import SwiftData
import SwiftUI
import UniformTypeIdentifiers

private extension UTType {
    /// OGG Vorbis audio — not built-in, so we define it manually.
    static let oggVorbis = UTType(filenameExtension: "ogg") ?? UTType.audio
}

/// Playlist view — manage tracks in a mix with transitions and export.
struct PlaylistView: View {
    let playlist: Playlist

    @Environment(PlayerViewModel.self) private var playerVM
    @Environment(PlaylistViewModel.self) private var playlistVM
    @EnvironmentObject private var libraryManager: LibraryManager
    @Environment(\.modelContext) private var modelContext

    @Query(sort: \Track.title) private var allTracks: [Track]
    @Query(sort: \Playlist.dateModified, order: .reverse) private var allPlaylists: [Playlist]
    @ObservedObject private var viewConfig = PlaylistViewConfig.shared
    @State private var showExportSheet = false
    @State private var showAddTracksSheet = false
    @State private var showGroupEditor = false
    @State private var draggedEntry: PlaylistEntry?
    @State private var isDropTargeted = false

    var body: some View {
        VStack(spacing: 0) {
            // Playlist header
            PlaylistHeader(
                playlist: playlist,
                mixDuration: playlistVM.mixDuration(for: playlist),
                onExport: { showExportSheet = true },
                onAddTracks: { showAddTracksSheet = true },
                onAddFiles: { addFilesFromDisk() },
                onAddFolder: { addFolderFromDisk() },
                onEditGrouping: { showGroupEditor = true },
                viewConfig: viewConfig
            )

            Divider()

            // Track list
            if playlist.entries.isEmpty {
                EmptyPlaylistView(
                    onAddTracks: { showAddTracksSheet = true },
                    onAddFiles: { addFilesFromDisk() },
                    onAddFolder: { addFolderFromDisk() }
                )
            } else {
                PlaylistEntryList(
                    playlist: playlist,
                    draggedEntry: $draggedEntry,
                    viewConfig: viewConfig
                )
            }
        }
        .overlay {
            if isDropTargeted {
                RoundedRectangle(cornerRadius: 8)
                    .stroke(Color.accentColor, lineWidth: 3)
                    .background(Color.accentColor.opacity(0.08))
                    .padding(4)
                    .allowsHitTesting(false)
            }
        }
        .onDrop(of: [.fileURL], isTargeted: $isDropTargeted) { providers in
            handleDrop(providers)
            return true
        }
        .sheet(isPresented: $showExportSheet) {
            ExportSheet(playlist: playlist)
        }
        .sheet(isPresented: $showAddTracksSheet) {
            AddTracksSheet(playlist: playlist, allTracks: allTracks)
        }
        .sheet(isPresented: $showGroupEditor) {
            GroupTemplateEditorSheet(playlist: playlist)
        }
    }

    // MARK: - Add Files from Disk

    private func addFilesFromDisk() {
        let panel = NSOpenPanel()
        panel.canChooseFiles = true
        panel.canChooseDirectories = false
        panel.allowsMultipleSelection = true
        panel.allowedContentTypes = [.audio, .mp3, .wav, .aiff, .oggVorbis]
        panel.message = "Select audio files to add to \"\(playlist.name)\""

        if panel.runModal() == .OK {
            Task {
                await playlistVM.importFilesToPlaylist(
                    urls: panel.urls,
                    playlist: playlist,
                    libraryManager: libraryManager,
                    context: modelContext
                )
            }
        }
    }

    private func addFolderFromDisk() {
        let panel = NSOpenPanel()
        panel.canChooseFiles = false
        panel.canChooseDirectories = true
        panel.allowsMultipleSelection = true
        panel.message = "Select a folder to scan for audio files"

        if panel.runModal() == .OK {
            let urls = expandDirectories(panel.urls)
            Task {
                await playlistVM.importFilesToPlaylist(
                    urls: urls,
                    playlist: playlist,
                    libraryManager: libraryManager,
                    context: modelContext
                )
            }
        }
    }

    private func handleDrop(_ providers: [NSItemProvider]) {
        for provider in providers {
            provider.loadItem(forTypeIdentifier: "public.file-url") { data, _ in
                guard let data = data as? Data,
                      let urlString = String(data: data, encoding: .utf8),
                      let url = URL(string: urlString) else { return }

                let urls = expandDirectories([url])
                Task { @MainActor in
                    await playlistVM.importFilesToPlaylist(
                        urls: urls,
                        playlist: playlist,
                        libraryManager: libraryManager,
                        context: modelContext
                    )
                }
            }
        }
    }

