<?php

namespace Modules\Core\Export;

/**
 * A generic columns + rows -> CSV file writer. No knowledge of any domain (GDPR,
 * catalog, accounting, ...) — a caller supplies the schema (CsvColumn[]) and the
 * data source (any iterable of records), and this writes one CSV. Reusable for
 * any future bulk-export need without modification.
 */
class CsvWriter
{
    /**
     * @param  array<int, CsvColumn>  $columns
     * @param  iterable<mixed>  $rows
     */
    public function write(array $columns, iterable $rows, string $path): void
    {
        $handle = fopen($path, 'w');

        fputcsv($handle, array_map(fn (CsvColumn $column) => $column->header, $columns));

        foreach ($rows as $row) {
            fputcsv($handle, array_map(
                fn (CsvColumn $column) => $this->stringify(($column->value)($row)),
                $columns
            ));
        }

        fclose($handle);
    }

    private function stringify(mixed $value): string
    {
        if ($value === null) {
            return '';
        }

        if (is_array($value)) {
            return json_encode($value);
        }

        return (string) $value;
    }
}