/// <summary>
/// 根据当前还款时间和还款周期，计算下一个还款时间
/// </summary>
/// <param name="thisPaymentDate">当前还款时间</param>
/// <param name="paymentCircle">还款周期</param>
/// <returns>一个还款时间</returns>
public static DateTime GetNextPaymentDate(DateTime thisPaymentDate, PaymentTermTypes paymentCircle)
{
DateTime nextPaymentDate = DateTime.MinValue;
switch (paymentCircle)
{
case PaymentTermTypes.Daily:
nextPaymentDate = thisPaymentDate.AddDays(1);
break;
case PaymentTermTypes.Weekly:
nextPaymentDate = thisPaymentDate.AddDays(7);
break;
case PaymentTermTypes.DoubleWeekly:
nextPaymentDate = thisPaymentDate.AddDays(14);
break;
case PaymentTermTypes.DoubleMonthly:
nextPaymentDate = thisPaymentDate.AddMonths(2);
break;
case PaymentTermTypes.Quarterly:
nextPaymentDate = thisPaymentDate.AddMonths(3);
break;
case PaymentTermTypes.SemiYearly:
nextPaymentDate = thisPaymentDate.AddMonths(6);
break;
case PaymentTermTypes.Annual:
nextPaymentDate = thisPaymentDate.AddYears(1);
break;
case PaymentTermTypes.Monthly:
default:
nextPaymentDate = thisPaymentDate.AddMonths(1);
break;
}
//贷款还款日期的时间精度仅仅控制到日，不对时分秒控制
return nextPaymentDate.Date;
}
/// <summary>
/// 根据周期类型获取利率
/// </summary>
/// <param name="loanTermType"></param>
/// <returns></returns>
public double GetRate(PaymentTermTypes loanTermType)
{
double rate = this.MonthlyRate;
switch (loanTermType)
{
case PaymentTermTypes.Daily:
rate = this.DailyRate;
break;
case PaymentTermTypes.Weekly:
rate = this.WeeklyRate;
break;
case PaymentTermTypes.DoubleWeekly:
rate = this.DoubleWeeklyRate;
break;
case PaymentTermTypes.Monthly:
rate = this.MonthlyRate;
break;
case PaymentTermTypes.DoubleMonthly:
rate = this.DoubleMonthlyRate;
break;
case PaymentTermTypes.Quarterly:
rate = this.QuarterlyRate;
break;
case PaymentTermTypes.SemiYearly:
rate = this.SemiYearlyRate;
break;
case PaymentTermTypes.Annual:
rate = this.AnnualRate;
break;
default:
break;
}
return rate;
}
/// <summary>
/// 按照一般算数方法进行的利率转换
/// </summary>
/// <param name="rate">利率值</param>
/// <param name="circle">利率周期</param>
public SimpleRateConverter(double rate, PaymentTermTypes circle)
{
switch (circle)
{
case PaymentTermTypes.Daily:
this.DailyRate = rate;
this.AnnualRate = rate * 365;
break;
case PaymentTermTypes.Weekly:
this.WeeklyRate = rate;
this.AnnualRate = rate * 52;
break;
case PaymentTermTypes.DoubleWeekly:
this.DoubleWeeklyRate = rate;
this.AnnualRate = rate * 26;
break;
case PaymentTermTypes.Monthly:
this.MonthlyRate = rate;
this.AnnualRate = rate * 12;
break;
case PaymentTermTypes.DoubleMonthly:
this.DoubleMonthlyRate = rate;
this.AnnualRate = rate * 6;
break;
case PaymentTermTypes.Quarterly:
this.QuarterlyRate = rate;
this.AnnualRate = rate * 4;
break;
case PaymentTermTypes.SemiYearly:
this.SemiYearlyRate = rate;
this.AnnualRate = rate * 2;
break;
case PaymentTermTypes.Annual:
default:
this.AnnualRate = rate;
break;
}
}
/// <summary>
/// 获取还款日程信息
/// </summary>
/// <param name="paymentNumber">指定要计算的还款档期序号</param>
/// <param name="rate">利率</param>
/// <param name="paymentCount">还款总期数</param>
/// <param name="totalAmount">贷款总费用</param>
/// <param name="dueDate">还款在每期的开始还是结尾时间，缺省为每期的结尾时间（大部分商业都是用结尾时间）</param>
/// <param name="getPaymentFunc">生成每期贷款的方法</param>
/// <returns>每期还款的额度</returns>
/// <remarks>参数rate和参数paymentCount是呼应的。即如果paymentCount按照月计数，那么rate就必须指定为月利率；
/// 如果paymentCount按照年计数，那么rate就必须指定为年利率。</remarks>
public static List<Payment> GetPaymentSchedule(double rate, double totalAmount, int paymentCount, PaymentTermTypes paymentCircle, DateTime loanStartDate, DueDate dueDate, Funcs<double, double, int, int, DueDate, Payment> getPaymentFunc)
{
//贷款还款日期的时间精度仅仅控制到日，不对时分秒控制
loanStartDate = loanStartDate.Date;
List<Payment> paymentSchedule = new List<Payment>();
double totalNeedPayPrinclepal = 0;
DateTime lastPaymentDate = DateTime.MinValue;
for (int i = 0; i < paymentCount; i++)
{
int paymentNumber = i + 1;
Payment payment = getPaymentFunc(rate, totalAmount, paymentCount, paymentNumber, dueDate);
totalNeedPayPrinclepal += payment.Principal;
payment.TotalPrincipal = totalNeedPayPrinclepal;
payment.PrincipalBalance = totalAmount - totalNeedPayPrinclepal;
if (lastPaymentDate == DateTime.MinValue)
{
if (dueDate == DueDate.BegOfPeriod)
{
lastPaymentDate = loanStartDate;
}
else
{
lastPaymentDate = LoanHelper.GetNextPaymentDate(loanStartDate, paymentCircle);
}
}
else
{
lastPaymentDate = LoanHelper.GetNextPaymentDate(lastPaymentDate, paymentCircle);
}
payment.PaymentDate = lastPaymentDate;
paymentSchedule.Add(payment);
}
return paymentSchedule;
}
/// <summary>
/// 获取还款日程信息
/// </summary>
/// <param name="paymentNumber">指定要计算的还款档期序号</param>
/// <param name="rate">利率</param>
/// <param name="paymentCount">还款总期数</param>
/// <param name="totalAmount">贷款总费用</param>
/// <param name="dueDate">还款在每期的开始还是结尾时间，缺省为每期的结尾时间（大部分商业都是用结尾时间）</param>
/// <returns>每期还款的额度</returns>
/// <remarks>参数rate和参数paymentCount是呼应的。即如果paymentCount按照月计数，那么rate就必须指定为月利率；
/// 如果paymentCount按照年计数，那么rate就必须指定为年利率。</remarks>
public static List<Payment> GetPaymentSchedule(double rate, double totalAmount, int paymentCount, PaymentTermTypes paymentCircle, DateTime loanStartDate, DueDate dueDate = DueDate.EndOfPeriod)
{
return LoanHelper.GetPaymentSchedule(rate, totalAmount, paymentCount, paymentCircle, loanStartDate, dueDate, GetPayment);
}
