//
// Copyright © 2022 osy. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

import SwiftUI

@MainActor
struct UTMSingleWindowView: View {
    private var isInteractive: Bool {
        data != nil
    }

    #if WITH_REMOTE
    typealias DataType = UTMRemoteData
    #else
    typealias DataType = UTMData
    #endif
    private let data: DataType?
    @State private var session: VMSessionState?
    @State private var identifier: VMSessionState.WindowID?

    private let vmSessionCreatedNotification = NotificationCenter.default.publisher(for: .vmSessionCreated)
    private let vmSessionEndedNotification = NotificationCenter.default.publisher(for: .vmSessionEnded)
    
    init(data: DataType? = nil) {
        self.data = data
    }
    
    var body: some View {
        ZStack {
            if let session = session {
                VMWindowView(id: identifier!, isInteractive: isInteractive).environmentObject(session)
            } else if isInteractive {
                #if WITH_REMOTE
                RemoteContentView(remoteClientState: data!.remoteClient.state).environmentObject(data!)
                #else
                ContentView().environmentObject(data!)
                #endif
            } else {
                VStack {
                    Text("Waiting for VM to connect to display...")
                        .font(.headline)
                    BusyIndicator()
                }
            }
        }
        .onAppear {
            session = VMSessionState.allActiveSessions.first?.value
            if let session = session {
                identifier = session.newWindow().windowID
            }
        }
        .onReceive(vmSessionCreatedNotification) { output in
            let newSession = output.userInfo!["Session"] as! VMSessionState
            withAnimation {
                session = newSession
                identifier = newSession.newWindow().windowID
            }
        }
        .onReceive(vmSessionEndedNotification) { output in
            let endedSession = output.userInfo!["Session"] as! VMSessionState
            if endedSession == session {
                withAnimation {
                    session = nil
                }
            }
        }
    }
}

struct UTMSingleWindowView_Previews: PreviewProvider {
    static var previews: some View {
        UTMSingleWindowView(data: UTMSingleWindowView.DataType())
    }
}