/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.internal.view;

import android.annotation.NonNull;
import android.annotation.Nullable;
import android.content.Context;
import android.graphics.Point;
import android.graphics.Rect;
import android.view.ActionMode;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.WindowManager;

import android.widget.PopupWindow;
import com.android.internal.R;
import com.android.internal.util.Preconditions;
import com.android.internal.view.menu.MenuBuilder;
import com.android.internal.widget.FloatingToolbar;

import java.util.Arrays;

public final class FloatingActionMode extends ActionMode {

    private static final int MAX_HIDE_DURATION = 3000;
    private static final int MOVING_HIDE_DELAY = 50;

    @NonNull private final Context mContext;
    @NonNull private final ActionMode.Callback2 mCallback;
    @NonNull private final MenuBuilder mMenu;
    @NonNull private final Rect mContentRect;
    @NonNull private final Rect mContentRectOnScreen;
    @NonNull private final Rect mPreviousContentRectOnScreen;
    @NonNull private final int[] mViewPositionOnScreen;
    @NonNull private final int[] mPreviousViewPositionOnScreen;
    @NonNull private final int[] mRootViewPositionOnScreen;
    @NonNull private final Rect mViewRectOnScreen;
    @NonNull private final Rect mPreviousViewRectOnScreen;
    @NonNull private final Rect mScreenRect;
    @NonNull private final View mOriginatingView;
    @NonNull private final Point mDisplaySize;
    private final int mBottomAllowance;

    private final Runnable mMovingOff = new Runnable() {
        public void run() {
            if (isViewStillActive()) {
                mFloatingToolbarVisibilityHelper.setMoving(false);
                mFloatingToolbarVisibilityHelper.updateToolbarVisibility();
            }
        }
    };

    private final Runnable mHideOff = new Runnable() {
        public void run() {
            if (isViewStillActive()) {
                mFloatingToolbarVisibilityHelper.setHideRequested(false);
                mFloatingToolbarVisibilityHelper.updateToolbarVisibility();
            }
        }
    };

    @NonNull private FloatingToolbar mFloatingToolbar;
    @NonNull private FloatingToolbarVisibilityHelper mFloatingToolbarVisibilityHelper;

    public FloatingActionMode(
            Context context, ActionMode.Callback2 callback,
            View originatingView, FloatingToolbar floatingToolbar) {
        mContext = Preconditions.checkNotNull(context);
        mCallback = Preconditions.checkNotNull(callback);
        mMenu = new MenuBuilder(context).setDefaultShowAsAction(
                MenuItem.SHOW_AS_ACTION_IF_ROOM);
        setType(ActionMode.TYPE_FLOATING);
        mMenu.setCallback(new MenuBuilder.Callback() {
            @Override
            public void onMenuModeChange(MenuBuilder menu) {}

            @Override
            public boolean onMenuItemSelected(MenuBuilder menu, MenuItem item) {
                return mCallback.onActionItemClicked(FloatingActionMode.this, item);
            }
        });
        mContentRect = new Rect();
        mContentRectOnScreen = new Rect();
        mPreviousContentRectOnScreen = new Rect();
        mViewPositionOnScreen = new int[2];
        mPreviousViewPositionOnScreen = new int[2];
        mRootViewPositionOnScreen = new int[2];
        mViewRectOnScreen = new Rect();
        mPreviousViewRectOnScreen = new Rect();
        mScreenRect = new Rect();
        mOriginatingView = Preconditions.checkNotNull(originatingView);
        mOriginatingView.getLocationOnScreen(mViewPositionOnScreen);
        // Allow the content rect to overshoot a little bit beyond the
        // bottom view bound if necessary.
        mBottomAllowance = context.getResources()
                .getDimensionPixelSize(R.dimen.content_rect_bottom_clip_allowance);
        mDisplaySize = new Point();
        setFloatingToolbar(Preconditions.checkNotNull(floatingToolbar));
    }

    private void setFloatingToolbar(FloatingToolbar floatingToolbar) {
        mFloatingToolbar = floatingToolbar
                .setMenu(mMenu)
                .setOnMenuItemClickListener(item -> mMenu.performItemAction(item, 0));
        mFloatingToolbarVisibilityHelper = new FloatingToolbarVisibilityHelper(mFloatingToolbar);
        mFloatingToolbarVisibilityHelper.activate();
    }

