public PersonalIncomeTax this[AssessableIncome income]
{
get
{
var progressiveTaxRateContainsAssessableIncome = _progressiveTaxes
.SingleOrDefault(p => p.HasAssessableIncomeWithinRange(income));
if (progressiveTaxRateContainsAssessableIncome is null)
{
return(new PersonalIncomeTax(Money.ZeroVND));
}
var pit = (income.Amount - progressiveTaxRateContainsAssessableIncome.LowerBound) *
progressiveTaxRateContainsAssessableIncome.Rate + _progressiveTaxes
.Where(_ => _.ProgressiveTaxRateLevel < progressiveTaxRateContainsAssessableIncome.ProgressiveTaxRateLevel)
.Select(p => p.MaxIncomeTaxPerLevel)
.Sum();
return(new PersonalIncomeTax(pit.Round()));
}
}
public bool HasAssessableIncomeWithinRange(AssessableIncome assessableIncome)
{
return(LowerBound <= assessableIncome.Amount && assessableIncome.Amount < UpperBound);
}