Avoid colliding failed-audio dump filenames

Include a short UUID token so two empty ONNX dumps in the same
second keep both WAV files. Sanitize model path characters too.

Author: jatinkrmalik

Sources/VocaMac/Services/FailedAudioDump.swift

@@ -27,13 +27,26 @@ enum FailedAudioDump {
         UserDefaults.standard.bool(forKey: preferenceKey)
     }
 
+    /// Build a dump filename that cannot collide within the same second.
+    static func makeFilename(
+        model: String,
+        date: Date = Date(),
+        uniqueID: String = UUID().uuidString
+    ) -> String {
+        let stamp = ISO8601DateFormatter.dumpFormatter.string(from: date)
+        let token = String(uniqueID.replacingOccurrences(of: "-", with: "").prefix(8))
+        let safeModel = model
+            .replacingOccurrences(of: "/", with: "-")
+            .replacingOccurrences(of: ":", with: "-")
+        return "\(stamp)-\(token)-\(safeModel).wav"
+    }
+
     /// Save `samples` if the user asked for dumps. Returns the file written.
     @discardableResult
     static func save(_ samples: [Float], model: String, sampleRate: Int = 16_000) -> URL? {
         guard isEnabled, !samples.isEmpty else { return nil }
 
-        let stamp = ISO8601DateFormatter.dumpFormatter.string(from: Date())
-        let url = directory.appendingPathComponent("\(stamp)-\(model).wav")
+        let url = directory.appendingPathComponent(makeFilename(model: model))
 
         do {
             try FileManager.default.createDirectory(

Tests/VocaMacTests/FailedAudioDumpTests.swift

@@ -28,3 +28,29 @@ final class FailedAudioDumpTests: XCTestCase {
         XCTAssertNil(FailedAudioDump.save([0.1, 0.2], model: "canary-180m-flash"))
     }
 }
+
+    func testDumpFilenamesDoNotCollideWithinTheSameSecond() {
+        let date = Date(timeIntervalSince1970: 1_700_000_000)
+        let left = FailedAudioDump.makeFilename(
+            model: "canary-180m-flash", date: date, uniqueID: "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"
+        )
+        let right = FailedAudioDump.makeFilename(
+            model: "canary-180m-flash", date: date, uniqueID: "ffffffff-1111-2222-3333-444444444444"
+        )
+        XCTAssertNotEqual(left, right)
+        XCTAssertTrue(left.hasSuffix("-canary-180m-flash.wav"))
+        XCTAssertTrue(left.contains("aaaaaaaa"))
+        XCTAssertTrue(right.contains("ffffffff"))
+    }
+
+    func testDumpFilenameSanitizesModelPathCharacters() {
+        let name = FailedAudioDump.makeFilename(
+            model: "path/with:chars",
+            date: Date(timeIntervalSince1970: 0),
+            uniqueID: "12345678-0000-0000-0000-000000000000"
+        )
+        XCTAssertFalse(name.contains("/"))
+        XCTAssertFalse(name.contains(":"))
+        XCTAssertTrue(name.hasSuffix("-path-with-chars.wav"))
+    }
+