import SwiftUI
import UniformTypeIdentifiers
import AppKit

struct ServerMenuItem: Identifiable, Hashable {
  let id: UUID
  let type: ServerNavigationType
  let name: String
  let image: String
  
  init(type: ServerNavigationType, name: String, image: String) {
    self.id = UUID()
    self.type = type
    self.name = name
    self.image = image
  }
  
  func hash(into hasher: inout Hasher) {
    hasher.combine(id)
  }
  
  static func == (lhs: ServerMenuItem, rhs: ServerMenuItem) -> Bool {
    switch lhs.type {
    case .user(let lhsUID):
      switch rhs.type {
      case .user(let rhsUID):
        return lhsUID == rhsUID
      default:
        break
      }
    default:
      break
    }
    return lhs.id == rhs.id
  }
}

struct ListItemView: View {
  @Environment(\.controlActiveState) private var controlActiveState
  
  let icon: String?
  let title: String
  let unread: Bool
  
  var body: some View {
    HStack(spacing: 5) {
      if let i = icon {
        Image(i)
          .resizable()
        //            .renderingMode(.template)
          .scaledToFit()
          .frame(width: 20, height: 20)
//          .padding(.leading, 2)
          .opacity(controlActiveState == .inactive ? 0.5 : 1.0)
      }
      
      Text(title)
        .lineLimit(1)
        .truncationMode(.tail)
      Spacer()
      if unread {
        Circle()
          .frame(width: 6, height: 6)
          .padding(EdgeInsets(top: 0, leading: 8, bottom: 0, trailing: 2))
          .opacity(0.5)
      }
    }
  }
}

extension FocusedValues {
  @Entry var activeHotlineModel: HotlineState?
  @Entry var activeServerState: ServerState?
}

struct ServerView: View {
  @Environment(\.dismiss) var dismiss
  @Environment(\.colorScheme) private var colorScheme
  @Environment(\.controlActiveState) private var controlActiveState
  @Environment(\.scenePhase) private var scenePhase
  @Environment(\.modelContext) private var modelContext
  
  @State private var model: HotlineState = HotlineState()
  @State private var state: ServerState = ServerState(selection: .chat)
  @State private var agreementShown: Bool = false
  @State private var connectAddress: String = ""
  @State private var connectLogin: String = ""
  @State private var connectPassword: String = ""
  @State private var connectNameSheetPresented: Bool = false
  @State private var connectName: String = ""

  @Binding var server: Server
  
  static var menuItems: [ServerMenuItem] = [
    ServerMenuItem(type: .chat, name: "Chat", image: "Section Chat"),
    ServerMenuItem(type: .board, name: "Board", image: "Section Board"),
    ServerMenuItem(type: .news, name: "News", image: "Section News"),
    ServerMenuItem(type: .files, name: "Files", image: "Section Files"),
    ServerMenuItem(type: .accounts, name: "Accounts", image: "Section Users"),
  ]
  
  static var classicMenuItems: [ServerMenuItem] = [
    ServerMenuItem(type: .chat, name: "Chat", image: "Section Chat"),
    ServerMenuItem(type: .board, name: "Board", image: "Section Board"),
    ServerMenuItem(type: .files, name: "Files", image: "Section Files"),
  ]
  
  enum FocusFields {
    case address
    case login
    case password
  }
  
  @FocusState private var focusedField: FocusFields?
  
  var body: some View {
    Group {
      if model.status == .disconnected {
        VStack(alignment: .center) {
          Spacer()
          self.connectForm
          Spacer()
        }
//        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .navigationTitle("Connect to Server")
      }
      else if case .failed(let error) = model.status {
        VStack {
          Image("Hotline")
            .resizable()
            .renderingMode(.template)
            .scaledToFit()
            .foregroundColor(Color(hex: 0xE10000))
            .frame(width: 18)
            .opacity(controlActiveState == .inactive ? 0.5 : 1.0)
            .padding(.trailing, 4)

