// Types.
import { AndroidApplication as AndroidApplicationDefinition } from '.';
import { AndroidActivityBackPressedEventData, AndroidActivityBundleEventData, AndroidActivityEventData, AndroidActivityNewIntentEventData, AndroidActivityRequestPermissionsEventData, AndroidActivityResultEventData, ApplicationEventData, CssChangedEventData, OrientationChangedEventData, SystemAppearanceChangedEventData } from './application-interfaces';

// TODO: explain why we need to this or remov it
// Use requires to ensure order of imports is maintained
const appCommon = require('./application-common');

// First reexport so that app module is initialized.
export * from './application-common';

import { View } from '../ui/core/view';
import { NavigationEntry, AndroidActivityCallbacks } from '../ui/frame/frame-interfaces';
import { Observable } from '../data/observable';

import { profile } from '../profiling';
import { initAccessibilityCssHelper } from '../accessibility/accessibility-css-helper';
import { initAccessibilityFontScale } from '../accessibility/font-scale';

const ActivityCreated = 'activityCreated';
const ActivityDestroyed = 'activityDestroyed';
const ActivityStarted = 'activityStarted';
const ActivityPaused = 'activityPaused';
const ActivityResumed = 'activityResumed';
const ActivityStopped = 'activityStopped';
const SaveActivityState = 'saveActivityState';
const ActivityResult = 'activityResult';
const ActivityBackPressed = 'activityBackPressed';
const ActivityNewIntent = 'activityNewIntent';
const ActivityRequestPermissions = 'activityRequestPermissions';

export class AndroidApplication extends Observable implements AndroidApplicationDefinition {
	public static activityCreatedEvent = ActivityCreated;
	public static activityDestroyedEvent = ActivityDestroyed;
	public static activityStartedEvent = ActivityStarted;
	public static activityPausedEvent = ActivityPaused;
	public static activityResumedEvent = ActivityResumed;
	public static activityStoppedEvent = ActivityStopped;
	public static saveActivityStateEvent = SaveActivityState;
	public static activityResultEvent = ActivityResult;
	public static activityBackPressedEvent = ActivityBackPressed;
	public static activityNewIntentEvent = ActivityNewIntent;
	public static activityRequestPermissionsEvent = ActivityRequestPermissions;

	private _orientation: 'portrait' | 'landscape' | 'unknown';
	private _systemAppearance: 'light' | 'dark';
	public paused: boolean;
	public nativeApp: android.app.Application;
	public context: android.content.Context;
	public foregroundActivity: androidx.appcompat.app.AppCompatActivity;
	public startActivity: androidx.appcompat.app.AppCompatActivity;
	public packageName: string;
	// we are using these property to store the callbacks to avoid early GC collection which would trigger MarkReachableObjects
	private callbacks: any = {};

	public init(nativeApp: android.app.Application): void {
		if (this.nativeApp === nativeApp) {
			return;
		}

		if (this.nativeApp) {
			throw new Error('application.android already initialized.');
		}

		this.nativeApp = nativeApp;
		this.packageName = nativeApp.getPackageName();
		this.context = nativeApp.getApplicationContext();
		// we store those callbacks and add a function for clearing them later so that the objects will be eligable for GC
		this.callbacks.lifecycleCallbacks = initLifecycleCallbacks();
		this.callbacks.componentCallbacks = initComponentCallbacks();
		this.nativeApp.registerActivityLifecycleCallbacks(this.callbacks.lifecycleCallbacks);
		this.nativeApp.registerComponentCallbacks(this.callbacks.componentCallbacks);

		this._registerPendingReceivers();
	}

	private _registeredReceivers = {};
	private _pendingReceiverRegistrations = new Array<(context: android.content.Context) => void>();
	private _registerPendingReceivers() {
		this._pendingReceiverRegistrations.forEach((func) => func(this.context));
		this._pendingReceiverRegistrations.length = 0;
	}

