<?php

namespace XaiCorp\AbcParser\Domain\Core;

class MultivalueAttribute
{
    /**
     * @var \XaiCorp\AbcParser\Domain\Core\Collection
     */
    protected $data;

    private function __construct()
    {
        $this->data = new Collection();
    }

    /**
     * @param string $item
     * @return \XaiCorp\AbcParser\Domain\Core\MultivalueAttribute
     */
    public static function create(string $item)
    {
        return (new self())->add($item);
    }

    /**
     * @param array $items
     * @return \XaiCorp\AbcParser\Domain\Core\MultivalueAttribute
     */
    public static function createFromArray(array $items)
    {
        $attribute = new self();

        foreach ($items as $item) {
            $attribute->add($item);
        }

        return $attribute;
    }

    /**
     * @param string $item
     * @return static
     */
    public function add(string $item)
    {
        $this->data = $this->data->push($item)->unique();

        return $this;
    }

    /**
     * @param MultivalueAttribute $attribute
     * @return static
     */
    public function merge(MultivalueAttribute $attribute)
    {
        $this->data = $this->data
            ->pushArray($attribute->data->toArray())
            ->unique();

        return $this;
    }

    /**
     * @return string
     */
    public function first()
    {
        return $this->data->firstOrDefault('');
    }

    /**
     * @return string[]
     */
    public function toArray()
    {
        return $this->data->toArray();
    }
}