    private func expandDirectories(_ urls: [URL]) -> [URL] {
        var result: [URL] = []
        let fm = FileManager.default
        for url in urls {
            var isDir: ObjCBool = false
            if fm.fileExists(atPath: url.path, isDirectory: &isDir), isDir.boolValue {
                if let enumerator = fm.enumerator(at: url, includingPropertiesForKeys: nil, options: [.skipsHiddenFiles]) {
                    for case let fileURL as URL in enumerator {
                        if MetadataService.isSupportedAudioFile(fileURL) {
                            result.append(fileURL)
                        }
                    }
                }
            } else if MetadataService.isSupportedAudioFile(url) {
                result.append(url)
            }
        }
        // Sort by full path with numeric sorting to preserve folder structure
        // (like iOS FolderBrowserView) — e.g. "01/01.mp3" < "01/02.mp3" < "02/01.mp3"
        return result.sorted { $0.path.compare($1.path, options: [.numeric, .caseInsensitive]) == .orderedAscending }
    }
}

// MARK: - Playlist Header (compact toolbar)

private struct PlaylistHeader: View {
    let playlist: Playlist
    let mixDuration: TimeInterval
    let onExport: () -> Void
    let onAddTracks: () -> Void
    let onAddFiles: () -> Void
    let onAddFolder: () -> Void
    let onEditGrouping: () -> Void
    @ObservedObject var viewConfig: PlaylistViewConfig
    @EnvironmentObject private var theme: AppTheme

    var body: some View {
        HStack(spacing: 6) {
            // Playlist name
            Text(playlist.name)
                .font(.system(size: 13, weight: .semibold))
                .foregroundStyle(theme.primaryText)
                .lineLimit(1)

            // Stats
            Text("[\(playlist.trackCount) tracks · \(formatDuration(mixDuration))]")
                .font(.system(size: 11))
                .foregroundStyle(theme.secondaryText)

            Spacer()

            // Toolbar buttons
            HStack(spacing: 6) {
                Menu {
                    Button("Add Files...") { onAddFiles() }
                    Button("Add Folder...") { onAddFolder() }
                    Divider()
                    Button("From Library...") { onAddTracks() }
                } label: {
                    Label("Add", systemImage: "plus")
                }
                .fixedSize()

                Menu {
                    ForEach(GroupTemplateResolver.presets, id: \.template) { preset in
                        Button {
                            playlist.groupTemplate = preset.template
                        } label: {
                            HStack {
                                Text(preset.name)
                                if playlist.groupTemplate == preset.template {
                                    Image(systemName: "checkmark")
                                }
                            }
                        }
                    }
                    Divider()
                    Button("Custom...") { onEditGrouping() }
                } label: {
                    Label(
                        playlist.groupTemplate.isEmpty ? "Group" : "Grouped",
                        systemImage: "rectangle.3.group"
                    )
                }
                .fixedSize()

                Button {
                    NSApp.sendAction(Selector(("showSettingsWindow:")), to: nil, from: nil)
                } label: {
                    Label("Settings", systemImage: "gearshape")
                }

                Button { onExport() } label: {
                    Label("Export", systemImage: "square.and.arrow.up")
                }
                .disabled(playlist.entries.isEmpty)
            }
            .controlSize(.small)
        }
        .padding(.horizontal, 10)
        .padding(.vertical, 7)
        .background(theme.toolbarBackground)
    }

    private func formatDuration(_ duration: TimeInterval) -> String {
        let total = Int(duration)
        let hours = total / 3600
        let minutes = (total % 3600) / 60
        let seconds = total % 60
        if hours > 0 {
            return String(format: "%d:%02d:%02d", hours, minutes, seconds)
        }
        return String(format: "%d:%02d", minutes, seconds)
    }
}

// MARK: - Playlist Entry List (with Grouping)

private struct PlaylistEntryList: View {
    let playlist: Playlist
    @Binding var draggedEntry: PlaylistEntry?
    @ObservedObject var viewConfig: PlaylistViewConfig

    @Environment(PlayerViewModel.self) private var playerVM
    @Environment(PlaylistViewModel.self) private var playlistVM
    @EnvironmentObject private var libraryManager: LibraryManager
    @Environment(\.modelContext) private var modelContext

    @Query(sort: \Playlist.dateModified, order: .reverse) private var allPlaylists: [Playlist]

    @State private var selectedEntryIDs: Set<UUID> = []
    @State private var scrollTarget: UUID?
    @State private var editingNotesTrack: Track?

