//
//  AlbumDetailView.swift
//  Mobile Music Assistant
//
//  Created by Sven Hanold on 26.03.26.
//

import SwiftUI

struct AlbumDetailView: View {
    @Environment(MAService.self) private var service
    @Environment(\.audioPlayer) private var audioPlayer
    let album: MAAlbum
    
    @State private var tracks: [MAMediaItem] = []
    @State private var isLoading = true
    @State private var errorMessage: String?
    @State private var showError = false
    @State private var showPlayerPicker = false
    @State private var selectedPlayer: MAPlayer?
    
    private var players: [MAPlayer] {
        Array(service.playerManager.players.values).sorted { $0.name < $1.name }
    }
    
    var body: some View {
        ScrollView {
            VStack(spacing: 24) {
                // Album Header
                albumHeader
                
                // Play Button
                playButton
                
                Divider()
                
                // Tracklist
                if isLoading {
                    ProgressView()
                        .padding()
                } else if tracks.isEmpty {
                    Text("No tracks found")
                        .foregroundStyle(.secondary)
                        .padding()
                } else {
                    trackList
                }
            }
        }
        .navigationTitle(album.name)
        .navigationBarTitleDisplayMode(.inline)
        .task {
            await loadTracks()
        }
        .alert("Error", isPresented: $showError) {
            Button("OK", role: .cancel) { }
        } message: {
            if let errorMessage {
                Text(errorMessage)
            }
        }
        .sheet(isPresented: $showPlayerPicker) {
            EnhancedPlayerPickerView(
                players: players,
                supportsLocalPlayback: audioPlayer != nil,
                onSelect: { selection in
                    Task {
                        switch selection {
                        case .localPlayer:
                            await playOnLocalPlayer()
                        case .remotePlayer(let player):
                            await playAlbum(on: player)
                        }
                    }
                }
            )
        }
    }
    
    // MARK: - Album Header
    
    @ViewBuilder
    private var albumHeader: some View {
        VStack(spacing: 16) {
            // Cover Art
            if let imageUrl = album.imageUrl {
                let coverURL = service.imageProxyURL(path: imageUrl, size: 512)
                
                CachedAsyncImage(url: coverURL) { image in
                    image
                        .resizable()
                        .aspectRatio(contentMode: .fill)
                } placeholder: {
                    Rectangle()
                        .fill(Color.gray.opacity(0.2))
                }
                .frame(width: 250, height: 250)
                .clipShape(RoundedRectangle(cornerRadius: 12))
                .shadow(radius: 10)
            } else {
                RoundedRectangle(cornerRadius: 12)
                    .fill(Color.gray.opacity(0.2))
                    .frame(width: 250, height: 250)
                    .overlay {
                        Image(systemName: "opticaldisc")
                            .font(.system(size: 60))
                            .foregroundStyle(.secondary)
                    }
            }
            
            // Album Info
            VStack(spacing: 8) {
                if let artists = album.artists, !artists.isEmpty {
                    Text(artists.map { $0.name }.joined(separator: ", "))
                        .font(.title3)
                        .foregroundStyle(.secondary)
                        .multilineTextAlignment(.center)
                }
                
                HStack {
                    if let year = album.year {
                        Text(String(year))
                            .font(.subheadline)
                            .foregroundStyle(.tertiary)
                    }
                    
                    if !tracks.isEmpty {
                        Text("•")
                            .foregroundStyle(.tertiary)
                        Text("\(tracks.count) tracks")
                            .font(.subheadline)
                            .foregroundStyle(.tertiary)
                    }
                }
            }
            .padding(.horizontal)
        }
        .padding(.top)
    }
    
    // MARK: - Play Button
    
    @ViewBuilder
    private var playButton: some View {
        Button {
            if players.count == 1 {
                selectedPlayer = players.first
                Task {
                    await playAlbum(on: players.first!)
                }
            } else {
                showPlayerPicker = true
            }
        } label: {
            Label("Play Album", systemImage: "play.fill")
                .font(.headline)
                .frame(maxWidth: .infinity)
                .padding()
                .background(Color.accentColor)
                .foregroundStyle(.white)
                .clipShape(RoundedRectangle(cornerRadius: 12))
        }
        .padding(.horizontal)
        .disabled(tracks.isEmpty || players.isEmpty)
    }
    
