//
//  ChatView.swift
//  Chat
//
//  Created by Sergey Tarasov on 24.07.2022.
//

import SwiftUI

extension CGFloat {
    static let sidePadding: CGFloat = 14
}

struct ChatView: View, KeyboardReadable {

    @State private var isKeyboardVisible = false
    @State var message: String = ""
    @State var messages: [String] = ["Display a short text message, called an alert, that draws attention to something new in your app.", "Play a notification sound.", "Set a badge number on the app’s icon to let the user know there are new items.", "Provide actions the user can take without opening the app.", "Show a media attachment.", "Be silent, allowing the app to perform a task in the background.", "No", "Group notifications into threads.", "Yes", "Edit or remove delivered notifications.", "Run code to change your notification before displaying it.", "Display a custom, interactive UI for your notification.", "And probably more.", "Yes", "Edit or remove delivered notifications.", "Run code to change your notification before displaying it.", "Display a custom, interactive UI for your notification.", "And probably more."]

    var body: some View {
        VStack(alignment: .center, spacing: 0) {
            ScrollView {
                ScrollViewReader { value in
                    VStack {
                        withAnimation {
                            ForEach(messages.indices, id: \.self) { i in
                                HStack {
                                    if messages[i] == messages[3] || messages[i] == messages[6] || messages[i] == messages[8] || i > 17{
                                        Spacer()
                                        MessageView(text: messages[i], time: "23:03", isSelf: true)
                                    } else {
                                        MessageView(text: messages[i], time: "23:03", isSelf: false)
                                        Spacer()
                                    }
                                }
                            }
                            .onChange(of: messages) { _ in
                                withAnimation {
                                    value.scrollTo(messages.count - 1, anchor: .bottomTrailing)
                                }
                            }
                            .onReceive(keyboardPublisher) { newIsKeyboardVisible in
                                isKeyboardVisible = newIsKeyboardVisible
                                withAnimation {
                                    value.scrollTo(messages.count - 2, anchor: .topTrailing)
                                }
                            }
                            .onAppear {
                                value.scrollTo(messages.count - 1, anchor: .top)
                            }
                        }
                    }
                    .padding(.horizontal, .sidePadding)
                    .padding(.vertical, 12)
                    .background(Color.indigo.opacity(0.0))
                }
            }
            Divider()
            HStack {
                TextField("Сообщение", text: $message)
                    .textFieldStyle(.automatic)
                    .padding(.vertical, 6)
                    .padding(.horizontal, 12)
                    .background(.background)
                Button {
                    messages.append(message)
                    message = ""
                } label: {
                    Image(systemName: "arrow.up.circle.fill")
                        .font(.title)
                        .foregroundColor(message.isEmpty ? .gray : .accentColor)
                }
                .disabled(message.isEmpty)
            }
            .padding(.horizontal, .sidePadding)
            .padding(.vertical, 6)
            .background()
        }
        .navigationBarTitleDisplayMode(.inline)
    }
}

struct ChatView_Previews: PreviewProvider {
    static var previews: some View {
        Group {
            NavigationView {
                ChatView()
            }
            NavigationView {
                ChatView()
                    .preferredColorScheme(.dark)
            }
        }
    }
}