id_list( $parsed_args['category'] );
		if ( count( $incategories ) ) {
			foreach ( $incategories as $incat ) {
				if ( empty( $category_query ) ) {
					$category_query = ' AND ( tt.term_id = ' . $incat . ' ';
				} else {
					$category_query .= ' OR tt.term_id = ' . $incat . ' ';
				}
			}
		}
	}
	if ( ! empty( $category_query ) ) {
		$category_query .= ") AND taxonomy = 'link_category'";
		$join            = " INNER JOIN $wpdb->term_relationships AS tr ON ($wpdb->links.link_id = tr.object_id) INNER JOIN $wpdb->term_taxonomy as tt ON tt.term_taxonomy_id = tr.term_taxonomy_id";
	}

	if ( $parsed_args['show_updated'] ) {
		$recently_updated_test = ', IF (DATE_ADD(link_updated, INTERVAL 120 MINUTE) >= NOW(), 1,0) as recently_updated ';
	} else {
		$recently_updated_test = '';
	}

	$get_updated = ( $parsed_args['show_updated'] ) ? ', UNIX_TIMESTAMP(link_updated) AS link_updated_f ' : '';

	$orderby = strtolower( $parsed_args['orderby'] );
	$length  = '';
	switch ( $orderby ) {
		case 'length':
			$length = ', CHAR_LENGTH(link_name) AS length';
			break;
		case 'rand':
			$orderby = 'rand()';
			break;
		case 'link_id':
			$orderby = "$wpdb->links.link_id";
			break;
		default:
			$orderparams = array();
			$keys        = array( 'link_id', 'link_name', 'link_url', 'link_visible', 'link_rating', 'link_owner', 'link_updated', 'link_notes', 'link_description' );
			foreach ( explode( ',', $orderby ) as $ordparam ) {
				$ordparam = trim( $ordparam );

				if ( in_array( 'link_' . $ordparam, $keys, true ) ) {
					$orderparams[] = 'link_' . $ordparam;
				} elseif ( in_array( $ordparam, $keys, true ) ) {
					$orderparams[] = $ordparam;
				}
			}
			$orderby = implode( ',', $orderparams );
	}

	if ( empty( $orderby ) ) {
		$orderby = 'link_name';
	}

	$order = strtoupper( $parsed_args['order'] );
	if ( '' !== $order && ! in_array( $order, array( 'ASC', 'DESC' ), true ) ) {
		$order = 'ASC';
	}

	$visible = '';
	if ( $parsed_args['hide_invisible'] ) {
		$visible = "AND link_visible = 'Y'";
	}

	$query  = "SELECT * $length $recently_updated_test $get_updated FROM $wpdb->links $join WHERE 1=1 $visible $category_query";
	$query .= " $exclusions $inclusions $search";
	$query .= " ORDER BY $orderby $order";
	if ( -1 != $parsed_args['limit'] ) {
		$query .= ' LIMIT ' . absint( $parsed_args['limit'] );
	}

	$results = $wpdb->get_results( $query );

	if ( 'rand()' !== $orderby ) {
		$cache[ $key ] = $results;
		wp_cache_set( 'get_bookmarks', $cache, 'bookmark' );
	}

	/** This filter is documented in wp-includes/bookmark.php */
	return apply_filters( 'get_bookmarks', $results, $parsed_args );
}

/**
 * Sanitizes all bookmark fields.
 *
 * @since 2.3.0
 *
 * @param stdClass|array $bookmark Bookmark row.
 * @param string         $context  Optional. How to filter the fields. Default 'display'.
 * @return stdClass|array Same type as $bookmark but with fields sanitized.
 */
function sanitize_bookmark( $bookmark, $context = 'display' ) {
	$fields = array(
		'link_id',
		'link_url',
		'link_name',
		'link_image',
		'link_target',
		'link_category',
		'link_description',
		'link_visible',
		'link_owner',
		'link_rating',
		'link_updated',
		'link_rel',
		'link_notes',
		'link_rss',
	);

