<?php

/**

 * Metadata API

 *

 * Functions for retrieving and manipulating metadata of various WordPress object types. Metadata

 * for an object is a represented by a simple key-value pair. Objects may contain multiple

 * metadata entries that share the same key and differ only in their value.

 *

 * @package WordPress

 * @subpackage Meta

 * @since 2.9.0

 */

/**

 * Add metadata for the specified object.

 *

 * @since 2.9.0

 * @uses $wpdb WordPress database object for queries.

 * @uses do_action() Calls 'added_{$meta_type}_meta' with meta_id of added metadata entry,

 * 		object ID, meta key, and meta value

 *

 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)

 * @param int $object_id ID of the object metadata is for

 * @param string $meta_key Metadata key

 * @param string $meta_value Metadata value

 * @param bool $unique Optional, default is false. Whether the specified metadata key should be

 * 		unique for the object. If true, and the object already has a value for the specified

 * 		metadata key, no change will be made

 * @return bool The meta ID on successful update, false on failure.

 */

function add_metadata($meta_type, $object_id, $meta_key, $meta_value, $unique = false) {

	if ( !$meta_type || !$meta_key )

		return false;

	if ( !$object_id = absint($object_id) )

		return false;

	if ( ! $table = _get_meta_table($meta_type) )

		return false;

	global $wpdb;

	$column = esc_sql($meta_type . '_id');

	// expected_slashed ($meta_key)

	$meta_key = stripslashes($meta_key);

	$meta_value = stripslashes_deep($meta_value);

	$meta_value = sanitize_meta( $meta_key, $meta_value, $meta_type );

	$check = apply_filters( "add_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $unique );

	if ( null !== $check )

		return $check;

	if ( $unique && $wpdb->get_var( $wpdb->prepare(

		"SELECT COUNT(*) FROM $table WHERE meta_key = %s AND $column = %d",

		$meta_key, $object_id ) ) )

		return false;

	$_meta_value = $meta_value;

	$meta_value = maybe_serialize( $meta_value );

	do_action( "add_{$meta_type}_meta", $object_id, $meta_key, $_meta_value );

	$result = $wpdb->insert( $table, array(

		$column => $object_id,

		'meta_key' => $meta_key,

		'meta_value' => $meta_value

	) );

	if ( ! $result )

		return false;

	$mid = (int) $wpdb->insert_id;

	wp_cache_delete($object_id, $meta_type . '_meta');

	do_action( "added_{$meta_type}_meta", $mid, $object_id, $meta_key, $_meta_value );

	return $mid;

}

/**

 * Update metadata for the specified object. If no value already exists for the specified object

 * ID and metadata key, the metadata will be added.

 *

 * @since 2.9.0

 * @uses $wpdb WordPress database object for queries.

 * @uses do_action() Calls 'update_{$meta_type}_meta' before updating metadata with meta_id of

 * 		metadata entry to update, object ID, meta key, and meta value

 * @uses do_action() Calls 'updated_{$meta_type}_meta' after updating metadata with meta_id of

 * 		updated metadata entry, object ID, meta key, and meta value

 *

 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)

 * @param int $object_id ID of the object metadata is for

 * @param string $meta_key Metadata key

 * @param string $meta_value Metadata value

 * @param string $prev_value Optional. If specified, only update existing metadata entries with

 * 		the specified value. Otherwise, update all entries.

 * @return bool True on successful update, false on failure.

 */

function update_metadata($meta_type, $object_id, $meta_key, $meta_value, $prev_value = '') {

	if ( !$meta_type || !$meta_key )

		return false;

	if ( !$object_id = absint($object_id) )

		return false;

	if ( ! $table = _get_meta_table($meta_type) )

		return false;

	global $wpdb;

	$column = esc_sql($meta_type . '_id');

	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';

	// expected_slashed ($meta_key)

	$meta_key = stripslashes($meta_key);

	$passed_value = $meta_value;

	$meta_value = stripslashes_deep($meta_value);

	$meta_value = sanitize_meta( $meta_key, $meta_value, $meta_type );

