feat: show download progress when downloading patch artifacts

packages/shorebird_cli/lib/src/artifact_manager.dart

@@ -18,6 +18,9 @@ final artifactManagerRef = create(ArtifactManager.new);
 /// The [ArtifactManager] instance available in the current zone.
 ArtifactManager get artifactManager => read(artifactManagerRef);
 
+/// A callback that reports progress as a double between 0 and 1.
+typedef ProgressCallback = void Function(double progress);
+
 /// Manages artifacts for the Shorebird CLI.
 class ArtifactManager {
   /// Generates a binary diff between two files and returns the path to the
@@ -53,10 +56,13 @@ class ArtifactManager {
   }
 
   /// Downloads the file at the given [uri] to a temporary directory and returns
-  /// the downloaded [File].
+  /// the downloaded [File]. If [onProgress] is provided, it will be called with
+  /// the download progress as a double between 0 and 1 as the response is
+  /// streamed in.
   Future<File> downloadFile(
     Uri uri, {
     String? outputPath,
+    ProgressCallback? onProgress,
   }) async {
     final request = http.Request('GET', uri);
     final response = await httpClient.send(request);
@@ -81,7 +87,15 @@ class ArtifactManager {
 
     final ioSink = outFile.openWrite();
     try {
-      await ioSink.addStream(response.stream);
+      var downloadedBytes = 0;
+      final totalBytes = response.contentLength;
+      await for (final chunk in response.stream) {
+        ioSink.add(chunk);
+        downloadedBytes += chunk.length;
+        if (onProgress != null && totalBytes != null) {
+          onProgress(downloadedBytes / totalBytes);
+        }
+      }
     } finally {
       await ioSink.close();
     }

packages/shorebird_cli/lib/src/commands/patch/android_patcher.dart

@@ -127,11 +127,19 @@ Looked in:
     final downloadReleaseArtifactProgress = logger.progress(
       'Downloading release artifacts',
     );
+    final numArtifacts = releaseArtifacts.length;
 
-    for (final releaseArtifact in releaseArtifacts.entries) {
+    for (final (i, releaseArtifact) in releaseArtifacts.entries.indexed) {
+      final baseMessage = 'Downloading release artifact ${i + 1}/$numArtifacts';
       try {
+        downloadReleaseArtifactProgress.update(baseMessage);
         final releaseArtifactFile = await artifactManager.downloadFile(
           Uri.parse(releaseArtifact.value.url),
+          onProgress: (progress) {
+            downloadReleaseArtifactProgress.update(
+              '$baseMessage (${(progress * 100).toStringAsFixed(0)}%)',
+            );
+          },
         );
         releaseArtifactPaths[releaseArtifact.key] = releaseArtifactFile.path;
       } catch (error) {

packages/shorebird_cli/lib/src/commands/patch/patch_command.dart

@@ -451,12 +451,18 @@ ${summary.join('\n')}
     required ReleaseArtifact releaseArtifact,
     required Patcher patcher,
   }) async {
-    final downloadProgress =
-        logger.progress('Downloading ${patcher.primaryReleaseArtifactArch}');
+    final downloadMessage = 'Downloading ${patcher.primaryReleaseArtifactArch}';
+    final downloadProgress = logger.progress(downloadMessage);
     final File artifactFile;
     try {
-      artifactFile =
-          await artifactManager.downloadFile(Uri.parse(releaseArtifact.url));
+      artifactFile = await artifactManager.downloadFile(
+        Uri.parse(releaseArtifact.url),
+        onProgress: (progress) {
+          downloadProgress.update(
+            '$downloadMessage (${(progress * 100).toStringAsFixed(0)}%)',
+          );
+        },
+      );
     } catch (e) {
       downloadProgress.fail(e.toString());
       throw ProcessExit(ExitCode.software.code);

