[SwiftUI]Presenterを抽象化して外部から注入できるようにする

protocol CommentDetailPresenterInput: ObservableObject {
    var comment: Proto_Comment { get }
    var goodButtonDisabled: Bool { get }

    func handleViewEvent(_ event: CommentDetailViewEvent)
}

import Foundation
import SwiftUI

final class CommentDetailHostingController: UIHostingController<CommentDetailView> {
    // ここの定義でエラーが出る
    init(presenter: CommentDetailPresenterInput) {
        super.init(
            rootView: CommentDetailView(
                presenter: presenter
            )
        )
    }

    @available(*, unavailable)
    @MainActor
    dynamic required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

protocol ObservableObject : AnyObject

final class SampleModel: ObservableObject {
	var value: Int = 0 { 
		willSet {
			objectWillChange.send()
		}
	}
}

objectWillChange
    .sink {
        // 実行処理
    }

protocol Drawable {
    func draw()
}

class Circle: Drawable {
    func draw() {
        print("Drawing a circle")
    }
}

class Square: Drawable {
    func draw() {
        print("Drawing a square")
    }
}

func drawShape<T: Drawable>(_ shape: T) {
    shape.draw()
}

let circle = Circle()
let square = Square()

drawShape(circle) // "Drawing a circle"
drawShape(square) // "Drawing a square"

protocol Identifiable {
    var id: String { get }
}

class User: Identifiable {
    var id: String
    var name: String

    init(id: String, name: String) {
        self.id = id
        self.name = name
    }
}

class Item<T: Identifiable> {
    var value: T

    init(value: T) {
        self.value = value
    }

    func printID() {
        print("ID: \(value.id)")
    }
}

let user = User(id: "123", name: "Alice")
let item = Item(value: user)
item.printID() // "ID: 123"

protocol Identifiable {

}

class Item {
    var value: Identifiable

    init(value: Identifiable) {
        self.value = value
    }

    func printID() {
        print("ID: \(value.id)")
    }
}

protocol Identifiable {
    var id: String { get }
}

class Item {
    var value: Identifiable

    init(value: Identifiable) {
        self.value = value
    }

    func printID() {
        print("ID: \(value.id)")
    }
}

class User: Identifiable {
    var id: String
    var name: String

    init(id: String, name: String) {
        self.id = id
        self.name = name
    }
}

let user = User(id: "123", name: "Alice")
let item = Item(value: user)
item.printID() // "ID: 123"

protocol Identifiable {
    var id: String { get }
}

class Item<T: Identifiable> {
    var value: T

    init(value: T) {
        self.value = value
    }

    func printID() {
        print("ID: \(value.id)")
    }
}

class User: Identifiable {
    var id: String
    var name: String

    init(id: String, name: String) {
        self.id = id
        self.name = name
    }
}

let user = User(id: "123", name: "Alice")
let item = Item(value: user)
item.printID() // "ID: 123"

@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
public protocol ObservableObject : AnyObject {

    /// The type of publisher that emits before the object has changed.
    associatedtype ObjectWillChangePublisher : Publisher = ObservableObjectPublisher where Self.ObjectWillChangePublisher.Failure == Never

    /// A publisher that emits before the object has changed.
    var objectWillChange: Self.ObjectWillChangePublisher { get }
}

@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
extension ObservableObject where Self.ObjectWillChangePublisher == ObservableObjectPublisher {

    /// A publisher that emits before the object has changed.
    public var objectWillChange: ObservableObjectPublisher { get }
}

/// A publisher that publishes changes from observable objects.
@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
final public class ObservableObjectPublisher : Publisher {

    /// The kind of values published by this publisher.
    public typealias Output = Void

    /// The kind of errors this publisher might publish.
    ///
    /// Use `Never` if this `Publisher` does not publish errors.
    public typealias Failure = Never

    /// Creates an observable object publisher instance.
    public init()

    /// Attaches the specified subscriber to this publisher.
    ///
    /// Implementations of ``Publisher`` must implement this method.
    ///
    /// The provided implementation of ``Publisher/subscribe(_:)-4u8kn``calls this method.
    ///
    /// - Parameter subscriber: The subscriber to attach to this ``Publisher``, after which it can receive values.
    final public func receive<S>(subscriber: S) where S : Subscriber, S.Failure == Never, S.Input == ()

    /// Sends the changed value to the downstream subscriber.
    final public func send()
}

Protocol 'CommentDetailPresenterInput' can only be used as a generic constraint because it has Self or associated type requirements

protocol CommentDetailPresenterInput: ObservableObject {
    var comment: Proto_Comment { get }
    var goodButtonDisabled: Bool { get }

    func handleViewEvent(_ event: CommentDetailViewEvent)
}

class CommentDetailPresenter<T: CommentDetailPresenterInput>: ObservableObject {
    @Published var presenter: T

    init(presenter: T) {
        self.presenter = presenter
    }
}

class MyPresenter: CommentDetailPresenterInput {
    @Published var comment: Proto_Comment
    @Published var goodButtonDisabled: Bool

    init(comment: Proto_Comment, goodButtonDisabled: Bool) {
        self.comment = comment
        self.goodButtonDisabled = goodButtonDisabled
    }

    func handleViewEvent(_ event: CommentDetailViewEvent) {
        // Handle the event
    }
}

let myPresenter = MyPresenter(comment: /* Proto_Comment */, goodButtonDisabled: false)
let commentDetailPresenter = CommentDetailPresenter(presenter: myPresenter)