import SwiftUI

struct WatchLibraryView: View {
    @EnvironmentObject var watchManager: WatchSessionManager
    @EnvironmentObject var audioPlayer: WatchAudioPlayer
    @EnvironmentObject var offlineStore: WatchOfflineStore
    
    var body: some View {
        TabView {
            // Now Playing
            WatchNowPlayingView()
            
            // Offline Library
            WatchOfflineLibraryView()
            
            // Browse Server
            WatchBrowseView()
            
            // Settings
            WatchSettingsView()
        }
        .tabViewStyle(.verticalPage)
    }
}

// MARK: - Offline Library
struct WatchOfflineLibraryView: View {
    @EnvironmentObject var offlineStore: WatchOfflineStore
    @EnvironmentObject var audioPlayer: WatchAudioPlayer
    @State private var showDeleteAll = false
    
    var body: some View {
        NavigationView {
            if offlineStore.songs.isEmpty {
                VStack(spacing: 8) {
                    Image(systemName: "arrow.down.circle")
                        .font(.title2)
                        .foregroundColor(.gray)
                    Text("No Offline Songs")
                        .font(.caption)
                        .foregroundColor(.gray)
                    Text("Send songs from your iPhone or download from Browse")
                        .font(.caption2)
                        .foregroundColor(.gray)
                        .multilineTextAlignment(.center)
                }
            } else {
                List {
                    // Play controls
                    Section {
                        Button(action: playAllOffline) {
                            HStack {
                                Image(systemName: "play.fill")
                                Text("Play All")
                            }
                            .foregroundColor(.pink)
                        }
                        
                        Button(action: shuffleOffline) {
                            HStack {
                                Image(systemName: "shuffle")
                                Text("Shuffle All")
                            }
                            .foregroundColor(.pink)
                        }
                    }
                    
                    // Songs by album (swipe to delete)
                    ForEach(Array(offlineStore.songsByAlbum.keys.sorted()), id: \.self) { album in
                        Section(album) {
                            ForEach(offlineStore.songsByAlbum[album] ?? []) { offline in
                                WatchSongRow(
                                    song: offline.song,
                                    isPlaying: audioPlayer.currentSong?.id == offline.id
                                ) {
                                    let albumSongs = (offlineStore.songsByAlbum[album] ?? []).map { $0.song }
                                    let idx = albumSongs.firstIndex(where: { $0.id == offline.id }) ?? 0
                                    audioPlayer.play(song: offline.song, fromQueue: albumSongs, at: idx)
                                }
                            }
                            .onDelete { indexSet in
                                let albumSongs = offlineStore.songsByAlbum[album] ?? []
                                for idx in indexSet {
                                    if idx < albumSongs.count {
                                        offlineStore.removeSong(albumSongs[idx].id)
                                    }
                                }
                            }
                        }
                    }
                    
                    // Storage info + delete all
                    Section {
                        HStack {
                            Text("\(offlineStore.songs.count) songs")
                                .font(.caption)
                                .foregroundColor(.gray)
                            Spacer()
                            Text(offlineStore.formattedSize)
                                .font(.caption)
                                .foregroundColor(.gray)
                        }
                        
                        Button(role: .destructive, action: { showDeleteAll = true }) {
                            HStack {
                                Image(systemName: "trash")
                                Text("Remove All")
                            }
                            .font(.caption)
                        }
                    }
                }
                .navigationTitle("Library")
                .alert("Remove All Songs?", isPresented: $showDeleteAll) {
                    Button("Remove", role: .destructive) { offlineStore.removeAll() }
                    Button("Cancel", role: .cancel) { }
                } message: {
                    Text("This will delete \(offlineStore.songs.count) songs (\(offlineStore.formattedSize)) from your watch.")
                }
            }
        }
    }
    
    private func playAllOffline() {
        let songs = offlineStore.songs.map { $0.song }
        guard let first = songs.first else { return }
        audioPlayer.play(song: first, fromQueue: songs)
    }
    
    private func shuffleOffline() {
        let songs = offlineStore.songs.map { $0.song }.shuffled()
        guard let first = songs.first else { return }
        audioPlayer.shuffleEnabled = true
        audioPlayer.play(song: first, fromQueue: songs)
    }
}