    @Override
    public void setTitle(CharSequence title) {}

    @Override
    public void setTitle(int resId) {}

    @Override
    public void setSubtitle(CharSequence subtitle) {}

    @Override
    public void setSubtitle(int resId) {}

    @Override
    public void setCustomView(View view) {}

    @Override
    public void invalidate() {
        mCallback.onPrepareActionMode(this, mMenu);
        invalidateContentRect();  // Will re-layout and show the toolbar if necessary.
    }

    @Override
    public void invalidateContentRect() {
        mCallback.onGetContentRect(this, mOriginatingView, mContentRect);
        repositionToolbar();
    }

    public void updateViewLocationInWindow() {
        mOriginatingView.getLocationOnScreen(mViewPositionOnScreen);
        mOriginatingView.getRootView().getLocationOnScreen(mRootViewPositionOnScreen);
        mOriginatingView.getGlobalVisibleRect(mViewRectOnScreen);
        mViewRectOnScreen.offset(mRootViewPositionOnScreen[0], mRootViewPositionOnScreen[1]);

        if (!Arrays.equals(mViewPositionOnScreen, mPreviousViewPositionOnScreen)
                || !mViewRectOnScreen.equals(mPreviousViewRectOnScreen)) {
            repositionToolbar();
            mPreviousViewPositionOnScreen[0] = mViewPositionOnScreen[0];
            mPreviousViewPositionOnScreen[1] = mViewPositionOnScreen[1];
            mPreviousViewRectOnScreen.set(mViewRectOnScreen);
        }
    }

    private void repositionToolbar() {
        mContentRectOnScreen.set(mContentRect);

        // Offset the content rect into screen coordinates, taking into account any transformations
        // that may be applied to the originating view or its ancestors.
        final ViewParent parent = mOriginatingView.getParent();
        if (parent instanceof ViewGroup) {
            ((ViewGroup) parent).getChildVisibleRect(
                    mOriginatingView, mContentRectOnScreen,
                    null /* offset */, true /* forceParentCheck */);
            mContentRectOnScreen.offset(mRootViewPositionOnScreen[0], mRootViewPositionOnScreen[1]);
        } else {
            mContentRectOnScreen.offset(mViewPositionOnScreen[0], mViewPositionOnScreen[1]);
        }

        if (isContentRectWithinBounds()) {
            mFloatingToolbarVisibilityHelper.setOutOfBounds(false);
            // Make sure that content rect is not out of the view's visible bounds.
            mContentRectOnScreen.set(
                    Math.max(mContentRectOnScreen.left, mViewRectOnScreen.left),
                    Math.max(mContentRectOnScreen.top, mViewRectOnScreen.top),
                    Math.min(mContentRectOnScreen.right, mViewRectOnScreen.right),
                    Math.min(mContentRectOnScreen.bottom,
                            mViewRectOnScreen.bottom + mBottomAllowance));

            if (!mContentRectOnScreen.equals(mPreviousContentRectOnScreen)) {
                // Content rect is moving.
                mOriginatingView.removeCallbacks(mMovingOff);
                mFloatingToolbarVisibilityHelper.setMoving(true);
                mOriginatingView.postDelayed(mMovingOff, MOVING_HIDE_DELAY);

                mFloatingToolbar.setContentRect(mContentRectOnScreen);
                mFloatingToolbar.updateLayout();
            }
        } else {
            mFloatingToolbarVisibilityHelper.setOutOfBounds(true);
            mContentRectOnScreen.setEmpty();
        }
        mFloatingToolbarVisibilityHelper.updateToolbarVisibility();

        mPreviousContentRectOnScreen.set(mContentRectOnScreen);
    }

    private boolean isContentRectWithinBounds() {
        mContext.getSystemService(WindowManager.class)
            .getDefaultDisplay().getRealSize(mDisplaySize);
        mScreenRect.set(0, 0, mDisplaySize.x, mDisplaySize.y);

        return intersectsClosed(mContentRectOnScreen, mScreenRect)
            && intersectsClosed(mContentRectOnScreen, mViewRectOnScreen);
    }

    /*
     * Same as Rect.intersects, but includes cases where the rectangles touch.
    */
    private static boolean intersectsClosed(Rect a, Rect b) {
         return a.left <= b.right && b.left <= a.right
                 && a.top <= b.bottom && b.top <= a.bottom;
    }

    @Override
    public void hide(long duration) {
        if (duration == ActionMode.DEFAULT_HIDE_DURATION) {
            duration = ViewConfiguration.getDefaultActionModeHideDuration();
        }
        duration = Math.min(MAX_HIDE_DURATION, duration);
        mOriginatingView.removeCallbacks(mHideOff);
        if (duration <= 0) {
            mHideOff.run();
        } else {
            mFloatingToolbarVisibilityHelper.setHideRequested(true);
            mFloatingToolbarVisibilityHelper.updateToolbarVisibility();
            mOriginatingView.postDelayed(mHideOff, duration);
        }
    }

