`_list_not_available` meta field values not unified in db

[florianrusch]

I was searching for the attribute which define if a listing is available or already sold or rented. On my search I've discovered, that the _list_not_available metadata field of a listing is not unified in the database. There are three different values which I saw: 0, 1, on.

In the php function is_listing_not_available which handles this field is a migration integrated from the old field _price_sold_rented. Maybe this is the reason why we have three different values?

I would suggest to add here maybe another migration to bring this values to a consistent type (0, 1).

wpcasa/wpcasa/includes/class-wpsight-listings.php

Lines 1323 to 1363 in c983038

	/**
	* is_listing_not_available()
	*
	* Check if a specific listing item is no longer available
	* (custom field '_listing_not_available').
	*
	* @param integer $post_id Post ID of the corresponding listing (defaults to current post)
	* @uses result()
	* @uses get_post_meta()
	* @uses update_post_meta()
	* @uses delete_post_meta()
	* @return bool $result True if _listing_not_available has value, else false
	*
	* @since 1.0.0
	*/
	public static function is_listing_not_available( $post_id = '' ) {
	// Set default post ID
	if ( ! $post_id )
	$post_id = get_the_ID();
	// Get old _price_sold_rented value
	$sold_rented = get_post_meta( $post_id, '_price_sold_rented', true );
	if ( ! empty( $sold_rented ) ) {
	// Update new field with old field value
	update_post_meta( $post_id, '_listing_not_available', $sold_rented );
	// Remove old field
	delete_post_meta( $post_id, '_price_sold_rented' );
	}
	// Get custom post meta and set result
	$result = get_post_meta( $post_id, '_listing_not_available', true ) ? true : false;
	return apply_filters( 'wpsight_is_listing_not_available', $result, $post_id );
	}