    /// Group entries by the playlist's groupTemplate.
    private var groupedEntries: [(key: String, entries: [(index: Int, entry: PlaylistEntry)])] {
        let sorted = playlist.sortedEntries
        let indexed = sorted.enumerated().map { (index: $0.offset, entry: $0.element) }

        guard !playlist.groupTemplate.isEmpty else {
            return [("", indexed)]
        }

        // Group consecutively by resolved template (preserves playlist order)
        var groups: [(String, [(index: Int, entry: PlaylistEntry)])] = []
        var currentHeader = ""
        var currentEntries: [(index: Int, entry: PlaylistEntry)] = []

        for item in indexed {
            let header: String
            if let track = item.entry.track {
                header = GroupTemplateResolver.resolve(template: playlist.groupTemplate, for: track)
            } else {
                header = "Unknown"
            }

            if header != currentHeader {
                if !currentEntries.isEmpty {
                    groups.append((currentHeader, currentEntries))
                }
                currentHeader = header
                currentEntries = [item]
            } else {
                currentEntries.append(item)
            }
        }
        if !currentEntries.isEmpty {
            groups.append((currentHeader, currentEntries))
        }

        return groups.map { (key: $0.0, entries: $0.1) }
    }

    var body: some View {
        VStack(spacing: 0) {
            // Selection toolbar
            if !selectedEntryIDs.isEmpty {
                SelectionToolbar(
                    count: selectedEntryIDs.count,
                    onSelectAll: { selectedEntryIDs = Set(playlist.entries.map(\.id)) },
                    onDeselect: { selectedEntryIDs.removeAll() },
                    onRemove: {
                        let toRemove = playlist.sortedEntries.filter { selectedEntryIDs.contains($0.id) }
                        for entry in toRemove {
                            playlistVM.removeEntry(entry, from: playlist, context: modelContext)
                        }
                        selectedEntryIDs.removeAll()
                    }
                )
                Divider()
            }

            // Column headers
            ColumnHeaderRow(viewConfig: viewConfig)
            Divider()

            List(selection: $selectedEntryIDs) {
                ForEach(groupedEntries, id: \.key) { group in
                    if !playlist.groupTemplate.isEmpty && !group.key.isEmpty {
                        Section {
                            groupContent(group.entries)
                        } header: {
                            GroupHeaderView(
                                title: group.key,
                                trackCount: group.entries.count,
                                firstTrack: group.entries.first?.entry.track,
                                showArtwork: viewConfig.showArtwork
                            )
                        }
                    } else {
                        groupContent(group.entries)
                    }
                }
            }
            .listStyle(.inset)
            // Enter key always plays selected track (like foobar2000)
            .onKeyPress(.return) {
                playSelectedTrack()
                return .handled
            }
            // Arrow keys for navigation
            .onKeyPress(.upArrow) {
                moveSelection(by: -1)
                return .handled
            }
            .onKeyPress(.downArrow) {
                moveSelection(by: 1)
                return .handled
            }
            // Backspace/Delete key removes selected entries (onDeleteCommand is the macOS-native way)
            .onDeleteCommand {
                removeSelectedEntries()
            }
            // Cursor follows playback: select playing entry
            .onChange(of: playerVM.currentPlayingEntryID) { _, newID in
                guard viewConfig.cursorFollowsPlayback, let entryID = newID else { return }
                selectedEntryIDs = [entryID]
            }
            // Sync cursor position to PlayerViewModel for "Playback follows cursor"
            .onChange(of: selectedEntryIDs) { _, newIDs in
                playerVM.cursorEntryID = newIDs.first
            }
            // When PlayerViewModel moves cursor (auto-advance), update the UI selection
            .onChange(of: playerVM.cursorEntryID) { _, newID in
                if let newID, !selectedEntryIDs.contains(newID) {
                    selectedEntryIDs = [newID]
                }
            }
            .sheet(item: $editingNotesTrack) { track in
                TrackNotesSheet(track: track)
            }
            // Double-click to play (via NSEvent monitor in MediaKeyHandler)
            .onReceive(NotificationCenter.default.publisher(for: .doubleClickPlayTrack)) { _ in
                playSelectedTrack()
            }
            // When this playlist view appears, restore cursor to playing entry if applicable
            .onAppear {
                if selectedEntryIDs.isEmpty,
                   let playingID = playerVM.currentPlayingEntryID,
                   playlist.sortedEntries.contains(where: { $0.id == playingID }) {
                    selectedEntryIDs = [playingID]
                    playerVM.cursorEntryID = playingID
                }
            }
        }
    }

