feat(SwiftDependencies): add a swift-dependencies library wrapper

* TTS is now usable out of the box with Point-Free `Dependencies`
  library.

Author: renaudjenny

Package.resolved

@@ -11,12 +11,19 @@ let package = Package(
     ],
     products: [
         .library(name: "SwiftTTS", targets: ["SwiftTTS"]),
+        .library(name: "SwiftTTSDependency", targets: ["SwiftTTSDependency"]),
         .library(name: "SwiftTTSCombine", targets: ["SwiftTTSCombine"]),
     ],
-    dependencies: [],
+    dependencies: [
+        .package(url: "https://github.com/pointfreeco/swift-dependencies", from: "0.2.0"),
+    ],
     targets: [
         .target(name: "SwiftTTS", dependencies: []),
         .testTarget(name: "SwiftTTSTests", dependencies: ["SwiftTTS"]),
+        .target(name: "SwiftTTSDependency", dependencies: [
+            .product(name: "Dependencies", package: "swift-dependencies"),
+            "SwiftTTS",
+        ]),
         .target(name: "SwiftTTSCombine", dependencies: []),
     ]
 )

Package.swift

@@ -8,6 +8,24 @@ public struct SwiftTTS {
     public var speak: (String) -> Void
     public var isSpeaking: () -> AsyncStream<Bool>
     public var speakingProgress: () -> AsyncStream<Double>
+
+    public init(
+        rateRatio: @escaping () -> Float,
+        setRateRatio: @escaping (Float) -> Void,
+        voice: @escaping () -> AVSpeechSynthesisVoice?,
+        setVoice: @escaping (AVSpeechSynthesisVoice) -> Void,
+        speak: @escaping (String) -> Void,
+        isSpeaking: @escaping () -> AsyncStream<Bool>,
+        speakingProgress: @escaping () -> AsyncStream<Double>
+    ) {
+        self.rateRatio = rateRatio
+        self.setRateRatio = setRateRatio
+        self.voice = voice
+        self.setVoice = setVoice
+        self.speak = speak
+        self.isSpeaking = isSpeaking
+        self.speakingProgress = speakingProgress
+    }
 }
 
 private final class Engine: NSObject, AVSpeechSynthesizerDelegate {

Sources/SwiftTTS/SwiftTTS.swift

@@ -0,0 +1,69 @@
+import AVFoundation
+import Dependencies
+import SwiftTTS
+import XCTestDynamicOverlay
+
+extension SwiftTTS {
+    static let test = Self(
+        rateRatio: unimplemented("SwiftTTS.rateRatio"),
+        setRateRatio: unimplemented("SwiftTTS.setRateRatio"),
+        voice: unimplemented("SwiftTTS.voice"),
+        setVoice: unimplemented("SwiftTTS.setVoice"),
+        speak: unimplemented("SwiftTTS.speak"),
+        isSpeaking: unimplemented("SwiftTTS.isSpeaking"),
+        speakingProgress: unimplemented("SwiftTTS.speakingProgress")
+    )
+    static let preview = {
+        var speakingCallbacks: [() -> Void] = []
+        let speak: (String) -> Void = {
+            print("Spoken utterance: \($0)")
+            for callback in speakingCallbacks {
+                callback()
+            }
+        }
+
+        let isSpeaking = AsyncStream { continuation in
+            speakingCallbacks.append {
+                continuation.yield(true)
+                Task {
+                    try await Task.sleep(nanoseconds: 2_000_000_000)
+                    continuation.yield(false)
+                }
+            }
+        }
+
+        let speakingProgress = AsyncStream { continuation in
+            speakingCallbacks.append {
+                Task {
+                    for seconds in 0...4 {
+                        continuation.yield(Double(seconds) / 4)
+                        try await Task.sleep(nanoseconds: 500_000_000)
+                    }
+                }
+            }
+        }
+
+        return Self(
+            rateRatio: { 1.0 },
+            setRateRatio: { _ in },
+            voice: { AVSpeechSynthesisVoice(language: "en-GB") },
+            setVoice: { _ in },
+            speak: speak,
+            isSpeaking: { isSpeaking },
+            speakingProgress: { speakingProgress }
+        )
+    }()
+}
+
+private enum SwiftTTSDependencyKey: DependencyKey {
+    static let liveValue = SwiftTTS.live
+    static let testValue = SwiftTTS.test
+    static let previewValue = SwiftTTS.preview
+}
+
+public extension DependencyValues {
+    var tts: SwiftTTS {
+        get { self[SwiftTTSDependencyKey.self] }
+        set { self[SwiftTTSDependencyKey.self] = newValue }
+    }
+}