/*
 * Copyright (C) 2022 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 androidx.window.extensions.embedding;

import static android.app.ActivityTaskManager.INVALID_TASK_ID;
import static android.app.WindowConfiguration.WINDOWING_MODE_MULTI_WINDOW;
import static android.app.WindowConfiguration.WINDOWING_MODE_PINNED;
import static android.app.WindowConfiguration.WINDOWING_MODE_UNDEFINED;

import android.app.Activity;
import android.app.WindowConfiguration;
import android.app.WindowConfiguration.WindowingMode;
import android.graphics.Rect;
import android.os.IBinder;
import android.util.ArraySet;
import android.window.TaskFragmentInfo;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

/** Represents TaskFragments and split pairs below a Task. */
class TaskContainer {

    /** The unique task id. */
    private final int mTaskId;

    /** Available window bounds of this Task. */
    private final Rect mTaskBounds = new Rect();

    /** Windowing mode of this Task. */
    @WindowingMode
    private int mWindowingMode = WINDOWING_MODE_UNDEFINED;

    /** Active TaskFragments in this Task. */
    @NonNull
    final List<TaskFragmentContainer> mContainers = new ArrayList<>();

    /** Active split pairs in this Task. */
    @NonNull
    final List<SplitContainer> mSplitContainers = new ArrayList<>();

    /**
     * TaskFragments that the organizer has requested to be closed. They should be removed when
     * the organizer receives {@link SplitController#onTaskFragmentVanished(TaskFragmentInfo)} event
     * for them.
     */
    final Set<IBinder> mFinishedContainer = new ArraySet<>();

    TaskContainer(int taskId) {
        if (taskId == INVALID_TASK_ID) {
            throw new IllegalArgumentException("Invalid Task id");
        }
        mTaskId = taskId;
    }

    int getTaskId() {
        return mTaskId;
    }

    @NonNull
    Rect getTaskBounds() {
        return mTaskBounds;
    }

    /** Returns {@code true} if the bounds is changed. */
    boolean setTaskBounds(@NonNull Rect taskBounds) {
        if (!taskBounds.isEmpty() && !mTaskBounds.equals(taskBounds)) {
            mTaskBounds.set(taskBounds);
            return true;
        }
        return false;
    }

    /** Whether the Task bounds has been initialized. */
    boolean isTaskBoundsInitialized() {
        return !mTaskBounds.isEmpty();
    }

    void setWindowingMode(int windowingMode) {
        mWindowingMode = windowingMode;
    }

    /** Whether the Task windowing mode has been initialized. */
    boolean isWindowingModeInitialized() {
        return mWindowingMode != WINDOWING_MODE_UNDEFINED;
    }

    /**
     * Returns the windowing mode for the TaskFragments below this Task, which should be split with
     * other TaskFragments.
     *
     * @param taskFragmentBounds    Requested bounds for the TaskFragment. It will be empty when
     *                              the pair of TaskFragments are stacked due to the limited space.
     */
    @WindowingMode
    int getWindowingModeForSplitTaskFragment(@Nullable Rect taskFragmentBounds) {
        // Only set to multi-windowing mode if the pair are showing side-by-side. Otherwise, it
        // will be set to UNDEFINED which will then inherit the Task windowing mode.
        if (taskFragmentBounds == null || taskFragmentBounds.isEmpty() || isInPictureInPicture()) {
            return WINDOWING_MODE_UNDEFINED;
        }
        // We use WINDOWING_MODE_MULTI_WINDOW when the Task is fullscreen.
        // However, when the Task is in other multi windowing mode, such as Freeform, we need to
        // have the activity windowing mode to match the Task, otherwise things like
        // DecorCaptionView won't work correctly. As a result, have the TaskFragment to be in the
        // Task windowing mode if the Task is in multi window.
        // TODO we won't need this anymore after we migrate Freeform caption to WM Shell.
        return WindowConfiguration.inMultiWindowMode(mWindowingMode)
                ? mWindowingMode
                : WINDOWING_MODE_MULTI_WINDOW;
    }

    boolean isInPictureInPicture() {
        return mWindowingMode == WINDOWING_MODE_PINNED;
    }

    /** Whether there is any {@link TaskFragmentContainer} below this Task. */
    boolean isEmpty() {
        return mContainers.isEmpty() && mFinishedContainer.isEmpty();
    }

    /** Called when the activity is destroyed. */
    void onActivityDestroyed(@NonNull Activity activity) {
        for (TaskFragmentContainer container : mContainers) {
            container.onActivityDestroyed(activity);
        }
    }

    /** Removes the pending appeared activity from all TaskFragments in this Task. */
    void cleanupPendingAppearedActivity(@NonNull Activity pendingAppearedActivity) {
        for (TaskFragmentContainer container : mContainers) {
            container.removePendingAppearedActivity(pendingAppearedActivity);
        }
    }

    @Nullable
    TaskFragmentContainer getTopTaskFragmentContainer() {
        if (mContainers.isEmpty()) {
            return null;
        }
        return mContainers.get(mContainers.size() - 1);
    }

    @Nullable
    Activity getTopNonFinishingActivity() {
        for (int i = mContainers.size() - 1; i >= 0; i--) {
            final Activity activity = mContainers.get(i).getTopNonFinishingActivity();
            if (activity != null) {
                return activity;
            }
        }
        return null;
    }

    int indexOf(@NonNull TaskFragmentContainer child) {
        return mContainers.indexOf(child);
    }
}