using System;
using System.Linq;
using EvoCalculator.Core.Models.BaseCalculation.Models.Request;
using EvoCalculator.Core.Models.BaseCalculation.Models.Response;
using EvoCalculator.Core.Tools.Array;

namespace EvoCalculator.Core.Calculation;

public class BaseCalculation
{
    const double IRR = 0.155;
    private Constants.Calculation constants;

    public BaseCalculation()
    {
        this.constants = new Constants.Calculation();
    }

    public ResponseBaseCalculation Calculate(RequestBaseCalculation requestBaseCalculation)
    {
        var initialPaymentSum =
            requestBaseCalculation.car_price * (decimal) (requestBaseCalculation.initial_payment / 100);
        var redemptionPaymentSum = requestBaseCalculation.car_price *
                                   (decimal) (requestBaseCalculation.redemption_payment / 100);

        var IRRperMonth = Math.Pow(1 + IRR / 12, requestBaseCalculation.lease_period - 2);
        var monthlyPayment = (IRR / 12) *
            (double) ((requestBaseCalculation.car_price - initialPaymentSum) *
                (decimal) IRRperMonth - redemptionPaymentSum) / (IRRperMonth - 1);
        
        var leaseContractSum = (requestBaseCalculation.lease_period - 2) * (decimal) monthlyPayment +
                               initialPaymentSum +
                               redemptionPaymentSum;
        var taxSavings = leaseContractSum * (decimal) (constants.VatValue / 1.2);

        var schedule = Array<decimal>.Concat(
            new decimal[] {initialPaymentSum}
            , Enumerable.Repeat((decimal) monthlyPayment, requestBaseCalculation.lease_period - 2).ToArray()
            , new decimal[] {redemptionPaymentSum}
        );


        return new ResponseBaseCalculation()
        {
            monthly_payment = (decimal) monthlyPayment,
            tax_savings = taxSavings,
            vat_reimbursement = taxSavings,
            schedule = schedule
        };
    }
}