          Text("Connection Failed")
            .font(.headline)
          Text(error)
            .font(.caption)
            .foregroundStyle(.secondary)
            .multilineTextAlignment(.center)
        }
        .frame(maxWidth: 300)
        .padding()
        .navigationTitle("Connection Failed")
      }
      else if model.status != .loggedIn {
        HStack {
          Image("Hotline")
            .resizable()
            .renderingMode(.template)
            .scaledToFit()
            .foregroundColor(Color(hex: 0xE10000))
            .frame(width: 18)
            .opacity(controlActiveState == .inactive ? 0.5 : 1.0)
            .padding(.trailing, 4)

          ProgressView(value: connectionStatusToProgress(status: model.status)) {
            Text(connectionStatusToLabel(status: model.status))
          }
          .accentColor(colorScheme == .dark ? .white : .black)
        }
        .frame(maxWidth: 300)
        .padding()
        .navigationTitle("Connecting to Server")
      }
      else {
        serverView
          .environment(model)
          .onChange(of: Prefs.shared.userIconID) {
            Task { try? await model.sendUserPreferences() }
          }
          .onChange(of: Prefs.shared.username) {
            Task { try? await model.sendUserPreferences() }
          }
          .onChange(of: Prefs.shared.refusePrivateMessages) {
            Task { try? await model.sendUserPreferences() }
          }
          .onChange(of: Prefs.shared.refusePrivateChat) {
            Task { try? await model.sendUserPreferences() }
          }
          .onChange(of: Prefs.shared.enableAutomaticMessage) {
            Task { try? await model.sendUserPreferences() }
          }
          .onChange(of: Prefs.shared.automaticMessage) {
            Task { try? await model.sendUserPreferences() }
          }
          .toolbar {
            if #available(macOS 26.0, *) {
              ToolbarItem(placement: .navigation) {
                Image("Server Large")
                  .resizable()
                  .scaledToFit()
                  .frame(width: 28)
                  .opacity(controlActiveState == .inactive ? 0.4 : 1.0)
              }
              .sharedBackgroundVisibility(.hidden)
            }
            else {
              ToolbarItem(placement: .navigation) {
                Image("Server Large")
                  .resizable()
                  .scaledToFit()
                  .frame(width: 28)
                  .opacity(controlActiveState == .inactive ? 0.4 : 1.0)
              }
            }
          }
      }
    }
    .onDisappear {
      Task {
        await model.disconnect()
      }
    }
    .onChange(of: model.serverTitle) {
      state.serverName = model.serverTitle
    }
//    .onChange(of: model.bannerImage) {
//      state.serverBanner = model.bannerImage
//    }
//    .onChange(of: model.bannerColors) {
//      guard let backgroundColor = model.bannerColors?.backgroundColor else {
//        state.bannerBackgroundColor = nil
//        return
//      }
//      state.bannerBackgroundColor = Color(nsColor: backgroundColor)
//    }
    .alert(model.errorMessage ?? "Server Error", isPresented: $model.errorDisplayed) {
      Button("OK") {}
    }
    .task {
      var address = server.address
      if server.port != HotlinePorts.DefaultServerPort {
        address += ":\(server.port)"
      }
      connectAddress = server.address
      connectLogin = server.login
      connectPassword = server.password
      
      // Connect to server automatically unless the option key is held down.
      if !NSEvent.modifierFlags.contains(.option) {
        connectToServer()
      }
    }
    .focusedSceneValue(\.activeHotlineModel, model)
    .focusedSceneValue(\.activeServerState, state)
  }
  
  var connectForm: some View {
    Form {
      HStack(alignment: .top, spacing: 10) {
        Image("Server Large")
          .resizable()
          .scaledToFit()
          .frame(width: 28, height: 28)
        
        VStack(alignment: .leading) {
          Text("Connect to Server")
          Text("Enter the address of a Hotline server to connect to.")
            .foregroundStyle(.secondary)
            .font(.subheadline)
        }
      }
      
      TextField(text: $connectAddress) {
        Text("Address:")
      }
      .focused($focusedField, equals: .address)
      
