using System;
using System.Globalization;
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
{
    private double IRR = 0;
    private Constants.Calculation constants = new();

    public BaseCalculation()
    {
        var envCalculationIRR = Environment.GetEnvironmentVariable("CALCULATION_IRR");
        IRR = float.Parse(envCalculationIRR, CultureInfo.InvariantCulture);
    }

    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 vat_reimbursement = leaseContractSum * (decimal)(constants.VatValue / 1.2);
        var tax_savings = leaseContractSum * (decimal)(0.25 / 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 = tax_savings,
            vat_reimbursement = vat_reimbursement,
            schedule = schedule
        };
    }
}