/*
 * Copyright (C) 2016 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 android.car.hardware;

import android.annotation.SystemApi;
import android.car.Car;
import android.car.CarManagerBase;
import android.car.CarNotConnectedException;
import android.car.hardware.property.CarPropertyManager;
import android.os.Handler;
import android.os.IBinder;
import android.util.ArraySet;

import com.android.internal.annotations.GuardedBy;

import java.lang.ref.WeakReference;
import java.util.Collection;
import java.util.List;

/**
 * API to access custom vehicle properties defined by OEMs.
 * <p>
 * System permission {@link Car#PERMISSION_VENDOR_EXTENSION} is required to get this manager.
 * </p>
 * @hide
 */
@SystemApi
public final class CarVendorExtensionManager implements CarManagerBase {

    private final static boolean DBG = false;
    private final static String TAG = CarVendorExtensionManager.class.getSimpleName();
    private final CarPropertyManager mPropertyManager;
    private CarPropertyEventListenerToBase mListenerToBase = null;

    @GuardedBy("mLock")
    private final ArraySet<CarVendorExtensionCallback> mCallbacks = new ArraySet<>();
    private final Object mLock = new Object();

    private static class CarPropertyEventListenerToBase implements
            CarPropertyManager.CarPropertyEventListener{
        private final WeakReference<CarVendorExtensionManager> mManager;

        CarPropertyEventListenerToBase(CarVendorExtensionManager manager) {
            mManager = new WeakReference<>(manager);
        }

        @Override
        public void onChangeEvent(CarPropertyValue value) {
            CarVendorExtensionManager manager = mManager.get();
            if (manager != null) {
                manager.handleOnChangeEvent(value);
            }
        }

        @Override
        public void onErrorEvent(int propertyId, int zone) {
            CarVendorExtensionManager manager = mManager.get();
            if (manager != null) {
                manager.handleOnErrorEvent(propertyId, zone);
            }
        }
    }

    private void handleOnChangeEvent(CarPropertyValue value) {
        Collection<CarVendorExtensionCallback> callbacks;
        synchronized (this) {
            callbacks = new ArraySet<>(mCallbacks);
        }
        for (CarVendorExtensionCallback l: callbacks) {
            l.onChangeEvent(value);
        }
    }

    private void handleOnErrorEvent(int propertyId, int zone) {
        Collection<CarVendorExtensionCallback> listeners;
        synchronized (this) {
            listeners = new ArraySet<>(mCallbacks);
        }
        if (!listeners.isEmpty()) {
            for (CarVendorExtensionCallback l: listeners) {
                l.onErrorEvent(propertyId, zone);
            }
        }
    }

    /**
     * Creates an instance of the {@link CarVendorExtensionManager}.
     *
     * <p>Should not be obtained directly by clients, use {@link Car#getCarManager(String)} instead.
     * @hide
     */
    public CarVendorExtensionManager(IBinder service, Handler handler) {
        mPropertyManager = new CarPropertyManager(service, handler, DBG, TAG);
    }

    /**
     * Contains callback functions that will be called when some event happens with vehicle
     * property.
     */
    public interface CarVendorExtensionCallback {
        /** Called when a property is updated */
        void onChangeEvent(CarPropertyValue value);

        /** Called when an error is detected with a property */
        void onErrorEvent(int propertyId, int zone);
    }

    /**
     * Registers listener. The methods of the listener will be called when new events arrived in
     * the main thread.
     */
    public void registerCallback(CarVendorExtensionCallback callback)
            throws CarNotConnectedException {
        synchronized (mLock) {
            if (mCallbacks.isEmpty()) {
                mListenerToBase = new CarPropertyEventListenerToBase(this);
            }

            List<CarPropertyConfig> configs = mPropertyManager.getPropertyList();
            for (CarPropertyConfig c : configs) {
                // Register each individual propertyId
                mPropertyManager.registerListener(mListenerToBase, c.getPropertyId(), 0);
            }
            mCallbacks.add(callback);
        }
    }