    /// Play the first selected entry.
    private func playSelectedTrack() {
        guard let firstID = selectedEntryIDs.first,
              let entry = playlist.sortedEntries.first(where: { $0.id == firstID }),
              let track = entry.track else { return }
        playerVM.loadAndPlay(track, entryID: entry.id, playlist: playlist)
    }

    /// Remove all selected entries from the playlist.
    private func removeSelectedEntries() {
        guard !selectedEntryIDs.isEmpty else { return }
        let toRemove = playlist.sortedEntries.filter { selectedEntryIDs.contains($0.id) }
        for entry in toRemove {
            playlistVM.removeEntry(entry, from: playlist, context: modelContext)
        }
        selectedEntryIDs.removeAll()
    }

    /// Move selection up or down by `offset` positions.
    private func moveSelection(by offset: Int) {
        let sorted = playlist.sortedEntries
        guard !sorted.isEmpty else { return }

        if let currentID = selectedEntryIDs.first,
           let currentIndex = sorted.firstIndex(where: { $0.id == currentID }) {
            let newIndex = max(0, min(sorted.count - 1, currentIndex + offset))
            selectedEntryIDs = [sorted[newIndex].id]
        } else {
            // Nothing selected — select first or last
            let entry = offset > 0 ? sorted.first! : sorted.last!
            selectedEntryIDs = [entry.id]
        }
    }

    @ViewBuilder
    private func groupContent(_ entries: [(index: Int, entry: PlaylistEntry)]) -> some View {
        ForEach(entries, id: \.entry.id) { item in
            ConfigurableEntryRow(
                entry: item.entry,
                index: item.index,
                isLast: item.index == playlist.entries.count - 1,
                viewConfig: viewConfig,
                isPlaying: playerVM.currentPlayingEntryID == item.entry.id
            )
            .tag(item.entry.id)
            .id(item.entry.id)
            .draggable(item.entry.track?.id.uuidString ?? "")
            .contextMenu {
                if let track = item.entry.track {
                    Button("Play") { playerVM.loadAndPlay(track, entryID: item.entry.id, playlist: playlist) }

                    Divider()

                    // Add to other playlists
                    let otherPlaylists = allPlaylists.filter { $0.id != playlist.id }
                    if !otherPlaylists.isEmpty {
                        Menu("Add to Playlist") {
                            ForEach(otherPlaylists) { targetPlaylist in
                                Button(targetPlaylist.name) {
                                    playlistVM.addTrack(track, to: targetPlaylist, context: modelContext)
                                }
                            }
                        }
                    }
                }

                Divider()

                Button {
                    viewConfig.cursorFollowsPlayback = true
                    viewConfig.playbackFollowsCursor = false
                } label: {
                    HStack {
                        Text("Cursor follows playback")
                        if viewConfig.cursorFollowsPlayback {
                            Spacer()
                            Image(systemName: "checkmark")
                        }
                    }
                }

                Button {
                    viewConfig.playbackFollowsCursor = true
                    viewConfig.cursorFollowsPlayback = false
                } label: {
                    HStack {
                        Text("Playback follows cursor")
                        if viewConfig.playbackFollowsCursor {
                            Spacer()
                            Image(systemName: "checkmark")
                        }
                    }
                }

                if let track = item.entry.track {
                    Divider()

                    Button("Analyze BPM & Key") {
                        Task { await libraryManager.analyzeTrack(track) }
                    }

                    Button("Rescan Metadata") {
                        Task {
                            await libraryManager.rescanMetadata(track)
                            try? modelContext.save()
                        }
                    }

                    Button("Edit Notes...") {
                        editingNotesTrack = track
                    }

                    // Quick add to mix targets
                    let otherMixSlots = (0..<3).filter { playlistVM.mixTargets[$0] != nil && playlistVM.mixTargets[$0]?.id != playlist.id }
                    if !otherMixSlots.isEmpty {
                        let mixShortcuts: [ShortcutAction] = [.addToMix1, .addToMix2, .addToMix3]
                        Menu("Add to Mix") {
                            ForEach(otherMixSlots, id: \.self) { slot in
                                let hint = KeyboardShortcutConfig.shared.binding(for: mixShortcuts[slot]).displayString
                                Button("\(playlistVM.mixTargetName(slot)) (\(hint))") {
                                    _ = playlistVM.quickAddToMix(slot: slot, track: track, context: modelContext)
                                }
                            }
                        }
                    }
                }