      TextField(text: $connectLogin, prompt: Text("Optional")) {
        Text("Login:")
      }
      .focused($focusedField, equals: .login)
      SecureField(text: $connectPassword, prompt: Text("Optional")) {
        Text("Password:")
      }
      .focused($focusedField, equals: .password)
      
      HStack {
        Button("Save...") {
          if !connectAddress.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
            connectNameSheetPresented = true
          }
        }
        .disabled(connectAddress.isEmpty)
        .controlSize(.regular)
        .buttonStyle(.automatic)
        .help("Bookmark server")
        
        Spacer()
        
        Button("Cancel") {
          dismiss()
        }
        .controlSize(.regular)
        .buttonStyle(.automatic)
        .keyboardShortcut(.cancelAction)
        
        Button("Connect") {
          connectToServer()
        }
        
        .controlSize(.regular)
        .buttonStyle(.automatic)
        .keyboardShortcut(.defaultAction)
      }
      .padding(.top, 8)
    }
    .formStyle(.grouped)
    .fixedSize(horizontal: false, vertical: true)
    .onChange(of: connectAddress) {
      let (a, p) = Server.parseServerAddressAndPort(connectAddress)
      server.address = a
      server.port = p
    }
    .onChange(of: connectLogin) {
      server.login = connectLogin.trimmingCharacters(in: .whitespacesAndNewlines)
    }
    .onChange(of: connectPassword) {
      server.password = connectPassword
    }
    .onAppear {
      focusedField = .address
    }
    .frame(maxWidth: 380)
    .padding()
    .sheet(isPresented: $connectNameSheetPresented) {
      VStack(alignment: .leading) {
        Text("Name this server bookmark:")
          .foregroundStyle(.secondary)
          .padding(.bottom, 4)
        TextField("Bookmark Name", text: $connectName)
          .textFieldStyle(.roundedBorder)
          .controlSize(.large)
      }
      .frame(width: 250)
      .padding()
      .toolbar {
        ToolbarItem(placement: .cancellationAction) {
          Button("Cancel") {
            connectNameSheetPresented = false
            connectName = ""
          }
        }
        
        ToolbarItem(placement: .confirmationAction) {
          Button("Save") {
            let name = String(connectName.trimmingCharacters(in: .whitespacesAndNewlines))
            if !name.isEmpty {
              connectNameSheetPresented = false
              connectName = ""

              let (host, port) = Server.parseServerAddressAndPort(connectAddress)
              let login: String? = connectLogin.isEmpty ? nil : connectLogin
              let password: String? = connectPassword.isEmpty ? nil : connectPassword
              
              if !host.isEmpty {
                let newBookmark = Bookmark(type: .server, name: name, address: host, port: port, login: login, password: password)
                Bookmark.add(newBookmark, context: modelContext)
              }
            }
          }
        }
      }
    }
  }
  
  var navigationList: some View {
    List(selection: $state.selection) {
      // Don't show news on older servers.
      ForEach(model.serverVersion < 151 ? ServerView.classicMenuItems : ServerView.menuItems) { menuItem in
        if menuItem.type == .chat {
          ListItemView(icon: menuItem.image, title: menuItem.name, unread: model.unreadPublicChat).tag(menuItem.type)
        }
        else if menuItem.type == .accounts {
          if model.access?.contains(.canOpenUsers) == true {
            ListItemView(icon: menuItem.image, title: menuItem.name, unread: false).tag(menuItem.type)
          }
        }
        else if menuItem.type == .files {
          ListItemView(icon: menuItem.image, title: menuItem.name, unread: false).tag(menuItem.type)
            .overlay(alignment: .trailing) {
              if case .searching(_, _) = model.fileSearchStatus {
                ProgressView()
                  .controlSize(.mini)
                  .padding(.trailing, 4)
              }
            }
        }
        else {
          ListItemView(icon: menuItem.image, title: menuItem.name, unread: false).tag(menuItem.type)
        }
      }
      
      if model.transfers.count > 0 {
        Divider()
        
        self.transfersSection
      }
      
      if model.users.count > 0 {
        Divider()
        
