//
//  MusicManager.swift
//  DynamicIsland
//
//  Created by Harsh Vardhan  Goswami  on 03/08/24.
//
import AppKit
import Combine
import Defaults
import SwiftUI

let defaultImage: NSImage = .init(
    systemSymbolName: "heart.fill",
    accessibilityDescription: "Album Art"
)!

class MusicManager: ObservableObject {
    // MARK: - Properties
    static let shared = MusicManager()
    private var cancellables = Set<AnyCancellable>()
    private var controllerCancellables = Set<AnyCancellable>()
    private var debounceIdleTask: Task<Void, Never>?

    // Helper to check if macOS has removed support for NowPlayingController
    public private(set) var isNowPlayingDeprecated: Bool = false
    private let mediaChecker = MediaChecker()

    // Active controller
    private var activeController: (any MediaControllerProtocol)?

    // Published properties for UI
    @Published var songTitle: String = "I'm Handsome"
    @Published var artistName: String = "Me"
    @Published var albumArt: NSImage = defaultImage
    @Published var isPlaying = false
    @Published var album: String = "Self Love"
    @Published var isPlayerIdle: Bool = true
    @Published var animations: DynamicIslandAnimations = .init()
    @Published var avgColor: NSColor = .white
    @Published var bundleIdentifier: String? = nil
    @Published var songDuration: TimeInterval = 0
    @Published var elapsedTime: TimeInterval = 0
    @Published var timestampDate: Date = .init()
    @Published var playbackRate: Double = 1
    @Published var isShuffled: Bool = false
    @Published var repeatMode: RepeatMode = .off
    @ObservedObject var coordinator = DynamicIslandViewCoordinator.shared
    @Published var usingAppIconForArtwork: Bool = false

    private var artworkData: Data? = nil

    // Store last values at the time artwork was changed
    private var lastArtworkTitle: String = "I'm Handsome"
    private var lastArtworkArtist: String = "Me"
    private var lastArtworkAlbum: String = "Self Love"
    private var lastArtworkBundleIdentifier: String? = nil

    @Published var flipAngle: Double = 0
    private let flipAnimationDuration: TimeInterval = 0.45

    @Published var isTransitioning: Bool = false
    private var transitionWorkItem: DispatchWorkItem?

    // MARK: - Initialization
    init() {
        // Listen for changes to the default controller preference
        NotificationCenter.default.publisher(for: Notification.Name.mediaControllerChanged)
            .sink { [weak self] _ in
                self?.setActiveControllerBasedOnPreference()
            }
            .store(in: &cancellables)

        // Initialize deprecation check asynchronously
        Task { @MainActor in
            do {
                self.isNowPlayingDeprecated = try await self.mediaChecker.checkDeprecationStatus()
                print("Deprecation check completed: \(self.isNowPlayingDeprecated)")
            } catch {
                print("Failed to check deprecation status: \(error). Defaulting to false.")
                self.isNowPlayingDeprecated = false
            }
            
            // Initialize the active controller after deprecation check
            self.setActiveControllerBasedOnPreference()
        }
    }

    deinit {
        destroy()
    }
    
    public func destroy() {
        debounceIdleTask?.cancel()
        cancellables.removeAll()
        controllerCancellables.removeAll()
        transitionWorkItem?.cancel()

        // Release active controller
        activeController = nil
    }

    // MARK: - Setup Methods
    private func createController(for type: MediaControllerType) -> (any MediaControllerProtocol)? {
        // Cleanup previous controller
        if activeController != nil {
            controllerCancellables.removeAll()
            activeController = nil
        }

        let newController: (any MediaControllerProtocol)?

        switch type {
        case .nowPlaying:
            // Only create NowPlayingController if not deprecated on this macOS version
            if !self.isNowPlayingDeprecated {
                newController = NowPlayingController()
            } else {
                return nil
            }
        case .appleMusic:
            newController = AppleMusicController()
        case .spotify:
            newController = SpotifyController()
        case .youtubeMusic:
            newController = YouTubeMusicController()
        }

        // Set up state observation for the new controller
        if let controller = newController {
            controller.playbackStatePublisher
                .receive(on: DispatchQueue.main)
                .sink { [weak self] state in
                    guard let self = self,
                          self.activeController === controller else { return }
                    self.updateFromPlaybackState(state)
                }
                .store(in: &controllerCancellables)
        }

        return newController
    }

    private func setActiveControllerBasedOnPreference() {
        let preferredType = Defaults[.mediaController]
        print("Preferred Media Controller: \(preferredType)")