                Divider()

                if selectedEntryIDs.count > 1 {
                    Button("Remove \(selectedEntryIDs.count) Selected", role: .destructive) {
                        let toRemove = playlist.sortedEntries.filter { selectedEntryIDs.contains($0.id) }
                        for e in toRemove {
                            playlistVM.removeEntry(e, from: playlist, context: modelContext)
                        }
                        selectedEntryIDs.removeAll()
                    }
                } else {
                    Button("Remove from Playlist", role: .destructive) {
                        playlistVM.removeEntry(item.entry, from: playlist, context: modelContext)
                    }
                }
            }
        }
        .onMove { source, destination in
            if let first = source.first {
                playlistVM.moveEntry(in: playlist, from: first, to: destination, context: modelContext)
            }
        }
    }
}

// MARK: - Selection Toolbar

private struct SelectionToolbar: View {
    let count: Int
    let onSelectAll: () -> Void
    let onDeselect: () -> Void
    let onRemove: () -> Void
    @EnvironmentObject private var theme: AppTheme

    var body: some View {
        HStack(spacing: 8) {
            Text("\(count) selected")
                .font(.system(size: theme.smallFontSize + 1))
                .foregroundStyle(theme.secondaryText)
            Spacer()
            Button("All", action: onSelectAll).font(.system(size: theme.smallFontSize + 1)).buttonStyle(.plain)
            Button("None", action: onDeselect).font(.system(size: theme.smallFontSize + 1)).buttonStyle(.plain)
            Button("Remove", role: .destructive, action: onRemove).font(.system(size: theme.smallFontSize + 1)).buttonStyle(.plain)
        }
        .padding(.horizontal, 8)
        .padding(.vertical, 2)
        .background(theme.toolbarBackground)
    }
}

// MARK: - Group Header with Artwork

private struct GroupHeaderView: View {
    let title: String
    let trackCount: Int
    let firstTrack: Track?
    let showArtwork: Bool
    @EnvironmentObject private var theme: AppTheme

    var body: some View {
        HStack(spacing: 6) {
            if showArtwork, let track = firstTrack {
                ArtworkView(track: track, size: 18)
            }

            Text(title)
                .font(.system(size: theme.dataFontSize, weight: .bold))
                .foregroundStyle(theme.groupHeaderText)

            Text("(\(trackCount))")
                .font(.system(size: theme.smallFontSize + 1))
                .foregroundStyle(theme.tertiaryText)
        }
        .padding(.vertical, 2)
    }
}

// MARK: - Column Header Row

private struct ColumnHeaderRow: View {
    @ObservedObject var viewConfig: PlaylistViewConfig
    @EnvironmentObject private var theme: AppTheme

    private let f = Font.system(size: 10, weight: .medium)
    private let fMono = Font.system(size: 10, weight: .medium, design: .monospaced)

    private var columns: [PlaylistViewConfig.Column] {
        viewConfig.visibleColumns
    }

    var body: some View {
        HStack(spacing: 0) {
            // # column or playing indicator space
            if columns.contains(.trackNumber) {
                Text("#")
                    .font(fMono)
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 32, alignment: .trailing)
                    .padding(.trailing, 4)
            }

            // Artwork spacer
            if columns.contains(.artwork) && viewConfig.showArtwork {
                Color.clear
                    .frame(width: 18)
                    .padding(.trailing, 4)
            }

            // Artist / Title combined header
            if columns.contains(.artist) || columns.contains(.title) {
                let parts = [
                    columns.contains(.artist) ? "Artist" : nil,
                    columns.contains(.title) ? "Title" : nil
                ].compactMap { $0 }

                Text(parts.joined(separator: " / "))
                    .font(f)
                    .foregroundStyle(theme.secondaryText)
                    .lineLimit(1)
            }

            Spacer(minLength: 8)

            if columns.contains(.album) {
                Text("Album")
                    .font(f)
                    .foregroundStyle(theme.secondaryText)
                    .frame(maxWidth: 150, alignment: .leading)
                    .padding(.trailing, 8)
            }

            if columns.contains(.genre) {
                Text("Genre")
                    .font(f)
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 70, alignment: .leading)
            }

            if columns.contains(.bpm) {
                Text("BPM")
                    .font(fMono)
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 45, alignment: .trailing)
            }

            if columns.contains(.key) {
                Text("Key")
                    .font(f)
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 42, alignment: .center)
            }

            if columns.contains(.duration) {
                Text("Time")
                    .font(fMono)
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 58, alignment: .trailing)
            }

