<?php

namespace Slack\Blockkit\Blocks;

use \Exception;
use Illuminate\Support\Collection;

use Slack\Blockkit\Blocks;
use Slack\Blockkit\Blocks\Elements\{Button,MultiStaticSelect};

final class Actions extends Blocks
{
	protected const LIMITS = [
		'block_id' => 255,			// @todo Should be unique for each message
	];

	private const MAX_ELEMENTS = 5;

	private const VALID_ELEMENTS = [
		Button::class,
		MultiStaticSelect::class,
		Blocks\Accessories\Overflow::class,
	];

	public function __construct()
	{
		parent::__construct();

		// Defaults
		$this->type = 'actions';
	}

	public static function item(): self
	{
		return new self();
	}

	public function jsonSerialize()
	{
		if (! $this->elements)
			throw new Exception('Must define at least 1 element');

		return parent::jsonSerialize();
	}

	/* OPTIONAL ITEMS */

	public function block_id(string $string): self
	{
		$this->block_id = $this->validate('block_id',$string);

		return $this;
	}

	public function elements(Collection $collection): self
	{
		if (count($collection) > self::MAX_ELEMENTS)
			throw new Exception(sprintf('Can only have maximum %d elements',self::MAX_ELEMENTS));

		// @todo Check that a valid element is added. https://api.slack.com/reference/block-kit/blocks#actions

		$this->elements = $collection;

		return $this;
	}
}