/// <summary>
/// Get list of exchange rates chart datapoints by model's criteria.
/// </summary>
/// <param name="statisticsModel"></param>
/// <returns></returns>
private List<CurrencyChartDataPoint> GetExchangeRates(ExchangeRatesStatisticsModel statisticsModel)
{
List<ExchangeRatesHistory> baseRatesHistory = GetExchangeRatesForCurrency(statisticsModel, statisticsModel.BaseCurrencyCode);
List<ExchangeRatesHistory> relationalRatesHistory = GetExchangeRatesForCurrency(statisticsModel, statisticsModel.RelationalCurrencyCode);
List<CurrencyChartDataPoint> resultingDataForChart = new List<CurrencyChartDataPoint>();
foreach (ExchangeRatesHistory baseRateHistoryItem in baseRatesHistory)
{
//database keeps rates only for USD, so we have to calculate any other rate
ExchangeRatesHistory relationalRateHistoryItem = relationalRatesHistory.Where(r => r.Date == baseRateHistoryItem.Date).First();
double calculatedRate = calculatedRate = relationalRateHistoryItem.CurrencyRate / baseRateHistoryItem.CurrencyRate;
//remember calculated rate in chart data
resultingDataForChart.Add(new CurrencyChartDataPoint(baseRateHistoryItem.Date, calculatedRate));
}
return resultingDataForChart.OrderBy(er => er.Date).ToList();
}
/// <summary>
/// Show to user exchange rates statistics by his query
/// </summary>
/// <param name="statisticsModel"></param>
/// <returns></returns>
public ActionResult GetExchangeRatesForPeriod(ExchangeRatesStatisticsModel statisticsModel)
{
if (statisticsModel.EndDate > statisticsModel.StartDate &&
(statisticsModel.EndDate - statisticsModel.StartDate).TotalDays < MaxStatisticsInterval)
{
statisticsModel.ExchangeRatesChartData = GetExchangeRates(statisticsModel);
}
else
{
ModelState.AddModelError("", string.Format(
"Wrong period. Start date must be earlier than end date. Period length must be less than {0} days", MaxStatisticsInterval));
}
ViewBag.AvailableCurrencies = GetAvailableCurrencies();
//the same view as in Index action
return View("Index", statisticsModel);
}
/// <summary>
/// Get list of exchange rates history entities for specific period (from model) for specific currency
/// </summary>
/// <param name="statisticsModel">Data Model</param>
/// <param name="currencyCode">Currency Code</param>
/// <returns></returns>
private List<ExchangeRatesHistory> GetExchangeRatesForCurrency(ExchangeRatesStatisticsModel statisticsModel, string currencyCode)
{
List<ExchangeRatesHistory> ratesHistory = new List<ExchangeRatesHistory>();
try
{
using (ExchangeRatesDataModelContainer dbModel = new ExchangeRatesDataModelContainer())
{
//Extract existing data from database
ratesHistory = dbModel.ExchangeRatesHistories
.Where(r =>
r.Date >= statisticsModel.StartDate &&
r.Date <= statisticsModel.EndDate &&
(r.Currency.ServiceCode == currencyCode))
.ToList();
}
}
catch (Exception e)
{
throw new ApplicationException("Unable to get rates history from Database", e);
}
for (DateTime currentDate = statisticsModel.StartDate; currentDate <= statisticsModel.EndDate; currentDate = currentDate.AddDays(1))
{
List<ExchangeRatesHistory> existingRate = ratesHistory
.Where(rh => rh.Date == currentDate).ToList();
if (existingRate.Count == 0)
{
List<ExchangeRatesHistory> ratesFromService = GetExchangeRatesFromService(currentDate)
.Where(r => r.Currency.ServiceCode == currencyCode).ToList();
AddRatesToDb(ratesFromService);
ratesHistory.AddRange(ratesFromService);
}
}
return ratesHistory;
}
/// <summary>
/// Initial action.
/// </summary>
/// <param name="statisticsModel"></param>
/// <returns></returns>
public ActionResult Index(ExchangeRatesStatisticsModel statisticsModel)
{
ViewBag.AvailableCurrencies = GetAvailableCurrencies();
return View(statisticsModel);
}