// Summary:
// Manually converting and mapping the exchange rates from default base currency vaalue to the target currency.
//
// Parameters:
// createConversionDto:
// An instance to CreateConversionDto.
// Return:
// showConversionDto
// An instance to ShowConversionDto
private float FindExchangeRate(LatestExchangeRates latestExchangeRates, string toCurrency)
{
if (latestExchangeRates.Rates.TryGetValue(toCurrency, out float exchangeRate))
{
return(exchangeRate);
}
return(0);
}
// Summary:
// Get the current exchange rate from the API repository and converts as ShowConversionDto.
//
// Parameters:
// createConversionDto:
// An instance to CreateConversionDto.
// Return:
// showConversionDto
// An instance to ShowConversionDto
private async Task <ShowConversionDto> CalculateValue(CreateConversionDto createConversionDto)
{
LatestExchangeRates latestExchangeRates = await _currencyRepository.GetLatestConversionRatesByCurrency("EUR");
ShowConversionDto showConversionDto = new ShowConversionDto(createConversionDto.FromCurrency, createConversionDto.ToCurrency, createConversionDto.Value);
showConversionDto.ExchangeRate = CalculateExchangeRateValue(showConversionDto, latestExchangeRates);
return(showConversionDto);
}
// Summary:
// Gets latest currency exchange rates for base currency {currencyCode}
//
// Parameters:
// string currencyCode:
// Currency codes like EUR, GBP, INR, etc,.
// Return:
// LatestExchangeRates
// Typed response from the Http as LatestExchangeRates
public async Task <LatestExchangeRates> GetLatestConversionRatesByCurrency(string currencyCode)
{
string apiUrl = $"/latest?base=EUR";
var responseMessage = await this._currencyApi.Call(apiUrl);
LatestExchangeRates latestExchangeRates = JsonConvert.DeserializeObject <LatestExchangeRates>(responseMessage);
return(latestExchangeRates);
}
// Summary:
// It internally converts the base currency to the targer currency since API only supports EUR
//
// Parameters:
// latestExchangeRates:
// An instance to LatestExchangeRates
// string:
// Currency code.
// Return:
// showExchangeRateDto
// An instance to ShowExchangeRateDto
private ShowExchangeRateDto ConvertAsBaseCurrency(LatestExchangeRates latestExchangeRates, string currencyCode)
{
ShowExchangeRateDto convertedRates = new ShowExchangeRateDto()
{
Base = currencyCode,
Timestamp = latestExchangeRates.Timestamp,
Date = latestExchangeRates.Date,
Rates = new Dictionary <string, float>()
};
if (latestExchangeRates.Base == currencyCode)
{
convertedRates.Rates = latestExchangeRates.Rates;
return(convertedRates);
}
foreach (KeyValuePair <string, float> entry in latestExchangeRates.Rates.ToList())
{
ShowConversionDto showConversionDto = new ShowConversionDto(currencyCode, entry.Key, 0);
convertedRates.Rates.Add(entry.Key, CalculateExchangeRateValue(showConversionDto, latestExchangeRates));
}
return(convertedRates);
}
// Summary:
// Manually converting and mapping the exchange rates from default base currency vaalue to the target currency.
//
// Parameters:
// LatestExchangeRates:
// An instance to LatestExchangeRates.
// ShowConversionDto:
// An instance to ShowConversionDto.
// Return:
// float
// Converted final exchange rate
private float CalculateExchangeRateValue(ShowConversionDto showConversionDto, LatestExchangeRates latestExchangeRates)
{
float fromVsBaseExchangeRate = showConversionDto.FromCurrency == latestExchangeRates.Base ? 1 : FindExchangeRate(latestExchangeRates, showConversionDto.FromCurrency);
float baseVsToExchangeRate = showConversionDto.ToCurrency == latestExchangeRates.Base ? 1 : FindExchangeRate(latestExchangeRates, showConversionDto.ToCurrency);
if (fromVsBaseExchangeRate > 0 && baseVsToExchangeRate > 0)
{
float finalExchangeRate = (1 / fromVsBaseExchangeRate) * baseVsToExchangeRate;
return(finalExchangeRate);
}
throw new NotSupportedException($"Conversion from {showConversionDto.FromCurrency} to {showConversionDto.ToCurrency} is not supported at the moment");
}
// Summary:
// Get latest exchange rates for a specific currency. By default it's EUR.
//
// Parameters:
// string:
// Currency code.
// Return:
// showExchangeRateDto
// An instance to ShowExchangeRateDto
public async Task <ShowExchangeRateDto> GetAllConversionRatesByCurrency(string currencyCode)
{
LatestExchangeRates latestExchangeRates = await _currencyRepository.GetLatestConversionRatesByCurrency("EUR");
return(ConvertAsBaseCurrency(latestExchangeRates, currencyCode));;
}
