/*
 * Copyright (C) 2018 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.quickstep.inputconsumers;

import static android.view.MotionEvent.ACTION_CANCEL;
import static android.view.MotionEvent.ACTION_DOWN;
import static android.view.MotionEvent.ACTION_MOVE;
import static android.view.MotionEvent.ACTION_POINTER_DOWN;
import static android.view.MotionEvent.ACTION_POINTER_UP;
import static android.view.MotionEvent.ACTION_UP;
import static android.view.MotionEvent.INVALID_POINTER_ID;

import static com.android.launcher3.PagedView.ACTION_MOVE_ALLOW_EASY_FLING;
import static com.android.launcher3.PagedView.DEBUG_FAILED_QUICKSWITCH;
import static com.android.launcher3.Utilities.EDGE_NAV_BAR;
import static com.android.launcher3.Utilities.squaredHypot;
import static com.android.launcher3.util.Executors.MAIN_EXECUTOR;
import static com.android.launcher3.util.VelocityUtils.PX_PER_MS;
import static com.android.quickstep.util.ActiveGestureLog.INTENT_EXTRA_LOG_TRACE_ID;

import android.content.Context;
import android.content.ContextWrapper;
import android.content.Intent;
import android.graphics.PointF;
import android.util.Log;
import android.view.MotionEvent;
import android.view.VelocityTracker;

import androidx.annotation.UiThread;

import com.android.launcher3.R;
import com.android.launcher3.Utilities;
import com.android.launcher3.testing.TestLogging;
import com.android.launcher3.testing.shared.TestProtocol;
import com.android.launcher3.util.Preconditions;
import com.android.launcher3.util.TraceHelper;
import com.android.quickstep.AbsSwipeUpHandler;
import com.android.quickstep.AbsSwipeUpHandler.Factory;
import com.android.quickstep.GestureState;
import com.android.quickstep.InputConsumer;
import com.android.quickstep.RecentsAnimationCallbacks;
import com.android.quickstep.RecentsAnimationController;
import com.android.quickstep.RecentsAnimationDeviceState;
import com.android.quickstep.RecentsAnimationTargets;
import com.android.quickstep.RotationTouchHelper;
import com.android.quickstep.TaskAnimationManager;
import com.android.quickstep.util.CachedEventDispatcher;
import com.android.quickstep.util.MotionPauseDetector;
import com.android.quickstep.util.NavBarPosition;
import com.android.systemui.shared.system.InputChannelCompat.InputEventReceiver;
import com.android.systemui.shared.system.InputMonitorCompat;

import java.util.function.Consumer;

/**
 * Input consumer for handling events originating from an activity other than Launcher
 */
public class OtherActivityInputConsumer extends ContextWrapper implements InputConsumer {

    public static final String DOWN_EVT = "OtherActivityInputConsumer.DOWN";
    private static final String UP_EVT = "OtherActivityInputConsumer.UP";

    // Minimum angle of a gesture's coordinate where a release goes to overview.
    public static final int OVERVIEW_MIN_DEGREES = 15;

    private final RecentsAnimationDeviceState mDeviceState;
    private final NavBarPosition mNavBarPosition;
    private final TaskAnimationManager mTaskAnimationManager;
    private final GestureState mGestureState;
    private final RotationTouchHelper mRotationTouchHelper;
    private RecentsAnimationCallbacks mActiveCallbacks;
    private final CachedEventDispatcher mRecentsViewDispatcher = new CachedEventDispatcher();
    private final InputMonitorCompat mInputMonitorCompat;
    private final InputEventReceiver mInputEventReceiver;
    private final AbsSwipeUpHandler.Factory mHandlerFactory;

    private final Consumer<OtherActivityInputConsumer> mOnCompleteCallback;
    private final MotionPauseDetector mMotionPauseDetector;
    private final float mMotionPauseMinDisplacement;

    private VelocityTracker mVelocityTracker;

    private AbsSwipeUpHandler mInteractionHandler;
    private final FinishImmediatelyHandler mCleanupHandler = new FinishImmediatelyHandler();

    private final boolean mIsDeferredDownTarget;
    private final PointF mDownPos = new PointF();
    private final PointF mLastPos = new PointF();
    private int mActivePointerId = INVALID_POINTER_ID;