	get orientation(): 'portrait' | 'landscape' | 'unknown' {
		if (!this._orientation) {
			const resources = this.context.getResources();
			const configuration = <android.content.res.Configuration>resources.getConfiguration();

			this._orientation = getOrientationValue(configuration);
		}

		return this._orientation;
	}

	set orientation(value: 'portrait' | 'landscape' | 'unknown') {
		this._orientation = value;
	}

	get systemAppearance(): 'light' | 'dark' {
		if (!this._systemAppearance) {
			const resources = this.context.getResources();
			const configuration = <android.content.res.Configuration>resources.getConfiguration();

			this._systemAppearance = getSystemAppearanceValue(configuration);
		}

		return this._systemAppearance;
	}

	set systemAppearance(value: 'light' | 'dark') {
		this._systemAppearance = value;
	}

	public registerBroadcastReceiver(intentFilter: string, onReceiveCallback: (context: android.content.Context, intent: android.content.Intent) => void): void {
		ensureBroadCastReceiverClass();
		const registerFunc = (context: android.content.Context) => {
			const receiver: android.content.BroadcastReceiver = new BroadcastReceiverClass(onReceiveCallback);
			context.registerReceiver(receiver, new android.content.IntentFilter(intentFilter));
			this._registeredReceivers[intentFilter] = receiver;
		};

		if (this.context) {
			registerFunc(this.context);
		} else {
			this._pendingReceiverRegistrations.push(registerFunc);
		}
	}

	public unregisterBroadcastReceiver(intentFilter: string): void {
		const receiver = this._registeredReceivers[intentFilter];
		if (receiver) {
			this.context.unregisterReceiver(receiver);
			this._registeredReceivers[intentFilter] = undefined;
			delete this._registeredReceivers[intentFilter];
		}
	}
}

// HACK: Use an interface with the same name, so that the class above fulfills the 'implements' requirement
// HACK: We use the 'implements' to verify the class above is the same as the one declared in the d.ts
// HACK: We declare all these 'on' statements, so that they can appear in the API reference
// HACK: Do we need this? Is it useful? There are static fields to the AndroidApplication class for the event names.
export interface AndroidApplication {
	on(eventNames: string, callback: (data: AndroidActivityEventData) => void, thisArg?: any);
	on(event: 'activityCreated', callback: (args: AndroidActivityBundleEventData) => void, thisArg?: any);
	on(event: 'activityDestroyed', callback: (args: AndroidActivityEventData) => void, thisArg?: any);
	on(event: 'activityStarted', callback: (args: AndroidActivityEventData) => void, thisArg?: any);
	on(event: 'activityPaused', callback: (args: AndroidActivityEventData) => void, thisArg?: any);
	on(event: 'activityResumed', callback: (args: AndroidActivityEventData) => void, thisArg?: any);
	on(event: 'activityStopped', callback: (args: AndroidActivityEventData) => void, thisArg?: any);
	on(event: 'saveActivityState', callback: (args: AndroidActivityBundleEventData) => void, thisArg?: any);
	on(event: 'activityResult', callback: (args: AndroidActivityResultEventData) => void, thisArg?: any);
	on(event: 'activityBackPressed', callback: (args: AndroidActivityBackPressedEventData) => void, thisArg?: any);
	on(event: 'activityNewIntent', callback: (args: AndroidActivityNewIntentEventData) => void, thisArg?: any);
	on(event: 'activityRequestPermissions', callback: (args: AndroidActivityRequestPermissionsEventData) => void, thisArg?: any);
}

const androidApp = new AndroidApplication();
export { androidApp as android };
appCommon.setApplication(androidApp);

let mainEntry: NavigationEntry;
let started = false;

export function run(entry?: NavigationEntry | string) {
	if (started) {
		throw new Error('Application is already started.');
	}

	started = true;
	mainEntry = typeof entry === 'string' ? { moduleName: entry } : entry;
	if (!androidApp.nativeApp) {
		const nativeApp = getNativeApplication();
		androidApp.init(nativeApp);
	}