	$check = apply_filters( "update_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $prev_value );

	if ( null !== $check )

		return (bool) $check;

	// Compare existing value to new value if no prev value given and the key exists only once.

	if ( empty($prev_value) ) {

		$old_value = get_metadata($meta_type, $object_id, $meta_key);

		if ( count($old_value) == 1 ) {

			if ( $old_value[0] === $meta_value )

				return false;

		}

	}

	$_meta_value = $meta_value;

	$meta_value = maybe_serialize( $meta_value );

	$data  = compact( 'meta_value' );

	$where = array( $column => $object_id, 'meta_key' => $meta_key );

	if ( !empty( $prev_value ) ) {

		$prev_value = maybe_serialize($prev_value);

		$where['meta_value'] = $prev_value;

	}

	do_action( "update_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );

	if ( 'post' == $meta_type )

		do_action( 'update_postmeta', $meta_id, $object_id, $meta_key, $meta_value );

	$wpdb->update( $table, $data, $where );

	wp_cache_delete($object_id, $meta_type . '_meta');

	do_action( "updated_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );

	if ( 'post' == $meta_type )

		do_action( 'updated_postmeta', $meta_id, $object_id, $meta_key, $meta_value );

	return true;

}

/**

 * Delete metadata for the specified object.

 *

 * @since 2.9.0

 * @uses $wpdb WordPress database object for queries.

 * @uses do_action() Calls 'deleted_{$meta_type}_meta' after deleting with meta_id of

 * 		deleted metadata entries, object ID, meta key, and meta value

 *

 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)

 * @param int $object_id ID of the object metadata is for

 * @param string $meta_key Metadata key

 * @param string $meta_value Optional. Metadata value. If specified, only delete metadata entries

 * 		with this value. Otherwise, delete all entries with the specified meta_key.

 * @param bool $delete_all Optional, default is false. If true, delete matching metadata entries

 * 		for all objects, ignoring the specified object_id. Otherwise, only delete matching

 * 		metadata entries for the specified object_id.

 * @return bool True on successful delete, false on failure.

 */

function delete_metadata($meta_type, $object_id, $meta_key, $meta_value = '', $delete_all = false) {

	if ( !$meta_type || !$meta_key )

		return false;

	if ( (!$object_id = absint($object_id)) && !$delete_all )

		return false;

	if ( ! $table = _get_meta_table($meta_type) )

		return false;

	global $wpdb;

	$type_column = esc_sql($meta_type . '_id');

	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';

	// expected_slashed ($meta_key)

	$meta_key = stripslashes($meta_key);

	$meta_value = stripslashes_deep($meta_value);

	$check = apply_filters( "delete_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $delete_all );

	if ( null !== $check )

		return (bool) $check;

	$_meta_value = $meta_value;

	$meta_value = maybe_serialize( $meta_value );

	$query = $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s", $meta_key );

	if ( !$delete_all )

		$query .= $wpdb->prepare(" AND $type_column = %d", $object_id );

	if ( $meta_value )

		$query .= $wpdb->prepare(" AND meta_value = %s", $meta_value );

	$meta_ids = $wpdb->get_col( $query );

	if ( !count( $meta_ids ) )

		return false;

	if ( $delete_all )

		$object_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $type_column FROM $table WHERE meta_key = %s", $meta_key ) );

	do_action( "delete_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $_meta_value );

	// Old-style action.

	if ( 'post' == $meta_type )

		do_action( 'delete_postmeta', $meta_ids );

	$query = "DELETE FROM $table WHERE $id_column IN( " . implode( ',', $meta_ids ) . " )";

	$count = $wpdb->query($query);

	if ( !$count )

		return false;

	if ( $delete_all ) {

		foreach ( (array) $object_ids as $o_id ) {

			wp_cache_delete($o_id, $meta_type . '_meta');

		}

	} else {

		wp_cache_delete($object_id, $meta_type . '_meta');

	}

	do_action( "deleted_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $_meta_value );

	// Old-style action.

	if ( 'post' == $meta_type )

		do_action( 'deleted_postmeta', $meta_ids );

	return true;

}

/**

 * Retrieve metadata for the specified object.