        self.usersSection
      }
    }
    .onChange(of: state.selection) {
      switch(state.selection) {
      case .chat:
        model.markPublicChatAsRead()
      case .user(let userID):
        model.markInstantMessagesAsRead(userID: userID)
      default:
        break
      }
    }
  }
  
  var transfersSection: some View {
//    Section("Transfers") {
      ForEach(model.transfers) { transfer in
        TransferItemView(transfer: transfer)
      }
//    }
  }
  
  var usersSection: some View {
//    Section("\(model.users.count) Online") {
      ForEach(model.users) { user in
        HStack(spacing: 5) {
          if let iconImage = HotlineState.getClassicIcon(Int(user.iconID)) {
            Image(nsImage: iconImage)
              .frame(width: 16, height: 16)
              .padding(.leading, 2)
              .padding(.trailing, 2)
          }
          else {
            Image("User")
              .frame(width: 16, height: 16)
              .padding(.leading, 2)
              .padding(.trailing, 2)
          }
          
          Text(user.name)
            .foregroundStyle(user.isAdmin ? Color.hotlineRed : .primary)
          
          Spacer()
          
          if model.hasUnreadInstantMessages(userID: user.id) {
            Circle()
              .frame(width: 6, height: 6)
              .foregroundStyle(user.isAdmin ? Color.hotlineRed : .primary.opacity(0.5))
              .padding(EdgeInsets(top: 0, leading: 8, bottom: 0, trailing: 2))
          }
        }
        .opacity(user.isIdle ? 0.5 : 1.0)
        .opacity(controlActiveState == .inactive ? 0.5 : 1.0)
        .tag(ServerNavigationType.user(userID: user.id))
      }
//    }
  }
  
  var serverView: some View {
    NavigationSplitView {
      self.navigationList
        .frame(maxWidth: .infinity)
        .navigationSplitViewColumnWidth(min: 150, ideal: 200, max: 500)
    } detail: {
        switch state.selection {
        case .chat:
          ChatView()
            .navigationTitle(model.serverTitle)
            .navigationSubtitle("Public Chat")
            .navigationSplitViewColumnWidth(min: 250, ideal: 500)
        case .news:
          NewsView()
            .navigationTitle(model.serverTitle)
            .navigationSubtitle("Newsgroups")
            .navigationSplitViewColumnWidth(min: 250, ideal: 500)
        case .board:
          MessageBoardView()
            .navigationTitle(model.serverTitle)
            .navigationSubtitle("Message Board")
            .navigationSplitViewColumnWidth(min: 250, ideal: 500)
        case .files:
          FilesView()
            .navigationTitle(model.serverTitle)
            .navigationSubtitle("Shared Files")
            .navigationSplitViewColumnWidth(min: 250, ideal: 500)
        case .accounts:
            AccountManagerView()
              .navigationTitle(model.serverTitle)
              .navigationSubtitle("Accounts")
              .navigationSplitViewColumnWidth(min: 250, ideal: 500)
        case .user(let userID):
          let user = model.users.first(where: { $0.id == userID })
          MessageView(userID: userID)
            .navigationTitle(model.serverTitle)
            .navigationSubtitle(user?.name ?? "Private Message")
            .navigationSplitViewColumnWidth(min: 250, ideal: 500)
            .onAppear {
              model.markInstantMessagesAsRead(userID: userID)
            }
        }
    }
    .toolbar(removing: .sidebarToggle)

  }
  
  
  // MARK: -
  
  @MainActor func connectToServer() {
    guard !server.address.isEmpty else {
      return
    }

    Task { @MainActor in
      do {
        // login() handles everything: connect, getUserList, sendPreferences, downloadBanner
        try await model.login(
          server: server,
          username: Prefs.shared.username,
          iconID: Prefs.shared.userIconID
        )
      } catch {
        print("ServerView: Login failed: \(error)")
      }
    }
  }
  
  private func connectionStatusToProgress(status: HotlineConnectionStatus) -> Double {
    switch status {
    case .disconnected:
      return 0.0
    case .connecting:
      return 0.4
    case .connected:
      return 0.9
    case .loggedIn:
      return 1.0
    case .failed:
      return 0.0
    }
  }

  private func connectionStatusToLabel(status: HotlineConnectionStatus) -> String {
    let n = server.name ?? server.address
    switch status {
    case .disconnected:
      return "Disconnected"
    case .connecting:
      return "Connecting to \(n)..."
    case .connected:
      return "Logging in to \(n)..."
    case .loggedIn:
      return "Logged in to \(n)"
    case .failed(let error):
      return "Failed: \(error)"
    }
  }
  