        // If NowPlaying is deprecated but that's the preference, use Apple Music instead
        let controllerType = (self.isNowPlayingDeprecated && preferredType == .nowPlaying)
            ? .appleMusic
            : preferredType

        if let controller = createController(for: controllerType) {
            setActiveController(controller)
        } else if controllerType != .appleMusic, let fallbackController = createController(for: .appleMusic) {
            // Fallback to Apple Music if preferred controller couldn't be created
            setActiveController(fallbackController)
        }
    }

    private func setActiveController(_ controller: any MediaControllerProtocol) {
        // Set new active controller
        activeController = controller

        // Get current state from active controller
        forceUpdate()
    }

    // MARK: - Update Methods
    @MainActor
    private func updateFromPlaybackState(_ state: PlaybackState) {
        // Check for playback state changes (playing/paused)
        if state.isPlaying != self.isPlaying {
            NSLog("Playback state changed: \(state.isPlaying ? "Playing" : "Paused")")
            withAnimation(.smooth) {
                self.isPlaying = state.isPlaying
                self.updateIdleState(state: state.isPlaying)
            }

            if state.isPlaying && !state.title.isEmpty && !state.artist.isEmpty {
                self.updateSneakPeek()
            }
        }

        // Check for changes in track metadata using last artwork change values
        let titleChanged = state.title != self.lastArtworkTitle
        let artistChanged = state.artist != self.lastArtworkArtist
        let albumChanged = state.album != self.lastArtworkAlbum
        let bundleChanged = state.bundleIdentifier != self.lastArtworkBundleIdentifier

        // Check for artwork changes
        let artworkChanged = state.artwork != nil && state.artwork != self.artworkData
        let hasContentChange = titleChanged || artistChanged || albumChanged || artworkChanged || bundleChanged

        // Handle artwork and visual transitions for changed content
        if hasContentChange {
            self.triggerFlipAnimation()

            if artworkChanged, let artwork = state.artwork {
                self.updateArtwork(artwork)
            } else if state.artwork == nil {
                // Try to use app icon if no artwork but track changed
                if let appIconImage = AppIconAsNSImage(for: state.bundleIdentifier) {
                    self.usingAppIconForArtwork = true
                    self.updateAlbumArt(newAlbumArt: appIconImage)
                }
            }
            self.artworkData = state.artwork

            if artworkChanged || state.artwork == nil {
                // Update last artwork change values
                self.lastArtworkTitle = state.title
                self.lastArtworkArtist = state.artist
                self.lastArtworkAlbum = state.album
                self.lastArtworkBundleIdentifier = state.bundleIdentifier
            }

            // Only update sneak peek if there's actual content and something changed
            if !state.title.isEmpty && !state.artist.isEmpty && state.isPlaying {
                self.updateSneakPeek()
            }
        }

        let timeChanged = state.currentTime != self.elapsedTime
        let durationChanged = state.duration != self.songDuration
        let playbackRateChanged = state.playbackRate != self.playbackRate
        let shuffleChanged = state.isShuffled != self.isShuffled
        let repeatModeChanged = state.repeatMode != self.repeatMode

        if state.title != self.songTitle {
            self.songTitle = state.title
        }

        if state.artist != self.artistName {
            self.artistName = state.artist
        }

        if state.album != self.album {
            self.album = state.album
        }

        if timeChanged {
            self.elapsedTime = state.currentTime
        }

        if durationChanged {
            self.songDuration = state.duration
        }

        if playbackRateChanged {
            self.playbackRate = state.playbackRate
        }
        
        if shuffleChanged {
            self.isShuffled = state.isShuffled
        }

        if state.bundleIdentifier != self.bundleIdentifier {
            self.bundleIdentifier = state.bundleIdentifier
        }

        if repeatModeChanged {
            self.repeatMode = state.repeatMode
        }
        
        self.timestampDate = state.lastUpdated
    }

    private func triggerFlipAnimation() {
        withAnimation(.easeInOut(duration: flipAnimationDuration)) {
            flipAngle += 180
        }
    }

    private func updateArtwork(_ artworkData: Data) {
        DispatchQueue.global(qos: .userInitiated).async { [weak self] in
            guard let self = self else { return }

            if let artworkImage = NSImage(data: artworkData) {
                DispatchQueue.main.async { [weak self] in
                    self?.usingAppIconForArtwork = false
                    self?.updateAlbumArt(newAlbumArt: artworkImage)
                }
            }
        }
    }

    private func updateIdleState(state: Bool) {
        if state {
            isPlayerIdle = false
            debounceIdleTask?.cancel()
        } else {
            debounceIdleTask?.cancel()
            debounceIdleTask = Task { [weak self] in
                guard let self = self else { return }
                try? await Task.sleep(for: .seconds(Defaults[.waitInterval]))
                withAnimation {
                    self.isPlayerIdle = !self.isPlaying
                }
            }
        }
    }

    private var workItem: DispatchWorkItem?