    // Distance after which we start dragging the window.
    private final float mTouchSlop;

    private final float mSquaredTouchSlop;
    private final boolean mDisableHorizontalSwipe;

    // Slop used to check when we start moving window.
    private boolean mPassedWindowMoveSlop;
    // Slop used to determine when we say that the gesture has started.
    private boolean mPassedPilferInputSlop;
    // Same as mPassedPilferInputSlop, except when continuing a gesture mPassedPilferInputSlop is
    // initially true while this one is false.
    private boolean mPassedSlopOnThisGesture;

    // Might be displacement in X or Y, depending on the direction we are swiping from the nav bar.
    private float mStartDisplacement;

    // The callback called upon finishing the recents transition if it was force-canceled
    private Runnable mForceFinishRecentsTransitionCallback;

    public OtherActivityInputConsumer(Context base, RecentsAnimationDeviceState deviceState,
            TaskAnimationManager taskAnimationManager, GestureState gestureState,
            boolean isDeferredDownTarget, Consumer<OtherActivityInputConsumer> onCompleteCallback,
            InputMonitorCompat inputMonitorCompat, InputEventReceiver inputEventReceiver,
            boolean disableHorizontalSwipe, Factory handlerFactory) {
        super(base);
        mDeviceState = deviceState;
        mNavBarPosition = mDeviceState.getNavBarPosition();
        mTaskAnimationManager = taskAnimationManager;
        mGestureState = gestureState;
        mHandlerFactory = handlerFactory;

        mMotionPauseDetector = new MotionPauseDetector(base, false,
                mNavBarPosition.isLeftEdge() || mNavBarPosition.isRightEdge()
                        ? MotionEvent.AXIS_X : MotionEvent.AXIS_Y);
        mMotionPauseMinDisplacement = base.getResources().getDimension(
                R.dimen.motion_pause_detector_min_displacement_from_app);
        mOnCompleteCallback = onCompleteCallback;
        mVelocityTracker = VelocityTracker.obtain();
        mInputMonitorCompat = inputMonitorCompat;
        mInputEventReceiver = inputEventReceiver;

        boolean continuingPreviousGesture = mTaskAnimationManager.isRecentsAnimationRunning();
        mIsDeferredDownTarget = !continuingPreviousGesture && isDeferredDownTarget;

        mTouchSlop = mDeviceState.getTouchSlop();
        mSquaredTouchSlop = mDeviceState.getSquaredTouchSlop();

        mPassedPilferInputSlop = mPassedWindowMoveSlop = continuingPreviousGesture;
        mStartDisplacement = continuingPreviousGesture ? 0 : -mTouchSlop;
        mDisableHorizontalSwipe = !mPassedPilferInputSlop && disableHorizontalSwipe;
        mRotationTouchHelper = mDeviceState.getRotationTouchHelper();
    }

    @Override
    public int getType() {
        return TYPE_OTHER_ACTIVITY;
    }

    @Override
    public boolean isConsumerDetachedFromGesture() {
        return true;
    }

    private void forceCancelGesture(MotionEvent ev) {
        int action = ev.getAction();
        ev.setAction(ACTION_CANCEL);
        finishTouchTracking(ev);
        ev.setAction(action);
    }

    @Override
    public void onMotionEvent(MotionEvent ev) {
        if (mVelocityTracker == null) {
            return;
        }

