import Foundation
import MusicAssistantCore
import XCTest

final class ProjectAutosaveServiceTests: XCTestCase {
    private var temporaryDirectoryURL: URL!

    override func setUpWithError() throws {
        temporaryDirectoryURL = FileManager.default.temporaryDirectory
            .appendingPathComponent("music-assistant-autosave-tests")
            .appendingPathComponent(UUID().uuidString)
    }

    override func tearDownWithError() throws {
        if let temporaryDirectoryURL {
            try? FileManager.default.removeItem(at: temporaryDirectoryURL)
        }
        temporaryDirectoryURL = nil
    }

    func testAutosavePersistsCurrentProjectWithoutCreatingExcessiveVersions() async throws {
        let store = LocalSongProjectStore(directoryURL: temporaryDirectoryURL)
        let autosaver = ProjectAutosaveService(
            store: store,
            policy: ProjectAutosavePolicy(minimumVersionInterval: 300)
        )
        var project = SongProject(
            id: "autosaved-project",
            title: "Draft",
            idea: "Initial idea",
            updatedAt: Date(timeIntervalSince1970: 50)
        )

        try await store.create(project)

        let firstAutosave = try await autosaver.autosave(
            project,
            at: Date(timeIntervalSince1970: 100)
        )

        XCTAssertTrue(firstAutosave.didCreateVersion)
        XCTAssertEqual(firstAutosave.project.versions.count, 1)
        XCTAssertEqual(firstAutosave.project.versions.first?.snapshot.title, "Draft")
        XCTAssertEqual(firstAutosave.project.updatedAt, Date(timeIntervalSince1970: 100))

        project = firstAutosave.project
        project.title = "Draft with small edit"

        let rapidAutosave = try await autosaver.autosave(
            project,
            at: Date(timeIntervalSince1970: 120)
        )

        XCTAssertFalse(rapidAutosave.didCreateVersion)
        XCTAssertEqual(rapidAutosave.project.versions.count, 1)
        XCTAssertEqual(rapidAutosave.project.title, "Draft with small edit")
        XCTAssertEqual(rapidAutosave.project.updatedAt, Date(timeIntervalSince1970: 120))

        let storedRapidAutosave = try await store.open(id: project.id)
        XCTAssertEqual(storedRapidAutosave, rapidAutosave.project)

        project = rapidAutosave.project
        project.idea = "Later autosaved idea"

        let laterAutosave = try await autosaver.autosave(
            project,
            at: Date(timeIntervalSince1970: 420)
        )

        XCTAssertTrue(laterAutosave.didCreateVersion)
        XCTAssertEqual(laterAutosave.project.versions.count, 2)
        XCTAssertEqual(laterAutosave.project.versions.last?.snapshot.idea, "Later autosaved idea")
        XCTAssertEqual(laterAutosave.project.updatedAt, Date(timeIntervalSince1970: 420))
    }

    func testAutosaveSkipsVersionWhenCurrentSnapshotMatchesLatestVersion() async throws {
        let store = LocalSongProjectStore(directoryURL: temporaryDirectoryURL)
        let autosaver = ProjectAutosaveService(
            store: store,
            policy: ProjectAutosavePolicy(minimumVersionInterval: 300)
        )
        var project = SongProject(
            id: "unchanged-autosave-project",
            title: "Stable",
            idea: "No meaningful changes"
        )
        _ = project.createVersion(
            id: "version-1",
            label: "Stable checkpoint",
            createdAt: Date(timeIntervalSince1970: 100)
        )

        try await store.create(project)

        let autosave = try await autosaver.autosave(
            project,
            at: Date(timeIntervalSince1970: 1_000)
        )

        XCTAssertFalse(autosave.didCreateVersion)
        XCTAssertEqual(autosave.project.versions.count, 1)
        XCTAssertEqual(autosave.project.updatedAt, Date(timeIntervalSince1970: 1_000))
    }
}