android/src/main/java/com/google/samples/apps/iosched/nearby/NearbyDevice.java

/*
 * Copyright 2014 Google Inc. All rights reserved.
 *
 * 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.google.samples.apps.iosched.nearby;

import android.bluetooth.BluetoothDevice;
import android.util.Log;

import java.util.ArrayList;
import java.util.List;

import static com.google.samples.apps.iosched.util.LogUtils.makeLogTag;

/**
 * Represents a nearby device emitting a BLE signal.
 */
public class NearbyDevice implements MetadataResolver.OnMetadataListener {
    String TAG = makeLogTag("NearbyDevice");
    private BluetoothDevice mBluetoothDevice;
    private DeviceMetadata mDeviceMetadata;
    private String mUrl;
    private NearbyDeviceAdapter mAdapter;

    private int HISTORY_LENGTH = 3;
    private List<Integer> mRSSIHistory;
    private long mLastSeen;

    NearbyDevice(BluetoothDevice bluetoothDevice, int RSSI) {
        mBluetoothDevice = bluetoothDevice;
        String url = MetadataResolver.getURLForDevice(this);
        initialize(url, RSSI);
    }

    private void initialize(String url, int RSSI) {
        mUrl = url;
        mLastSeen = System.nanoTime();

        mRSSIHistory = new ArrayList<Integer>();
        mRSSIHistory.add(RSSI);
    }

    public void setAdapter(NearbyDeviceAdapter adapter) {
        mAdapter = adapter;
    }

    public DeviceMetadata getInfo() {
        return mDeviceMetadata;
    }

    public int getLastRSSI() {
        return mRSSIHistory.get(mRSSIHistory.size() - 1);
    }

    public int getAverageRSSI() {
        Log.i(TAG, "getAverageRSSI. Elements: " + mRSSIHistory.size());
        int sum = 0;
        for (int rssi : mRSSIHistory) {
            sum += rssi;
        }
        return sum/mRSSIHistory.size();
    }

    public String getUrl() {
        return mUrl;
    }

    public String getName() {
        if (mBluetoothDevice != null) {
            String name = mBluetoothDevice.getName();
            if (name != null) {
                return name;
            } else {
                return "No device name";
            }
        } else {
            return mUrl;
        }
    }

    public void updateLastSeen(int RSSI) {
        mLastSeen = System.nanoTime();

        if (mRSSIHistory.size() >= HISTORY_LENGTH) {
            mRSSIHistory.remove(0);
            }
        mRSSIHistory.add(RSSI);
    }

    public boolean isLastSeenAfter(long threshold) {
        long notSeenMs = (System.nanoTime() - mLastSeen) / 1000000;
        return notSeenMs > threshold;
    }

    @Override
    public void onDeviceInfo(DeviceMetadata deviceMetadata) {
        mDeviceMetadata = deviceMetadata;
        if (mAdapter != null) {
            mAdapter.updateListUI();
        }
    }

    public boolean isBroadcastingUrl() {
        return mUrl != null;
    }

}