	initAccessibilityCssHelper();
	initAccessibilityFontScale();
}

export function addCss(cssText: string, attributeScoped?: boolean): void {
	appCommon.notify(<CssChangedEventData>{
		eventName: 'cssChanged',
		object: androidApp,
		cssText: cssText,
	});
	if (!attributeScoped) {
		const rootView = getRootView();
		if (rootView) {
			rootView._onCssStateChange();
		}
	}
}

const CALLBACKS = '_callbacks';

export function _resetRootView(entry?: NavigationEntry | string): void {
	const activity = androidApp.foregroundActivity || androidApp.startActivity;
	if (!activity) {
		throw new Error('Cannot find android activity.');
	}

	mainEntry = typeof entry === 'string' ? { moduleName: entry } : entry;
	const callbacks: AndroidActivityCallbacks = activity[CALLBACKS];
	if (!callbacks) {
		throw new Error('Cannot find android activity callbacks.');
	}
	callbacks.resetActivityContent(activity);
}

export function getMainEntry() {
	return mainEntry;
}

export function getRootView(): View {
	// Use start activity as a backup when foregroundActivity is still not set
	// in cases when we are getting the root view before activity.onResumed event is fired
	const activity = androidApp.foregroundActivity || androidApp.startActivity;
	if (!activity) {
		return undefined;
	}
	const callbacks: AndroidActivityCallbacks = activity[CALLBACKS];

	return callbacks ? callbacks.getRootView() : undefined;
}

export function getNativeApplication(): android.app.Application {
	// Try getting it from module - check whether application.android.init has been explicitly called
	let nativeApp = androidApp.nativeApp;
	if (!nativeApp) {
		// check whether the com.tns.NativeScriptApplication type exists
		if (!nativeApp && com.tns.NativeScriptApplication) {
			nativeApp = com.tns.NativeScriptApplication.getInstance();
		}

		// the getInstance might return null if com.tns.NativeScriptApplication exists but is  not the starting app type
		if (!nativeApp) {
			// TODO: Should we handle the case when a custom application type is provided and the user has not explicitly initialized the application module?
			const clazz = java.lang.Class.forName('android.app.ActivityThread');
			if (clazz) {
				const method = clazz.getMethod('currentApplication', null);
				if (method) {
					nativeApp = method.invoke(null, null);
				}
			}
		}

		// we cannot work without having the app instance
		if (!nativeApp) {
			throw new Error("Failed to retrieve native Android Application object. If you have a custom android.app.Application type implemented make sure that you've called the '<application-module>.android.init' method.");
		}
	}

	return nativeApp;
}

export function orientation(): 'portrait' | 'landscape' | 'unknown' {
	return androidApp.orientation;
}

export function systemAppearance(): 'dark' | 'light' {
	return androidApp.systemAppearance;
}

global.__onLiveSync = function __onLiveSync(context?: ModuleContext) {
	if (androidApp && androidApp.paused) {
		return;
	}

	const rootView = getRootView();
	appCommon.livesync(rootView, context);
};

function getOrientationValue(configuration: android.content.res.Configuration): 'portrait' | 'landscape' | 'unknown' {
	const orientation = configuration.orientation;

	switch (orientation) {
		case android.content.res.Configuration.ORIENTATION_LANDSCAPE:
			return 'landscape';
		case android.content.res.Configuration.ORIENTATION_PORTRAIT:
			return 'portrait';
		default:
			return 'unknown';
	}
}