        // Proxy events to recents view
        if (mPassedWindowMoveSlop && mInteractionHandler != null
                && !mRecentsViewDispatcher.hasConsumer()) {
            mRecentsViewDispatcher.setConsumer(mInteractionHandler
                    .getRecentsViewDispatcher(mNavBarPosition.getRotation()));
            int action = ev.getAction();
            ev.setAction(ACTION_MOVE_ALLOW_EASY_FLING);
            mRecentsViewDispatcher.dispatchEvent(ev);
            ev.setAction(action);
        }
        int edgeFlags = ev.getEdgeFlags();
        ev.setEdgeFlags(edgeFlags | EDGE_NAV_BAR);

        if (mGestureState.isTrackpadGesture()) {
            // Disable scrolling in RecentsView for 3-finger trackpad gesture. We don't know if a
            // trackpad motion event is 3-finger or 4-finger with the U API until ACTION_MOVE (we
            // skip ACTION_POINTER_UP events in TouchInteractionService), so in order to make sure
            // that RecentsView always get a closed sequence of motion events and yet disable
            // 3-finger scroll, we do the following (1) always dispatch ACTION_DOWN and ACTION_UP
            // trackpad multi-finger motion events. (2) only dispatch 4-finger ACTION_MOVE motion
            // events.
            switch (ev.getActionMasked()) {
                case ACTION_MOVE -> {
                    if (mGestureState.isFourFingerTrackpadGesture()) {
                        mRecentsViewDispatcher.dispatchEvent(ev);
                    }
                }
                default -> mRecentsViewDispatcher.dispatchEvent(ev);
            }
        } else {
            mRecentsViewDispatcher.dispatchEvent(ev);
        }
        ev.setEdgeFlags(edgeFlags);

        mVelocityTracker.addMovement(ev);
        if (ev.getActionMasked() == ACTION_POINTER_UP) {
            mVelocityTracker.clear();
            mMotionPauseDetector.clear();
        }

        switch (ev.getActionMasked()) {
            case ACTION_DOWN: {
                // Until we detect the gesture, handle events as we receive them
                mInputEventReceiver.setBatchingEnabled(false);

                TraceHelper.INSTANCE.beginSection(DOWN_EVT);
                mActivePointerId = ev.getPointerId(0);
                mDownPos.set(ev.getX(), ev.getY());
                mLastPos.set(mDownPos);

                // Start the window animation on down to give more time for launcher to draw if the
                // user didn't start the gesture over the back button
                if (!mIsDeferredDownTarget) {
                    startTouchTrackingForWindowAnimation(ev.getEventTime());
                }

                TraceHelper.INSTANCE.endSection();
                break;
            }
            case ACTION_POINTER_DOWN: {
                if (!mPassedPilferInputSlop) {
                    // Cancel interaction in case of multi-touch interaction
                    int ptrIdx = ev.getActionIndex();
                    if (!mRotationTouchHelper.isInSwipeUpTouchRegion(ev, ptrIdx)) {
                        forceCancelGesture(ev);
                    }
                }
                break;
            }
            case ACTION_POINTER_UP: {
                int ptrIdx = ev.getActionIndex();
                int ptrId = ev.getPointerId(ptrIdx);
                if (ptrId == mActivePointerId) {
                    final int newPointerIdx = ptrIdx == 0 ? 1 : 0;
                    mDownPos.set(
                            ev.getX(newPointerIdx) - (mLastPos.x - mDownPos.x),
                            ev.getY(newPointerIdx) - (mLastPos.y - mDownPos.y));
                    mLastPos.set(ev.getX(newPointerIdx), ev.getY(newPointerIdx));
                    mActivePointerId = ev.getPointerId(newPointerIdx);
                }
                break;
            }
            case ACTION_MOVE: {
                int pointerIndex = ev.findPointerIndex(mActivePointerId);
                if (pointerIndex == INVALID_POINTER_ID) {
                    break;
                }
                mLastPos.set(ev.getX(pointerIndex), ev.getY(pointerIndex));
                float displacement = getDisplacement(ev);
                float displacementX = mLastPos.x - mDownPos.x;
                float displacementY = mLastPos.y - mDownPos.y;

