import Foundation
import XCTest
import VelodyDomain
import VelodyPlayback
import VelodyPersistence
@testable import VelodyiPhone

@MainActor
final class iPhoneLibraryViewModelPlaybackTests: XCTestCase {
    func testNowPlayingCardShowsTitleArtistAndArtwork() async throws {
        let artwork = RemoteArtwork(
            artworkId: "artwork-midnight",
            sha256: String(repeating: "b", count: 64),
            mimeType: "image/png"
        )
        let track = makeRemoteTrack(
            trackId: "remote-midnight-city",
            assetId: "asset-midnight-city",
            title: "Midnight City",
            artwork: artwork
        )
        let player = TestPlayer()
        let viewModel = makeViewModel(
            remoteTracks: [track],
            downloadStates: [makeDownloadedState(for: track)],
            audioFiles: [localFilePath(for: track): Data([0x1, 0x2])],
            artworkPayloadsByArtworkID: [artwork.artworkId: Data([0x9, 0x8])],
            player: player
        )

        await viewModel.loadIfNeeded()
        viewModel.togglePlayback(trackID: track.trackId)

        let card = try XCTUnwrap(viewModel.nowPlayingCard)
        XCTAssertEqual(card.title, track.title)
        XCTAssertEqual(card.artist, track.artist)
        XCTAssertEqual(card.artworkLocalFilePath, localArtworkFilePath(for: artwork))
        XCTAssertEqual(card.downloadBadge, .downloaded)
        XCTAssertEqual(card.playbackStateText, "Playing")
    }

    func testMissingLocalFilePreventsPlayingAndDisablesSeek() async throws {
        let track = makeRemoteTrack(
            trackId: "remote-missing-file",
            assetId: "asset-missing-file",
            title: "Lost Signal"
        )
        let player = TestPlayer()
        player.missingTrackIDs.insert(track.trackId)
        let viewModel = makeViewModel(
            remoteTracks: [track],
            downloadStates: [makeDownloadedState(for: track)],
            player: player
        )

        await viewModel.loadIfNeeded()
        viewModel.togglePlayback(trackID: track.trackId)

        let card = try XCTUnwrap(viewModel.nowPlayingCard)
        XCTAssertEqual(viewModel.nowPlaying.playbackState, .missingFile)
        XCTAssertFalse(viewModel.nowPlaying.isPlaying)
        XCTAssertFalse(card.canSeek)
        XCTAssertEqual(card.downloadBadge, .missing)
        XCTAssertEqual(card.title, track.title)
        XCTAssertEqual(card.artist, track.artist)
        XCTAssertEqual(card.playbackStateText, "Missing file")
        XCTAssertEqual(card.errorMessage, "The local file could not be found: \(localFilePath(for: track))")
    }

    func testPauseStopsProgressUpdates() async throws {
        let track = makeRemoteTrack(
            trackId: "remote-pause",
            assetId: "asset-pause",
            title: "Pause Study"
        )
        let player = TestPlayer()
        let viewModel = makeViewModel(
            remoteTracks: [track],
            downloadStates: [makeDownloadedState(for: track)],
            audioFiles: [localFilePath(for: track): Data([0x1])],
            player: player
        )

        await viewModel.loadIfNeeded()
        viewModel.togglePlayback(trackID: track.trackId)
        player.advanceProgress(by: 12)

        XCTAssertEqual(viewModel.nowPlaying.currentTime, 12)

        viewModel.togglePlayback(trackID: track.trackId)
        player.advanceProgress(by: 8)

        XCTAssertEqual(viewModel.nowPlaying.playbackState, .paused)
        XCTAssertEqual(viewModel.nowPlaying.currentTime, 12)
    }

    func testStopResetsProgressSafely() async throws {
        let track = makeRemoteTrack(
            trackId: "remote-stop",
            assetId: "asset-stop",
            title: "Stop Motion"
        )
        let player = TestPlayer()
        let viewModel = makeViewModel(
            remoteTracks: [track],
            downloadStates: [makeDownloadedState(for: track)],
            audioFiles: [localFilePath(for: track): Data([0x1])],
            player: player
        )

        await viewModel.loadIfNeeded()
        viewModel.togglePlayback(trackID: track.trackId)
        player.advanceProgress(by: 33)

        viewModel.stopPlayback()

        XCTAssertEqual(viewModel.nowPlaying.playbackState, .stopped)
        XCTAssertEqual(viewModel.nowPlaying.currentTime, 0)
        XCTAssertEqual(viewModel.nowPlaying.duration, 245)
    }

    func testSearchDoesNotClearNowPlaying() async throws {
        let firstTrack = makeRemoteTrack(
            trackId: "remote-first-search",
            assetId: "asset-first-search",
            title: "Blue Avenue"
        )
        let secondTrack = makeRemoteTrack(
            trackId: "remote-second-search",
            assetId: "asset-second-search",
            title: "Golden Hour"
        )
        let player = TestPlayer()
        let viewModel = makeViewModel(
            remoteTracks: [firstTrack, secondTrack],
            downloadStates: [
                makeDownloadedState(for: firstTrack),
                makeDownloadedState(for: secondTrack),
            ],
            audioFiles: [
                localFilePath(for: firstTrack): Data([0x1]),
                localFilePath(for: secondTrack): Data([0x2]),
            ],
            player: player
        )

