Add AI request error states

Sources/MusicAssistantCore/Services/AI/AIRequestState.swift

@@ -0,0 +1,46 @@
+import Foundation
+
+public enum AIRequestState: Equatable, Sendable {
+    case idle
+    case loading
+    case failed(AIProviderErrorState)
+}
+
+public enum AIProviderErrorState: Equatable, Sendable {
+    case offline
+    case missingConfiguration
+    case rateLimited(retryAfter: TimeInterval?)
+    case unavailable
+    case invalidResponse
+    case unsupportedCapability
+}
+
+public struct AIProviderErrorPresenter: Sendable {
+    public init() {}
+
+    public func state(for error: Error) -> AIProviderErrorState {
+        if let urlError = error as? URLError,
+           urlError.code == .notConnectedToInternet || urlError.code == .networkConnectionLost {
+            return .offline
+        }
+
+        if let clientError = error as? OpenAIClientError {
+            switch clientError {
+            case .missingAPIKey:
+                return .missingConfiguration
+            case let .rateLimited(retryAfter):
+                return .rateLimited(retryAfter: retryAfter)
+            case .serverError, .unacceptableStatusCode:
+                return .unavailable
+            case .invalidResponse:
+                return .invalidResponse
+            }
+        }
+
+        if error as? AIServiceCapabilityError != nil {
+            return .unsupportedCapability
+        }
+
+        return .unavailable
+    }
+}

Tests/MusicAssistantCoreTests/AIRequestStateTests.swift

@@ -0,0 +1,15 @@
+import MusicAssistantCore
+import XCTest
+
+final class AIRequestStateTests: XCTestCase {
+    func testPresenterMapsOfflineAndProviderFailures() {
+        let presenter = AIProviderErrorPresenter()
+
+        XCTAssertEqual(presenter.state(for: URLError(.notConnectedToInternet)), .offline)
+        XCTAssertEqual(presenter.state(for: OpenAIClientError.missingAPIKey), .missingConfiguration)
+        XCTAssertEqual(presenter.state(for: OpenAIClientError.rateLimited(retryAfter: 30)), .rateLimited(retryAfter: 30))
+        XCTAssertEqual(presenter.state(for: OpenAIClientError.serverError(503)), .unavailable)
+        XCTAssertEqual(presenter.state(for: OpenAIClientError.invalidResponse), .invalidResponse)
+        XCTAssertEqual(presenter.state(for: AIServiceCapabilityError.discussionNotSupported), .unsupportedCapability)
+    }
+}

docs/TASKS.md

@@ -113,7 +113,7 @@ requirement is missing and blocks implementation, record it in
 ## Phase 9 --- Quality
 
 -   [x] Add validation for contradictory/invalid project settings.
--   [ ] Add loading, offline and provider-error states.
+-   [x] Add loading, offline and provider-error states.
 -   [ ] Add accessibility labels and keyboard navigation.
 -   [ ] Test project/version recovery.
 -   [ ] Test AI output against locked user choices.