/*
 * Copyright (C) 2013 The Android Open Source Project
 * This software is based on Apache-licensed code from the above.
 * 
 * Copyright (C) 2013 APUS
 *
 *     This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.

 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package pro.apus.bleconnect;

import android.app.Notification;
import android.app.PendingIntent;
import android.app.Service;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattDescriptor;
import android.bluetooth.BluetoothGattService;
import android.bluetooth.BluetoothManager;
import android.bluetooth.BluetoothProfile;
import android.content.Context;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;

import java.util.Date;
import java.util.List;
import java.util.UUID;

import pro.apus.heartrate.R;

/**
 * Service for managing connection and data communication with a GATT server
 * hosted on a given Bluetooth LE device.
 */
public class BluetoothLeService extends Service {
	private final static String TAG = BluetoothLeService.class.getSimpleName();

	
	private BluetoothManager mBluetoothManager;
	private BluetoothAdapter mBluetoothAdapter;
	private String mBluetoothDeviceAddress;
	private BluetoothGatt mBluetoothGatt;
	private int mConnectionState = STATE_DISCONNECTED;

	private static final int STATE_DISCONNECTED = 0;
	private static final int STATE_CONNECTING = 1;
	private static final int STATE_CONNECTED = 2;

	public final static String ACTION_GATT_CONNECTED = "pro.apus.heartrate.ACTION_GATT_CONNECTED";
	public final static String ACTION_GATT_DISCONNECTED = "pro.apus.heartrate.ACTION_GATT_DISCONNECTED";
	public final static String ACTION_GATT_SERVICES_DISCOVERED = "pro.apus.heartrate.ACTION_GATT_SERVICES_DISCOVERED";
	public final static String ACTION_DATA_AVAILABLE = "pro.apus.heartrate.ACTION_DATA_AVAILABLE";
	public final static String EXTRA_DATA = "pro.apus.heartrate.EXTRA_DATA";

	public final static UUID UUID_HEART_RATE_MEASUREMENT = UUID
			.fromString(SampleGattAttributes.HEART_RATE_MEASUREMENT);

	 @Override
     public int onStartCommand(Intent intent, int flags, int startId) {
             
             Notification notification = new Notification(R.drawable.ic_launcher, "BLE Logger",
                             System.currentTimeMillis());
             Intent notificationIntent = new Intent(this, BluetoothLeService.class);
             PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
             notification.setLatestEventInfo(this, "BLE","BLE Logger", pendingIntent);
             this.startForeground(1, notification);
            
             return Service.START_NOT_STICKY;
     }
	 
	// Implements callback methods for GATT events that the app cares about. For
	// example,
	// connection change and services discovered.
	private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
		@Override
		public void onConnectionStateChange(BluetoothGatt gatt, int status,
				int newState) {
			String intentAction;
			if (newState == BluetoothProfile.STATE_CONNECTED) {
				intentAction = ACTION_GATT_CONNECTED;
				mConnectionState = STATE_CONNECTED;
				broadcastUpdate(intentAction);
				Log.i(TAG, "Connected to GATT server.");
				// Attempts to discover services after successful connection.
				Log.i(TAG, "Attempting to start service discovery:"
						+ mBluetoothGatt.discoverServices());

			} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
				intentAction = ACTION_GATT_DISCONNECTED;
				mConnectionState = STATE_DISCONNECTED;
				Log.i(TAG, "Disconnected from GATT server.");
				broadcastUpdate(intentAction);
			}
		}

		@Override
		public void onServicesDiscovered(BluetoothGatt gatt, int status) {
			if (status == BluetoothGatt.GATT_SUCCESS) {
				broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
			} else {
				Log.w(TAG, "onServicesDiscovered received: " + status);
			}
		}

		@Override
		public void onCharacteristicRead(BluetoothGatt gatt,
				BluetoothGattCharacteristic characteristic, int status) {
			if (status == BluetoothGatt.GATT_SUCCESS) {
				broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
			}
		}

		@Override
		public void onCharacteristicChanged(BluetoothGatt gatt,
				BluetoothGattCharacteristic characteristic) {
			broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
		}
	};

	private void broadcastUpdate(final String action) {
		final Intent intent = new Intent(action);
		sendBroadcast(intent);
	}

	private void broadcastUpdate(final String action,
			final BluetoothGattCharacteristic characteristic) {
		final Intent intent = new Intent(action);

		// This is special handling for the Heart Rate Measurement profile. Data
		// parsing is
		// carried out as per profile specifications:
		// http://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.heart_rate_measurement.xml
		if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
			int flag = characteristic.getProperties();
			int format = -1;
			if ((flag & 0x01) != 0) {
				format = BluetoothGattCharacteristic.FORMAT_UINT16;
				Log.d(TAG, "Heart rate format UINT16.");
			} else {
				format = BluetoothGattCharacteristic.FORMAT_UINT8;
				Log.d(TAG, "Heart rate format UINT8.");
			}
			final int heartRate = characteristic.getIntValue(format, 1);
			Log.d(TAG, String.format("Received heart rate: %d", heartRate));
			intent.putExtra(EXTRA_DATA, String.valueOf(heartRate));
		} else {
			// For all other profiles, writes the data formatted in HEX.
			final byte[] data = characteristic.getValue();
			if (data != null && data.length > 0) {
				final StringBuilder stringBuilder = new StringBuilder(
						data.length);
				for (byte byteChar : data)
					stringBuilder.append(String.format("%02X ", byteChar));
				intent.putExtra(EXTRA_DATA, new String(data) + "\n"
						+ stringBuilder.toString());
			}
		}
		sendBroadcast(intent);
	}

	public class LocalBinder extends Binder {
		BluetoothLeService getService() {
			return BluetoothLeService.this;
		}
	}

