Add HUDPresenter

Sources/HUDFeature/HUDPresenter.swift

+import Combine
+import Dependencies
+import UIKit
+import SwiftUI
+
+public final class HUDPresenter {
+  public init() {
+    hudManager.observe()
+      .receive(on: DispatchQueue.main)
+      .sink { [unowned self] model in
+        if let model = model {
+          show(model)
+        } else {
+          hide()
+        }
+      }
+      .store(in: &cancellables)
+  }
+
+  public weak var parentController: UIViewController?
+
+  @Dependency(\.hudManager) var hudManager
+  var cancellables = Set<AnyCancellable>()
+  var hudController: UIViewController?
+  let animationDuration: TimeInterval = 0.2
+
+  func show(_ model: HUDModel) {
+    if hudController != nil { hide() }
+    guard let parentController else { return }
+    let hudController = UIHostingController(rootView: HUDView(model: model))
+    hudController.view.alpha = 0
+    hudController.view.backgroundColor = .clear
+    parentController.addChild(hudController)
+    parentController.view.addSubview(hudController.view)
+    hudController.view.frame = parentController.view.bounds
+    hudController.didMove(toParent: parentController)
+    self.hudController = hudController
+    UIView.animate(withDuration: animationDuration) {
+      hudController.view.alpha = 1
+    }
+  }
+
+  func hide() {
+    guard let hudController else { return }
+    hudController.willMove(toParent: nil)
+    self.hudController = nil
+    UIView.animate(withDuration: animationDuration) {
+      hudController.view.alpha = 0
+    } completion: { _ in
+      hudController.view.removeFromSuperview()
+      hudController.removeFromParent()
+    }
+  }
+}