            if columns.contains(.format) {
                Text("Fmt")
                    .font(.system(size: 9, weight: .medium))
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 38, alignment: .center)
            }

            if columns.contains(.sampleRate) {
                Text("Rate")
                    .font(.system(size: 9, weight: .medium, design: .monospaced))
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 58, alignment: .trailing)
            }

            if columns.contains(.bitDepth) {
                Text("Bit")
                    .font(.system(size: 9, weight: .medium, design: .monospaced))
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 20, alignment: .trailing)
            }

            if columns.contains(.fileSize) {
                Text("Size")
                    .font(.system(size: 9, weight: .medium, design: .monospaced))
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 65, alignment: .trailing)
            }

            if columns.contains(.rating) {
                Text("Rating")
                    .font(.system(size: 9, weight: .medium))
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 50, alignment: .center)
            }

            if columns.contains(.playCount) {
                Text("Plays")
                    .font(.system(size: 9, weight: .medium, design: .monospaced))
                    .foregroundStyle(theme.secondaryText)
                    .frame(width: 25, alignment: .trailing)
            }
        }
        .frame(height: 22)
        .padding(.horizontal, 20)
        .background(theme.columnHeaderBackground)
    }
}

// MARK: - Configurable Entry Row

private struct ConfigurableEntryRow: View {
    let entry: PlaylistEntry
    let index: Int
    let isLast: Bool
    @ObservedObject var viewConfig: PlaylistViewConfig
    var isPlaying: Bool = false

    @Environment(PlayerViewModel.self) private var playerVM
    @Environment(PlaylistViewModel.self) private var playlistVM
    @Environment(\.modelContext) private var modelContext

    @State private var crossfade: Double = 0
    @State private var gain: Double = 0

    private var f: Font { .system(size: theme.dataFontSize) }
    private var fMono: Font { .system(size: theme.dataFontSize, design: .monospaced) }

    private var columns: [PlaylistViewConfig.Column] {
        viewConfig.visibleColumns
    }

    @EnvironmentObject private var theme: AppTheme

    var body: some View {
        HStack(spacing: 0) {
            if let track = entry.track {
                // Playing indicator (narrow)
                if isPlaying {
                    Text("▶")
                        .font(.system(size: 8))
                        .foregroundStyle(theme.playingHighlight)
                        .frame(width: 12)
                } else if columns.contains(.trackNumber) {
                    Text("\(index + 1)")
                        .font(fMono)
                        .foregroundStyle(theme.tertiaryText)
                        .frame(width: 32, alignment: .trailing)
                        .padding(.trailing, 4)
                }

                // Artwork (small)
                if columns.contains(.artwork) && viewConfig.showArtwork {
                    ArtworkView(track: track, size: 18)
                        .padding(.trailing, 4)
                }

                // Artist - Title (main text, takes remaining space)
                if columns.contains(.artist) && !track.artist.isEmpty {
                    Text(track.artist)
                        .font(f)
                        .foregroundStyle(theme.secondaryText)
                        .lineLimit(1)

                    Text(" – ")
                        .font(f)
                        .foregroundStyle(theme.tertiaryText)
                }

                if columns.contains(.title) {
                    Text(track.title)
                        .font(f.weight(isPlaying ? .bold : .regular))
                        .foregroundStyle(isPlaying ? theme.playingHighlight : theme.primaryText)
                        .lineLimit(1)
                }

                Spacer(minLength: 8)

                // Album
                if columns.contains(.album) && !track.album.isEmpty {
                    Text(track.album)
                        .font(f)
                        .foregroundStyle(theme.tertiaryText)
                        .lineLimit(1)
                        .frame(maxWidth: 150, alignment: .leading)
                        .padding(.trailing, 8)
                }

                // Genre
                if columns.contains(.genre) && !track.genre.isEmpty {
                    Text(track.genre)
                        .font(f)
                        .foregroundStyle(theme.tertiaryText)
                        .frame(width: 70, alignment: .leading)
                }

                // BPM
                if columns.contains(.bpm) {
                    Text(track.bpm.map { String(format: "%.0f", $0) } ?? "")
                        .font(fMono)
                        .foregroundStyle(theme.secondaryText)
                        .frame(width: 45, alignment: .trailing)
                }

                // Key
                if columns.contains(.key) {
                    Text(track.musicalKey ?? "")
                        .font(f)
                        .foregroundStyle(theme.secondaryText)
                        .frame(width: 42, alignment: .center)
                }