 *

 * @since 2.9.0

 *

 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)

 * @param int $object_id ID of the object metadata is for

 * @param string $meta_key Optional. Metadata key. If not specified, retrieve all metadata for

 * 		the specified object.

 * @param bool $single Optional, default is false. If true, return only the first value of the

 * 		specified meta_key. This parameter has no effect if meta_key is not specified.

 * @return string|array Single metadata value, or array of values

 */

function get_metadata($meta_type, $object_id, $meta_key = '', $single = false) {

	if ( !$meta_type )

		return false;

	if ( !$object_id = absint($object_id) )

		return false;

	$check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, $single );

	if ( null !== $check ) {

		if ( $single && is_array( $check ) )

			return $check[0];

		else

			return $check;

	}

	$meta_cache = wp_cache_get($object_id, $meta_type . '_meta');

	if ( !$meta_cache ) {

		$meta_cache = update_meta_cache( $meta_type, array( $object_id ) );

		$meta_cache = $meta_cache[$object_id];

	}

	if ( !$meta_key )

		return $meta_cache;

	if ( isset($meta_cache[$meta_key]) ) {

		if ( $single )

			return maybe_unserialize( $meta_cache[$meta_key][0] );

		else

			return array_map('maybe_unserialize', $meta_cache[$meta_key]);

	}

	if ($single)

		return '';

	else

		return array();

}

/**

 * Determine if a meta key is set for a given object

 *

 * @since 3.3.0

 *

 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)

 * @param int $object_id ID of the object metadata is for

 * @param string $meta_key Metadata key.

 * @return boolean true of the key is set, false if not.

 */

function metadata_exists( $meta_type, $object_id, $meta_key ) {

	if ( ! $meta_type )

		return false;

	if ( ! $object_id = absint( $object_id ) )

		return false;

	$check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, true );

	if ( null !== $check )

		return true;

	$meta_cache = wp_cache_get( $object_id, $meta_type . '_meta' );

	if ( !$meta_cache ) {

		$meta_cache = update_meta_cache( $meta_type, array( $object_id ) );

		$meta_cache = $meta_cache[$object_id];

	}

	if ( isset( $meta_cache[ $meta_key ] ) )

		return true;

	return false;

}

/**

 * Get meta data by meta ID

 *

 * @since 3.3.0

 *

 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)

 * @param int $meta_id ID for a specific meta row

 * @return object Meta object or false.

 */

function get_metadata_by_mid( $meta_type, $meta_id ) {

	global $wpdb;

	if ( ! $meta_type )

		return false;

	if ( !$meta_id = absint( $meta_id ) )

		return false;

	if ( ! $table = _get_meta_table($meta_type) )

		return false;

	$id_column = ( 'user' == $meta_type ) ? 'umeta_id' : 'meta_id';

	$meta = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $table WHERE $id_column = %d", $meta_id ) );

	if ( empty( $meta ) )

		return false;

	if ( isset( $meta->meta_value ) )

		$meta->meta_value = maybe_unserialize( $meta->meta_value );

	return $meta;

}

/**

 * Update meta data by meta ID

 *

 * @since 3.3.0

 *

 * @uses get_metadata_by_mid() Calls get_metadata_by_mid() to fetch the meta key, value

 *		and object_id of the given meta_id.

 *

 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)

 * @param int $meta_id ID for a specific meta row

 * @param string $meta_value Metadata value

 * @param string $meta_key Optional, you can provide a meta key to update it

 * @return bool True on successful update, false on failure.

 */

function update_metadata_by_mid( $meta_type, $meta_id, $meta_value, $meta_key = false ) {

	global $wpdb;

	// Make sure everything is valid.

	if ( ! $meta_type )

		return false;

	if ( ! $meta_id = absint( $meta_id ) )

		return false;

	if ( ! $table = _get_meta_table( $meta_type ) )

		return false;

	$column = esc_sql($meta_type . '_id');

	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';

	// Fetch the meta and go on if it's found.

	if ( $meta = get_metadata_by_mid( $meta_type, $meta_id ) ) {

		$original_key = $meta->meta_key;