// MARK: - Browse Server
struct WatchBrowseView: View {
    @EnvironmentObject var watchManager: WatchSessionManager
    
    var body: some View {
        NavigationView {
            List {
                NavigationLink(destination: WatchRecentAlbumsView()) {
                    Label("Recent Albums", systemImage: "clock")
                }
                
                NavigationLink(destination: WatchPlaylistsListView()) {
                    Label("Playlists", systemImage: "list.bullet")
                }
                
                NavigationLink(destination: WatchSearchView()) {
                    Label("Search", systemImage: "magnifyingglass")
                }
                
                // Server info
                if let server = watchManager.activeServer {
                    Section {
                        VStack(alignment: .leading, spacing: 2) {
                            Text(server.name)
                                .font(.caption)
                            Text(server.url)
                                .font(.caption2)
                                .foregroundColor(.gray)
                                .lineLimit(1)
                        }
                    }
                }
            }
            .navigationTitle("Browse")
        }
    }
}

// MARK: - Recent Albums on Watch
struct WatchRecentAlbumsView: View {
    @EnvironmentObject var watchManager: WatchSessionManager
    @State private var albums: [Album] = []
    @State private var isLoading = true
    
    var body: some View {
        Group {
            if isLoading {
                ProgressView()
            } else {
                List(albums) { album in
                    NavigationLink(destination: WatchAlbumDetailView(albumId: album.id)) {
                        VStack(alignment: .leading, spacing: 2) {
                            Text(album.name)
                                .font(.caption)
                                .lineLimit(1)
                            Text(album.artist ?? "")
                                .font(.caption2)
                                .foregroundColor(.gray)
                                .lineLimit(1)
                        }
                    }
                }
            }
        }
        .navigationTitle("Recent")
        .task {
            do {
                albums = try await watchManager.getAlbumList(type: "newest", size: 30)
                isLoading = false
            } catch {
                isLoading = false
            }
        }
    }
}

// MARK: - Album Detail on Watch
struct WatchAlbumDetailView: View {
    @EnvironmentObject var watchManager: WatchSessionManager
    @EnvironmentObject var audioPlayer: WatchAudioPlayer
    @EnvironmentObject var offlineStore: WatchOfflineStore
    
    let albumId: String
    @State private var album: AlbumWithSongs?
    @State private var isLoading = true
    @State private var isDownloading = false
    
    var body: some View {
        Group {
            if isLoading {
                ProgressView()
            } else if let album = album {
                List {
                    // Album header
                    VStack(spacing: 4) {
                        Text(album.name)
                            .font(.caption)
                            .fontWeight(.bold)
                            .multilineTextAlignment(.center)
                        Text(album.artist ?? "")
                            .font(.caption2)
                            .foregroundColor(.pink)
                    }
                    .frame(maxWidth: .infinity)
                    .listRowBackground(Color.clear)
                    
                    // Play / Download buttons
                    Button(action: { playAlbum(shuffle: false) }) {
                        Label("Play", systemImage: "play.fill")
                            .foregroundColor(.pink)
                    }
                    
                    Button(action: { playAlbum(shuffle: true) }) {
                        Label("Shuffle", systemImage: "shuffle")
                            .foregroundColor(.pink)
                    }
                    
                    Button(action: downloadAll) {
                        HStack {
                            if isDownloading {
                                ProgressView().scaleEffect(0.6)
                            }
                            Label(
                                isDownloading ? "Downloading..." : "Download for Offline",
                                systemImage: "arrow.down.circle"
                            )
                        }
                        .foregroundColor(.blue)
                    }
                    .disabled(isDownloading)
                    
                    // Songs
                    ForEach(album.song ?? []) { song in
                        WatchSongRow(
                            song: song,
                            isPlaying: audioPlayer.currentSong?.id == song.id,
                            isOffline: offlineStore.isSongAvailable(song.id)
                        ) {
                            let songs = album.song ?? []
                            let idx = songs.firstIndex(where: { $0.id == song.id }) ?? 0
                            audioPlayer.play(song: song, fromQueue: songs, at: idx)
                        }
                    }
                }
            }
        }
        .task {
            do {
                album = try await watchManager.getAlbum(id: albumId)
                isLoading = false
            } catch {
                isLoading = false
            }
        }
    }
    
    private func playAlbum(shuffle: Bool) {
        guard let songs = album?.song, let first = songs.first else { return }
        if shuffle { audioPlayer.shuffleEnabled = true }
        audioPlayer.play(song: first, fromQueue: songs)
    }
    
    private func downloadAll() {
        guard let album = album else { return }
        isDownloading = true
        Task {
            await offlineStore.downloadAlbum(album)
            await MainActor.run { isDownloading = false }
        }
    }
}