                // Duration
                if columns.contains(.duration) {
                    Text(track.formattedDuration)
                        .font(fMono)
                        .foregroundStyle(theme.secondaryText)
                        .frame(width: 58, alignment: .trailing)
                }

                // Format
                if columns.contains(.format) {
                    Text(track.fileFormat)
                        .font(.system(size: theme.smallFontSize))
                        .foregroundStyle(theme.tertiaryText)
                        .frame(width: 38, alignment: .center)
                }

                // Sample Rate
                if columns.contains(.sampleRate) {
                    Text("\(Int(track.sampleRate))Hz")
                        .font(.system(size: theme.smallFontSize, design: .monospaced))
                        .foregroundStyle(theme.tertiaryText)
                        .frame(width: 58, alignment: .trailing)
                }

                // Bit Depth
                if columns.contains(.bitDepth) {
                    Text("\(track.bitDepth)")
                        .font(.system(size: theme.smallFontSize, design: .monospaced))
                        .foregroundStyle(theme.tertiaryText)
                        .frame(width: 20, alignment: .trailing)
                }

                // File Size
                if columns.contains(.fileSize) {
                    Text(track.formattedFileSize)
                        .font(.system(size: theme.smallFontSize, design: .monospaced))
                        .foregroundStyle(theme.tertiaryText)
                        .frame(width: 65, alignment: .trailing)
                }

                // Rating
                if columns.contains(.rating) && track.rating > 0 {
                    Text(String(repeating: "★", count: track.rating))
                        .font(.system(size: theme.smallFontSize))
                        .foregroundStyle(.yellow)
                        .frame(width: 50, alignment: .center)
                }

                // Play Count
                if columns.contains(.playCount) && track.playCount > 0 {
                    Text("\(track.playCount)×")
                        .font(.system(size: theme.smallFontSize, design: .monospaced))
                        .foregroundStyle(theme.tertiaryText)
                        .frame(width: 25, alignment: .trailing)
                }
            }
        }
        .frame(height: theme.rowHeight)
        .onAppear {
            crossfade = entry.crossfadeDuration
            gain = entry.gainAdjustment
        }
    }
}

// MARK: - Empty Playlist

private struct EmptyPlaylistView: View {
    let onAddTracks: () -> Void
    let onAddFiles: () -> Void
    let onAddFolder: () -> Void

    var body: some View {
        VStack(spacing: 12) {
            Spacer()

            Text("Empty playlist")
                .font(.system(size: 12))
                .foregroundStyle(.secondary)

            Text("Drop files here, or use Add menu above")
                .font(.system(size: 11))
                .foregroundStyle(.tertiary)

            HStack(spacing: 8) {
                Button("Add Files...") { onAddFiles() }
                    .font(.system(size: 11))
                Button("Add Folder...") { onAddFolder() }
                    .font(.system(size: 11))
            }

            Spacer()
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}

// MARK: - Column Config Sheet

private struct ColumnConfigSheet: View {
    @ObservedObject var viewConfig: PlaylistViewConfig
    @Environment(\.dismiss) private var dismiss

    var body: some View {
        VStack(spacing: 0) {
            HStack {
                Text("Configure Playlist View")
                    .font(.headline)
                Spacer()
                Button("Done") { dismiss() }
                    .keyboardShortcut(.defaultAction)
            }
            .padding()

            Divider()

            ScrollView {
                VStack(alignment: .leading, spacing: 20) {
                    // Artwork settings
                    VStack(alignment: .leading, spacing: 8) {
                        Text("Artwork")
                            .font(.subheadline.bold())

                        Toggle("Show artwork", isOn: $viewConfig.showArtwork)

                        if viewConfig.showArtwork {
                            Picker("Size", selection: $viewConfig.artworkSize) {
                                ForEach(PlaylistViewConfig.ArtworkSize.allCases) { size in
                                    Text(size.rawValue).tag(size)
                                }
                            }
                            .pickerStyle(.segmented)
                            .frame(width: 250)
                        }
                    }

                    Divider()

                    // Playback behavior
                    VStack(alignment: .leading, spacing: 8) {
                        Text("Playback Behavior")
                            .font(.subheadline.bold())

                        Toggle("Cursor follows playback", isOn: $viewConfig.cursorFollowsPlayback)
                        Text("Auto-select and scroll to the currently playing track")
                            .font(.caption)
                            .foregroundStyle(.secondary)

                        Toggle("Playback follows cursor", isOn: $viewConfig.playbackFollowsCursor)
                        Text("Press Enter/Return to play the selected track")
                            .font(.caption)
                            .foregroundStyle(.secondary)
                    }