	@Override
	public IBinder onBind(Intent intent) {
		return mBinder;
	}

	@Override
	public boolean onUnbind(Intent intent) {
		// After using a given device, you should make sure that
		// BluetoothGatt.close() is called
		// such that resources are cleaned up properly. In this particular
		// example, close() is
		// invoked when the UI is disconnected from the Service.
		close();
		return super.onUnbind(intent);
	}

	private final IBinder mBinder = new LocalBinder();

	/**
	 * Initializes a reference to the local Bluetooth adapter.
	 * 
	 * @return Return true if the initialization is successful.
	 */
	public boolean initialize() {
		// For API level 18 and above, get a reference to BluetoothAdapter
		// through
		// BluetoothManager.
		if (mBluetoothManager == null) {
			mBluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
			if (mBluetoothManager == null) {
				Log.e(TAG, "Unable to initialize BluetoothManager.");
				return false;
			}
		}

		mBluetoothAdapter = mBluetoothManager.getAdapter();
		if (mBluetoothAdapter == null) {
			Log.e(TAG, "Unable to obtain a BluetoothAdapter.");
			return false;
		}

		return true;
	}

	/**
	 * Connects to the GATT server hosted on the Bluetooth LE device.
	 * 
	 * @param address
	 *            The device address of the destination device.
	 * 
	 * @return Return true if the connection is initiated successfully. The
	 *         connection result is reported asynchronously through the
	 *         {@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
	 *         callback.
	 */
	public boolean connect(final String address) {
		if (mBluetoothAdapter == null || address == null) {
			Log.w(TAG,
					"BluetoothAdapter not initialized or unspecified address.");
			return false;
		}

		// Previously connected device. Try to reconnect.
		if (mBluetoothDeviceAddress != null
				&& address.equals(mBluetoothDeviceAddress)
				&& mBluetoothGatt != null) {
			Log.d(TAG,
					"Trying to use an existing mBluetoothGatt for connection.");
			if (mBluetoothGatt.connect()) {
				mConnectionState = STATE_CONNECTING;
				return true;
			} else {
				return false;
			}
		}

		final BluetoothDevice device = mBluetoothAdapter
				.getRemoteDevice(address);
		if (device == null) {
			Log.w(TAG, "Device not found.  Unable to connect.");
			return false;
		}
		// We want to directly connect to the device, so we are setting the
		// autoConnect
		// parameter to false.
		mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
		Log.d(TAG, "Trying to create a new connection.");
		mBluetoothDeviceAddress = address;
		mConnectionState = STATE_CONNECTING;
		return true;
	}

	/**
	 * Disconnects an existing connection or cancel a pending connection. The
	 * disconnection result is reported asynchronously through the
	 * {@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
	 * callback.
	 */
	public void disconnect() {
		if (mBluetoothAdapter == null || mBluetoothGatt == null) {
			Log.w(TAG, "BluetoothAdapter not initialized");
			return;
		}
		mBluetoothGatt.disconnect();
	}

	/**
	 * After using a given BLE device, the app must call this method to ensure
	 * resources are released properly.
	 */
	public void close() {
		if (mBluetoothGatt == null) {
			return;
		}
		mBluetoothGatt.close();
		mBluetoothGatt = null;
	}

	/**
	 * Request a read on a given {@code BluetoothGattCharacteristic}. The read
	 * result is reported asynchronously through the
	 * {@code BluetoothGattCallback#onCharacteristicRead(android.bluetooth.BluetoothGatt, android.bluetooth.BluetoothGattCharacteristic, int)}
	 * callback.
	 * 
	 * @param characteristic
	 *            The characteristic to read from.
	 */
	public void readCharacteristic(BluetoothGattCharacteristic characteristic) {
		if (mBluetoothAdapter == null || mBluetoothGatt == null) {
			Log.w(TAG, "BluetoothAdapter not initialized");
			return;
		}
		mBluetoothGatt.readCharacteristic(characteristic);
	}

	/**
	 * Enables or disables notification on a give characteristic.
	 * 
	 * @param characteristic
	 *            Characteristic to act on.
	 * @param enabled
	 *            If true, enable notification. False otherwise.
	 */
	public void setCharacteristicNotification(
			BluetoothGattCharacteristic characteristic, boolean enabled) {
		if (mBluetoothAdapter == null || mBluetoothGatt == null) {
			Log.w(TAG, "BluetoothAdapter not initialized");
			return;
		}
		mBluetoothGatt.setCharacteristicNotification(characteristic, enabled);

		try {
			// This is specific to Heart Rate Measurement.
			if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
				BluetoothGattDescriptor descriptor = characteristic
						.getDescriptor(UUID
								.fromString(SampleGattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
				descriptor
						.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
				mBluetoothGatt.writeDescriptor(descriptor);

			}
		} catch (Exception e) {
			Log.d(TAG,
					"Exception while setting up notification for heartrate.", e);
		}
	}

	/**
	 * Retrieves a list of supported GATT services on the connected device. This
	 * should be invoked only after {@code BluetoothGatt#discoverServices()}
	 * completes successfully.
	 * 
	 * @return A {@code List} of supported services.
	 */
	public List<BluetoothGattService> getSupportedGattServices() {
		if (mBluetoothGatt == null)
			return null;

		return mBluetoothGatt.getServices();
	}
}