                if (!mPassedWindowMoveSlop) {
                    if (!mIsDeferredDownTarget) {
                        // Normal gesture, ensure we pass the drag slop before we start tracking
                        // the gesture
                        if (mGestureState.isTrackpadGesture() || Math.abs(displacement)
                                > mTouchSlop) {
                            mPassedWindowMoveSlop = true;
                            mStartDisplacement = -mTouchSlop;
                        }
                    }
                }

                float horizontalDist = Math.abs(displacementX);
                float upDist = -displacement;
                boolean passedSlop = mGestureState.isTrackpadGesture()
                        || (squaredHypot(displacementX, displacementY) >= mSquaredTouchSlop
                            && !mGestureState.isInExtendedSlopRegion());

                if (!mPassedSlopOnThisGesture && passedSlop) {
                    mPassedSlopOnThisGesture = true;
                }
                // Until passing slop, we don't know what direction we're going, so assume
                // we're quick switching to avoid translating recents away when continuing
                // the gesture (in which case mPassedPilferInputSlop starts as true).
                boolean haveNotPassedSlopOnContinuedGesture =
                        !mPassedSlopOnThisGesture && mPassedPilferInputSlop;
                double degrees = Math.toDegrees(Math.atan(upDist / horizontalDist));

                // Regarding degrees >= -OVERVIEW_MIN_DEGREES - Trackpad gestures can start anywhere
                // on the screen, allowing downward swipes. We want to impose the same angle in that
                // scenario.
                boolean swipeWithinQuickSwitchRange = degrees <= OVERVIEW_MIN_DEGREES
                        && (!mGestureState.isTrackpadGesture() || degrees >= -OVERVIEW_MIN_DEGREES);
                boolean isLikelyToStartNewTask =
                        haveNotPassedSlopOnContinuedGesture || swipeWithinQuickSwitchRange;

                if (!mPassedPilferInputSlop) {
                    if (passedSlop) {
                        // Horizontal gesture is not allowed in this region
                        boolean isHorizontalSwipeWhenDisabled =
                                (mDisableHorizontalSwipe && Math.abs(displacementX) > Math.abs(
                                        displacementY));
                        // Do not allow quick switch for trackpad 3-finger gestures
                        // TODO(b/261815244): might need to impose stronger conditions for the swipe
                        //  angle
                        boolean noQuickSwitchForThreeFingerGesture = isLikelyToStartNewTask
                                && mGestureState.isThreeFingerTrackpadGesture();
                        boolean noQuickstepForFourFingerGesture = !isLikelyToStartNewTask
                                && mGestureState.isFourFingerTrackpadGesture();
                        if (isHorizontalSwipeWhenDisabled || noQuickSwitchForThreeFingerGesture
                                || noQuickstepForFourFingerGesture) {
                            forceCancelGesture(ev);
                            break;
                        }

                        mPassedPilferInputSlop = true;

                        if (mIsDeferredDownTarget) {
                            // Deferred gesture, start the animation and gesture tracking once
                            // we pass the actual touch slop
                            startTouchTrackingForWindowAnimation(ev.getEventTime());
                        }
                        if (!mPassedWindowMoveSlop) {
                            mPassedWindowMoveSlop = true;
                            mStartDisplacement = -mTouchSlop;
                        }
                        notifyGestureStarted(isLikelyToStartNewTask);
                    }
                }

                if (mInteractionHandler != null) {
                    if (mPassedWindowMoveSlop) {
                        // Move
                        mInteractionHandler.updateDisplacement(displacement - mStartDisplacement);
                    }