    
If this is set to true, the action mode view will dismiss itself on touch events outside of
its window. This only makes sense if the action mode view is a PopupWindow that is touchable
but not focusable, which means touches outside of the window will be delivered to the window
behind. The default is false.
This is for internal use only and the approach to this may change.
Params:
outsideTouchable – whether or not this action mode is "outside touchable"
onDismiss – optional. Sets a callback for when this action mode popup dismisses itself
@hide
/**
     * If this is set to true, the action mode view will dismiss itself on touch events outside of
     * its window. This only makes sense if the action mode view is a PopupWindow that is touchable
     * but not focusable, which means touches outside of the window will be delivered to the window
     * behind. The default is false.
     *
     * This is for internal use only and the approach to this may change.
     * @hide
     *
     * @param outsideTouchable whether or not this action mode is "outside touchable"
     * @param onDismiss optional. Sets a callback for when this action mode popup dismisses itself
     */
    public void setOutsideTouchable(
            boolean outsideTouchable, @Nullable PopupWindow.OnDismissListener onDismiss) {
        mFloatingToolbar.setOutsideTouchable(outsideTouchable, onDismiss);
    }

    @Override
    public void onWindowFocusChanged(boolean hasWindowFocus) {
        mFloatingToolbarVisibilityHelper.setWindowFocused(hasWindowFocus);
        mFloatingToolbarVisibilityHelper.updateToolbarVisibility();
    }

    @Override
    public void finish() {
        reset();
        mCallback.onDestroyActionMode(this);
    }

    @Override
    public Menu getMenu() {
        return mMenu;
    }

    @Override
    public CharSequence getTitle() {
        return null;
    }

    @Override
    public CharSequence getSubtitle() {
        return null;
    }

    @Override
    public View getCustomView() {
        return null;
    }

    @Override
    public MenuInflater getMenuInflater() {
        return new MenuInflater(mContext);
    }

    private void reset() {
        mFloatingToolbar.dismiss();
        mFloatingToolbarVisibilityHelper.deactivate();
        mOriginatingView.removeCallbacks(mMovingOff);
        mOriginatingView.removeCallbacks(mHideOff);
    }

    private boolean isViewStillActive() {
        return mOriginatingView.getWindowVisibility() == View.VISIBLE
                && mOriginatingView.isShown();
    }

    
A helper for showing/hiding the floating toolbar depending on certain states.
/**
     * A helper for showing/hiding the floating toolbar depending on certain states.
     */
    private static final class FloatingToolbarVisibilityHelper {

        private static final long MIN_SHOW_DURATION_FOR_MOVE_HIDE = 500;

        private final FloatingToolbar mToolbar;

        private boolean mHideRequested;
        private boolean mMoving;
        private boolean mOutOfBounds;
        private boolean mWindowFocused = true;

        private boolean mActive;

        private long mLastShowTime;

        public FloatingToolbarVisibilityHelper(FloatingToolbar toolbar) {
            mToolbar = Preconditions.checkNotNull(toolbar);
        }

        public void activate() {
            mHideRequested = false;
            mMoving = false;
            mOutOfBounds = false;
            mWindowFocused = true;

            mActive = true;
        }

        public void deactivate() {
            mActive = false;
            mToolbar.dismiss();
        }

        public void setHideRequested(boolean hide) {
            mHideRequested = hide;
        }

        public void setMoving(boolean moving) {
            // Avoid unintended flickering by allowing the toolbar to show long enough before
            // triggering the 'moving' flag - which signals a hide.
            final boolean showingLongEnough =
                System.currentTimeMillis() - mLastShowTime > MIN_SHOW_DURATION_FOR_MOVE_HIDE;
            if (!moving || showingLongEnough) {
                mMoving = moving;
            }
        }

        public void setOutOfBounds(boolean outOfBounds) {
            mOutOfBounds = outOfBounds;
        }

        public void setWindowFocused(boolean windowFocused) {
            mWindowFocused = windowFocused;
        }

        public void updateToolbarVisibility() {
            if (!mActive) {
                return;
            }

            if (mHideRequested || mMoving || mOutOfBounds || !mWindowFocused) {
                mToolbar.hide();
            } else {
                mToolbar.show();
                mLastShowTime = System.currentTimeMillis();
            }
        }
    }
}