        await viewModel.loadIfNeeded()
        viewModel.togglePlayback(trackID: firstTrack.trackId)
        viewModel.searchText = secondTrack.title

        let card = try XCTUnwrap(viewModel.nowPlayingCard)
        XCTAssertEqual(card.trackID, firstTrack.trackId)
        XCTAssertNil(remoteRow(in: viewModel, trackID: firstTrack.trackId))
        XCTAssertEqual(viewModel.remoteTracks.count, 1)
    }

    func testPlaybackErrorDoesNotLeaveStateAsPlaying() async throws {
        let track = makeRemoteTrack(
            trackId: "remote-failure",
            assetId: "asset-failure",
            title: "Hard Stop"
        )
        let player = TestPlayer()
        player.failingTrackIDs.insert(track.trackId)
        let viewModel = makeViewModel(
            remoteTracks: [track],
            downloadStates: [makeDownloadedState(for: track)],
            audioFiles: [localFilePath(for: track): Data([0x1])],
            player: player
        )

        await viewModel.loadIfNeeded()
        viewModel.togglePlayback(trackID: track.trackId)

        XCTAssertEqual(viewModel.nowPlaying.playbackState, .failed)
        XCTAssertFalse(viewModel.nowPlaying.isPlaying)
        XCTAssertEqual(viewModel.nowPlaying.errorMessage, "Playback could not be started.")
    }

    func testSeekUpdatesCurrentTimeWhenTrackIsLoaded() async throws {
        let track = makeRemoteTrack(
            trackId: "remote-seek",
            assetId: "asset-seek",
            title: "Seeklight"
        )
        let player = TestPlayer()
        let viewModel = makeViewModel(
            remoteTracks: [track],
            downloadStates: [makeDownloadedState(for: track)],
            audioFiles: [localFilePath(for: track): Data([0x1])],
            player: player
        )

        await viewModel.loadIfNeeded()
        viewModel.togglePlayback(trackID: track.trackId)
        viewModel.seekPlayback(to: 90)

        XCTAssertEqual(viewModel.nowPlaying.currentTime, 90)
        XCTAssertEqual(viewModel.nowPlaying.duration, 245)
    }

    func testRelaunchRestoresMetadataButDoesNotAutoplay() {
        let suiteName = "de.diyaa.velody.tests.\(UUID().uuidString)"
        let defaults = UserDefaults(suiteName: suiteName)!
        defer {
            defaults.removePersistentDomain(forName: suiteName)
        }

        let sessionStore = iPhonePlaybackSessionStore(
            userDefaults: defaults,
            storageKey: "playback"
        )
        let track = LibraryTrack(
            id: "remote-restore",
            title: "Restore Point",
            artist: "Velody Artist",
            durationSeconds: 245,
            localFilePath: "/in-memory/asset-restore.mp3",
            remoteTrackId: "remote-restore"
        )

        let firstEngine = FakePlaybackEngine()
        firstEngine.durationByPath[track.localFilePath] = 245
        let firstPlayer = iPhonePlaybackControllerPlayer(
            controller: PlaybackController(
                engine: firstEngine,
                sessionStore: sessionStore
            )
        )
        firstPlayer.setCatalogTracks([track])
        firstPlayer.play(trackID: track.id)
        firstEngine.currentTime = 48
        firstPlayer.pause()

        let storedSession = sessionStore.loadSession()
        XCTAssertEqual(storedSession?.currentTrackID, track.id)
        XCTAssertEqual(storedSession?.currentTime, 48)
        XCTAssertEqual(storedSession?.queueTrackIDs, [])

        let secondEngine = FakePlaybackEngine()
        secondEngine.durationByPath[track.localFilePath] = 245
        let relaunchedPlayer = iPhonePlaybackControllerPlayer(
            controller: PlaybackController(
                engine: secondEngine,
                sessionStore: sessionStore
            )
        )
        relaunchedPlayer.setCatalogTracks([track])

        XCTAssertEqual(relaunchedPlayer.state.trackID, track.id)
        XCTAssertEqual(relaunchedPlayer.state.title, track.title)
        XCTAssertEqual(relaunchedPlayer.state.artist, track.artist)
        XCTAssertEqual(relaunchedPlayer.state.currentTime, 48)
        XCTAssertEqual(relaunchedPlayer.state.playbackState, .paused)
        XCTAssertFalse(relaunchedPlayer.state.isPlaying)
        XCTAssertNil(relaunchedPlayer.state.errorMessage)
    }
}

@MainActor
private final class FakePlaybackEngine: PlaybackEngine {
    var onEvent: (@MainActor @Sendable (PlaybackEngineEvent) -> Void)?
    var currentTime: Double = 0
    var duration: Double = 0
    var isPlaying = false
    var durationByPath: [String: Double] = [:]

    func loadTrack(at fileURL: URL, startTime: Double) throws {
        currentTime = startTime
        duration = durationByPath[fileURL.path] ?? 0
        isPlaying = false
    }

    func play() throws {
        isPlaying = true
    }

    func pause() {
        isPlaying = false
    }

    func stop() {
        isPlaying = false
        currentTime = 0
    }

    func seek(to time: Double) throws {
        currentTime = min(max(time, 0), duration)
    }
}