NativeScript/tns-core-modules/ui/page/page.ios.ts

// Definitions.
import { Frame } from "../frame";

// Types.
import { ios as iosView } from "../core/view";
import {
    PageBase, View, ViewBase, layout,
    actionBarHiddenProperty, statusBarStyleProperty,
    traceEnabled, traceWrite, traceCategories, PercentLength, Color
} from "./page-common";
import { ios as iosApp } from "../../application";
import { device } from "../../platform";
// HACK: Webpack. Use a fully-qualified import to allow resolve.extensions(.ios.js) to
// kick in. `../utils` doesn't seem to trigger the webpack extensions mechanism.
import * as uiUtils from "../../ui/utils";
import { profile } from "../../profiling";

export * from "./page-common";

import { ios } from "../../utils/utils";
import getter = ios.getter;

const ENTRY = "_entry";
const DELEGATE = "_delegate";

function isBackNavigationTo(page: Page, entry): boolean {
    const frame = page.frame;
    if (!frame) {
        return false;
    }

    if (frame.navigationQueueIsEmpty()) {
        return true;
    } else {
        const navigationQueue = (<any>frame)._navigationQueue;
        for (let i = 0; i < navigationQueue.length; i++) {
            if (navigationQueue[i].entry === entry) {
                return navigationQueue[i].isBackNavigation;
            }
        }
    }

    return false;
}

function isBackNavigationFrom(controller: UIViewControllerImpl, page: Page): boolean {
    if (!page.frame) {
        return false;
    }

    // Controller is cleared or backstack skipped
    if (controller.isBackstackCleared || controller.isBackstackSkipped) {
        return false;
    }

    if (controller.navigationController && controller.navigationController.viewControllers.containsObject(controller)) {
        return false;
    }

    return true;
}

class UIViewControllerImpl extends UIViewController {

    private _owner: WeakRef<Page>;

    public isBackstackSkipped: boolean;
    public isBackstackCleared: boolean;

    public static initWithOwner(owner: WeakRef<Page>): UIViewControllerImpl {
        const controller = <UIViewControllerImpl>UIViewControllerImpl.new();
        controller._owner = owner;
        return controller;
    }

    public viewWillAppear(animated: boolean): void {
        super.viewWillAppear(animated);
        const owner = this._owner.get();
        if (!owner) {
            return;
        }

        const frame = this.navigationController ? (<any>this.navigationController).owner : null;
        const newEntry = this[ENTRY];
        const modalParent = owner._modalParent;

        // Don't raise event if currentPage was showing modal page.
        if (!owner._presentedViewController && newEntry && (!frame || frame.currentPage !== owner)) {
            const isBack = isBackNavigationTo(owner, newEntry);
            owner.onNavigatingTo(newEntry.entry.context, isBack, newEntry.entry.bindingContext);
        }

        if (frame) {
            if (!owner.parent) {
                owner._frame = frame;
                if (!frame._styleScope) {
                    // Make sure page will have styleScope even if frame don't.
                    owner._updateStyleScope();
                }

                frame._addView(owner);
            } else if (owner.parent !== frame) {
                throw new Error("Page is already shown on another frame.");
            }

            frame._updateActionBar(owner);
        }

        // Pages in backstack are unloaded so raise loaded here.
        if (!owner.isLoaded) {
            owner.callLoaded();
        }
    }

    @profile
    public viewDidAppear(animated: boolean): void {
        super.viewDidAppear(animated);

        const owner = this._owner.get();
        if (!owner) {
            return;
        }

        const navigationController = this.navigationController;
        const frame = navigationController ? (<any>navigationController).owner : null;
        // Skip navigation events if modal page is shown.
        if (!owner._presentedViewController && frame) {
            const newEntry = this[ENTRY];
            
            let isBack: boolean;
            // We are on the current page which happens when navigation is canceled so isBack should be false.
            if (frame.currentPage === owner && frame._navigationQueue.length === 0) {
                isBack = false;
            } else {
                isBack = isBackNavigationTo(owner, newEntry);
            }

            frame._updateBackstack(newEntry, isBack);
            frame.setCurrent(newEntry, isBack);

            // If page was shown with custom animation - we need to set the navigationController.delegate to the animatedDelegate.
            frame.ios.controller.delegate = this[DELEGATE];

            frame._processNavigationQueue(owner);

