public async Task<bool> GetPollutionsForPlaceAsync(Place place)
{
var result = await _HttpService.GetStringAsync($"{_BaseUrl}/pollutions&zip={place.Zip}");
if (result != null)
{
var update = JsonConvert.DeserializeObject<Place>(result);
place.PollutionToday = update.PollutionToday;
place.PollutionTomorrow = update.PollutionTomorrow;
place.PollutionAfterTomorrow = update.PollutionAfterTomorrow;
return true;
}
return false;
}
/// <summary>
/// Checks if the last update for this city is older than 12 hours and updates it if needed.
/// Provides the pollution values afterwards
/// </summary>
/// <param name="zip">Zip code of the city</param>
/// <returns>List of pollution values</returns>
public ServiceResult<Place> GetPollutionsForPlace(string zip)
{
// Get the latest update for this city
var latestUpdate =
(from p in pollutionTable
where p.City_Zip == zip
orderby p.TimeStamp descending
select p.TimeStamp).FirstOrDefault();
// Check if pollution is available and up to date
var lastAllowedDate = DateTime.Now.AddHours(-12);
if (latestUpdate == null || latestUpdate < lastAllowedDate)
{
// Upadate this place
var updateResult = updateService.GetUpdatedPollutions(zip, pollenTable.ToList());
if (updateResult.Success)
// Use the DataTableHelper for Bulk Inserts, because SubmitChanges() updates each row as a single transaction
updateResult.Content.BulkCopyToDatabase(DataContext);
}
// Get latest pollution for this city
var pollutions =
from pollution in pollutionTable
join pollen in pollenTable on pollution.Pollen_Id equals pollen.Id
join city in cityTable on pollution.City_Zip equals city.Zip into joined
where pollution.City_Zip == zip
from c in joined.DefaultIfEmpty()
group new
{
pollution,
pollen,
city = c
}
by pollution.Pollen_Id into grp
select grp.OrderByDescending(g => g.pollution.TimeStamp).First();
var place = new Place();
place.Zip = zip;
foreach (var p in pollutions)
{
place.PollutionToday.Add(new Pollution { Pollen = p.pollen.ToPollen(), Intensity = p.pollution.ValueToday, Date = p.pollution.TimeStamp });
place.PollutionTomorrow.Add(new Pollution { Pollen = p.pollen.ToPollen(), Intensity = p.pollution.ValueTomorrow, Date = p.pollution.TimeStamp });
place.PollutionAfterTomorrow.Add(new Pollution { Pollen = p.pollen.ToPollen(), Intensity = p.pollution.ValueAfterTomorrow, Date = p.pollution.TimeStamp });
}
return new ServiceResult<Place>(place);
}
public async Task RefreshAsync()
{
IsLoading = true;
Places.Clear();
// Check settings
await _SettingsService.LoadSettingsAsync();
if (_SettingsService.CurrentSettings.UseCurrentLocation)
{
// Add current location
var geolocation = await _PlaceService.GetCurrentGeoLocationAsync();
if (geolocation != null)
{
var currentPlace = new Place();
currentPlace.Name = "Current position";
currentPlace.Zip = geolocation.Zip;
currentPlace.IsCurrentPosition = true;
Places.Add(currentPlace);
}
}
// Load locally saved places
var savedPlaces = await _FileSystemService.ReadObjectFromFileAsync<List<Place>>("places.json");
if (savedPlaces != null)
{
foreach(var place in savedPlaces)
{
Places.Add(place);
}
}
// Update
foreach (var place in Places)
{
var success = await _PollenService.GetPollutionsForPlaceAsync(place);
place.RecalculateMaxPollution();
}
IsLoading = false;
IsLoaded = true;
}