feat(frontend): download responsable history csv

eme-frontend/lib/screens/responsable_screen.dart

@@ -4,6 +4,7 @@ import "package:google_fonts/google_fonts.dart";
 import "../demo_identity.dart";
 import "../services/responsable_service.dart";
 import "../theme/ensup_colors.dart";
+import "../utils/file_download.dart";
 
 const _workspaceBackground = Color(0xFFF3F6F9);
 const _orange = Color(0xFFD97706);
@@ -19,6 +20,7 @@ class _ResponsableScreenState extends State<ResponsableScreen> {
   late Future<_ResponsableData> _future = _charger();
   int _onglet = 0;
   bool _transitionEnCours = false;
+  bool _exportEnCours = false;
 
   Future<_ResponsableData> _charger() async {
     final dashboard = await ResponsableService.dashboard();
@@ -79,6 +81,33 @@ class _ResponsableScreenState extends State<ResponsableScreen> {
     }
   }
 
+  Future<void> _exporterHistorique() async {
+    if (_exportEnCours) return;
+
+    setState(() => _exportEnCours = true);
+    try {
+      final file = await ResponsableService.exporterHistorique();
+      downloadFile(
+        bytes: file.bytes,
+        fileName: file.fileName,
+        contentType: file.contentType,
+      );
+      if (!mounted) return;
+      ScaffoldMessenger.of(
+        context,
+      ).showSnackBar(const SnackBar(content: Text("Export CSV téléchargé.")));
+    } catch (error) {
+      if (!mounted) return;
+      ScaffoldMessenger.of(
+        context,
+      ).showSnackBar(SnackBar(content: Text(error.toString())));
+    } finally {
+      if (mounted) {
+        setState(() => _exportEnCours = false);
+      }
+    }
+  }
+
   String? _prochainStatut(String? statut) {
     return switch (statut) {
       "DETECTEE" => "EN_COURS_TRAITEMENT",
@@ -195,17 +224,15 @@ class _ResponsableScreenState extends State<ResponsableScreen> {
         items: data.historique,
         builder: _historiqueTile,
         action: OutlinedButton.icon(
-          onPressed: () {
-            ScaffoldMessenger.of(context).showSnackBar(
-              const SnackBar(
-                content: Text(
-                  "Export disponible via /api/responsable/historique/export.csv",
-                ),
-              ),
-            );
-          },
-          icon: const Icon(Icons.download_outlined, size: 16),
-          label: const Text("Export CSV"),
+          onPressed: _exportEnCours ? null : _exporterHistorique,
+          icon: _exportEnCours
+              ? const SizedBox(
+                  width: 16,
+                  height: 16,
+                  child: CircularProgressIndicator(strokeWidth: 2),
+                )
+              : const Icon(Icons.download_outlined, size: 16),
+          label: Text(_exportEnCours ? "Export en cours" : "Export CSV"),
         ),
         searchableText: (item) => "${item["action"]} ${item["description"]}",
       ),

eme-frontend/lib/services/api_client.dart

@@ -1,4 +1,5 @@
 import "dart:convert";
+import "dart:typed_data";
 import "package:http/http.dart" as http;
 
 /// Erreur levée par le client API (serveur injoignable ou réponse en échec).
@@ -11,6 +12,18 @@ class ApiException implements Exception {
   String toString() => message;
 }
 
+class ApiFile {
+  const ApiFile({
+    required this.bytes,
+    required this.fileName,
+    required this.contentType,
+  });
+
+  final Uint8List bytes;
+  final String fileName;
+  final String contentType;
+}
+
 /// Point d'accès unique au backend : centralise l'URL de base, l'en-tête
 /// d'authentification (simulée) et la gestion des erreurs.
 class ApiClient {
@@ -44,6 +57,37 @@ class ApiClient {
     throw ApiException(_messageErreur(reponse));
   }
 
+  static Future<ApiFile> getFile(
+    String chemin, {
+    required String fallbackFileName,
+    String utilisateurEmail = _utilisateurEmail,
+  }) async {
+    final uri = Uri.parse("$_baseUrl$chemin");
+
+    late final http.Response reponse;
+    try {
+      reponse = await http.get(
+        uri,
+        headers: {"x-user-email": utilisateurEmail},
+      );
+    } catch (_) {
+      throw const ApiException(
+        "Impossible de joindre le serveur. Vérifiez que le backend est démarré.",
+      );
+    }
+
+    if (reponse.statusCode < 200 || reponse.statusCode >= 300) {
+      throw ApiException(_messageErreur(reponse));
+    }
+
+    return ApiFile(
+      bytes: reponse.bodyBytes,
+      fileName: _fileName(reponse, fallbackFileName),
+      contentType:
+          reponse.headers["content-type"] ?? "application/octet-stream",
+    );
+  }
+
   static Future<dynamic> post(
     String chemin,
     Map<String, dynamic> body, {
@@ -116,4 +160,15 @@ class ApiClient {
     }
     return "Erreur ${reponse.statusCode}";
   }
+
+  static String _fileName(http.Response reponse, String fallback) {
+    final disposition = reponse.headers["content-disposition"];
+    if (disposition == null) return fallback;
+
+    final match = RegExp(
+      "filename=\"?([^\";]+)\"?",
+      caseSensitive: false,
+    ).firstMatch(disposition);
+    return match?.group(1) ?? fallback;
+  }
 }

eme-frontend/lib/services/responsable_service.dart

@@ -29,6 +29,12 @@ class ResponsableService {
   static Future<List<Map<String, dynamic>>> historique() =>
       _liste("/responsable/historique");
 
+  static Future<ApiFile> exporterHistorique() => ApiClient.getFile(
+    "/responsable/historique/export.csv",
+    fallbackFileName: "historique-responsable.csv",
+    utilisateurEmail: _email,
+  );
+
   static Future<int> marquerNotificationsLues() async {
     final reponse = await ApiClient.patch(
       "/responsable/notifications/lu-toutes",

eme-frontend/lib/utils/file_download.dart

@@ -0,0 +1,21 @@
+// ignore_for_file: avoid_web_libraries_in_flutter, deprecated_member_use
+
+import "dart:html" as html;
+import "dart:typed_data";
+
+void downloadFile({
+  required Uint8List bytes,
+  required String fileName,
+  required String contentType,
+}) {
+  final blob = html.Blob([bytes], contentType);
+  final url = html.Url.createObjectUrlFromBlob(blob);
+  final anchor = html.AnchorElement(href: url)
+    ..download = fileName
+    ..style.display = "none";
+
+  html.document.body?.children.add(anchor);
+  anchor.click();
+  anchor.remove();
+  html.Url.revokeObjectUrl(url);
+}