import SwiftUI
import UIKit

struct ConversationTextInput: View {
    @Environment(\.router) var router
    @EnvironmentObject var conversation: ConversationStore

    @State private var messageStr = ""
    @FocusState private var isFocused: Bool
    @Binding var autoScroll: Bool

    var body: some View {
        VStack(spacing: 0) {
            Rectangle()
                .foregroundColor(.Material.Shape.separator)
                .frame(height: 0.5)
                .padding(.bottom, 8)
            if !conversation.replyText.isEmpty {
                VStack(spacing: 0) {
                    HStack(alignment: .top) {
                        Text(conversation.replyText)
                            .font(.body3)
                            .foregroundColor(Color.Material.Text.main)
                            .multilineTextAlignment(.leading)
                            .lineLimit(3)
                            .padding(8)
                        Spacer()
                        Image(systemName: "xmark")
                            .font(.title2)
                            .foregroundColor(.Material.Elements.active)
                            .padding(.leading, 8)
                            .tappablePadding(.symmetric(8)) {
                                conversation.replyText = ""
                            }
                            .padding(8)
                    }
                    .frame(maxWidth: .infinity)
                    .background(RoundedRectangle(cornerRadius: 4)
                        .foregroundColor(.Material.Background.light)
                        .shadow(radius: 0.5)
                    )
                    .padding(.bottom, 8)
                    .padding(.horizontal, 8)
                }
                .padding(.horizontal, 8)
            }
            HStack {
                Image(systemName: "paperclip")
                    .font(.title2)
                    .foregroundColor(.Material.Elements.active)
                    .padding(.leading, 8)
                    .tappablePadding(.symmetric(8)) {
                        router.showScreen(.fullScreenCover) { _ in
                            AttachmentPickerScreen(attachmentsStore: conversation.attachmentsStore)
                                .environmentObject(conversation)
                        }
                    }
                TextField("", text: $messageStr, prompt: Text(L10n.Chat.textfieldPrompt).foregroundColor(.Material.Shape.separator))
                    .font(.body1)
                    .foregroundColor(Color.Material.Text.main)
                    .accentColor(.Material.Shape.black)
                    .focused($isFocused)
                    .padding(.horizontal, 8)
                    .padding(.vertical, 4)
                    .background(Color.Material.Shape.white)
                    .clipShape(RoundedRectangle(cornerRadius: 8))
                    .padding(.vertical, 4)
                let img = messageStr.isEmpty ? "paperplane" : "paperplane.fill"
                Image(systemName: img)
                    .font(.title2)
                    .foregroundColor(messageStr.isEmpty ? .Material.Elements.inactive : .Material.Elements.active)
                    .padding(.trailing, 8)
                    .tappablePadding(.symmetric(8)) {
                        if !messageStr.isEmpty {
                            Task(priority: .userInitiated) {
                                await conversation.sendMessage(composedMessage)
                                messageStr = ""
                                autoScroll = true
                            }
                        }
                    }
            }
        }
        .padding(.bottom, 8)
        .background(Color.Material.Background.dark)
        .onChange(of: conversation.replyText) { new in
            if !new.isEmpty {
                isFocused = true
            }
        }
    }

    private var composedMessage: String {
        var result = ""
        if !conversation.replyText.isEmpty {
            result += conversation.replyText + "\n\n"
        }
        result += messageStr
        return result
    }
}