}

struct TransferItemView: View {
  let transfer: TransferInfo
    
  @Environment(\.controlActiveState) private var controlActiveState
  @Environment(HotlineState.self) private var model: HotlineState
  @State private var hovered: Bool = false
  @State private var buttonHovered: Bool = false
  
  private func formattedProgressHelp() -> String {
    if self.transfer.completed {
      return "File transfer complete"
    }
    else if self.transfer.failed {
      return "File transfer failed"
    }
    else if self.transfer.progress > 0.0 {
      if let estimate = self.transfer.timeRemaining, estimate > 0.0 {
        return "\(round(self.transfer.progress * 100.0))% – \(estimate) seconds left"
      }
      else {
        return "\(round(self.transfer.progress * 100.0))% complete"
      }
    }
    return ""
  }
  
  var body: some View {
    HStack(alignment: .center, spacing: 5) {
      HStack(spacing: 0) {
        Spacer()
        if transfer.isFolder {
          Image("Folder")
            .resizable()
            .scaledToFit()
            .frame(width: 16, height: 16)
            .opacity(controlActiveState == .inactive ? 0.5 : 1.0)
        }
        else {
          FileIconView(filename: transfer.title, fileType: nil)
            .frame(width: 16, height: 16)
            .opacity(controlActiveState == .inactive ? 0.5 : 1.0)
        }
        Spacer()
      }
      .frame(width: 20)
      
      Text(transfer.title)
        .lineLimit(1)
        .truncationMode(.middle)
      
      Spacer()
      
      if self.hovered {
        Button {
          AppState.shared.cancelTransfer(id: transfer.id)
        } label: {
          Image(systemName: self.buttonHovered ? "xmark.circle.fill" : "xmark.circle")
            .resizable()
            .aspectRatio(contentMode: .fit)
            .frame(width: 16, height: 16)
            .opacity(self.buttonHovered ? 1.0 : 0.5)
        }
        .buttonStyle(.plain)
        .padding(0)
        .frame(width: 16, height: 16)
        .opacity(controlActiveState == .inactive ? 0.5 : 1.0)
        .help(transfer.completed || transfer.failed ? "Remove" : "Cancel Transfer")
        .onHover { hovered in
          self.buttonHovered = hovered
        }
      }
      else if transfer.failed {
        Image(systemName: "exclamationmark.triangle.fill")
          .resizable()
          .symbolRenderingMode(.multicolor)
          .aspectRatio(contentMode: .fit)
          .frame(width: 16, height: 16)
          .opacity(controlActiveState == .inactive ? 0.5 : 1.0)
      }
      else if transfer.completed {
        Image(systemName: "checkmark.circle.fill")
          .resizable()
          .symbolRenderingMode(.palette)
          .foregroundStyle(.white, .fileComplete)
          .aspectRatio(contentMode: .fit)
          .frame(width: 16, height: 16)
          .opacity(controlActiveState == .inactive ? 0.5 : 1.0)
      }
      else if transfer.progress == 0.0 {
        ProgressView()
          .progressViewStyle(.circular)
          .controlSize(.small)
      }
      else {
        ProgressView(value: transfer.progress, total: 1.0)
          .progressViewStyle(.circular)
          .controlSize(.small)
      }
    }
    .onHover { hovered in
      withAnimation(.easeOut(duration: 0.25)) {
        self.hovered = hovered
      }
    }
    .onTapGesture(count: 2) {
      guard transfer.completed, let url = transfer.fileURL else {
        return
      }

      NSWorkspace.shared.activateFileViewerSelecting([url])
    }
    .help(formattedProgressHelp())
  }
}