/**
 * Do not import other files here to avoid circular dependencies.
 * Used to define helper functions and variables that are shared between Android and iOS
 * without introducing platform-specific code directly.
 */
let nativeApp: UIApplication | android.app.Application;

/**
 * Get the current application instance.
 * @returns current application instance, UIApplication on iOS or android.app.Application on Android.
 */
export function getNativeApp() {
	return nativeApp;
}

/**
 * This is called internally to set the native application instance.
 * You typically do not need to call this directly.
 * However, it's exposed for special case purposes, such as custom application initialization.
 * @param app The native application instance to set.
 * This should be called once during application startup to set the native app instance.
 */
export function setNativeApp(app: UIApplication | android.app.Application) {
	nativeApp = app;
}

let rootView: any;

export function getRootView() {
	return rootView;
}

export function setRootView(view: any) {
	rootView = view;
}

let _appInBackground: boolean = false;
export function isAppInBackground() {
	return _appInBackground;
}
export function setAppInBackground(value: boolean) {
	_appInBackground = value;
}

let _iosWindow: UIWindow;
export function getiOSWindow(): UIWindow {
	return _iosWindow;
}
export function setiOSWindow(value: UIWindow) {
	_iosWindow = value;
}

let _appMainEntry: any /* NavigationEntry */;

export function getAppMainEntry(): any /* NavigationEntry */ {
	return _appMainEntry;
}
export function setAppMainEntry(entry: any /* NavigationEntry */) {
	_appMainEntry = entry;
}

// Aids avoiding circular dependencies by allowing the application event listeners to be toggled
let _toggleApplicationEventListenersHandler: (toAdd: boolean, callback: (args: any) => void) => void;
export function toggleApplicationEventListeners(toAdd: boolean, callback: (args: any) => void) {
	if (_toggleApplicationEventListenersHandler) {
		_toggleApplicationEventListenersHandler(toAdd, callback);
	}
}
export function setToggleApplicationEventListenersCallback(callback: (toAdd: boolean, callback: (args: any) => void) => void) {
	_toggleApplicationEventListenersHandler = callback;
}

// Aids avoiding circular dependencies by allowing the application properties to be retrieved
type ApplicationPropertyValues = { orientation: 'portrait' | 'landscape' | 'unknown'; systemAppearance: 'dark' | 'light' | null };
let _applicationPropertiesCallback: () => ApplicationPropertyValues;
export function getApplicationProperties(): ApplicationPropertyValues {
	if (_applicationPropertiesCallback) {
		return _applicationPropertiesCallback();
	}
	return { orientation: 'unknown', systemAppearance: null };
}
export function setApplicationPropertiesCallback(callback: () => ApplicationPropertyValues) {
	_applicationPropertiesCallback = callback;
}

let _a11yUpdatePropertiesCallback: (view: any /* View */) => void;
export function setA11yUpdatePropertiesCallback(callback: (view: any /* View */) => void) {
	_a11yUpdatePropertiesCallback = callback;
}
export function updateA11yPropertiesCallback(view: any /* View */) {
	if (_a11yUpdatePropertiesCallback) {
		_a11yUpdatePropertiesCallback(view);
	}
}

/**
 * Internal Android app helpers
 */
// Circular dependency avoidance for image fetching on android
let _imageFetcher: org.nativescript.widgets.image.Fetcher;
export function getImageFetcher(): org.nativescript.widgets.image.Fetcher {
	return _imageFetcher;
}
export function setImageFetcher(fetcher: org.nativescript.widgets.image.Fetcher) {
	_imageFetcher = fetcher;
}
export enum CacheMode {
	none,
	memory,
	diskAndMemory,
}

let _currentCacheMode: CacheMode;

export function initImageCache(context: android.content.Context, mode = CacheMode.diskAndMemory, memoryCacheSize = 0.25, diskCacheSize: number = 10 * 1024 * 1024): void {
	if (_currentCacheMode === mode) {
		return;
	}

	_currentCacheMode = mode;
	if (!getImageFetcher()) {
		setImageFetcher(org.nativescript.widgets.image.Fetcher.getInstance(context));
	} else {
		getImageFetcher().clearCache();
	}

	const params = new org.nativescript.widgets.image.Cache.CacheParams();
	params.memoryCacheEnabled = mode !== CacheMode.none;
	params.setMemCacheSizePercent(memoryCacheSize); // Set memory cache to % of app memory
	params.diskCacheEnabled = mode === CacheMode.diskAndMemory;
	params.diskCacheSize = diskCacheSize;
	const imageCache = org.nativescript.widgets.image.Cache.getInstance(params);
	getImageFetcher().addImageCache(imageCache);
	getImageFetcher().initCache();
}