	if ( is_object( $bookmark ) ) {
		$do_object = true;
		$link_id   = $bookmark->link_id;
	} else {
		$do_object = false;
		$link_id   = $bookmark['link_id'];
	}

	foreach ( $fields as $field ) {
		if ( $do_object ) {
			if ( isset( $bookmark->$field ) ) {
				$bookmark->$field = sanitize_bookmark_field( $field, $bookmark->$field, $link_id, $context );
			}
		} else {
			if ( isset( $bookmark[ $field ] ) ) {
				$bookmark[ $field ] = sanitize_bookmark_field( $field, $bookmark[ $field ], $link_id, $context );
			}
		}
	}

	return $bookmark;
}

/**
 * Sanitizes a bookmark field.
 *
 * Sanitizes the bookmark fields based on what the field name is. If the field
 * has a strict value set, then it will be tested for that, else a more generic
 * filtering is applied. After the more strict filter is applied, if the `$context`
 * is 'raw' then the value is immediately return.
 *
 * Hooks exist for the more generic cases. With the 'edit' context, the {@see 'edit_$field'}
 * filter will be called and passed the `$value` and `$bookmark_id` respectively.
 *
 * With the 'db' context, the {@see 'pre_$field'} filter is called and passed the value.
 * The 'display' context is the final context and has the `$field` has the filter name
 * and is passed the `$value`, `$bookmark_id`, and `$context`, respectively.
 *
 * @since 2.3.0
 *
 * @param string $field       The bookmark field.
 * @param mixed  $value       The bookmark field value.
 * @param int    $bookmark_id Bookmark ID.
 * @param string $context     How to filter the field value. Accepts 'raw', 'edit', 'db',
 *                            'display', 'attribute', or 'js'. Default 'display'.
 * @return mixed The filtered value.
 */
function sanitize_bookmark_field( $field, $value, $bookmark_id, $context ) {
	$int_fields = array( 'link_id', 'link_rating' );
	if ( in_array( $field, $int_fields, true ) ) {
		$value = (int) $value;
	}

	switch ( $field ) {
		case 'link_category': // array( ints )
			$value = array_map( 'absint', (array) $value );
			/*
			 * We return here so that the categories aren't filtered.
			 * The 'link_category' filter is for the name of a link category, not an array of a link's link categories.
			 */
			return $value;

		case 'link_visible': // bool stored as Y|N
			$value = preg_replace( '/[^YNyn]/', '', $value );
			break;
		case 'link_target': // "enum"
			$targets = array( '_top', '_blank' );
			if ( ! in_array( $value, $targets, true ) ) {
				$value = '';
			}
			break;
	}

	if ( 'raw' === $context ) {
		return $value;
	}

	if ( 'edit' === $context ) {
		/** This filter is documented in wp-includes/post.php */
		$value = apply_filters( "edit_{$field}", $value, $bookmark_id );

		if ( 'link_notes' === $field ) {
			$value = esc_html( $value ); // textarea_escaped
		} else {
			$value = esc_attr( $value );
		}
	} elseif ( 'db' === $context ) {
		/** This filter is documented in wp-includes/post.php */
		$value = apply_filters( "pre_{$field}", $value );
	} else {
		/** This filter is documented in wp-includes/post.php */
		$value = apply_filters( "{$field}", $value, $bookmark_id, $context );

		if ( 'attribute' === $context ) {
			$value = esc_attr( $value );
		} elseif ( 'js' === $context ) {
			$value = esc_js( $value );
		}
	}

	// Restore the type for integer fields after esc_attr().
	if ( in_array( $field, $int_fields, true ) ) {
		$value = (int) $value;
	}

	return $value;
}

/**
 * Deletes the bookmark cache.
 *
 * @since 2.7.0
 *
 * @param int $bookmark_id Bookmark ID.
 */
function clean_bookmark_cache( $bookmark_id ) {
	wp_cache_delete( $bookmark_id, 'bookmark' );
	wp_cache_delete( 'get_bookmarks', 'bookmark' );
	clean_object_term_cache( $bookmark_id, 'link' );
}