merge: reject a local track as a recording source

lib/estado/estado_grabacion.dart

@@ -18,6 +18,23 @@ import '../servicios/servicio_grabacion_radio.dart';
 /// `EstadoRadio` consumers (S4-R5). Playback orchestration (stop recording on
 /// pause/stop/station switch) stays in `EstadoRadio`, which keeps a reference
 /// to this notifier.
+/// Whether [emisora] is something the recorder can actually capture: a live
+/// network stream.
+///
+/// The recorder opens the URL as an HTTP stream and writes the bytes to disk,
+/// so anything else fails inside the HTTP client with a message no user can
+/// act on ("Unsupported scheme 'content' in URI content://...").
+///
+/// This is not hypothetical tidiness. `PluriWaveAudioHandler._cambiarFuente`
+/// sets `emisoraActual` for EVERY source it plays, so a local MP3 shows up
+/// here as an `Emisora` whose `url` is the `content://` document URI it was
+/// opened from. Recording a local file makes no sense anyway — it is already
+/// on the device.
+bool esEmisoraGrabable(Emisora emisora) {
+  final esquema = Uri.tryParse(emisora.url)?.scheme.toLowerCase();
+  return esquema == 'http' || esquema == 'https';
+}
+
 class EstadoGrabacion extends ChangeNotifier {
   EstadoGrabacion({
     ServicioGrabacionRadio? servicio,
@@ -72,7 +89,13 @@ class EstadoGrabacion extends ChangeNotifier {
 
   Future<void> iniciar({Duration? duracion}) async {
     final actual = _emisoraActual();
-    if (actual == null) {
+    // `emisoraActual` is set by `_cambiarFuente` for EVERY source, local
+    // tracks included -- a local file becomes an `Emisora` whose `url` is the
+    // SAF `content://` URI it was opened from. Handing that to the recorder
+    // produced "Unsupported scheme 'content' in URI content://..." on screen,
+    // and it started happening only once local music playback existed: before
+    // that, whatever was playing was always a real station.
+    if (actual == null || !esEmisoraGrabable(actual)) {
       _alError?.call(_textos.recordingSelectStationFirst);
       return;
     }

test/estado/estado_grabacion_fuente_grabable_test.dart

@@ -0,0 +1,57 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pluriwave/estado/estado_grabacion.dart';
+import 'package:pluriwave/modelos/emisora.dart';
+
+/// Reported: recording a station stopped working, with this on screen —
+///
+///   No se pudo iniciar la grabación: Invalid argument(s): Unsupported scheme
+///   'content' in URI content://com.android.externalstorage.documents/tree/
+///   primary%3AMusic/document/primary%3AMusic%2F...%2FNew Limit - Smile.mp3
+///
+/// The URI in the message is a LOCAL MP3, not a station.
+/// `PluriWaveAudioHandler._cambiarFuente` sets `emisoraActual` for every
+/// source it plays, so a local track becomes an `Emisora` whose `url` is the
+/// SAF `content://` document URI it was opened from. The recorder then tried
+/// to open that as an HTTP stream.
+///
+/// "It used to work" is accurate: before local music playback existed,
+/// whatever was playing was always a real station, so this could not happen.
+void main() {
+  Emisora conUrl(String url) => Emisora(uuid: 'u', nombre: 'n', url: url);
+
+  test('un stream de red es grabable', () {
+    expect(esEmisoraGrabable(conUrl('http://stream.example.com/live')), isTrue);
+    expect(
+      esEmisoraGrabable(conUrl('https://stream.example.com/live')),
+      isTrue,
+    );
+    expect(
+      esEmisoraGrabable(conUrl('HTTPS://STREAM.EXAMPLE.COM/live')),
+      isTrue,
+      reason: 'el esquema no distingue mayúsculas',
+    );
+  });
+
+  test('la URI content:// de una pista local NO es grabable — el caso '
+      'exacto del reporte', () {
+    expect(
+      esEmisoraGrabable(
+        conUrl(
+          'content://com.android.externalstorage.documents/tree/'
+          'primary%3AMusic/document/primary%3AMusic%2FNew%20Limit%20-%20'
+          'Smile.mp3',
+        ),
+      ),
+      isFalse,
+    );
+  });
+
+  test('ni un fichero local, ni una url vacía o rota', () {
+    expect(
+      esEmisoraGrabable(conUrl('file:///storage/emulated/0/a.mp3')),
+      isFalse,
+    );
+    expect(esEmisoraGrabable(conUrl('')), isFalse);
+    expect(esEmisoraGrabable(conUrl('no es una uri')), isFalse);
+  });
+}