mesreleves-php/app/Http/Controllers/ExportController.php

<?php

namespace App\Http\Controllers;

use App\Enums\FieldType;
use App\Models\Source;
use Illuminate\Http\Response;

class ExportController extends Controller
{
    /** Export CSV de tous les relevés d'une source */
    public function sourceCsv(Source $source): Response
    {
        $this->authorize('view', $source);

        $source->load(['sourceType.fields', 'releves']);
        $fields = $source->sourceType->fields->sortBy('order');

        $handle = fopen('php://temp', 'r+');

        // BOM UTF-8 pour la compatibilité Excel
        fwrite($handle, "\xEF\xBB\xBF");

        // En-tête
        fputcsv($handle, $fields->pluck('label')->toArray(), ';');

        // Lignes
        foreach ($source->releves as $releve) {
            $row = [];
            foreach ($fields as $field) {
                $val   = $releve->data[$field->name] ?? null;
                $row[] = $this->formatCsvValue($val, $field->type);
            }
            fputcsv($handle, $row, ';');
        }

        rewind($handle);
        $csv = stream_get_contents($handle);
        fclose($handle);

        $filename = $this->sanitizeFilename($source->nom) . '.csv';

        return response($csv, 200, [
            'Content-Type'        => 'text/csv; charset=UTF-8',
            'Content-Disposition' => "attachment; filename=\"{$filename}\"",
        ]);
    }

    private function formatCsvValue(mixed $val, FieldType $type): string
    {
        if ($val === null || $val === '') {
            return '';
        }

        return match ($type) {
            FieldType::Boolean => $val ? 'Oui' : 'Non',
            FieldType::Date    => is_array($val)
                ? trim(($val['valeur'] ?? '') . (
                    ! empty($val['calendrier']) && $val['calendrier'] !== 'gregorien'
                        ? ' (' . $val['calendrier'] . ')'
                        : ''
                ))
                : (string) $val,
            FieldType::Place   => is_array($val) ? ($val['nom_long'] ?? '') : (string) $val,
            default            => (string) $val,
        };
    }

    private function sanitizeFilename(string $name): string
    {
        $name = iconv('UTF-8', 'ASCII//TRANSLIT', $name) ?: $name;
        return preg_replace('/[^a-zA-Z0-9_-]/', '_', $name);
    }
}