/**
* Financial calculation utilities
*/
/**
* Calculate monthly payment using French amortization system
* Formula: Cuota = P * [r(1+r)^n] / [(1+r)^n - 1]
*
* @param principal - Loan amount
* @param annualRate - Annual interest rate (percentage, e.g., 15 for 15%)
* @param months - Loan term in months
* @returns Monthly payment amount
*/
export function calculateFrenchPayment(
principal: number,
annualRate: number,
months: number
): number {
const monthlyRate = annualRate / 100 / 12;
if (monthlyRate === 0) return principal / months;
return (
(principal * (monthlyRate * Math.pow(1 + monthlyRate, months))) /
(Math.pow(1 + monthlyRate, months) - 1)
);
}
/**
* Calculate total loan cost
*/
export function calculateTotalCost(monthlyPayment: number, months: number): number {
return monthlyPayment * months;
}
/**
* Calculate total interest paid
*/
export function calculateTotalInterest(
principal: number,
monthlyPayment: number,
months: number
): number {
return monthlyPayment * months - principal;
}
/**
* Generate loan payment summary
*/
export function generateLoanSummary(
principal: number,
annualRate: number,
termMonths: number
): {
principal: number;
annualRate: number;
termMonths: number;
monthlyPayment: number;
totalAmount: number;
totalInterest: number;
currency: string;
} {
const monthlyPayment = calculateFrenchPayment(principal, annualRate, termMonths);
const totalAmount = calculateTotalCost(monthlyPayment, termMonths);
const totalInterest = calculateTotalInterest(principal, monthlyPayment, termMonths);
return {
principal,
annualRate,
termMonths,
monthlyPayment: Math.round(monthlyPayment),
totalAmount: Math.round(totalAmount),
totalInterest: Math.round(totalInterest),
currency: '$U',
};
}
