<?php

/**
 * League.Csv (https://csv.thephpleague.com)
 *
 * (c) Ignace Nyamagana Butera <nyamsprod@gmail.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
declare (strict_types=1);
namespace IAWPSCOPED\League\Csv;

use function array_fill_keys;
use function array_filter;
use function array_reduce;
use function array_unique;
use function count;
use function iterator_to_array;
use function strlen;
use function strpos;
use const COUNT_RECURSIVE;
/** @internal */
final class Info implements ByteSequence
{
    private const BOM_SEQUENCE_LIST = [self::BOM_UTF32_BE, self::BOM_UTF32_LE, self::BOM_UTF16_BE, self::BOM_UTF16_LE, self::BOM_UTF8];
    /**
     * Returns the BOM sequence found at the start of the string.
     *
     * If no valid BOM sequence is found an empty string is returned
     */
    public static function fetchBOMSequence(string $str) : ?string
    {
        foreach (self::BOM_SEQUENCE_LIST as $sequence) {
            if (0 === strpos($str, $sequence)) {
                return $sequence;
            }
        }
        return null;
    }
    /**
     * Detect Delimiters usage in a {@link Reader} object.
     *
     * Returns a associative array where each key represents
     * a submitted delimiter and each value the number CSV fields found
     * when processing at most $limit CSV records with the given delimiter
     *
     * @param string[] $delimiters
     *
     * @return array<string, int>
     */
    public static function getDelimiterStats(Reader $csv, array $delimiters, int $limit = 1) : array
    {
        $delimiterFilter = static function (string $value) : bool {
            return 1 === strlen($value);
        };
        $recordFilter = static function (array $record) : bool {
            return 1 < count($record);
        };
        $stmt = Statement::create()->offset(0)->limit($limit);
        $delimiterStats = static function (array $stats, string $delimiter) use($csv, $stmt, $recordFilter) : array {
            $csv->setDelimiter($delimiter);
            $foundRecords = array_filter(iterator_to_array($stmt->process($csv)->getRecords(), \false), $recordFilter);
            $stats[$delimiter] = count($foundRecords, COUNT_RECURSIVE);
            return $stats;
        };
        $currentDelimiter = $csv->getDelimiter();
        $currentHeaderOffset = $csv->getHeaderOffset();
        $csv->setHeaderOffset(null);
        $stats = array_reduce(array_unique(array_filter($delimiters, $delimiterFilter)), $delimiterStats, array_fill_keys($delimiters, 0));
        $csv->setHeaderOffset($currentHeaderOffset);
        $csv->setDelimiter($currentDelimiter);
        return $stats;
    }
}
