Add MusicPlayerExample

.github/workflows/build-test-and-docs.yml

@@ -58,7 +58,8 @@ jobs:
         swift build --target NotesExample && \
         swift build --target PathsExample && \
         swift build --target WebViewExample && \
-        swift build --target AdvancedCustomizationExample
+        swift build --target AdvancedCustomizationExample && \
+        swift build --target MusicPlayerExample
 
     - name: Test
       run: swift test --test-product swift-cross-uiPackageTests
@@ -114,6 +115,7 @@ jobs:
             buildtarget PathsExample
             buildtarget WebViewExample
             buildtarget AdvancedCustomizationExample
+            buildtarget MusicPlayerExample
 
             if [ $device_type != TV ]; then
               # Slider is not implemented for tvOS
@@ -179,6 +181,7 @@ jobs:
         buildtarget RandomNumberGeneratorExample
         buildtarget WebViewExample
         buildtarget AdvancedCustomizationExample
+        buildtarget MusicPlayerExample
         # TODO test whether this works on Catalyst
         # buildtarget SplitExample
 
@@ -323,7 +326,8 @@ jobs:
         swift build --target SpreadsheetExample && \
         swift build --target NotesExample && \
         swift build --target PathsExample && \
-        swift build --target AdvancedCustomizationExample
+        swift build --target AdvancedCustomizationExample && \
+        swift build --target MusicPlayerExample
 
     - name: Test
       run: swift test --test-product swift-cross-uiPackageTests

Examples/Bundler.toml

@@ -74,3 +74,9 @@ version = '0.1.0'
 identifier = 'dev.swiftcrossui.AdvancedCustomizationExample'
 product = 'AdvancedCustomizationExample'
 version = '0.1.0'
+
+[apps.MusicPlayerExample]
+identifier = 'dev.swiftcrossui.MusicPlayerExample'
+product = 'MusicPlayerExample'
+version = '0.1.0'
+icon = 'Icons/MusicPlayerExample.png'

Examples/Package.swift

@@ -31,6 +31,10 @@ let package = Package(
     platforms: [.macOS(.v10_15), .iOS(.v13), .tvOS(.v13), .macCatalyst(.v13)],
     dependencies: [
         .package(name: "swift-cross-ui", path: ".."),
+        .package(
+            url: "https://github.com/stackotter/swift-miniaudio",
+            .upToNextMinor(from: "0.1.0")
+        ),
     ] + hotReloadingDependencies,
     targets: [
         .executableTarget(
@@ -94,6 +98,12 @@ let package = Package(
             name: "AdvancedCustomizationExample",
             dependencies: exampleDependencies,
             resources: [.copy("Banner.png")]
+        ),
+        .executableTarget(
+            name: "MusicPlayerExample",
+            dependencies: [
+                .product(name: "MiniAudio", package: "swift-miniaudio")
+            ] + exampleDependencies
         )
     ]
 )

Examples/Sources/MusicPlayerExample/Config.swift

@@ -0,0 +1,20 @@
+import Foundation
+
+/// The user's configuration. Just contains the user's playlists for now.
+struct Config: Codable {
+    /// The default configuration used when the configuration file is invalid
+    /// or missing.
+    static let `default` = Self(playlists: [], songs: [])
+
+    /// The user's playlists.
+    var playlists: [Playlist]
+
+    /// The user's songs
+    var songs: [Song]
+
+    func song(withId id: UUID) -> Song? {
+        songs.first { song in
+            song.id == id
+        }
+    }
+}

Examples/Sources/MusicPlayerExample/MediaControlButton.swift

@@ -0,0 +1,28 @@
+import SwiftCrossUI
+
+struct MediaControlButton: View {
+    @Environment(\.isEnabled) var isEnabled
+
+    var isPlaying: Bool
+
+    var playbackButtonColor: Color {
+        isEnabled ? .green : .gray
+    }
+
+    var body: some View {
+        Group {
+            if isPlaying {
+                applyShapeStyle(PauseButton())
+            } else {
+                applyShapeStyle(PlayButton())
+            }
+        }
+    }
+
+    func applyShapeStyle<S: Shape>(_ shape: S) -> some StyledShape {
+        shape.stroke(
+            playbackButtonColor,
+            style: StrokeStyle(width: 4, cap: .round, join: .round)
+        ).fill(playbackButtonColor)
+    }
+}