                    Divider()

                    // Visible columns
                    VStack(alignment: .leading, spacing: 8) {
                        HStack {
                            Text("Visible Columns")
                                .font(.subheadline.bold())

                            Spacer()

                            Button("Reset to Defaults") {
                                viewConfig.resetToDefaults()
                            }
                            .font(.caption)
                        }

                        Text("Check the columns you want to display. Drag to reorder.")
                            .font(.caption)
                            .foregroundStyle(.secondary)

                        LazyVGrid(columns: [GridItem(.adaptive(minimum: 140))], spacing: 6) {
                            ForEach(PlaylistViewConfig.Column.allCases) { column in
                                Toggle(column.rawValue, isOn: Binding(
                                    get: { viewConfig.isColumnVisible(column) },
                                    set: { _ in viewConfig.toggleColumn(column) }
                                ))
                                .toggleStyle(.checkbox)
                                .font(.caption)
                            }
                        }
                    }
                }
                .padding(20)
            }
        }
        .frame(width: 450, height: 520)
    }
}

// MARK: - Add Tracks Sheet

private struct AddTracksSheet: View {
    let playlist: Playlist
    let allTracks: [Track]

    @Environment(PlaylistViewModel.self) private var playlistVM
    @Environment(\.modelContext) private var modelContext
    @Environment(\.dismiss) private var dismiss

    @State private var searchText = ""
    @State private var selectedTracks: Set<UUID> = []

    var filteredTracks: [Track] {
        if searchText.isEmpty { return allTracks }
        let query = searchText.lowercased()
        return allTracks.filter {
            $0.title.lowercased().contains(query) ||
            $0.artist.lowercased().contains(query)
        }
    }

    var body: some View {
        VStack(spacing: 0) {
            HStack {
                Text("Add Tracks to \(playlist.name)")
                    .font(.headline)
                Spacer()
                Text("\(selectedTracks.count) selected")
                    .foregroundStyle(.secondary)
            }
            .padding()

            TextField("Search tracks...", text: $searchText)
                .textFieldStyle(.roundedBorder)
                .padding(.horizontal)

            List(filteredTracks, selection: $selectedTracks) { track in
                HStack {
                    TrackRow(track: track)
                    Spacer()
                    if let bpm = track.bpm {
                        Text("\(String(format: "%.0f", bpm))")
                            .font(.caption)
                            .foregroundStyle(.secondary)
                    }
                    Text(track.formattedDuration)
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }
            }
            .listStyle(.inset)

            Divider()

            HStack {
                Button("Cancel") { dismiss() }
                    .keyboardShortcut(.cancelAction)
                Spacer()
                Button("Add \(selectedTracks.count) Track\(selectedTracks.count == 1 ? "" : "s")") {
                    let tracks = allTracks.filter { selectedTracks.contains($0.id) }
                    playlistVM.addTracks(tracks, to: playlist, context: modelContext)
                    dismiss()
                }
                .keyboardShortcut(.defaultAction)
                .disabled(selectedTracks.isEmpty)
            }
            .padding()
        }
        .frame(width: 500, height: 600)
    }
}

// MARK: - Track Notes Sheet

private struct TrackNotesSheet: View {
    let track: Track

    @Environment(\.dismiss) private var dismiss
    @Environment(\.modelContext) private var modelContext
    @State private var notes: String = ""

    var body: some View {
        VStack(spacing: 12) {
            HStack {
                VStack(alignment: .leading, spacing: 2) {
                    Text(track.title)
                        .font(.headline)
                    if !track.artist.isEmpty {
                        Text(track.artist)
                            .font(.subheadline)
                            .foregroundStyle(.secondary)
                    }
                }
                Spacer()
                Button("Done") {
                    track.notes = notes
                    try? modelContext.save()
                    dismiss()
                }
                .keyboardShortcut(.defaultAction)
            }

            TextEditor(text: $notes)
                .font(.system(size: 13))
                .frame(minHeight: 100)
                .scrollContentBackground(.hidden)
                .padding(4)
                .background(Color.gray.opacity(0.1))
                .cornerRadius(6)

            HStack {
                Text("Notes are saved with the track and included in exports")
                    .font(.caption)
                    .foregroundStyle(.secondary)
                Spacer()
            }
        }
        .padding(16)
        .frame(width: 400, height: 220)
        .onAppear {
            notes = track.notes
        }
    }
}

// MARK: - Double-Click Handler (NSViewRepresentable)