// MARK: - Playlists on Watch
struct WatchPlaylistsListView: View {
    @EnvironmentObject var watchManager: WatchSessionManager
    @State private var playlists: [Playlist] = []
    @State private var isLoading = true
    
    var body: some View {
        Group {
            if isLoading {
                ProgressView()
            } else if playlists.isEmpty {
                Text("No Playlists")
                    .font(.caption)
                    .foregroundColor(.gray)
            } else {
                List(playlists) { playlist in
                    NavigationLink(destination: WatchPlaylistDetailView(playlistId: playlist.id)) {
                        VStack(alignment: .leading, spacing: 2) {
                            Text(playlist.name)
                                .font(.caption)
                                .lineLimit(1)
                            Text("\(playlist.songCount ?? 0) songs")
                                .font(.caption2)
                                .foregroundColor(.gray)
                        }
                    }
                }
            }
        }
        .navigationTitle("Playlists")
        .task {
            do {
                playlists = try await watchManager.getPlaylists()
                isLoading = false
            } catch { isLoading = false }
        }
    }
}

// MARK: - Playlist Detail on Watch
struct WatchPlaylistDetailView: View {
    @EnvironmentObject var watchManager: WatchSessionManager
    @EnvironmentObject var audioPlayer: WatchAudioPlayer
    @EnvironmentObject var offlineStore: WatchOfflineStore
    
    let playlistId: String
    @State private var playlist: PlaylistWithSongs?
    @State private var isLoading = true
    @State private var isDownloading = false
    
    var body: some View {
        Group {
            if isLoading {
                ProgressView()
            } else if let playlist = playlist {
                List {
                    Button(action: {
                        let songs = playlist.entry ?? []
                        guard let first = songs.first else { return }
                        audioPlayer.play(song: first, fromQueue: songs)
                    }) {
                        Label("Play All", systemImage: "play.fill")
                            .foregroundColor(.pink)
                    }
                    
                    Button(action: downloadPlaylist) {
                        HStack {
                            if isDownloading { ProgressView().scaleEffect(0.6) }
                            Label(isDownloading ? "Downloading..." : "Download All", systemImage: "arrow.down.circle")
                        }
                        .foregroundColor(.blue)
                    }
                    .disabled(isDownloading)
                    
                    ForEach(playlist.entry ?? []) { song in
                        WatchSongRow(
                            song: song,
                            isPlaying: audioPlayer.currentSong?.id == song.id,
                            isOffline: offlineStore.isSongAvailable(song.id)
                        ) {
                            let songs = playlist.entry ?? []
                            let idx = songs.firstIndex(where: { $0.id == song.id }) ?? 0
                            audioPlayer.play(song: song, fromQueue: songs, at: idx)
                        }
                    }
                }
                .navigationTitle(playlist.name)
            }
        }
        .task {
            do {
                playlist = try await watchManager.getPlaylist(id: playlistId)
                isLoading = false
            } catch { isLoading = false }
        }
    }
    
    private func downloadPlaylist() {
        guard let entries = playlist?.entry else { return }
        isDownloading = true
        Task {
            for song in entries {
                await offlineStore.downloadFromServer(song: song)
            }
            await MainActor.run { isDownloading = false }
        }
    }
}

// MARK: - Search on Watch
struct WatchSearchView: View {
    @EnvironmentObject var watchManager: WatchSessionManager
    @EnvironmentObject var audioPlayer: WatchAudioPlayer
    
