/*
 * Copyright (C) 2019 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.systemui.assist;

import android.content.Context;

import androidx.annotation.Nullable;

import com.android.systemui.Dependency;
import com.android.systemui.assist.AssistHandleBehaviorController.BehaviorController;
import com.android.systemui.plugins.statusbar.StatusBarStateController;
import com.android.systemui.recents.OverviewProxyService;
import com.android.systemui.shared.system.QuickStepContract;

import java.io.PrintWriter;

/**
 * Assistant Handle behavior that makes Assistant handles show/hide when the home handle is
 * shown/hidden, respectively.
 */
final class AssistHandleLikeHomeBehavior implements BehaviorController {

    private final StatusBarStateController.StateListener mStatusBarStateListener =
            new StatusBarStateController.StateListener() {
                @Override
                public void onDozingChanged(boolean isDozing) {
                    handleDozingChanged(isDozing);
                }
            };
    private final OverviewProxyService.OverviewProxyListener mOverviewProxyListener =
            new OverviewProxyService.OverviewProxyListener() {
        @Override
        public void onSystemUiStateChanged(int sysuiStateFlags) {
            handleSystemUiStateChange(sysuiStateFlags);
        }
    };
    private final StatusBarStateController mStatusBarStateController;
    private final OverviewProxyService mOverviewProxyService;

    private boolean mIsDozing;
    private boolean mIsHomeHandleHiding;

    @Nullable private AssistHandleCallbacks mAssistHandleCallbacks;

    AssistHandleLikeHomeBehavior() {
        mStatusBarStateController = Dependency.get(StatusBarStateController.class);
        mOverviewProxyService = Dependency.get(OverviewProxyService.class);
    }

    @Override
    public void onModeActivated(Context context, AssistHandleCallbacks callbacks) {
        mAssistHandleCallbacks = callbacks;
        mIsDozing = mStatusBarStateController.isDozing();
        mStatusBarStateController.addCallback(mStatusBarStateListener);
        mOverviewProxyService.addCallback(mOverviewProxyListener);
        callbackForCurrentState();
    }

    @Override
    public void onModeDeactivated() {
        mAssistHandleCallbacks = null;
        mOverviewProxyService.removeCallback(mOverviewProxyListener);
    }

    private static boolean isHomeHandleHiding(int sysuiStateFlags) {
        return (sysuiStateFlags & QuickStepContract.SYSUI_STATE_NAV_BAR_HIDDEN) != 0;
    }

    private void handleDozingChanged(boolean isDozing) {
        if (mIsDozing == isDozing) {
            return;
        }

        mIsDozing = isDozing;
        callbackForCurrentState();
    }

    private void handleSystemUiStateChange(int sysuiStateFlags) {
        boolean isHomeHandleHiding = isHomeHandleHiding(sysuiStateFlags);
        if (mIsHomeHandleHiding == isHomeHandleHiding) {
            return;
        }

        mIsHomeHandleHiding = isHomeHandleHiding;
        callbackForCurrentState();
    }

    private void callbackForCurrentState() {
        if (mAssistHandleCallbacks == null) {
            return;
        }

        if (mIsHomeHandleHiding || mIsDozing) {
            mAssistHandleCallbacks.hide();
        } else {
            mAssistHandleCallbacks.showAndStay();
        }
    }

    @Override
    public void dump(PrintWriter pw, String prefix) {
        pw.println("Current AssistHandleLikeHomeBehavior State:");

        pw.println(prefix + "   mIsDozing=" + mIsDozing);
        pw.println(prefix + "   mIsHomeHandleHiding=" + mIsHomeHandleHiding);
    }
}