    /** Unregisters listener that was previously registered. */
    public void unregisterCallback(CarVendorExtensionCallback callback)
            throws CarNotConnectedException {
        synchronized (mLock) {
            mCallbacks.remove(callback);
            List<CarPropertyConfig> configs = mPropertyManager.getPropertyList();
            for (CarPropertyConfig c : configs) {
                // Register each individual propertyId
                mPropertyManager.unregisterListener(mListenerToBase, c.getPropertyId());
            }
            if (mCallbacks.isEmpty()) {
                mListenerToBase = null;
            }
        }
    }

    /** Get list of properties represented by CarVendorExtensionManager for this car. */
    public List<CarPropertyConfig> getProperties() throws CarNotConnectedException {
        return mPropertyManager.getPropertyList();
    }

    /**
     * Check whether a given property is available or disabled based on the cars current state.
     * @return true if the property is AVAILABLE, false otherwise
     */
    public boolean isPropertyAvailable(int propertyId, int area)
            throws CarNotConnectedException {
        return mPropertyManager.isPropertyAvailable(propertyId, area);
    }

    /**
     * Returns property value. Use this function for global vehicle properties.
     *
     * @param propertyClass - data type of the given property, for example property that was
     *        defined as {@code VEHICLE_VALUE_TYPE_INT32} in vehicle HAL could be accessed using
     *        {@code Integer.class}.
     * @param propId - property id which is matched with the one defined in vehicle HAL
     *
     * @throws CarNotConnectedException if the connection to the car service has been lost.
     */
    public <E> E getGlobalProperty(Class<E> propertyClass, int propId)
            throws CarNotConnectedException {
        return getProperty(propertyClass, propId, 0 /* area */);
    }

    /**
     * Returns property value. Use this function for "zoned" vehicle properties.
     *
     * @param propertyClass - data type of the given property, for example property that was
     *        defined as {@code VEHICLE_VALUE_TYPE_INT32} in vehicle HAL could be accessed using
     *        {@code Integer.class}.
     * @param propId - property id which is matched with the one defined in vehicle HAL
     * @param area - vehicle area (e.g. {@code VehicleAreaSeat.ROW_1_LEFT}
     *        or {@code VEHICLE_MIRROR_DRIVER_LEFT}
     *
     * @throws CarNotConnectedException if the connection to the car service has been lost.
     */
    public <E> E getProperty(Class<E> propertyClass, int propId, int area)
            throws CarNotConnectedException {
        return mPropertyManager.getProperty(propertyClass, propId, area).getValue();
    }

    /**
     * Call this function to set a value to global vehicle property.
     *
     * @param propertyClass - data type of the given property, for example property that was
     *        defined as {@code VEHICLE_VALUE_TYPE_INT32} in vehicle HAL could be accessed using
     *        {@code Integer.class}.
     * @param propId - property id which is matched with the one defined in vehicle HAL
     * @param value - new value, this object should match a class provided in {@code propertyClass}
     *        argument.
     *
     * @throws CarNotConnectedException if the connection to the car service has been lost.
     */
    public <E> void setGlobalProperty(Class<E> propertyClass, int propId, E value)
            throws CarNotConnectedException {
        mPropertyManager.setProperty(propertyClass, propId, 0 /* area */, value);
    }

    /**
     * Call this function to set a value to "zoned" vehicle property.
     *
     * @param propertyClass - data type of the given property, for example property that was
     *        defined as {@code VEHICLE_VALUE_TYPE_INT32} in vehicle HAL could be accessed using
     *        {@code Integer.class}.
     * @param propId - property id which is matched with the one defined in vehicle HAL
     * @param area - vehicle area (e.g. {@code VehicleAreaSeat.ROW_1_LEFT}
     *        or {@code VEHICLE_MIRROR_DRIVER_LEFT}
     * @param value - new value, this object should match a class provided in {@code propertyClass}
     *        argument.
     *
     * @throws CarNotConnectedException if the connection to the car service has been lost.
     */
    public <E> void setProperty(Class<E> propertyClass, int propId, int area, E value)
            throws CarNotConnectedException {
        mPropertyManager.setProperty(propertyClass, propId, area, value);
    }

    /** @hide */
    @Override
    public void onCarDisconnected() {
        mPropertyManager.onCarDisconnected();
    }
}