Create bubbles DropTargetManager

/*

 * Copyright (C) 2025 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.wm.shell.shared.bubbles

/**

 * Manages animating drop targets in response to dragging bubble icons or bubble expanded views

 * across different drag zones.

 */

class DropTargetManager(

    private val isLayoutRtl: Boolean,

    private val dragZoneChangedListener: DragZoneChangedListener

) {

    private var state: DragState? = null

    /** Must be called when a drag gesture is starting. */

    fun onDragStarted(draggedObject: DraggedObject, dragZones: List<DragZone>) {

        val state = DragState(dragZones, draggedObject)

        dragZoneChangedListener.onInitialDragZoneSet(state.initialDragZone)

        this.state = state

    }

    /** Called when the user drags to a new location. */

    fun onDragUpdated(x: Int, y: Int) {

        val state = state ?: return

        val oldDragZone = state.currentDragZone

        val newDragZone = state.getMatchingDragZone(x = x, y = y)

        state.currentDragZone = newDragZone

        if (oldDragZone != newDragZone) {

            dragZoneChangedListener.onDragZoneChanged(from = oldDragZone, to = newDragZone)

        }

    }

    /** Called when the drag ended. */

    fun onDragEnded() {

        state = null

    }

    /** Stores the current drag state. */

    private inner class DragState(

        private val dragZones: List<DragZone>,

        draggedObject: DraggedObject

    ) {

        val initialDragZone =

            if (draggedObject.initialLocation.isOnLeft(isLayoutRtl)) {

                dragZones.filterIsInstance<DragZone.Bubble.Left>().first()

            } else {

                dragZones.filterIsInstance<DragZone.Bubble.Right>().first()

            }

        var currentDragZone: DragZone = initialDragZone

        fun getMatchingDragZone(x: Int, y: Int): DragZone {

            return dragZones.firstOrNull { it.contains(x, y) } ?: currentDragZone

        }

    }

    /** An interface to be notified when drag zones change. */

    interface DragZoneChangedListener {

        /** An initial drag zone was set. Called when a drag starts. */

        fun onInitialDragZoneSet(dragZone: DragZone)

        /** Called when the object was dragged to a different drag zone. */

        fun onDragZoneChanged(from: DragZone, to: DragZone)

    }

}

/*

 * Copyright (C) 2025 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.wm.shell.shared.bubbles

import android.graphics.Rect

import androidx.test.ext.junit.runners.AndroidJUnit4

import androidx.test.filters.SmallTest

import com.google.common.truth.Truth.assertThat

import org.junit.Before

import org.junit.Test

import org.junit.runner.RunWith

import kotlin.test.assertFails

/** Unit tests for [DropTargetManager]. */

@SmallTest

@RunWith(AndroidJUnit4::class)

class DropTargetManagerTest {

    private lateinit var dropTargetManager: DropTargetManager

    private lateinit var dragZoneChangedListener: FakeDragZoneChangedListener

    private val dropTarget = Rect(0, 0, 0, 0)

    // create 3 drop zones that are horizontally next to each other

    // -------------------------------------------------

    // |               |               |               |

    // |    bubble     |               |    bubble     |

    // |               |    dismiss    |               |

    // |     left      |               |     right     |

    // |               |               |               |

    // -------------------------------------------------

    private val bubbleLeftDragZone =

        DragZone.Bubble.Left(bounds = Rect(0, 0, 100, 100), dropTarget = dropTarget)

    private val dismissDragZone = DragZone.Dismiss(bounds = Rect(100, 0, 200, 100))

    private val bubbleRightDragZone =

        DragZone.Bubble.Right(bounds = Rect(200, 0, 300, 100), dropTarget = dropTarget)

    @Before

    fun setUp() {

        dragZoneChangedListener = FakeDragZoneChangedListener()

        dropTargetManager = DropTargetManager(isLayoutRtl = false, dragZoneChangedListener)

    }

    @Test

    fun onDragStarted_notifiesInitialDragZone() {

        dropTargetManager.onDragStarted(

            DraggedObject.Bubble(BubbleBarLocation.LEFT),

            listOf(bubbleLeftDragZone, bubbleRightDragZone)

        )

        assertThat(dragZoneChangedListener.initialDragZone).isEqualTo(bubbleLeftDragZone)

    }

    @Test

    fun onDragStarted_missingExpectedDragZone_fails() {

        assertFails {

            dropTargetManager.onDragStarted(

                DraggedObject.Bubble(BubbleBarLocation.RIGHT),

                listOf(bubbleLeftDragZone)

            )

        }

    }

    @Test

    fun onDragUpdated_notifiesDragZoneChanged() {

        dropTargetManager.onDragStarted(

            DraggedObject.Bubble(BubbleBarLocation.LEFT),

            listOf(bubbleLeftDragZone, bubbleRightDragZone, dismissDragZone)

        )

        dropTargetManager.onDragUpdated(

            bubbleRightDragZone.bounds.centerX(),

            bubbleRightDragZone.bounds.centerY()