            // _processNavigationQueue will shift navigationQueue. Check canGoBack after that.
            // Workaround for disabled backswipe on second custom native transition
            if (frame.canGoBack()) {
                navigationController.interactivePopGestureRecognizer.delegate = navigationController;
                navigationController.interactivePopGestureRecognizer.enabled = owner.enableSwipeBackNavigation;
            } else {
                navigationController.interactivePopGestureRecognizer.enabled = false;
            }
        }

        if (!this.presentedViewController) {
            // clear presented viewController here only if no presented controller.
            // this is needed because in iOS9 the order of events could be - willAppear, willDisappear, didAppear.
            // If we clean it when we have viewController then once presented VC is dismissed then
            owner._presentedViewController = null;
        }
    }

    @profile
    public viewWillDisappear(animated: boolean): void {
        super.viewWillDisappear(animated);

        const owner = this._owner.get();
        if (!owner) {
            return;
        }

        // Cache presentedViewController if any. We don't want to raise
        // navigation events in case of presenting view controller.
        if (!owner._presentedViewController) {
            owner._presentedViewController = this.presentedViewController;
        }

        const frame = owner.frame;
        // Skip navigation events if we are hiding because we are about to show modal page
        // or because we are in tab and another controller is selected.
        const tab = this.tabBarController;
        if (!owner._presentedViewController && frame && frame.currentPage === owner) {
            const willSelectViewController = tab && (<any>tab)._willSelectViewController;
            if (!willSelectViewController
                || willSelectViewController === tab.selectedViewController) {
                let isBack = isBackNavigationFrom(this, owner);
                owner.onNavigatingFrom(isBack);
            }
        }
    }

    @profile
    public viewDidDisappear(animated: boolean): void {
        super.viewDidDisappear(animated);

        const page = this._owner.get();
        // Exit if no page or page is hiding because it shows another page modally.
        if (!page || page.modal || page._presentedViewController) {
            return;
        }

        // Forward navigation does not remove page from frame so we raise unloaded manually.
        if (page.isLoaded) {
            page.callUnloaded();
        }
    }

    public viewWillLayoutSubviews(): void {
        super.viewWillLayoutSubviews();
        const owner = this._owner.get();
        if (owner) {
            iosView.updateConstraints(this, owner);
        }
    }

    public viewDidLayoutSubviews(): void {
        super.viewDidLayoutSubviews();
        const owner = this._owner.get();
        if (owner) {
            // layout(owner.actionBar)
            // layout(owner.content)
            iosView.layoutView(this, owner);
        }
    }
}

const whiteColor = new Color("white").ios;
export class Page extends PageBase {
    nativeViewProtected: UIView;
    viewController: UIViewControllerImpl;

    private _ios: UIViewControllerImpl;
    public _presentedViewController: UIViewController; // used when our page present native viewController without going through our abstraction.

    constructor() {
        super();
        const controller = UIViewControllerImpl.initWithOwner(new WeakRef(this));
        this.viewController = this._ios = controller;
        this.nativeViewProtected = controller.view;
        this.nativeViewProtected.backgroundColor = whiteColor;
    }

    get ios(): UIViewController {
        return this._ios;
    }

    get frame(): Frame {
        return this._frame;
    }

    public layoutNativeView(left: number, top: number, right: number, bottom: number): void {
        //
    }

    public _setNativeViewFrame(nativeView: UIView, frame: CGRect) {
        //
    }

    public onLoaded(): void {
        super.onLoaded();
        if (this.hasActionBar) {
            this.actionBar.update();
        }
    }

    public updateStatusBar() {
        this._updateStatusBarStyle(this.statusBarStyle);
    }

    public _updateStatusBarStyle(value?: string) {
        const frame = this.frame;
        if (this.frame && value) {
            const navigationController: UINavigationController = frame.ios.controller;
            const navigationBar = navigationController.navigationBar;

            navigationBar.barStyle = value === "dark" ? UIBarStyle.Black : UIBarStyle.Default;
        }
    }

    public _updateEnableSwipeBackNavigation(enabled: boolean) {
        const navController = this._ios.navigationController;
        if (this.frame && navController && navController.interactivePopGestureRecognizer) {
            // Make sure we don't set true if cannot go back
            enabled = enabled && this.frame.canGoBack();
            navController.interactivePopGestureRecognizer.enabled = enabled;
        }
    }

    public onMeasure(widthMeasureSpec: number, heightMeasureSpec: number) {
        const width = layout.getMeasureSpecSize(widthMeasureSpec);
        const widthMode = layout.getMeasureSpecMode(widthMeasureSpec);