                    if (mDeviceState.isFullyGesturalNavMode()
                            || mGestureState.isTrackpadGesture()) {
                        boolean minSwipeMet = upDist >= Math.max(mMotionPauseMinDisplacement,
                                mInteractionHandler.getThresholdToAllowMotionPause());
                        mInteractionHandler.setCanSlowSwipeGoHome(minSwipeMet);
                        mMotionPauseDetector.setDisallowPause(!minSwipeMet
                                || isLikelyToStartNewTask);
                        mMotionPauseDetector.addPosition(ev);
                        mInteractionHandler.setIsLikelyToStartNewTask(isLikelyToStartNewTask);
                    }
                }
                break;
            }
            case ACTION_CANCEL:
            case ACTION_UP: {
                if (DEBUG_FAILED_QUICKSWITCH && !mPassedWindowMoveSlop) {
                    float displacementX = mLastPos.x - mDownPos.x;
                    float displacementY = mLastPos.y - mDownPos.y;
                    Log.d("Quickswitch", "mPassedWindowMoveSlop=false"
                            + " disp=" + squaredHypot(displacementX, displacementY)
                            + " slop=" + mSquaredTouchSlop);
                }
                finishTouchTracking(ev);
                break;
            }
        }
    }

    private void notifyGestureStarted(boolean isLikelyToStartNewTask) {
        if (mInteractionHandler == null) {
            return;
        }
        TestLogging.recordEvent(TestProtocol.SEQUENCE_PILFER, "pilferPointers");
        mInputMonitorCompat.pilferPointers();
        // Once we detect the gesture, we can enable batching to reduce further updates
        mInputEventReceiver.setBatchingEnabled(true);

        // Notify the handler that the gesture has actually started
        mInteractionHandler.onGestureStarted(isLikelyToStartNewTask);
    }

    private void startTouchTrackingForWindowAnimation(long touchTimeMs) {
        mInteractionHandler = mHandlerFactory.newHandler(mGestureState, touchTimeMs);
        mInteractionHandler.setGestureEndCallback(this::onInteractionGestureFinished);
        mMotionPauseDetector.setOnMotionPauseListener(mInteractionHandler.getMotionPauseListener());
        mInteractionHandler.initWhenReady(
                "OtherActivityInputConsumer.startTouchTrackingForWindowAnimation");

        if (mTaskAnimationManager.isRecentsAnimationRunning()) {
            mActiveCallbacks = mTaskAnimationManager.continueRecentsAnimation(mGestureState);
            mActiveCallbacks.removeListener(mCleanupHandler);
            mActiveCallbacks.addListener(mInteractionHandler);
            mTaskAnimationManager.notifyRecentsAnimationState(mInteractionHandler);
            notifyGestureStarted(true /*isLikelyToStartNewTask*/);
        } else {
            Intent intent = new Intent(mInteractionHandler.getLaunchIntent());
            intent.putExtra(INTENT_EXTRA_LOG_TRACE_ID, mGestureState.getGestureId());
            mActiveCallbacks = mTaskAnimationManager.startRecentsAnimation(mGestureState, intent,
                    mInteractionHandler);
        }
    }

    /**
     * Returns whether this input consumer has started touch tracking (if touch tracking is not
     * deferred).
     */
    public boolean hasStartedTouchTracking() {
        return mInteractionHandler != null;
    }

    /**
     * Called when the gesture has ended. Does not correlate to the completion of the interaction as
     * the animation can still be running.
     */
    private void finishTouchTracking(MotionEvent ev) {
        TraceHelper.INSTANCE.beginSection(UP_EVT);