        )

        assertThat(dragZoneChangedListener.fromDragZone).isEqualTo(bubbleLeftDragZone)

        assertThat(dragZoneChangedListener.toDragZone).isEqualTo(bubbleRightDragZone)

        dropTargetManager.onDragUpdated(

            dismissDragZone.bounds.centerX(),

            dismissDragZone.bounds.centerY()

        )

        assertThat(dragZoneChangedListener.fromDragZone).isEqualTo(bubbleRightDragZone)

        assertThat(dragZoneChangedListener.toDragZone).isEqualTo(dismissDragZone)

    }

    @Test

    fun onDragUpdated_withinSameZone_doesNotNotify() {

        dropTargetManager.onDragStarted(

            DraggedObject.Bubble(BubbleBarLocation.LEFT),

            listOf(bubbleLeftDragZone, bubbleRightDragZone, dismissDragZone)

        )

        dropTargetManager.onDragUpdated(

            bubbleLeftDragZone.bounds.centerX(),

            bubbleLeftDragZone.bounds.centerY()

        )

        assertThat(dragZoneChangedListener.fromDragZone).isNull()

        assertThat(dragZoneChangedListener.toDragZone).isNull()

    }

    @Test

    fun onDragUpdated_outsideAllZones_doesNotNotify() {

        dropTargetManager.onDragStarted(

            DraggedObject.Bubble(BubbleBarLocation.LEFT),

            listOf(bubbleLeftDragZone, bubbleRightDragZone)

        )

        val pointX = 200

        val pointY = 200

        assertThat(bubbleLeftDragZone.contains(pointX, pointY)).isFalse()

        assertThat(bubbleRightDragZone.contains(pointX, pointY)).isFalse()

        dropTargetManager.onDragUpdated(pointX, pointY)

        assertThat(dragZoneChangedListener.fromDragZone).isNull()

        assertThat(dragZoneChangedListener.toDragZone).isNull()

    }

    @Test

    fun onDragUpdated_hasOverlappingZones_notifiesFirstDragZoneChanged() {

        // create a drag zone that spans across the width of all 3 drag zones, but extends below

        // them

        val splitDragZone = DragZone.Split.Left(bounds = Rect(0, 0, 300, 200))

        dropTargetManager.onDragStarted(

            DraggedObject.Bubble(BubbleBarLocation.LEFT),

            listOf(bubbleLeftDragZone, bubbleRightDragZone, dismissDragZone, splitDragZone)

        )

        // drag to a point that is within both the bubble right zone and split zone

        val (pointX, pointY) =

            Pair(

                bubbleRightDragZone.bounds.centerX(),

                bubbleRightDragZone.bounds.centerY()

            )

        assertThat(splitDragZone.contains(pointX, pointY)).isTrue()

        dropTargetManager.onDragUpdated(pointX, pointY)

        // verify we dragged to the bubble right zone because that has higher priority than split

        assertThat(dragZoneChangedListener.fromDragZone).isEqualTo(bubbleLeftDragZone)

        assertThat(dragZoneChangedListener.toDragZone).isEqualTo(bubbleRightDragZone)

        dropTargetManager.onDragUpdated(

            bubbleRightDragZone.bounds.centerX(),

            150 // below the bubble and dismiss drag zones but within split

        )

        assertThat(dragZoneChangedListener.fromDragZone).isEqualTo(bubbleRightDragZone)

        assertThat(dragZoneChangedListener.toDragZone).isEqualTo(splitDragZone)

        val (dismissPointX, dismissPointY) =

            Pair(dismissDragZone.bounds.centerX(), dismissDragZone.bounds.centerY())

        assertThat(splitDragZone.contains(dismissPointX, dismissPointY)).isTrue()

        dropTargetManager.onDragUpdated(dismissPointX, dismissPointY)

        assertThat(dragZoneChangedListener.fromDragZone).isEqualTo(splitDragZone)

        assertThat(dragZoneChangedListener.toDragZone).isEqualTo(dismissDragZone)

    }

    @Test

    fun onDragUpdated_afterDragEnded_doesNotNotify() {

        dropTargetManager.onDragStarted(

            DraggedObject.Bubble(BubbleBarLocation.LEFT),

            listOf(bubbleLeftDragZone, bubbleRightDragZone, dismissDragZone)

        )

        dropTargetManager.onDragEnded()

        dropTargetManager.onDragUpdated(

            bubbleRightDragZone.bounds.centerX(),

            bubbleRightDragZone.bounds.centerY()

        )

        assertThat(dragZoneChangedListener.fromDragZone).isNull()

        assertThat(dragZoneChangedListener.toDragZone).isNull()

    }

    private class FakeDragZoneChangedListener : DropTargetManager.DragZoneChangedListener {

        var initialDragZone: DragZone? = null

        var fromDragZone: DragZone? = null

        var toDragZone: DragZone? = null

        override fun onInitialDragZoneSet(dragZone: DragZone) {

            initialDragZone = dragZone

        }

        override fun onDragZoneChanged(from: DragZone, to: DragZone) {

            fromDragZone = from

            toDragZone = to

        }

    }

}