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<?php

namespace WPGMZA;

require_once(plugin_dir_path(__FILE__) . 'class.custom-field-filter.php');

/**
 * This class deals with custom fields in general, as opposed to custom fields concerning a specific object.
 */
 
class CustomFields implements \IteratorAggregate, \JsonSerializable, \Countable
{
    private static $installed = null;
    private $fields;
    
    public function __construct($map_id=null)
    {
        global $wpdb;
        global $WPGMZA_TABLE_NAME_CUSTOM_FIELDS;
        global $WPGMZA_TABLE_NAME_MAPS_HAS_CUSTOM_FIELDS_FILTERS;
        
        if(!CustomFields::installed())
            CustomFields::install();
        
        $qstr = "SELECT * FROM $WPGMZA_TABLE_NAME_CUSTOM_FIELDS";
        
        if($map_id != null)
        {
            $map_id = (int)$map_id;
            
            $qstr .= " WHERE id IN (SELECT field_id FROM $WPGMZA_TABLE_NAME_MAPS_HAS_CUSTOM_FIELDS_FILTERS WHERE map_id=$map_id)";
        }
        
        $this->fields = $wpdb->get_results($qstr);
    }
    
    /**
     * Installs the DB tables for custom fields
     * @return void
     */
    public static function install()
    {
        require_once(ABSPATH . 'wp-admin/includes/upgrade.php');
        
        global $WPGMZA_TABLE_NAME_CUSTOM_FIELDS;
        global $WPGMZA_TABLE_NAME_MARKERS_HAS_CUSTOM_FIELDS;
        global $WPGMZA_TABLE_NAME_MAPS_HAS_CUSTOM_FIELDS_FILTERS;
                
        dbDelta("
            CREATE TABLE `$WPGMZA_TABLE_NAME_CUSTOM_FIELDS` (
                `id` int(11) NOT NULL AUTO_INCREMENT,
                `name` VARCHAR(128) NOT NULL,
                `icon` VARCHAR(128) NOT NULL,
                `attributes` TEXT,
                `widget_type` VARCHAR(128) DEFAULT 'none',
                PRIMARY KEY  (id),
                UNIQUE KEY name (name)
            );
        ");
        
        dbDelta("
            CREATE TABLE `$WPGMZA_TABLE_NAME_MARKERS_HAS_CUSTOM_FIELDS` (
                `field_id` int(11) NOT NULL,
                `object_id` int(11) NOT NULL,
                `value` TEXT,
                PRIMARY KEY  (`field_id`, `object_id`)
            );
        ");
        
        dbDelta("
            CREATE TABLE `$WPGMZA_TABLE_NAME_MAPS_HAS_CUSTOM_FIELDS_FILTERS` (
                `map_id` int(11) NOT NULL,
                `field_id` int(11) NOT NULL,
                PRIMARY KEY  (`map_id`, `field_id`)
            );
        ");
        
        CustomFields::$installed = true;
    }
    
    /**
     * Returns true if the custom fields tables are installed, caches the 
     * result of the DB query for performance.
     * TODO: Modify this to count instead so that adding polygon tables etc. will be done
     * @return bool
     */
    public static function installed()
    {
        global $wpdb;
        global $WPGMZA_TABLE_NAME_CUSTOM_FIELDS;
        
        if(CustomFields::$installed !== null)
            return CustomFields::$installed;
        
        CustomFields::$installed = $wpdb->get_var("SHOW TABLES LIKE '$WPGMZA_TABLE_NAME_CUSTOM_FIELDS'");
        
        return CustomFields::$installed;
    }
    
    /**
     * Get iterator for looping over fields with foreach
     * @return \ArrayIterator
     */
    public function getIterator()
    {
        return new \ArrayIterator($this->fields);
    }
    
    /**
     * Gets the fields to be serialized as JSON, useful for export
     * @return array
     */
    public function jsonSerialize()
    {
        return $this->fields;
    }
    
    
    public function count() {
        return count($this->fields);
    }
    
}