CheckDataService.java

package com.nilhcem.bblfr.jobs.splashscreen.checkdata;

import android.content.Context;
import android.location.Location;
import android.util.Pair;

import com.nilhcem.bblfr.core.map.LocationProvider;
import com.nilhcem.bblfr.core.prefs.Preferences;
import com.nilhcem.bblfr.model.baggers.City;
import com.nilhcem.bblfr.model.baggers.dao.BaggersDao;
import com.nilhcem.bblfr.model.baggers.dao.CitiesDao;
import com.nilhcem.bblfr.model.locations.dao.LocationsDao;

import java.util.List;

import javax.inject.Inject;

import rx.Observable;
import timber.log.Timber;

public class CheckDataService {

    private final Preferences mPrefs;
    private final CitiesDao mCitiesDao;
    private final BaggersDao mBaggersDao;
    private final LocationsDao mLocationsDao;
    private final LocationProvider mProvider;

    @Inject
    public CheckDataService(Preferences prefs, CitiesDao citiesDao, BaggersDao baggersDao, LocationsDao locationsDao, LocationProvider locationProvider) {
        mPrefs = prefs;
        mCitiesDao = citiesDao;
        mBaggersDao = baggersDao;
        mLocationsDao = locationsDao;
        mProvider = locationProvider;
    }

    public Observable<Pair<Boolean, City>> checkData(Context context) {
        return Observable.zip(
                checkDatabase(),
                getFavoriteCity(context),
                Pair::create);
    }

    private Observable<Boolean> checkDatabase() {
        return Observable.fromCallable(() ->
                mCitiesDao.hasData() && mBaggersDao.hasData() && mLocationsDao.hasData()
        );
    }

    private Observable<City> getFavoriteCity(Context context) {
        return Observable.fromCallable(() -> {
            mProvider.initSync(context);
            City city = null;

            Pair<String, String> latLng = mPrefs.getFavoriteCityLatLng();
            if (latLng != null) {
                Timber.d("Favorite city found");
                city = mCitiesDao.getCityByLatLng(latLng.first, latLng.second);
            }

            if (city == null) {
                Timber.d("Try to find the closest city");
                city = findClosestCity(mProvider.getLastKnownLocation(), mCitiesDao.getCities());
                if (city != null) {
                    mPrefs.setFavoriteCity(city);
                }
            }
            return city;
        });
    }

    City findClosestCity(Location location, List<City> cities) {
        City closestCity = null;
        float closestDistance = Float.MAX_VALUE;

        if (location != null && cities != null) {
            for (City city : cities) {
                float[] results = new float[1];
                Location.distanceBetween(city.lat, city.lng, location.getLatitude(), location.getLongitude(), results);
                if (results[0] < closestDistance) {
                    closestCity = city;
                    closestDistance = results[0];
                }
            }
        }
        return closestCity;
    }
}