        const height = layout.getMeasureSpecSize(heightMeasureSpec);
        const heightMode = layout.getMeasureSpecMode(heightMeasureSpec);

        if (this.frame && this.frame._getNavBarVisible(this)) {
            const { width, height } = this.actionBar._getActualSize;
            const widthSpec = layout.makeMeasureSpec(width, layout.EXACTLY);
            const heightSpec = layout.makeMeasureSpec(height, layout.EXACTLY);
            View.measureChild(this, this.actionBar, widthSpec, heightSpec);
        }

        const result = View.measureChild(this, this.layoutView, widthMeasureSpec, heightMeasureSpec);

        const measureWidth = Math.max(result.measuredWidth, this.effectiveMinWidth);
        const measureHeight = Math.max(result.measuredHeight, this.effectiveMinHeight);

        const widthAndState = View.resolveSizeAndState(measureWidth, width, widthMode, 0);
        const heightAndState = View.resolveSizeAndState(measureHeight, height, heightMode, 0);

        this.setMeasuredDimension(widthAndState, heightAndState);
    }

    public onLayout(left: number, top: number, right: number, bottom: number) {
        const { width: actionBarWidth, height: actionBarHeight } = this.actionBar._getActualSize;
        View.layoutChild(this, this.actionBar, 0, 0, actionBarWidth, actionBarHeight);
        View.layoutChild(this, this.layoutView, left, top, right, bottom);
    }

    public _addViewToNativeVisualTree(child: View, atIndex: number): boolean {
        // ActionBar is handled by the UINavigationController
        if (child === this.actionBar) {
            return true;
        }

        const nativeParent = this.nativeViewProtected;
        const nativeChild = child.nativeViewProtected;

        const viewController = child.ios instanceof UIViewController ? child.ios : child.viewController;
        if (viewController) {
            // Adding modal controllers to as child will make app freeze.
            if (this.viewController.presentedViewController === viewController) {
                return true;
            }
            
            this.viewController.addChildViewController(viewController);
        }

        if (nativeParent && nativeChild) {
            if (typeof atIndex !== "number" || atIndex >= nativeParent.subviews.count) {
                nativeParent.addSubview(nativeChild);
            } else {
                nativeParent.insertSubviewAtIndex(nativeChild, atIndex);
            }

            return true;
        }

        return false;
    }

    public _removeViewFromNativeVisualTree(child: View): void {
        // ActionBar is handled by the UINavigationController
        if (child === this.actionBar) {
            return;
        }

        const viewController = child.ios instanceof UIViewController ? child.ios : child.viewController;
        if (viewController) {
            viewController.removeFromParentViewController();
        }

        super._removeViewFromNativeVisualTree(child);
    }

    [actionBarHiddenProperty.setNative](value: boolean) {
        this._updateEnableSwipeBackNavigation(value);

        // Invalidate all inner controller.
        invalidateTopmostController(this.viewController);

        const frame = this.frame;
        if (frame) {
            // Update nav-bar visibility with disabled animations
            frame._updateActionBar(this, true);
        }
    }

    [statusBarStyleProperty.getDefault](): UIBarStyle {
        return UIBarStyle.Default;
    }
    [statusBarStyleProperty.setNative](value: string | UIBarStyle) {
        const frame = this.frame;
        if (frame) {
            const navigationBar = (<UINavigationController>frame.ios.controller).navigationBar;
            if (typeof value === "string") {
                navigationBar.barStyle = value === "dark" ? UIBarStyle.Black : UIBarStyle.Default;
            } else {
                navigationBar.barStyle = value;
            }
        }
    }
}

function invalidateTopmostController(controller: UIViewController): void {
    if (!controller) {
        return;
    }

    controller.view.setNeedsLayout();

    const presentedViewController = controller.presentedViewController;
    if (presentedViewController) {
        return invalidateTopmostController(presentedViewController);
    }

    const childControllers = controller.childViewControllers;
    let size = controller.childViewControllers.count;
    while (size > 0) {
        const childController = childControllers[--size];
        if (childController instanceof UITabBarController) {
            invalidateTopmostController(childController.selectedViewController);
        } else if (childController instanceof UINavigationController) {
            invalidateTopmostController(childController.topViewController);
        } else if (childController instanceof UISplitViewController) {
            invalidateTopmostController(childController.viewControllers.lastObject);
        } else {
            invalidateTopmostController(childController);
        }
    }
}