Hopefully a more convenient method to present Alerts in SwiftUI at runtime

CustomSwiftUIAlert.swift

//
//  CustomSwiftUIAlert.swift
//  Field
//
//  Created by Cesare Forelli on 24/04/24.
//

import SwiftUI


/// ## Bindable object to be presented at runtime in a SwiftUI Alert
///
/// Whenever a `CustomSwiftUIAlert` @State variable has a value, SwiftUI automatically presents an Alert via the the provided custom view modifier:
///
///```swift
/// .alert(with customSwiftUIAlert: Binding<CustomSwiftUIAlert?>)
/// ```
///
/// The Alert can have up to 2 customisable buttons: a required Default button and an _optional_ Cancel button.
///
/// Closures can be _optionally_ passed to perform actions upon Button presses.
///
/// ### Parameters:
///  - id: Alert binding objects need to conform to Identifiable; a default UUID value is generated automatically
///  - title: _Required_ title to be displayed in the Alert
///  - message: _Required_ body message to be displayed in the Alert
///  - defaultButtonTitle: _Optional_ title for the confirmation button; if not provided, defaults to "OK"
///  - defaultButtonAction: _Optional_ closure containing code to be executed when the Default button in pressed
///  - hasCancelButton: By default, no Cancel button is displayed; set to `true` to include a default localised Cancel button in the Alert
///  - cancelButtonAction: _Optional_ closure containing code to be executed when the Cancel button in pressed
///
/// ---
///
/// ### Usage:
///  1. In your SwiftUI file, declare a
///
/// ```swift
/// @State private var customSwiftUIAlert: CustomSwiftUIAlert?
/// ```
///
/// 2. Apply the provided ``CustomAlertViewModifier`` modifier to your SwiftUI View:
///
/// ```swift
/// content
///  .alert(with customSwiftUIAlert: Binding<CustomSwiftUIAlert?>)
/// ```
///
/// 3. Whenever you need to display an Alert at runtime, set the `customSwiftUIAlert` variable _(1)_ to a new ``CustomSwiftUIAlert`` object:
///
/// ```swift
/// customSwiftUIAlert = CustomSwiftUIAlert(title: "Uh oh",
///                                         message: "The server went up in flames",
///                                         defaultButtonTitle: "I'm sad",
///                                         defaultButtonAction: {
///                                             print("You need to purchase a new server")
///                                         },
///                                         hasCancelButton: true,
///                                         cancelButtonAction: nil)
/// ```
/// 
/// **SwiftUI will take care of presenting the Alert when `customSwiftUIAlert` has a value**.
///
struct CustomSwiftUIAlert: Identifiable {
    
    let id = UUID()
    
    var title: String
    var message : String
    
    var defaultButtonTitle = "OK"
    var defaultButtonAction : (() -> Void)? = {}
    
    var hasCancelButton = false
    var cancelButtonAction : (() -> Void)? = {}
}


struct CustomAlertViewModifier: ViewModifier {
    
    @Binding var customSwiftUIAlert: CustomSwiftUIAlert?
    
    func body(content: Content) -> some View {
        
        content
            .alert(item: $customSwiftUIAlert) { customSwiftUIAlert in
                
                if customSwiftUIAlert.hasCancelButton {
                    
                    Alert(
                        title: Text(customSwiftUIAlert.title),
                        message: Text(customSwiftUIAlert.message),
                        primaryButton: .default(
                            Text(customSwiftUIAlert.defaultButtonTitle),
                            action: customSwiftUIAlert.defaultButtonAction
                        ),
                        secondaryButton: .cancel(customSwiftUIAlert.cancelButtonAction)
                    )
                    
                } else {
                    
                    Alert(
                        title: Text(customSwiftUIAlert.title),
                        message: Text(customSwiftUIAlert.message),
                        dismissButton: .default(
                            Text(customSwiftUIAlert.defaultButtonTitle),
                            action: customSwiftUIAlert.defaultButtonAction
                        )
                    )
                }
            }
    }
}


extension View {
    
    /// Convenience custom View modifier to present a ``CustomSwiftUIAlert`` Binding at runtime
    func alert(with customSwiftUIAlert: Binding<CustomSwiftUIAlert?>) -> some View {
        modifier(CustomAlertViewModifier(customSwiftUIAlert: customSwiftUIAlert))
    }
}