⭐️ Impl: Add RNIModalWindowMap

Related:
* `TODO:2023-03-31-18-33-34` - Unify/streamline/consolidate logic for invoking modal focus/blur.

ios/src_library/React Native/RNIModal/RNIModalWindowMap.swift

@@ -0,0 +1,140 @@
+//
+//  RNIModalWindowMap.swift
+//  react-native-ios-modal
+//
+//  Created by Dominic Go on 4/8/23.
+//
+
+import Foundation
+
+
+internal class RNIWindowMapData {
+
+  // MARK: - Properties
+  // ------------------
+
+  weak var window: UIWindow?;
+
+  private(set) var modalIndexCurrent: Int = -1;
+  private(set) var modalIndexPrev: Int = -1;
+  private(set) var modalIndexNext: Int?;
+
+  private(set) weak var nextModalToFocus: (any RNIModal)?;
+  private(set) weak var nextModalToBlur: (any RNIModal)?;
+
+  #if DEBUG
+  var modalIndexNext_: String {
+    self.modalIndexNext == nil ? "N/A" : "\(self.modalIndexNext!)"
+  };
+  #endif
+
+  // MARK: - Functions
+  // -----------------
+
+  init(window: UIWindow){
+    self.window = window;
+  };
+
+  func set(nextModalToFocus modalToFocus: any RNIModal) {
+    self.nextModalToFocus = modalToFocus;
+
+    let modalIndexCurrent =
+      RNIModalManager.computeModalIndex(forWindow: modalToFocus.window);
+
+    let modalIndexPrev = self.modalIndexCurrent;
+
+    self.modalIndexCurrent = modalIndexCurrent;
+    self.modalIndexNext = modalIndexCurrent + 1;
+    self.modalIndexPrev = modalIndexPrev;
+  };
+
+  func apply(forFocusedModal focusedModal: any RNIModal) {
+    self.nextModalToFocus = nil;
+
+    let modalIndexCurrent =
+      RNIModalManager.computeModalIndex(forWindow: focusedModal.window);
+
+    let modalIndexPrev = self.modalIndexCurrent;
+
+    self.modalIndexCurrent = modalIndexCurrent;
+    self.modalIndexNext = nil;
+    self.modalIndexPrev = modalIndexPrev;
+
+    focusedModal.modalIndexPrev = modalIndexPrev;
+    focusedModal.modalIndex = modalIndexCurrent;
+  };
+
+  func set(nextModalToBlur modalToBlur: any RNIModal) {
+    self.nextModalToBlur = modalToBlur;
+
+    let modalIndexCurrent =
+      RNIModalManager.computeModalIndex(forWindow: modalToBlur.window);
+
+    let modalIndexPrev = self.modalIndexCurrent;
+
+    self.modalIndexCurrent = modalIndexCurrent;
+    self.modalIndexNext = modalIndexCurrent - 1;
+    self.modalIndexPrev = modalIndexPrev;
+  };
+
+  func apply(forBlurredModal blurredModal: any RNIModal) {
+    self.nextModalToBlur = nil;
+
+    let modalIndexCurrent =
+      RNIModalManager.computeModalIndex(forWindow: blurredModal.window);
+
+    let modalIndexPrev = self.modalIndexCurrent;
+
+    self.modalIndexCurrent = modalIndexCurrent;
+    self.modalIndexNext = nil;
+    self.modalIndexPrev = modalIndexPrev;
+
+    blurredModal.modalIndexPrev = modalIndexPrev;
+    blurredModal.modalIndex = modalIndexCurrent;
+  };
+
+  // MARK: - Properties - Computed
+  // -----------------------------
+
+  var windowID: String? {
+    self.window?.synthesizedStringID;
+  };
+};
+
+// MARK: - RNIModalWindowMap
+// -------------------------
+
+internal let RNIModalWindowMapShared = RNIModalWindowMap.sharedInstance;
+
+internal class RNIModalWindowMap {
+
+  // MARK: - Properties - Static
+  // ---------------------------
+
+  static var sharedInstance = RNIModalWindowMap();
+
+  // MARK: - Properties
+  // ------------------
+
+  private(set) var windowDataMap: Dictionary<String, RNIWindowMapData> = [:];
+
+  // MARK: - Functions
+  // -----------------
+
+  func set(forWindow window: UIWindow, data: RNIWindowMapData){
+    self.windowDataMap[window.synthesizedStringID] = data;
+  };
+
+  func get(forWindow window: UIWindow) -> RNIWindowMapData {
+    guard let windowData = self.windowDataMap[window.synthesizedStringID] else {
+      // No corresponding "modal index" for window yet, so initialize
+      // with value
+      let windowDataNew = RNIWindowMapData(window: window);
+      self.set(forWindow: window, data: windowDataNew);
+
+      return windowDataNew;
+    };
+
+    return windowData;
+  };
+};