import MusicAssistantCore
import XCTest

final class AIServiceTests: XCTestCase {
    func testProviderIndependentServiceGeneratesStructuredProjectResult() async throws {
        let service = MockAIService()
        let request = SongProjectGenerationRequest(
            context: AIRequestContext(
                userInstruction: "Write a hopeful cinematic pop song.",
                conversation: [
                    AIConversationMessage(role: .user, content: "Use piano and violin.")
                ],
                localeIdentifier: "en_US"
            ),
            discussionMode: .discuss
        )

        let result = try await service.generateSongProject(from: request)

        XCTAssertEqual(result.project.title, "Generated Song")
        XCTAssertEqual(result.project.idea, request.context.userInstruction)
        XCTAssertEqual(result.project.conversationMode, .discuss)
        XCTAssertEqual(result.notes, ["Generated by a provider-independent mock."])
        XCTAssertEqual(result.followUpQuestions, ["Should the chorus be bigger?"])
    }

    func testProviderIndependentServiceReturnsDiscussionQuestionsWithoutProjectUpdate() async throws {
        let service = MockAIService()
        let project = SongProject(
            title: "Discussion Project",
            idea: "Plan the chorus",
            conversationMode: .discuss
        )
        let request = SongProjectDiscussionRequest(
            context: AIRequestContext(userInstruction: "Ask what is still missing."),
            project: project
        )

        let result = try await service.discussSongProject(from: request)

        XCTAssertEqual(result.questions, ["Which vocal delivery should lead the chorus?"])
        XCTAssertEqual(result.notes, ["Discussion only; no project update was proposed."])
    }

    func testProviderIndependentServiceRevisesLyricsWithStructuredResult() async throws {
        let service = MockAIService()
        let project = SongProject(title: "Lyric Project", idea: "Improve words")
        let sourceLyrics = Lyrics(text: "rough draft")
        let request = LyricsRevisionRequest(
            context: AIRequestContext(userInstruction: "Make it stronger."),
            project: project,
            sourceLyrics: sourceLyrics,
            mode: .improve
        )

        let result = try await service.reviseLyrics(from: request)

        XCTAssertEqual(result.lyrics.text, "rough draft\nMake it stronger.")
        XCTAssertEqual(result.notes, ["improve"])
    }

    func testProviderIndependentServiceProposesScopedProjectUpdates() async throws {
        let service = MockAIService()
        let project = SongProject(title: "Scoped Project", idea: "Add tempo")
        let request = SongProjectUpdateRequest(
            context: AIRequestContext(userInstruction: "Set tempo manually."),
            project: project,
            allowedScopes: [.musicalParameters]
        )

        let result = try await service.proposeProjectUpdate(from: request)

        XCTAssertEqual(result.project.bpm, ManualAutoValue(mode: .manual, value: 96))
        XCTAssertEqual(result.changedScopes, [.musicalParameters])
        XCTAssertEqual(result.notes, ["Updated only requested scopes."])
    }
}

private struct MockAIService: AIService {
    func generateSongProject(from request: SongProjectGenerationRequest) async throws -> SongProjectGenerationResult {
        SongProjectGenerationResult(
            project: SongProject(
                title: "Generated Song",
                idea: request.context.userInstruction,
                conversationMode: request.discussionMode
            ),
            notes: ["Generated by a provider-independent mock."],
            followUpQuestions: ["Should the chorus be bigger?"]
        )
    }

    func discussSongProject(from request: SongProjectDiscussionRequest) async throws -> SongProjectDiscussionResult {
        SongProjectDiscussionResult(
            questions: ["Which vocal delivery should lead the chorus?"],
            notes: ["Discussion only; no project update was proposed."]
        )
    }

    func reviseLyrics(from request: LyricsRevisionRequest) async throws -> LyricsRevisionResult {
        LyricsRevisionResult(
            lyrics: Lyrics(text: "\(request.sourceLyrics.text)\n\(request.context.userInstruction)"),
            notes: [request.mode.rawValue]
        )
    }

    func proposeProjectUpdate(from request: SongProjectUpdateRequest) async throws -> SongProjectUpdateResult {
        var project = request.project
        var changedScopes: [SongProjectUpdateScope] = []

        if request.allowedScopes.contains(.musicalParameters) {
            project.setBPMManually(96)
            changedScopes.append(.musicalParameters)
        }

        return SongProjectUpdateResult(
            project: project,
            changedScopes: changedScopes,
            notes: ["Updated only requested scopes."]
        )
    }
}