packages/shorebird_cli/test/src/artifact_manager_test.dart

@@ -242,6 +242,64 @@ void main() {
 
         expect(result.path, equals(outFile.path));
       });
+
+      group('with progress update', () {
+        group('when response contentLength is null', () {
+          setUp(() {
+            when(() => httpClient.send(any())).thenAnswer(
+              (_) async => http.StreamedResponse(
+                Stream.fromIterable([
+                  [1],
+                  [2],
+                  [3],
+                ]),
+                HttpStatus.ok,
+              ),
+            );
+          });
+
+          test('does not call onProgress callback', () async {
+            await runWithOverrides(
+              () => artifactManager.downloadFile(
+                Uri.parse('https://example.com'),
+                onProgress: (progress) {
+                  fail(
+                    '''onProgress should not be called when the response does not have a contentLength''',
+                  );
+                },
+              ),
+            );
+          });
+        });
+
+        group('when response contentLength is not null', () {
+          setUp(() {
+            when(() => httpClient.send(any())).thenAnswer(
+              (_) async => http.StreamedResponse(
+                Stream.fromIterable([
+                  [1],
+                  [2],
+                  [3],
+                ]),
+                HttpStatus.ok,
+                contentLength: 3,
+              ),
+            );
+          });
+
+          test('calls onProgress with correct percentage', () async {
+            final progressUpdates = <double>[];
+            await runWithOverrides(
+              () => artifactManager.downloadFile(
+                Uri.parse('https://example.com'),
+                onProgress: progressUpdates.add,
+              ),
+            );
+
+            expect(progressUpdates, equals([1 / 3, 2 / 3, 3 / 3]));
+          });
+        });
+      });
     });
 
     group('extractZip', () {

packages/shorebird_cli/test/src/commands/patch/android_patcher_test.dart

@@ -439,14 +439,21 @@ Looked in:
             Arch.x86_64: releaseArtifact,
           },
         );
-        when(() => artifactManager.downloadFile(any()))
-            .thenAnswer((_) async => File(''));
+        when(
+          () => artifactManager.downloadFile(
+            any(),
+            onProgress: any(named: 'onProgress'),
+          ),
+        ).thenAnswer((_) async => File(''));
       });
 
       group('when release artifact fails to download', () {
         setUp(() {
           when(
-            () => artifactManager.downloadFile(any()),
+            () => artifactManager.downloadFile(
+              any(),
+              onProgress: any(named: 'onProgress'),
+            ),
           ).thenThrow(Exception('error'));
         });
 
@@ -544,6 +551,31 @@ Looked in:
           }
         });
 
+        test('updates progress with download percentage', () async {
+          await runWithOverrides(
+            () => patcher.createPatchArtifacts(
+              appId: 'appId',
+              releaseId: 0,
+              releaseArtifact: File('release.aab'),
+            ),
+          );
+
+          final capturedOnProgress = verify(
+            () => artifactManager.downloadFile(
+              any(),
+              onProgress: captureAny(named: 'onProgress'),
+            ),
+          ).captured.first as ProgressCallback;
+
+          capturedOnProgress(0.5);
+
+          verify(
+            () => progress.update(
+              'Downloading release artifact 1/3 (50%)',
+            ),
+          ).called(1);
+        });
+
         group('when a private key is provided', () {
           setUp(() {
             final privateKey = File(

packages/shorebird_cli/test/src/commands/patch/patch_command_test.dart

@@ -169,7 +169,10 @@ void main() {
       when(aotTools.isLinkDebugInfoSupported).thenAnswer((_) async => true);
 
       when(
-        () => artifactManager.downloadFile(any()),
+        () => artifactManager.downloadFile(
+          any(),
+          onProgress: any(named: 'onProgress'),
+        ),
       ).thenAnswer((_) async => File(''));
 
       when(() => cache.updateAll()).thenAnswer((_) async => {});
@@ -888,7 +891,12 @@ Please re-run the release command for this version or create a new release.''',
       final error = Exception('Failed to download primary release artifact.');
 
       setUp(() {
-        when(() => artifactManager.downloadFile(any())).thenThrow(error);
+        when(
+          () => artifactManager.downloadFile(
+            any(),
+            onProgress: any(named: 'onProgress'),
+          ),
+        ).thenThrow(error);
       });
 
       test('logs error and exits with code 70', () async {
@@ -967,5 +975,32 @@ Please re-run the release command for this version or create a new release.''',
         ).called(1);
       });
     });
+
+    group('downloadPrimaryReleaseArtifact', () {
+      setUp(() {
+        final releaseArtifact = MockReleaseArtifact();
+        when(() => releaseArtifact.url).thenReturn('http://example.com');
+      });
+
+      test('updates progress with download percentage', () async {
+        await runWithOverrides(
+          () => command.downloadPrimaryReleaseArtifact(
+            releaseArtifact: releaseArtifact,
+            patcher: patcher,
+          ),
+        );
+
+        final capturedOnProgress = verify(
+          () => artifactManager.downloadFile(
+            Uri.parse(releaseArtifact.url),
+            onProgress: captureAny(named: 'onProgress'),
+          ),
+        ).captured.single as ProgressCallback;
+
+        capturedOnProgress(0.5);
+
+        verify(() => progress.update('Downloading aab (50%)')).called(1);
+      });
+    });
   });
 }