// https://developer.android.com/guide/topics/ui/look-and-feel/darktheme#configuration_changes
function getSystemAppearanceValue(configuration: android.content.res.Configuration): 'dark' | 'light' {
	const systemAppearance = configuration.uiMode & android.content.res.Configuration.UI_MODE_NIGHT_MASK;

	switch (systemAppearance) {
		case android.content.res.Configuration.UI_MODE_NIGHT_YES:
			return 'dark';
		case android.content.res.Configuration.UI_MODE_NIGHT_NO:
		case android.content.res.Configuration.UI_MODE_NIGHT_UNDEFINED:
			return 'light';
	}
}

function initLifecycleCallbacks() {
	const setThemeOnLaunch = profile('setThemeOnLaunch', (activity: androidx.appcompat.app.AppCompatActivity) => {
		// Set app theme after launch screen was used during startup
		const activityInfo = activity.getPackageManager().getActivityInfo(activity.getComponentName(), android.content.pm.PackageManager.GET_META_DATA);
		if (activityInfo.metaData) {
			const setThemeOnLaunch = activityInfo.metaData.getInt('SET_THEME_ON_LAUNCH', -1);
			if (setThemeOnLaunch !== -1) {
				activity.setTheme(setThemeOnLaunch);
			}
		}
	});

	const notifyActivityCreated = profile('notifyActivityCreated', function (activity: androidx.appcompat.app.AppCompatActivity, savedInstanceState: android.os.Bundle) {
		androidApp.notify(<AndroidActivityBundleEventData>{
			eventName: ActivityCreated,
			object: androidApp,
			activity,
			bundle: savedInstanceState,
		});
	});

	const subscribeForGlobalLayout = profile('subscribeForGlobalLayout', function (activity: androidx.appcompat.app.AppCompatActivity) {
		const rootView = activity.getWindow().getDecorView().getRootView();
		// store the listener not to trigger GC collection before collecting the method
		global.onGlobalLayoutListener = new android.view.ViewTreeObserver.OnGlobalLayoutListener({
			onGlobalLayout() {
				appCommon.notify({
					eventName: appCommon.displayedEvent,
					object: androidApp,
					activity,
				});
				const viewTreeObserver = rootView.getViewTreeObserver();
				viewTreeObserver.removeOnGlobalLayoutListener(global.onGlobalLayoutListener);
			},
		});
		rootView.getViewTreeObserver().addOnGlobalLayoutListener(global.onGlobalLayoutListener);
	});

	const lifecycleCallbacks = new android.app.Application.ActivityLifecycleCallbacks(<any>{
		onActivityCreated: <any>profile('onActivityCreated', function (activity: androidx.appcompat.app.AppCompatActivity, savedInstanceState: android.os.Bundle) {
			setThemeOnLaunch(activity, undefined, undefined);

			if (!androidApp.startActivity) {
				androidApp.startActivity = activity;
			}

			notifyActivityCreated(activity, <any>savedInstanceState, undefined);

			if (appCommon.hasListeners(appCommon.displayedEvent)) {
				subscribeForGlobalLayout(activity, undefined, undefined);
			}
		}),

		onActivityDestroyed: <any>profile('onActivityDestroyed', function (activity: androidx.appcompat.app.AppCompatActivity) {
			if (activity === androidApp.foregroundActivity) {
				androidApp.foregroundActivity = undefined;
			}

			if (activity === androidApp.startActivity) {
				androidApp.startActivity = undefined;
			}

			androidApp.notify(<AndroidActivityEventData>{
				eventName: ActivityDestroyed,
				object: androidApp,
				activity: activity,
			});
			// TODO: This is a temporary workaround to force the V8's Garbage Collector, which will force the related Java Object to be collected.
			gc();
		}),

		onActivityPaused: <any>profile('onActivityPaused', function (activity: androidx.appcompat.app.AppCompatActivity) {
			if ((<any>activity).isNativeScriptActivity) {
				androidApp.paused = true;
				appCommon.notify(<ApplicationEventData>{
					eventName: appCommon.suspendEvent,
					object: androidApp,
					android: activity,
				});
			}

			androidApp.notify(<AndroidActivityEventData>{
				eventName: ActivityPaused,
				object: androidApp,
				activity: activity,
			});
		}),

		onActivityResumed: <any>profile('onActivityResumed', function (activity: androidx.appcompat.app.AppCompatActivity) {
			androidApp.foregroundActivity = activity;

