/// <summary>
/// <para>Method that parse csv string to IEnumerable of euro exchanges</para>
/// If header (first line where are column definitions) is not exactly as CSV_HEADERS method returns an empty array
/// </summary>
/// <param name="source">source string(csv)</param>
/// <returns>IEnumerable of euro exchanges</returns>
private IEnumerable <EuroExchange> parseCsvData(string source)
{
var lines = source.Replace("\r", "").Split('\n');
// check if first line is correct
if (lines.FirstOrDefault() == CSV_HEADERS)
{
// ignore first line (headers)
foreach (var line in lines.Skip(1))
{
var fields = line.Split(',');
var currency = fields.ElementAtOrDefault(CurrencyIndex);
var timePeriod = fields.ElementAtOrDefault(TimePeriodIndex);;
var obsValue = fields.ElementAtOrDefault(ObsValuevIndex)?.Replace('.', ',');
if (string.IsNullOrEmpty(currency) == true ||
string.IsNullOrEmpty(timePeriod) == true ||
string.IsNullOrEmpty(obsValue) == true)
{
continue;
}
var currencyExchange = new EuroExchange()
{
Date = DateTime.Parse(timePeriod),
Currency = currency,
ExchangeRate = Convert.ToDouble(obsValue)
};
yield return(currencyExchange);
}
}
}
/// <summary>
/// Method that converts currencies by using their euro rates
/// </summary>
/// <param name="from">EuroExchange with base currency</param>
/// <param name="to">EuroExchange with target currency</param>
/// <param name="date">exchange date</param>
public static CurrencyExchangeDTO Create(
EuroExchange from,
EuroExchange to,
DateTime date)
{
return(new CurrencyExchangeDTO()
{
CurrencyFrom = from.Currency,
CurrencyTo = to.Currency,
Date = date.ToString("yyyy-MM-dd"),
ExchangeRate = Math.Round(1 / from.ExchangeRate * to.ExchangeRate, 4)
});
}
/// <summary>
/// Method that generates currency exchanges from currency codes list and euro rates
/// </summary>
/// <param name="currencyCodes">requested codes to be exchanged</param>
/// <param name="euroExchangesPerDay">euro exchanges to all currencies</param>
/// <param name="startDate">first day</param>
/// <param name="endDate">last day</param>
/// <returns>generated IEnumerable of CurrencyExchanges</returns>
private IEnumerable <CurrencyExchangeDTO> generateCurrencyExchanges(
List <KeyValuePair <string, string> > currencyCodes,
Dictionary <DateTime, List <EuroExchange> > euroExchangesPerDay,
DateTime startDate,
DateTime endDate)
{
// set euro
var euro = new EuroExchange()
{
Currency = "EUR", ExchangeRate = 1
};
// get date of first usefull element in given euroexchanges
var firstCurrencyDate = euroExchangesPerDay
.Where(e => e.Key <= startDate)
.Select(e => e.Key)
.LastOrDefault();
// get enumerators
var currentEnumerator = euroExchangesPerDay.GetEnumerator();
var nextEnumerator = euroExchangesPerDay.Skip(1).GetEnumerator();
var canMoveToNext = true;
var bankingHolidays = new List <BankingHoliday>();
// generate currency-currency exchange rates
var currentDay = substractWorkingDaysFromDate(startDate, 3);
while (currentDay <= endDate)
{
// check if next enumerator cover next day
if (canMoveToNext && currentDay >= nextEnumerator.Current.Key)
{
currentEnumerator.MoveNext();
canMoveToNext = nextEnumerator.MoveNext();
}
if (currentDay != currentEnumerator.Current.Key &&
currentDay.DayOfWeek != DayOfWeek.Saturday &&
currentDay.DayOfWeek != DayOfWeek.Sunday &&
currentDay.Date < DateTime.Now)
{
bankingHolidays.Add(new BankingHoliday(currentDay));
}
if (currentDay >= startDate)
{
foreach (var codePair in currencyCodes)
{
var fromEuroRate = codePair.Key == "EUR" ? euro : currentEnumerator.Current.Value?.FirstOrDefault(e => e.Currency == codePair.Key);
var toEuroRate = codePair.Value == "EUR" ? euro : currentEnumerator.Current.Value?.FirstOrDefault(e => e.Currency == codePair.Value);
if (fromEuroRate != null && toEuroRate != null)
{
yield return(CurrencyExchangeDTO.Create(fromEuroRate, toEuroRate, currentDay));
}
}
}
currentDay = currentDay.AddDays(1);
}
_dataCachingService.StoreBankingHolidays(bankingHolidays);
}
