<?php

namespace app\ht\helpers;

use function count;
use function ob_start;
use function fopen;
use function iconv;
use function fputcsv;
use function fclose;
use function ob_get_clean;
use function gmdate;
use function header;

/**
 * Class CsvHelper
 * @package app\ht\helpers
 */
class CsvHelper
{

    /**
     * @param array $array
     * @return null|string
     */
    protected static function array2csv(array &$array)
    {
        if (count($array) == 0) {
            return null;
        }
        ob_start();
        $df = fopen("php://output", 'w');
        foreach ($array as $row) {
            foreach ($row as $i => $v) {
                $row[$i] = iconv('utf-8', 'gbk', $v);
            }
            fputcsv($df, $row);
        }
        fclose($df);
        return ob_get_clean();
    }

    /**
     * @param $filename
     */
    protected static function downloadSendHeaders($filename)
    {
        // disable caching
        $now = gmdate("D, d M Y H:i:s");
        header("Expires: Tue, 03 Jul 2001 06:00:00 GMT");
        header("Cache-Control: max-age=0, no-cache, must-revalidate, proxy-revalidate");
        header("Last-Modified: {$now} GMT");

        // force download
        header("Content-Type: application/force-download");
        header("Content-Type: application/octet-stream");
        header("Content-Type: application/download");

        // disposition / encoding on response body
        header("Content-Disposition: attachment;filename={$filename}");
        header("Content-Transfer-Encoding: binary");
    }

    /**
     * @param array $array
     * @param $filename
     */
    public static function export(array &$array, $filename)
    {
        self::downloadSendHeaders($filename . ".csv");
        echo self::array2csv($array);
        die();
    }
}