    // MARK: - Track List
    
    @ViewBuilder
    private var trackList: some View {
        LazyVStack(spacing: 0) {
            ForEach(Array(tracks.enumerated()), id: \.element.id) { index, track in
                TrackRow(track: track, trackNumber: index + 1)
                    .contentShape(Rectangle())
                    .onTapGesture {
                        if players.count == 1 {
                            Task {
                                await playTrack(track, on: players.first!)
                            }
                        } else {
                            showPlayerPicker = true
                        }
                    }
                
                if index < tracks.count - 1 {
                    Divider()
                        .padding(.leading, 60)
                }
            }
        }
        .background(Color(.systemBackground))
        .clipShape(RoundedRectangle(cornerRadius: 12))
        .padding(.horizontal)
    }
    
    // MARK: - Actions
    
    private func loadTracks() async {
        isLoading = true
        errorMessage = nil
        
        do {
            tracks = try await service.libraryManager.getAlbumTracks(albumUri: album.uri)
            isLoading = false
        } catch {
            errorMessage = error.localizedDescription
            showError = true
            isLoading = false
        }
    }
    
    private func playAlbum(on player: MAPlayer) async {
        do {
            try await service.playerManager.playMedia(
                playerId: player.playerId,
                uri: album.uri
            )
        } catch {
            errorMessage = error.localizedDescription
            showError = true
        }
    }
    
    private func playOnLocalPlayer() async {
        guard let audioPlayer else {
            errorMessage = "Local player not available"
            showError = true
            return
        }
        
        do {
            // Play first track on local player
            // Note: We use "local_player" as a virtual queue ID
            if let firstTrack = tracks.first {
                try await audioPlayer.playMediaItem(
                    uri: firstTrack.uri,
                    queueId: "local_player"
                )
            }
        } catch {
            errorMessage = error.localizedDescription
            showError = true
        }
    }
    
    private func playTrack(_ track: MAMediaItem, on player: MAPlayer) async {
        do {
            try await service.playerManager.playMedia(
                playerId: player.playerId,
                uri: track.uri
            )
        } catch {
            errorMessage = error.localizedDescription
            showError = true
        }
    }
}

// MARK: - Track Row

struct TrackRow: View {
    let track: MAMediaItem
    let trackNumber: Int
    
    var body: some View {
        HStack(spacing: 12) {
            // Track Number
            Text("\(trackNumber)")
                .font(.subheadline)
                .foregroundStyle(.secondary)
                .frame(width: 30, alignment: .trailing)
            
            // Track Info
            VStack(alignment: .leading, spacing: 4) {
                Text(track.name)
                    .font(.body)
                    .lineLimit(1)
                
                if let artists = track.artists, !artists.isEmpty {
                    Text(artists.map { $0.name }.joined(separator: ", "))
                        .font(.caption)
                        .foregroundStyle(.secondary)
                        .lineLimit(1)
                }
            }
            
            Spacer()
            
            // Duration
            if let duration = track.duration {
                Text(formatDuration(duration))
                    .font(.caption)
                    .foregroundStyle(.secondary)
            }
        }
        .padding(.vertical, 8)
        .padding(.horizontal)
    }
    
    private func formatDuration(_ seconds: Int) -> String {
        let minutes = seconds / 60
        let remainingSeconds = seconds % 60
        return String(format: "%d:%02d", minutes, remainingSeconds)
    }
}

#Preview {
    NavigationStack {
        AlbumDetailView(
            album: MAAlbum(
                uri: "library://album/1",
                name: "Test Album",
                artists: [
                    MAArtist(uri: "library://artist/1", name: "Test Artist", imageUrl: nil, sortName: nil, musicbrainzId: nil)
                ],
                imageUrl: nil,
                year: 2024
            )
        )
        .environment(MAService())
    }
}