    func updateAlbumArt(newAlbumArt: NSImage) {
        workItem?.cancel()
        workItem = DispatchWorkItem { [weak self] in
            withAnimation(.smooth) {
                self?.albumArt = newAlbumArt
                if Defaults[.coloredSpectrogram] {
                    self?.calculateAverageColor()
                }
            }
        }
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.4, execute: workItem!)
    }

    // MARK: - Playback Position Estimation
    public func estimatedPlaybackPosition(at date: Date = Date()) -> TimeInterval {
        guard isPlaying else { return min(elapsedTime, songDuration) }

        let timeDifference = date.timeIntervalSince(timestampDate)
        let estimated = elapsedTime + (timeDifference * playbackRate)
        return min(max(0, estimated), songDuration)
    }

    func calculateAverageColor() {
        albumArt.averageColor { [weak self] color in
            DispatchQueue.main.async {
                withAnimation(.smooth) {
                    self?.avgColor = color ?? .white
                }
            }
        }
    }

    private func updateSneakPeek() {
        if isPlaying && Defaults[.enableSneakPeek] {
            if Defaults[.sneakPeekStyles] == .standard {
                coordinator.toggleSneakPeek(status: true, type: .music)
            } else {
                coordinator.toggleExpandingView(status: true, type: .music)
            }
        }
    }

    // MARK: - Public Methods for controlling playback
    func playPause() {
        Task {
            await activeController?.togglePlay()
        }
    }

    func play() {
        Task {
            await activeController?.play()
        }
    }

    func pause() {
        Task {
            await activeController?.pause()
        }
    }

    func toggleShuffle() {
        Task {
            await activeController?.toggleShuffle()
        }
    }

    func toggleRepeat() {
        Task {
            await activeController?.toggleRepeat()
        }
    }
    
    func togglePlay() {
        Task {
            await activeController?.togglePlay()
        }
    }

    func nextTrack() {
        Task {
            await activeController?.nextTrack()
        }
    }

    func previousTrack() {
        Task {
            await activeController?.previousTrack()
        }
    }

    func seek(to position: TimeInterval) {
        Task {
            await activeController?.seek(to: position)
        }
    }

    func openMusicApp() {
        guard let bundleID = bundleIdentifier else {
            print("Error: appBundleIdentifier is nil")
            return
        }

        let workspace = NSWorkspace.shared
        if let appURL = workspace.urlForApplication(withBundleIdentifier: bundleID) {
            let configuration = NSWorkspace.OpenConfiguration()
            workspace.openApplication(at: appURL, configuration: configuration) { (app, error) in
                if let error = error {
                    print("Failed to launch app with bundle ID: \(bundleID), error: \(error)")
                } else {
                    print("Launched app with bundle ID: \(bundleID)")
                }
            }
        } else {
            print("Failed to find app with bundle ID: \(bundleID)")
        }
    }

    func forceUpdate() {
        // Request immediate update from the active controller
        Task { [weak self] in
            if self?.activeController?.isActive() == true {
                if let youtubeController = self?.activeController as? YouTubeMusicController {
                    await youtubeController.pollPlaybackState()
                } else {
                    await self?.activeController?.updatePlaybackInfo()
                }
            }
        }
    }
}

// MARK: - Album Art Flip Helper

private struct AlbumArtFlipModifier: ViewModifier {
    let angle: Double

    private var normalizedAngle: Double {
        var value = angle.truncatingRemainder(dividingBy: 360)
        if value < 0 { value += 360 }
        return value
    }

    private var mirrorScale: CGFloat {
        (normalizedAngle > 90 && normalizedAngle < 270) ? -1 : 1
    }

    func body(content: Content) -> some View {
        content
            .rotation3DEffect(
                .degrees(angle),
                axis: (x: 0, y: 1, z: 0),
                perspective: 0.65
            )
            .scaleEffect(x: mirrorScale, y: 1)
    }
}

extension View {
    func albumArtFlip(angle: Double) -> some View {
        modifier(AlbumArtFlipModifier(angle: angle))
    }
}