/*
 * Copyright 2017 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.hardware.location;

import android.annotation.NonNull;
import android.annotation.RequiresPermission;
import android.annotation.SystemApi;
import android.os.RemoteException;

import com.android.internal.util.Preconditions;

import dalvik.system.CloseGuard;

import java.io.Closeable;
import java.util.concurrent.atomic.AtomicBoolean;

A class describing a client of the Context Hub Service.
Clients can send messages to nanoapps at a Context Hub through this object. The APIs supported
by this object are thread-safe and can be used without external synchronization.
@hide
/**
 * A class describing a client of the Context Hub Service.
 *
 * Clients can send messages to nanoapps at a Context Hub through this object. The APIs supported
 * by this object are thread-safe and can be used without external synchronization.
 *
 * @hide
 */
@SystemApi
public class ContextHubClient implements Closeable {
    /*
     * The proxy to the client interface at the service.
     */
    private IContextHubClient mClientProxy = null;

    /*
     * The Context Hub that this client is attached to.
     */
    private final ContextHubInfo mAttachedHub;

    private final CloseGuard mCloseGuard = CloseGuard.get();

    private final AtomicBoolean mIsClosed = new AtomicBoolean(false);

    /* package */ ContextHubClient(ContextHubInfo hubInfo) {
        mAttachedHub = hubInfo;
        mCloseGuard.open("close");
    }

    
Sets the proxy interface of the client at the service. This method should always be called
by the ContextHubManager after the client is registered at the service, and should only be
called once.
Params:
clientProxy – the proxy of the client at the service/**
     * Sets the proxy interface of the client at the service. This method should always be called
     * by the ContextHubManager after the client is registered at the service, and should only be
     * called once.
     *
     * @param clientProxy the proxy of the client at the service
     */
    /* package */ void setClientProxy(IContextHubClient clientProxy) {
        Preconditions.checkNotNull(clientProxy, "IContextHubClient cannot be null");
        if (mClientProxy != null) {
            throw new IllegalStateException("Cannot change client proxy multiple times");
        }

        mClientProxy = clientProxy;
    }

    
Returns the hub that this client is attached to.
Returns:
the ContextHubInfo of the attached hub/**
     * Returns the hub that this client is attached to.
     *
     * @return the ContextHubInfo of the attached hub
     */
    @NonNull
    public ContextHubInfo getAttachedHub() {
        return mAttachedHub;
    }

    
Closes the connection for this client and the Context Hub Service.
When this function is invoked, the messaging associated with this client is invalidated.
All futures messages targeted for this client are dropped at the service.
/**
     * Closes the connection for this client and the Context Hub Service.
     *
     * When this function is invoked, the messaging associated with this client is invalidated.
     * All futures messages targeted for this client are dropped at the service.
     */
    public void close() {
        if (!mIsClosed.getAndSet(true)) {
            mCloseGuard.close();
            try {
                mClientProxy.close();
            } catch (RemoteException e) {
                throw e.rethrowFromSystemServer();
            }
        }
    }

    
Sends a message to a nanoapp through the Context Hub Service.
This function returns TRANSACTION_SUCCESS if the message has reached the HAL, but
does not guarantee delivery of the message to the target nanoapp.
Params:
message – the message object to send
Throws:
NullPointerException – if NanoAppMessage is null
See Also:
NanoAppMessage
Result
Returns:
the result of sending the message defined as in ContextHubTransaction.Result/**
     * Sends a message to a nanoapp through the Context Hub Service.
     *
     * This function returns TRANSACTION_SUCCESS if the message has reached the HAL, but
     * does not guarantee delivery of the message to the target nanoapp.
     *
     * @param message the message object to send
     *
     * @return the result of sending the message defined as in ContextHubTransaction.Result
     *
     * @throws NullPointerException if NanoAppMessage is null
     *
     * @see NanoAppMessage
     * @see ContextHubTransaction.Result
     */
    @RequiresPermission(android.Manifest.permission.LOCATION_HARDWARE)
    @ContextHubTransaction.Result
    public int sendMessageToNanoApp(@NonNull NanoAppMessage message) {
        Preconditions.checkNotNull(message, "NanoAppMessage cannot be null");

        try {
            return mClientProxy.sendMessageToNanoApp(message);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    @Override
    protected void finalize() throws Throwable {
        try {
            if (mCloseGuard != null) {
                mCloseGuard.warnIfOpen();
            }
            close();
        } finally {
            super.finalize();
        }
    }
}