			androidApp.notify(<AndroidActivityEventData>{
				eventName: ActivityResumed,
				object: androidApp,
				activity: activity,
			});
		}),

		onActivitySaveInstanceState: <any>profile('onActivitySaveInstanceState', function (activity: androidx.appcompat.app.AppCompatActivity, outState: android.os.Bundle) {
			androidApp.notify(<AndroidActivityBundleEventData>{
				eventName: SaveActivityState,
				object: androidApp,
				activity: activity,
				bundle: outState,
			});
		}),

		onActivityStarted: <any>profile('onActivityStarted', function (activity: androidx.appcompat.app.AppCompatActivity) {
			androidApp.notify(<AndroidActivityEventData>{
				eventName: ActivityStarted,
				object: androidApp,
				activity: activity,
			});
		}),

		onActivityStopped: <any>profile('onActivityStopped', function (activity: androidx.appcompat.app.AppCompatActivity) {
			androidApp.notify(<AndroidActivityEventData>{
				eventName: ActivityStopped,
				object: androidApp,
				activity: activity,
			});
		}),
	});

	return lifecycleCallbacks;
}

function initComponentCallbacks() {
	const componentCallbacks = new android.content.ComponentCallbacks2({
		onLowMemory: <any>profile('onLowMemory', function () {
			gc();
			java.lang.System.gc();
			appCommon.notify(<ApplicationEventData>{
				eventName: appCommon.lowMemoryEvent,
				object: this,
				android: this,
			});
		}),

		onTrimMemory: <any>profile('onTrimMemory', function (level: number) {
			// TODO: This is skipped for now, test carefully for OutOfMemory exceptions
		}),

		onConfigurationChanged: <any>profile('onConfigurationChanged', function (newConfiguration: android.content.res.Configuration) {
			const rootView = getRootView();
			const newOrientation = getOrientationValue(newConfiguration);

			if (androidApp.orientation !== newOrientation) {
				androidApp.orientation = newOrientation;
				appCommon.orientationChanged(rootView, newOrientation);

				appCommon.notify(<OrientationChangedEventData>{
					eventName: appCommon.orientationChangedEvent,
					android: androidApp.nativeApp,
					newValue: androidApp.orientation,
					object: androidApp,
				});

				return;
			}

			const newSystemAppearance = getSystemAppearanceValue(newConfiguration);

			if (androidApp.systemAppearance !== newSystemAppearance) {
				androidApp.systemAppearance = newSystemAppearance;
				appCommon.systemAppearanceChanged(rootView, newSystemAppearance);

				appCommon.notify(<SystemAppearanceChangedEventData>{
					eventName: appCommon.systemAppearanceChangedEvent,
					android: androidApp.nativeApp,
					newValue: androidApp.systemAppearance,
					object: androidApp,
				});
			}
		}),
	});

	return componentCallbacks;
}

let BroadcastReceiverClass;
function ensureBroadCastReceiverClass() {
	if (BroadcastReceiverClass) {
		return;
	}

	@NativeClass
	class BroadcastReceiver extends android.content.BroadcastReceiver {
		private _onReceiveCallback: (context: android.content.Context, intent: android.content.Intent) => void;

		constructor(onReceiveCallback: (context: android.content.Context, intent: android.content.Intent) => void) {
			super();
			this._onReceiveCallback = onReceiveCallback;

			return global.__native(this);
		}

		public onReceive(context: android.content.Context, intent: android.content.Intent) {
			if (this._onReceiveCallback) {
				this._onReceiveCallback(context, intent);
			}
		}
	}

	BroadcastReceiverClass = BroadcastReceiver;
}

declare namespace com {
	namespace tns {
		class NativeScriptApplication extends android.app.Application {
			static getInstance(): NativeScriptApplication;
		}
	}
}

// core exports this symbol so apps may import them in general
// technically they are only available for use when running that platform
// helps avoid a webpack nonexistent warning
export const iOSApplication = undefined;