/*
 * Copyright (C) 2015 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.media.midi;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.IBinder;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.util.Log;

A service that implements a virtual MIDI device. Subclasses must implement the onGetInputPortReceivers method to provide a list of MidiReceivers to receive data sent to the device's input ports. Similarly, subclasses can call getOutputPortReceivers to fetch a list of MidiReceivers for sending data out the output ports. 
To extend this class, you must declare the service in your manifest file with an intent filter with the SERVICE_INTERFACE action and meta-data to describe the virtual device. For example:
<service android:name=".VirtualDeviceService"
         android:label="@string/service_name">
    <intent-filter>
        <action android:name="android.media.midi.MidiDeviceService" />
    </intent-filter>
          <meta-data android:name="android.media.midi.MidiDeviceService"
android:resource="@xml/device_info" />
</service>
/**
 * A service that implements a virtual MIDI device.
 * Subclasses must implement the {@link #onGetInputPortReceivers} method to provide a
 * list of {@link MidiReceiver}s to receive data sent to the device's input ports.
 * Similarly, subclasses can call {@link #getOutputPortReceivers} to fetch a list
 * of {@link MidiReceiver}s for sending data out the output ports.
 *
 * <p>To extend this class, you must declare the service in your manifest file with
 * an intent filter with the {@link #SERVICE_INTERFACE} action
 * and meta-data to describe the virtual device.
 For example:</p>
 * <pre>
 * &lt;service android:name=".VirtualDeviceService"
 *          android:label="&#64;string/service_name">
 *     &lt;intent-filter>
 *         &lt;action android:name="android.media.midi.MidiDeviceService" />
 *     &lt;/intent-filter>
 *           &lt;meta-data android:name="android.media.midi.MidiDeviceService"
                android:resource="@xml/device_info" />
 * &lt;/service></pre>
 */
abstract public class MidiDeviceService extends Service {
    private static final String TAG = "MidiDeviceService";

    public static final String SERVICE_INTERFACE = "android.media.midi.MidiDeviceService";

    private IMidiManager mMidiManager;
    private MidiDeviceServer mServer;
    private MidiDeviceInfo mDeviceInfo;

    private final MidiDeviceServer.Callback mCallback = new MidiDeviceServer.Callback() {
        @Override
        public void onDeviceStatusChanged(MidiDeviceServer server, MidiDeviceStatus status) {
            MidiDeviceService.this.onDeviceStatusChanged(status);
        }

        @Override
        public void onClose() {
            MidiDeviceService.this.onClose();
        }
    };

    @Override
    public void onCreate() {
        mMidiManager = IMidiManager.Stub.asInterface(
                    ServiceManager.getService(Context.MIDI_SERVICE));
        MidiDeviceServer server;
        try {
            MidiDeviceInfo deviceInfo = mMidiManager.getServiceDeviceInfo(getPackageName(),
                    this.getClass().getName());
            if (deviceInfo == null) {
                Log.e(TAG, "Could not find MidiDeviceInfo for MidiDeviceService " + this);
                return;
            }
            mDeviceInfo = deviceInfo;
            MidiReceiver[] inputPortReceivers = onGetInputPortReceivers();
            if (inputPortReceivers == null) {
                inputPortReceivers = new MidiReceiver[0];
            }
            server = new MidiDeviceServer(mMidiManager, inputPortReceivers, deviceInfo, mCallback);
        } catch (RemoteException e) {
            Log.e(TAG, "RemoteException in IMidiManager.getServiceDeviceInfo");
            server = null;
        }
        mServer = server;
   }

    
Returns an array of MidiReceiver for the device's input ports. Subclasses must override this to provide the receivers which will receive data sent to the device's input ports. An empty array should be returned if the device has no input ports. 
Returns:
array of MidiReceivers/**
     * Returns an array of {@link MidiReceiver} for the device's input ports.
     * Subclasses must override this to provide the receivers which will receive
     * data sent to the device's input ports. An empty array should be returned if
     * the device has no input ports.
     * @return array of MidiReceivers
     */
    abstract public MidiReceiver[] onGetInputPortReceivers();

    
Returns an array of MidiReceiver for the device's output ports. These can be used to send data out the device's output ports. 
Returns:
array of MidiReceivers/**
     * Returns an array of {@link MidiReceiver} for the device's output ports.
     * These can be used to send data out the device's output ports.
     * @return array of MidiReceivers
     */
    public final MidiReceiver[] getOutputPortReceivers() {
        if (mServer == null) {
            return null;
        } else {
            return mServer.getOutputPortReceivers();
        }
    }

    
returns the MidiDeviceInfo instance for this service 
Returns:
our MidiDeviceInfo/**
     * returns the {@link MidiDeviceInfo} instance for this service
     * @return our MidiDeviceInfo
     */
    public final MidiDeviceInfo getDeviceInfo() {
        return mDeviceInfo;
    }

    
Called to notify when an our MidiDeviceStatus has changed 
Params:
status – the number of the port that was opened/**
     * Called to notify when an our {@link MidiDeviceStatus} has changed
     * @param status the number of the port that was opened
     */
    public void onDeviceStatusChanged(MidiDeviceStatus status) {
    }

    
Called to notify when our device has been closed by all its clients
/**
     * Called to notify when our device has been closed by all its clients
     */
    public void onClose() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        if (SERVICE_INTERFACE.equals(intent.getAction()) && mServer != null) {
             return mServer.getBinderInterface().asBinder();
        } else {
             return null;
       }
    }
}