<?php
/**
 * This source file is part of the open source project
 * ExpressionEngine (https://expressionengine.com)
 *
 * @link      https://expressionengine.com/
 * @copyright Copyright (c) 2003-2022, Packet Tide, LLC (https://www.packettide.com)
 * @license   https://expressionengine.com/license Licensed under Apache License, Version 2.0
 */

namespace ExpressionEngine\Service\Model\Association;

use ExpressionEngine\Service\Model\Collection;

/**
 * Model Service: To One Association
 */
class ToOne extends Association
{
    private $fk_value = null;

    public function foreignKeyChanged($value)
    {
        if ($value != $this->fk_value) {
            return parent::foreignKeyChanged($value);
        }
    }

    public function fill($related, $_skip_inverse = false)
    {
        if ($related instanceof Collection) {
            $related = $related->first();
        }

        if (is_array($related)) {
            $related = array_shift($related);
        }

        $this->cacheFKValue($related);

        return parent::fill($related, $_skip_inverse);
    }

    protected function ensureExists($model)
    {
        if ($this->related !== $model) {
            $this->cacheFKValue($model);

            $this->related = $model;
            parent::ensureExists($model);
        }
    }

    protected function ensureDoesNotExist($model)
    {
        if ($this->related === $model) {
            $this->cacheFKValue(null);

            $this->related = null;
            parent::ensureDoesNotExist($model);
        }
    }

    private function cacheFKValue($model)
    {
        $fk = $this->getForeignKey();

        if ($model && $model->hasProperty($fk)) {
            $this->fk_value = $model->$fk;
        } else {
            $this->fk_value = null;
        }
    }
}

// EOF
