<?php
/**
 * Class JsonData
 *
 * Example:
 *    return [
 *        'some_items' => (new JsonData(Some::all()))
 *            ->with(['id', 'message', 'created_at'])
 *            ->child('user', ['id', 'login', 'photo'])
 *            ->render()
 *    ];
 *
 */
class JsonData
{
    /**
     * Source object
     * @var
     */
    private $_object;

    /**
     * Filters
     * @var array
     */
    private $_filters = [];

    /**
     * Children objects
     * @var array
     */
    private $_children = [];

    /**
     * @param $object
     */
    public function __construct($object)
    {
        $this->_object = $object;
    }

    /**
     * Add filter
     * @param $names
     * @return $this
     */
    public function with($names)
    {
        if (!is_array($names)) {
            $names = [$names];
        }
        foreach ($names as $name) {
            $this->_filters[] = $name;
        }
        return $this;
    }

    /**
     * Add child
     * @param $name
     * @param $attrs
     * @return $this
     */
    public function child($name, $attrs)
    {
        $this->_children[$name] = $attrs;
        return $this;
    }

    /**
     * Parse data
     * @return array
     */
    protected function getResult()
    {
        $createItem = function($item)
        {
            $response = [];
            foreach ($this->_filters as $f) {
                $response[$f] = $item->$f;
            }

            foreach ($this->_children as $child => $attrs) {
                $response[$child] = [];
                foreach ($attrs as $attr) {
                    $response[$child][$attr] = $item->$child->$attr;
                }
            }
            return $response;
        };

        $result = [];
        foreach ($this->_object as $item) {
            $result[] = $createItem($item);
        }
        return $result;
    }

    /**
     * Return result
     * @return array
     */
    public function render()
    {
        return $this->getResult();
    }
}