import SwiftUI

struct ToastViewModifier: ViewModifier {

    @Binding var message: String?
    var style: Toast.Style
    var alignment: Alignment

    @State private var workItem: DispatchWorkItem?

    func body(content: Content) -> some View {
        content
            .overlay(alignment: alignment) {
                ZStack {
                    toastView
                }
                .animation(.bouncy, value: message)
            }
            .onChange(of: message) { _, _ in
                showToast()
            }
    }

    @ViewBuilder private var toastView: some View {
        if let message {
            Toast(message: message, style: style)
        }
    }

    private func showToast() {
        workItem?.cancel()
        let item = DispatchWorkItem {
            withAnimation {
                self.message = nil
            }
            workItem?.cancel()
            workItem = nil
        }
        workItem = item
        DispatchQueue.main.asyncAfter(deadline: .now() + 2.0, execute: item)
    }
}

extension View {

    func toast(message: Binding<String?>,
               style: Toast.Style = .default,
               alignment: Alignment = .center) -> some View {
        modifier(
            ToastViewModifier(message: message, style: style, alignment: alignment)
        )
    }
}