From c7640470c63a92a8f6a4de58c0dd9ee4ebc56c28 Mon Sep 17 00:00:00 2001
From: diyaa <info@diyaa.de>
Date: Mon, 14 Sep 2026 22:08:04 +0200
Subject: [PATCH] Validate compiled Suno output

---
 .../PromptCompiler/SunoOutputValidation.swift | 29 +++++++++++++++++++
 .../SunoOutputValidationTests.swift           | 19 ++++++++++++
 docs/TASKS.md                                 |  2 +-
 3 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 Sources/MusicAssistantCore/Services/PromptCompiler/SunoOutputValidation.swift
 create mode 100644 Tests/MusicAssistantCoreTests/SunoOutputValidationTests.swift

diff --git a/Sources/MusicAssistantCore/Services/PromptCompiler/SunoOutputValidation.swift b/Sources/MusicAssistantCore/Services/PromptCompiler/SunoOutputValidation.swift
new file mode 100644
index 0000000..775cc41
--- /dev/null
+++ b/Sources/MusicAssistantCore/Services/PromptCompiler/SunoOutputValidation.swift
@@ -0,0 +1,29 @@
+import Foundation
+
+public protocol SunoOutputValidating: Sendable {
+    func validate(_ output: CompiledSunoOutput) throws
+}
+
+public enum SunoOutputValidationError: Error, Equatable, LocalizedError, Sendable {
+    case missingContent
+
+    public var errorDescription: String? {
+        switch self {
+        case .missingContent:
+            return "Add lyrics or a style prompt before sending the song to Suno."
+        }
+    }
+}
+
+public struct CompiledSunoOutputValidator: SunoOutputValidating {
+    public init() {}
+
+    public func validate(_ output: CompiledSunoOutput) throws {
+        let lyrics = output.lyricsText.trimmingCharacters(in: .whitespacesAndNewlines)
+        let style = output.stylePrompt.trimmingCharacters(in: .whitespacesAndNewlines)
+
+        guard !lyrics.isEmpty || !style.isEmpty else {
+            throw SunoOutputValidationError.missingContent
+        }
+    }
+}
diff --git a/Tests/MusicAssistantCoreTests/SunoOutputValidationTests.swift b/Tests/MusicAssistantCoreTests/SunoOutputValidationTests.swift
new file mode 100644
index 0000000..a306b9a
--- /dev/null
+++ b/Tests/MusicAssistantCoreTests/SunoOutputValidationTests.swift
@@ -0,0 +1,19 @@
+import MusicAssistantCore
+import XCTest
+
+final class SunoOutputValidationTests: XCTestCase {
+    func testValidatorRejectsOutputWithoutSunoContent() {
+        let output = CompiledSunoOutput(lyricsText: " \n ", stylePrompt: "\t")
+
+        XCTAssertThrowsError(try CompiledSunoOutputValidator().validate(output)) { error in
+            XCTAssertEqual(error as? SunoOutputValidationError, .missingContent)
+        }
+    }
+
+    func testValidatorAllowsLyricsOrAStylePrompt() throws {
+        let validator = CompiledSunoOutputValidator()
+
+        XCTAssertNoThrow(try validator.validate(CompiledSunoOutput(lyricsText: "Lyrics", stylePrompt: "")))
+        XCTAssertNoThrow(try validator.validate(CompiledSunoOutput(lyricsText: "", stylePrompt: "Cinematic folk")))
+    }
+}
diff --git a/docs/TASKS.md b/docs/TASKS.md
index 9721042..af4c273 100644
--- a/docs/TASKS.md
+++ b/docs/TASKS.md
@@ -102,7 +102,7 @@ requirement is missing and blocks implementation, record it in
     appropriate.
 -   [x] Generate style prompt from genre blend, instrumentation, vocals,
     tempo, harmony, emotion and production instructions.
--   [ ] Validate output before handoff.
+-   [x] Validate output before handoff.
 -   [ ] Keep compiler independent from UI and OpenAI client.
 
 ## Phase 8 --- Suno Handoff