<?php

declare(strict_types = 1);

namespace App\Model\Service\Feed;

use TomasKarlik\CsvResponse2\IDataSource;


class CsvExporter implements IDataSource
{

	/**
	 * @var array
	 */
	private $data = [
		['name' => 'honza', 'date' => '2016-01-01', 'score' => 1],
		['name' => 'pepa', 'date' => '2016-01-02', 'score' => 2],
		['name' => 'david', 'date' => '2016-01-03', 'score' => 3]
	];

	/**
	 * @var int
	 */
	private $index = 0;


	public function next(): ?array
	{
		if ( ! isset($this->data[$this->index])) {
			return NULL;
		}

		return $this->data[$this->index++];
	}

}

public function actionExportCsv(int $id): void
{
	$response = new CsvResponse($this->csvExporter, sprintf('export-%d.csv', $id));
	$response->addColumnCallback('score', [$this, 'myScoreFormatCallback']);
	$this->sendResponse($response);
}