import SwiftData
import SwiftUI

/// Main screen — list of playlists with Library and Settings in toolbar.
struct PlaylistListView: View {
    @Environment(PlayerViewModel.self) private var playerVM
    @Environment(PlaylistViewModel.self) private var playlistVM
    @EnvironmentObject private var libraryManager: LibraryManager
    @EnvironmentObject private var theme: AppTheme
    @Environment(\.modelContext) private var modelContext

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

    @State private var showNewPlaylist = false
    @State private var newPlaylistName = ""
    @State private var showLibrary = false
    @State private var showSettings = false
    @State private var showCloudBrowser = false

    var body: some View {
        NavigationStack {
            Group {
                if playlists.isEmpty {
                    emptyState
                } else {
                    playlistList
                }
            }
            .navigationTitle("MixBoard")
            .toolbar {
                ToolbarItem(placement: .topBarLeading) {
                    HStack(spacing: 12) {
                        Button {
                            showLibrary = true
                        } label: {
                            Image(systemName: "music.note.list")
                        }
                        .accessibilityIdentifier("libraryButton")

                        Button {
                            showCloudBrowser = true
                        } label: {
                            Image(systemName: "cloud.fill")
                        }
                        .accessibilityIdentifier("cloudBrowserButton")

                        Button {
                            showSettings = true
                        } label: {
                            Image(systemName: "gearshape")
                        }
                        .accessibilityIdentifier("settingsButton")
                    }
                }

                ToolbarItem(placement: .topBarTrailing) {
                    Button {
                        showNewPlaylist = true
                    } label: {
                        Image(systemName: "plus")
                    }
                    .accessibilityIdentifier("newPlaylistButton")
                    .accessibilityIdentifier("newPlaylistButton")
                }
            }
            .alert("New Playlist", isPresented: $showNewPlaylist) {
                TextField("Playlist name", text: $newPlaylistName)
                Button("Cancel", role: .cancel) { newPlaylistName = "" }
                Button("Create") {
                    guard !newPlaylistName.isEmpty else { return }
                    let pl = playlistVM.createPlaylist(name: newPlaylistName, context: modelContext)
                    playlistVM.selectedPlaylist = pl
                    newPlaylistName = ""
                }
            } message: {
                Text("Enter a name for your new playlist")
            }
            .sheet(isPresented: $showLibrary) {
                LibraryView()
                    .environmentObject(theme)
            }
            .sheet(isPresented: $showSettings) {
                SettingsView()
                    .environmentObject(theme)
            }
            .sheet(isPresented: $showCloudBrowser) {
                CloudBrowserView()
                    .environmentObject(theme)
            }
        }
    }

    // MARK: - Playlist List

    private var playlistList: some View {
        List {
            ForEach(playlists) { playlist in
                NavigationLink {
                    PlaylistDetailView(playlist: playlist)
                } label: {
                    PlaylistRowView(playlist: playlist)
                }
                .swipeActions(edge: .trailing) {
                    Button(role: .destructive) {
                        playlistVM.deletePlaylist(playlist, context: modelContext)
                    } label: {
                        Label("Delete", systemImage: "trash")
                    }
                }
                .swipeActions(edge: .leading) {
                    Button {
                        playlistVM.targetPlaylist = playlist
                        playlistVM.showStatus("Target: \(playlist.name)")
                    } label: {
                        Label("Target", systemImage: "star.fill")
                    }
                    .tint(.orange)
                }
                .contextMenu {
                    Button {
                        playlistVM.targetPlaylist = playlist
                        playlistVM.showStatus("Target: \(playlist.name)")
                    } label: {
                        Label(
                            playlistVM.targetPlaylist?.id == playlist.id ? "Current Target" : "Set as Target",
                            systemImage: "star.fill"
                        )
                    }

                    Button(role: .destructive) {
                        playlistVM.deletePlaylist(playlist, context: modelContext)
                    } label: {
                        Label("Delete", systemImage: "trash")
                    }
                }
            }
        }
        .listStyle(.insetGrouped)
        .accessibilityIdentifier("playlistList")
    }

    // MARK: - Empty State

    private var emptyState: some View {
        VStack(spacing: 20) {
            Spacer()
            Image(systemName: "music.note.list")
                .font(.system(size: 60))
                .foregroundStyle(theme.tertiaryText)
            Text("No playlists yet")
                .font(.title2)
                .foregroundStyle(theme.secondaryText)
                .accessibilityIdentifier("emptyStateTitle")
            Text("Create a playlist to start building your mix")
                .font(.subheadline)
                .foregroundStyle(theme.tertiaryText)
            Button {
                showNewPlaylist = true
            } label: {
                Label("New Playlist", systemImage: "plus.circle.fill")
                    .font(.headline)
                    .padding(.horizontal, 24)
                    .padding(.vertical, 12)
            }
            .buttonStyle(.borderedProminent)
            .tint(theme.accent)
            .accessibilityIdentifier("emptyStateNewPlaylistButton")
            Spacer()
        }
        .accessibilityIdentifier("emptyState")
    }
}

// MARK: - Playlist Row

struct PlaylistRowView: View {
    let playlist: Playlist
    @Environment(PlaylistViewModel.self) private var playlistVM
    @EnvironmentObject private var theme: AppTheme

    private var isTarget: Bool {
        guard let target = playlistVM.mixTargets.first(where: { $0?.id == playlist.id }) else { return false }
        return target != nil
    }

    var body: some View {
        HStack(spacing: 12) {
            // Color indicator
            Circle()
                .fill(Color(hex: playlist.color) ?? theme.accent)
                .frame(width: 12, height: 12)

            VStack(alignment: .leading, spacing: 2) {
                HStack(spacing: 6) {
                    Text(playlist.name)
                        .font(.headline)
                        .foregroundStyle(theme.primaryText)

                    if isTarget {
                        Image(systemName: "star.fill")
                            .font(.caption2)
                            .foregroundStyle(.orange)
                    }
                }

                HStack(spacing: 8) {
                    Text("\(playlist.trackCount) tracks")
                        .font(.caption)
                        .foregroundStyle(theme.secondaryText)
                }
            }

            Spacer()
        }
        .padding(.vertical, 4)
        .accessibilityIdentifier("playlistRow_\(playlist.name)")
    }
}