    @State private var query = ""
    @State private var results: SearchResult3?
    @State private var isSearching = false
    
    var body: some View {
        VStack {
            TextField("Search", text: $query)
                .onSubmit { performSearch() }
            
            if isSearching {
                ProgressView()
            } else if let results = results {
                List {
                    if let songs = results.song, !songs.isEmpty {
                        Section("Songs") {
                            ForEach(songs.prefix(10)) { song in
                                WatchSongRow(
                                    song: song,
                                    isPlaying: audioPlayer.currentSong?.id == song.id
                                ) {
                                    audioPlayer.play(song: song, fromQueue: songs)
                                }
                            }
                        }
                    }
                    
                    if let albums = results.album, !albums.isEmpty {
                        Section("Albums") {
                            ForEach(albums.prefix(5)) { album in
                                NavigationLink(destination: WatchAlbumDetailView(albumId: album.id)) {
                                    VStack(alignment: .leading) {
                                        Text(album.name).font(.caption).lineLimit(1)
                                        Text(album.artist ?? "").font(.caption2).foregroundColor(.gray)
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
        .navigationTitle("Search")
    }
    
    private func performSearch() {
        guard !query.isEmpty else { return }
        isSearching = true
        Task {
            do {
                results = try await watchManager.search(query: query)
                isSearching = false
            } catch { isSearching = false }
        }
    }
}

// MARK: - Reusable Song Row
struct WatchSongRow: View {
    let song: Song
    let isPlaying: Bool
    var isOffline: Bool = false
    let onTap: () -> Void
    
    var body: some View {
        Button(action: onTap) {
            HStack(spacing: 6) {
                if isPlaying {
                    Image(systemName: "waveform")
                        .font(.caption2)
                        .foregroundColor(.pink)
                        .frame(width: 14)
                } else if isOffline {
                    Image(systemName: "checkmark.circle.fill")
                        .font(.caption2)
                        .foregroundColor(.green)
                        .frame(width: 14)
                }
                
                VStack(alignment: .leading, spacing: 1) {
                    Text(song.title)
                        .font(.caption)
                        .foregroundColor(isPlaying ? .pink : .white)
                        .lineLimit(1)
                    
                    Text(song.artist ?? "")
                        .font(.caption2)
                        .foregroundColor(.gray)
                        .lineLimit(1)
                }
                
                Spacer()
                
                Text(song.durationFormatted)
                    .font(.caption2)
                    .foregroundColor(.gray)
            }
        }
    }
}

// MARK: - Watch Settings
struct WatchSettingsView: View {
    @EnvironmentObject var watchManager: WatchSessionManager
    @EnvironmentObject var offlineStore: WatchOfflineStore
    
    @State private var showAddServer = false
    
    var body: some View {
        NavigationView {
            List {
                Section("Server") {
                    ForEach(watchManager.servers) { server in
                        VStack(alignment: .leading, spacing: 2) {
                            HStack {
                                Text(server.name)
                                    .font(.caption)
                                if watchManager.activeServer?.id == server.id {
                                    Image(systemName: "checkmark")
                                        .font(.caption2)
                                        .foregroundColor(.pink)
                                }
                            }
                            Text(server.url)
                                .font(.caption2)
                                .foregroundColor(.gray)
                                .lineLimit(1)
                        }
                        .contentShape(Rectangle())
                        .onTapGesture {
                            watchManager.setActive(server)
                        }
                    }
                    
                    Button("Add Server") { showAddServer = true }
                        .font(.caption)
                        .foregroundColor(.pink)
                    
                    Button("Sync from iPhone") {
                        watchManager.requestServersFromPhone()
                    }
                    .font(.caption)
                }
                
                Section("Storage") {
                    HStack {
                        Text("Offline Songs")
                            .font(.caption)
                        Spacer()
                        Text("\(offlineStore.songs.count)")
                            .font(.caption)
                            .foregroundColor(.gray)
                    }
                    
                    HStack {
                        Text("Used")
                            .font(.caption)
                        Spacer()
                        Text(offlineStore.formattedSize)
                            .font(.caption)
                            .foregroundColor(.gray)
                    }
                    
                    if !offlineStore.songs.isEmpty {
                        Button("Remove All Downloads", role: .destructive) {
                            offlineStore.removeAll()
                        }
                        .font(.caption)
                    }
                }
                
                Section("Phone") {
                    HStack {
                        Circle()
                            .fill(watchManager.isPhoneReachable ? .green : .orange)
                            .frame(width: 6, height: 6)
                        Text(watchManager.isPhoneReachable ? "Connected" : "Not Reachable")
                            .font(.caption)
                            .foregroundColor(.gray)
                    }
                }
            }
            .navigationTitle("Settings")
        }
        .sheet(isPresented: $showAddServer) {
            WatchAddServerView()
        }
    }
}