Add support for playing album on cast.ente.io (#1694)

lib/gateways/cast_gw.dart

@@ -0,0 +1,50 @@
+import "package:dio/dio.dart";
+
+class CastGateway {
+  final Dio _enteDio;
+
+  CastGateway(this._enteDio);
+
+  Future<String?> getPublicKey(String deviceCode) async {
+    try {
+      final response = await _enteDio.get(
+        "/cast/device-info/$deviceCode",
+      );
+      return response.data["publicKey"];
+    } catch (e) {
+      if (e is DioError &&
+          e.response != null &&
+          e.response!.statusCode == 404) {
+        return null;
+      }
+      rethrow;
+    }
+  }
+
+  Future<void> publishCastPayload(
+    String code,
+    String castPayload,
+    int collectionID,
+    String castToken,
+  ) {
+    return _enteDio.post(
+      "/cast/cast-data/",
+      data: {
+        "deviceCode": code,
+        "encPayload": castPayload,
+        "collectionID": collectionID,
+        "castToken": castToken,
+      },
+    );
+  }
+
+  Future<void> revokeAllTokens() async {
+    try {
+      await _enteDio.delete(
+        "/cast/revoke-all-tokens/",
+      );
+    } catch (e) {
+      // swallow error
+    }
+  }
+}

lib/l10n/intl_en.arb

@@ -1187,5 +1187,10 @@
   "selectALocationFirst": "Select a location first",
   "changeLocationOfSelectedItems": "Change location of selected items?",
   "editsToLocationWillOnlyBeSeenWithinEnte": "Edits to location will only be seen within Ente",
-  "cleanUncategorized": "Clean Uncategorized"
+  "cleanUncategorized": "Clean Uncategorized",
+  "playOnTv": "Play album on TV",
+  "pair": "Pair",
+  "deviceNotFound": "Device not found",
+  "castInstruction": "Visit cast.ente.io on the device you want to pair.\n\nEnter the code below to play the album on your TV.",
+  "deviceCodeHint": "Enter the code"
 }

lib/services/collections_service.dart

@@ -473,6 +473,23 @@ class CollectionsService {
     });
   }
 
+  String getCastData(
+    String castToken,
+    Collection collection,
+    String publicKey,
+  ) {
+    final String payload = jsonEncode({
+      "collectionID": collection.id,
+      "castToken": castToken,
+      "collectionKey": CryptoUtil.bin2base64(getCollectionKey(collection.id)),
+    });
+    final encPayload = CryptoUtil.sealSync(
+      CryptoUtil.base642bin(base64Encode(payload.codeUnits)),
+      CryptoUtil.base642bin(publicKey),
+    );
+    return CryptoUtil.bin2base64(encPayload);
+  }
+
   Future<List<User>> share(
     int collectionID,
     String email,

lib/ui/viewer/gallery/gallery_app_bar_widget.dart

@@ -6,10 +6,14 @@ import "package:flutter/cupertino.dart";
 import 'package:flutter/material.dart';
 import 'package:logging/logging.dart';
 import 'package:photos/core/configuration.dart';
+import "package:photos/core/constants.dart";
 import 'package:photos/core/event_bus.dart';
+import "package:photos/core/network/network.dart";
 import "package:photos/db/files_db.dart";
 import 'package:photos/events/subscription_purchased_event.dart';
+import "package:photos/gateways/cast_gw.dart";
 import "package:photos/generated/l10n.dart";
+import "package:photos/l10n/l10n.dart";
 import 'package:photos/models/backup_status.dart';
 import 'package:photos/models/collection/collection.dart';
 import 'package:photos/models/device_collection.dart';
@@ -36,6 +40,7 @@ import 'package:photos/utils/dialog_util.dart';
 import 'package:photos/utils/magic_util.dart';
 import 'package:photos/utils/navigation_util.dart';
 import 'package:photos/utils/toast_util.dart';
+import "package:uuid/uuid.dart";
 
 class GalleryAppBarWidget extends StatefulWidget {
   final GalleryType type;
@@ -64,6 +69,7 @@ enum AlbumPopupAction {
   ownedArchive,
   sharedArchive,
   ownedHide,
+  playOnTv,
   sort,
   leave,
   freeUpSpace,
@@ -472,6 +478,22 @@ class _GalleryAppBarWidgetState extends State<GalleryAppBarWidget> {
         ),
       );
     }
+    if (widget.collection != null && isInternalUser) {
+      items.add(
+        PopupMenuItem(
+          value: AlbumPopupAction.playOnTv,
+          child: Row(
+            children: [
+              const Icon(Icons.tv_outlined),
+              const Padding(
+                padding: EdgeInsets.all(8),
+              ),
+              Text(context.l10n.playOnTv),
+            ],
+          ),
+        ),
+      );
+    }
 
     if (galleryType.canDelete()) {
       items.add(
@@ -579,6 +601,8 @@ class _GalleryAppBarWidgetState extends State<GalleryAppBarWidget> {
               await _removeQuickLink();
             } else if (value == AlbumPopupAction.leave) {
               await _leaveAlbum(context);
+            } else if (value == AlbumPopupAction.playOnTv) {
+              await castAlbum();
             } else if (value == AlbumPopupAction.freeUpSpace) {
               await _deleteBackedUpFiles(context);
             } else if (value == AlbumPopupAction.setCover) {
@@ -797,4 +821,40 @@ class _GalleryAppBarWidgetState extends State<GalleryAppBarWidget> {
     );
     setState(() {});
   }
+
+  Future<void> castAlbum() async {
+    final gw = CastGateway(NetworkClient.instance.enteDio);
+    // stop any existing cast session
+    gw.revokeAllTokens().ignore();
+    await showTextInputDialog(
+      context,
+      title: context.l10n.playOnTv,
+      body: S.of(context).castInstruction,
+      submitButtonLabel: S.of(context).pair,
+      textInputType: TextInputType.streetAddress,
+      hintText: context.l10n.deviceCodeHint,
+      onSubmit: (String text) async {
+        try {
+          String code = text.trim();
+          final String? publicKey = await gw.getPublicKey(code);
+          if (publicKey == null) {
+            showToast(context, S.of(context).deviceNotFound);
+            return;
+          }
+          final String castToken = Uuid().v4().toString();
+          final castPayload = CollectionsService.instance
+              .getCastData(castToken, widget.collection!, publicKey);
+          await gw.publishCastPayload(
+            code,
+            castPayload,
+            widget.collection!.id,
+            castToken,
+          );
+        } catch (e, s) {
+          _logger.severe("Failed to cast album", e, s);
+          await showGenericErrorDialog(context: context, error: e);
+        }
+      },
+    );
+  }
 }