Examples/Sources/MusicPlayerExample/MediaPlayer.swift

@@ -0,0 +1,108 @@
+import Foundation
+import SwiftCrossUI
+
+class MediaPlayer: SwiftCrossUI.ObservableObject {
+    @SwiftCrossUI.Published
+    var currentSong: UUID?
+
+    /// The cursor of the current song in seconds.
+    @SwiftCrossUI.Published
+    var cursor: Double = 0
+
+    var progress: Double? {
+        if let duration = songFile?.duration, duration != 0 {
+            cursor / duration
+        } else {
+            nil
+        }
+    }
+
+    @SwiftCrossUI.Published
+    var isPlaying = false
+
+    private var songFile: SongStorage.SongFile?
+    private var progressTask: Task<Void, Never>?
+
+    func isPlayingSong(id: UUID) -> Bool {
+        id == currentSong && isPlaying
+    }
+
+    func play(_ songFile: SongStorage.SongFile, id: UUID) throws {
+        if id != currentSong {
+            // Rewind new song to the start if it's not the current song.
+            try songFile.sound.seek(toSecond: 0)
+
+            if let currentSongFile = self.songFile {
+                // Stop current song if the new song is different.
+                try currentSongFile.sound.stop()
+            }
+        }
+
+        cursor = try songFile.sound.cursor
+
+        // Make sure that the last fallible step is starting the song, otherwise
+        // errors could be kinda annoying.
+        try songFile.sound.start()
+
+        progressTask?.cancel()
+        progressTask = createProgressTask(for: songFile)
+
+        isPlaying = true
+        self.currentSong = id
+        self.songFile = songFile
+    }
+
+    func pause() throws {
+        if isPlaying, let songFile {
+            try songFile.sound.stop()
+            progressTask?.cancel()
+            isPlaying = false
+        }
+    }
+
+    func resume() throws {
+        if !isPlaying, let songFile {
+            try songFile.sound.start()
+            progressTask = createProgressTask(for: songFile)
+            isPlaying = true
+        }
+    }
+
+    /// If the current song is playing, pauses it, otherwise resumes it.
+    func toggleCurrentSong() throws {
+        if isPlaying {
+            try pause()
+        } else {
+            try resume()
+        }
+    }
+
+    /// Creates a task which updates the current song's progress at a given
+    /// frequency (updates per second).
+    private func createProgressTask(
+        for songFile: SongStorage.SongFile,
+        frequency: Double = 30
+    ) -> Task<Void, Never> {
+        Task {
+            while true {
+                do {
+                    try await Task.sleep(nanoseconds: UInt64(1 / frequency * 1_000_000_000))
+                } catch {
+                    break
+                }
+
+                do {
+                    let cursor = try songFile.sound.cursor
+                    // TODO: Is this needed? If so, can SwiftCrossUI enforce it?
+                    Task { @MainActor in
+                        self.cursor = cursor
+                    }
+                } catch {
+                    // TODO: Propagate this warning to the user
+                    print("warning: Failed to update song cursor")
+                    break
+                }
+            }
+        }
+    }
+}

Examples/Sources/MusicPlayerExample/MusicPlayerApp.swift

@@ -0,0 +1,88 @@
+import DefaultBackend
+import Foundation
+import SwiftCrossUI
+import MiniAudio
+
+#if canImport(SwiftBundlerRuntime)
+    import SwiftBundlerRuntime
+#endif
+
+@main
+@HotReloadable
+struct MusicPlayerApp: App {
+    @Environment(\.presentAlert) var presentAlert
+
+    @State var storage: Storage?
+    @State var initializationError: String?
+    @State var mediaPlayer = MediaPlayer()
+    var engine: Engine?
+
+    init() {
+        let identifier = Self.metadata?.identifier ?? "com.example.MusicPlayerExample"
+
+        let engine: Engine
+        do {
+            engine = try Engine()
+        } catch {
+            initializationError = "Failed to load MiniAudio engine: \(error.localizedDescription)"
+            return
+        }
+        self.engine = engine
+
+        let applicationSupport: URL
+        do {
+            applicationSupport = try FileManager.default.url(
+                for: .applicationSupportDirectory,
+                in: .userDomainMask,
+                appropriateFor: nil,
+                create: true
+            )
+        } catch {
+            initializationError = """
+                Failed to get application support directory: \(error.localizedDescription)
+                """
+            return
+        }
+
+        let directory = applicationSupport.appendingPathComponent(identifier)
+        let storage = Storage(directory: directory, engine: engine)
+        _storage = State(wrappedValue: storage)
+    }
+
+    var body: some Scene {
+        WindowGroup("Music Player") {
+            #hotReloadable {
+                content
+            }
+        }
+    }
+
+    var content: some View {
+        VStack {
+            if let initializationError {
+                Text(initializationError)
+                    .frame(maxWidth: 400)
+                    .font(.system(size: 20, weight: nil, design: nil))
+
+                Button("Exit app") {
+                    Foundation.exit(1)
+                }
+            } else if let storage, storage.loaded {
+                RootView(storage: storage, mediaPlayer: mediaPlayer)
+            } else {
+                ProgressView("Loading")
+            }
+        }.task {
+            guard let storage else {
+                initializationError = "Failed to load storage: unknown reason"
+                return
+            }
+
+            do {
+                try storage.load()
+            } catch {
+                initializationError = "Failed to load config: \(error.localizedDescription)"
+            }
+        }
+    }
+}

Examples/Sources/MusicPlayerExample/MusicPlayerError.swift

@@ -0,0 +1,9 @@
+import Foundation
+
+struct MusicPlayerError: LocalizedError {
+    var message: String
+
+    var errorDescription: String? {
+        message
+    }
+}

Examples/Sources/MusicPlayerExample/PauseButton.swift

@@ -0,0 +1,17 @@
+import SwiftCrossUI
+
+struct PauseButton: Shape {
+    func path(in bounds: Path.Rect) -> Path {
+        let yInset: Double = 2
+        let xInset: Double = 4
+        return Path()
+            .move(to: [xInset, yInset])
+            .addLine(to: [xInset, bounds.maxY - yInset])
+            .move(to: [bounds.maxX - xInset, yInset])
+            .addLine(to: [bounds.maxX - xInset, bounds.maxY - yInset])
+    }
+
+    func size(fitting proposal: ProposedViewSize) -> ViewSize {
+        ViewSize(17, 22)
+    }
+}

Examples/Sources/MusicPlayerExample/PlayButton.swift

@@ -0,0 +1,16 @@
+import SwiftCrossUI
+
+struct PlayButton: Shape {
+    func path(in bounds: Path.Rect) -> Path {
+        let inset: Double = 2
+        return Path()
+            .move(to: [inset, inset])
+            .addLine(to: [bounds.maxX - inset, bounds.y + bounds.height / 2])
+            .addLine(to: [inset, bounds.maxY - inset])
+            .addLine(to: [inset, inset])
+    }
+
+    func size(fitting proposal: ProposedViewSize) -> ViewSize {
+        ViewSize(17, 22)
+    }
+}