        boolean isCanceled = ev.getActionMasked() == ACTION_CANCEL;
        if (mPassedWindowMoveSlop && mInteractionHandler != null) {
            if (isCanceled) {
                mInteractionHandler.onGestureCancelled();
            } else {
                mVelocityTracker.computeCurrentVelocity(PX_PER_MS);
                float velocityXPxPerMs = mVelocityTracker.getXVelocity(mActivePointerId);
                float velocityYPxPerMs = mVelocityTracker.getYVelocity(mActivePointerId);
                float velocityPxPerMs = mNavBarPosition.isRightEdge()
                        ? velocityXPxPerMs
                        : mNavBarPosition.isLeftEdge()
                                ? -velocityXPxPerMs
                                : velocityYPxPerMs;
                mInteractionHandler.updateDisplacement(getDisplacement(ev) - mStartDisplacement);
                mInteractionHandler.onGestureEnded(velocityPxPerMs,
                        new PointF(velocityXPxPerMs, velocityYPxPerMs));
            }
        } else {
            // Since we start touch tracking on DOWN, we may reach this state without actually
            // starting the gesture. In that case, we need to clean-up an unfinished or un-started
            // animation.
            if (mActiveCallbacks != null && mInteractionHandler != null) {
                if (mTaskAnimationManager.isRecentsAnimationRunning()) {
                    // The animation started, but with no movement, in this case, there will be no
                    // animateToProgress so we have to manually finish here. In the case of
                    // ACTION_CANCEL, someone else may be doing something so finish synchronously.
                    mTaskAnimationManager.finishRunningRecentsAnimation(false /* toHome */,
                            isCanceled /* forceFinish */, mForceFinishRecentsTransitionCallback);
                } else {
                    // The animation hasn't started yet, so insert a replacement handler into the
                    // callbacks which immediately finishes the animation after it starts.
                    mActiveCallbacks.addListener(mCleanupHandler);
                }
            }
            onConsumerAboutToBeSwitched();
            onInteractionGestureFinished();
        }
        cleanupAfterGesture();
        TraceHelper.INSTANCE.endSection();
    }

    private void cleanupAfterGesture() {
        if (mVelocityTracker != null) {
            mVelocityTracker.recycle();
            mVelocityTracker = null;
        }
        mMotionPauseDetector.clear();
    }

    @Override
    public void notifyOrientationSetup() {
        mRotationTouchHelper.onStartGesture();
    }

    @Override
    public void onConsumerAboutToBeSwitched() {
        Preconditions.assertUIThread();
        if (mInteractionHandler != null) {
            // The consumer is being switched while we are active. Set up the shared state to be
            // used by the next animation
            removeListener();
            mInteractionHandler.onConsumerAboutToBeSwitched();
        }
    }

    @UiThread
    private void onInteractionGestureFinished() {
        Preconditions.assertUIThread();
        removeListener();
        mInteractionHandler = null;
        cleanupAfterGesture();
        mOnCompleteCallback.accept(this);
    }

    private void removeListener() {
        if (mActiveCallbacks != null && mInteractionHandler != null) {
            mActiveCallbacks.removeListener(mInteractionHandler);
        }
    }

    private float getDisplacement(MotionEvent ev) {
        if (mNavBarPosition.isRightEdge()) {
            return ev.getX() - mDownPos.x;
        } else if (mNavBarPosition.isLeftEdge()) {
            return mDownPos.x - ev.getX();
        } else {
            return ev.getY() - mDownPos.y;
        }
    }

    @Override
    public boolean allowInterceptByParent() {
        return !mPassedPilferInputSlop;
    }

    /**
     * Sets a callback to be called when the recents transition is force-canceled by another input
     * consumer being made active.
     */
    public void setForceFinishRecentsTransitionCallback(Runnable r) {
        mForceFinishRecentsTransitionCallback = r;
    }

    /**
     * A listener which just finishes the animation immediately after starting. Replaces
     * AbsSwipeUpHandler if the gesture itself finishes before the animation even starts.
     */
    private static class FinishImmediatelyHandler
            implements RecentsAnimationCallbacks.RecentsAnimationListener {

        public void onRecentsAnimationStart(RecentsAnimationController controller,
                RecentsAnimationTargets targets) {
            Utilities.postAsyncCallback(MAIN_EXECUTOR.getHandler(), () -> {
                controller.finish(false /* toRecents */, null);
            });
        }
    }
}