package nodomain.freeyourgadget.gadgetbridge.devices;

import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.support.v4.content.LocalBroadcastManager;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;

import nodomain.freeyourgadget.gadgetbridge.impl.GBDevice;
import nodomain.freeyourgadget.gadgetbridge.util.DeviceHelper;

/**
 * Provides access to the list of devices managed by Gadgetbridge.
 * Changes to the devices (e.g. connection state) or the list of devices
 * are broadcasted via #ACTION_DEVICE_CHANGED
 */
public class DeviceManager {
    private static final Logger LOG = LoggerFactory.getLogger(DeviceManager.class);

    /**
     * Intent action to notify that the list of devices has changed.
     */
    public static final String ACTION_DEVICES_CHANGED
            = "nodomain.freeyourgadget.gadgetbridge.devices.devicemanager.action.devices_changed";
    /**
     * Intent action to notify this class that the list of devices shall be refreshed.
     */
    public static final String ACTION_REFRESH_DEVICELIST
            = "nodomain.freeyourgadget.gadgetbridge.devices.devicemanager.action.set_version";
    private final Context context;
    /**
     * This list is final, it will never be recreated. Only its contents change.
     * This allows direct access to the list from ListAdapters.
     */
    private final List<GBDevice> deviceList = new ArrayList<>();
    private GBDevice selectedDevice = null;

    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            switch (action) {
                case ACTION_REFRESH_DEVICELIST:
                case BluetoothDevice.ACTION_BOND_STATE_CHANGED:
                    refreshPairedDevices();
                    break;
                case GBDevice.ACTION_DEVICE_CHANGED:
                    GBDevice dev = intent.getParcelableExtra(GBDevice.EXTRA_DEVICE);
                    if (dev.getAddress() != null) {
                        int index = deviceList.indexOf(dev); // search by address
                        if (index >= 0) {
                            deviceList.set(index, dev);
                        } else {
                            deviceList.add(dev);
                        }
                    }
                    updateSelectedDevice(dev);
                    refreshPairedDevices();
                    break;
            }
        }
    };

    public DeviceManager(Context context) {
        this.context = context;
        IntentFilter filterLocal = new IntentFilter();
        filterLocal.addAction(DeviceManager.ACTION_REFRESH_DEVICELIST);
        filterLocal.addAction(GBDevice.ACTION_DEVICE_CHANGED);
        filterLocal.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
        LocalBroadcastManager.getInstance(context).registerReceiver(mReceiver, filterLocal);
        context.registerReceiver(mReceiver, new IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED));

        refreshPairedDevices();
    }

    private void updateSelectedDevice(GBDevice dev) {
        if (selectedDevice == null) {
            selectedDevice = dev;
        } else {
            if (!selectedDevice.equals(dev)) {
                if (selectedDevice.isConnected() && dev.isConnected()) {
                    LOG.warn("multiple connected devices -- this is currently not really supported");
                    selectedDevice = dev; // use the last one that changed
                }
                if (!selectedDevice.isConnected()) {
                    selectedDevice = dev; // use the last one that changed
                }
            }
        }
    }

    private void refreshPairedDevices() {
        Set<GBDevice> availableDevices = DeviceHelper.getInstance().getAvailableDevices(context);
        deviceList.retainAll(availableDevices);
        for (GBDevice availableDevice : availableDevices) {
            if (!deviceList.contains(availableDevice)) {
                deviceList.add(availableDevice);
            }
        }

        notifyDevicesChanged();
    }

    /**
     * The returned list is final, it will never be recreated. Only its contents change.
     * This allows direct access to the list from ListAdapters.
     */
    public List<GBDevice> getDevices() {
        return Collections.unmodifiableList(deviceList);
    }

    public GBDevice getSelectedDevice() {
        return selectedDevice;
    }

    private void notifyDevicesChanged() {
        LocalBroadcastManager.getInstance(context).sendBroadcast(new Intent(ACTION_DEVICES_CHANGED));
    }
}