document.addEventListener("DOMContentLoaded", function () {

    function getValue(id) {
        var el = document.getElementsByName(id)[0];
        return el ? parseFloat(el.value) || 0 : 0;
    }

    function setValue(id, val) {
        var el = document.getElementsByName(id)[0];
        if (el) el.value = Number(val).toFixed(2);
    }

    window.calculate = function () {

        // --- BASIC INPUTS ---
        var gross_total_income = getValue("gross_total_income");
        var disallowance_14a = getValue("disallowance_14a");
        var disallowance_37 = getValue("disallowance_37");

        // -- total gross income --
        var gross_total = gross_total_income + disallowance_37 + disallowance_14a
        setValue("gti_as_per_ao", gross_total);

        // --- DEDUCTIONS ---
        var d80_business = getValue("deduction_80ia_business");
        var d80_misc = getValue("deduction_80ia_misc");
        var d80_other = getValue("deduction_80ia_other");
        var d80_sec37 = getValue("deduction_sec37_disallowance");

        var deduction = d80_business + d80_misc + d80_other + d80_sec37 - 1.35;

        var deduction_80g = getValue("deduction_80g");

        // --- NET TAXABLE INCOME ---
        var net_taxable_income = gross_total - deduction - deduction_80g;
        setValue("net_taxable_income", net_taxable_income);

        // ----------------------- TAX A% ---------------------
        var per_a = getValue("per_a");
        var tax30 = net_taxable_income * (per_a / 100);
        setValue("tax_30_percent", tax30);

        var per_surcharge_a = getValue("per_surcharge_a");
        var surcharge_a = tax30 * (per_surcharge_a / 100);
        setValue("surcharge_a", surcharge_a);

        var per_cess_a = getValue("per_cess_a");
        var edu_cess_a = (tax30 + surcharge_a) * (per_cess_a / 100);
        setValue("edu_cess_a", edu_cess_a);

        var sum_of_a = tax30 + surcharge_a + edu_cess_a;
        setValue("sum_of_a", sum_of_a);


        // -------------------- TAX PAYABLE B% (18.5%) ---------------------------
        var tax185 = getValue("tax_book_profit_18_5");

        var per_surcharge_b = getValue("per_surcharge_b");
        var surcharge_b = tax185 * (per_surcharge_b / 100);
        setValue("surcharge_b", surcharge_b);

        var per_cess_b = getValue("per_cess_b");
        var edu_cess_b = (tax185 + surcharge_b) * (per_cess_b / 100);
        setValue("edu_cess_b", edu_cess_b);

        var sum_of_b = tax185 + surcharge_b + edu_cess_b;
        setValue("sum_of_b", sum_of_b);


        // --- Tax Payable (Higher of A or B): ---
        var tax_payable = (tax30 > tax185) ? tax30 : tax185;
        setValue("tax_payable", tax_payable);
        // ---- total_tax_payable ----
        var total_tax_payable = (tax30 > tax185) ? sum_of_a : sum_of_b;
        setValue("total_tax_payable", total_tax_payable);


        // --- mat_credit_created --- new
        // setValue("mat_credit_created", Math.max(tax185 - total_tax_payable, 0));
        // // --- mat credit_utilized --- new
        // setValue("mat_credit_utilized", Math.max(total_tax_payable - tax185, 0));

        // --- mat credit_utilized ---
        var a = sum_of_a
        var b = sum_of_b
        var result = 0
        var zero = 0
        if (a < b) {
            result = b - a
            setValue("mat_credit_created", result);
            setValue("mat_credit_utilized", zero);
        }
        else {
            result = a - b
            setValue("mat_credit_utilized", result);
            setValue("mat_credit_created", zero);
        }

        // --- FINAL TAX ---
        var mat_credit_utilized = getValue("mat_credit_utilized");
        var interest_234c = getValue("interest_234c");

        // var total_tax = total_tax_payable + mat_credit + interest_234c;
        var total_tax = total_tax_payable + interest_234c - mat_credit_utilized;
        setValue("total_tax", total_tax);

        // --- ASSESSMENT ---
        var adv_tax = getValue("advance_tax");
        var tds = getValue("tds");
        var tcs = getValue("tcs");
        var tax_on_regular_assessment = getValue("tax_on_assessment");

        var all_tax = adv_tax + tds + tcs + tax_on_regular_assessment;

        var refund = total_tax - all_tax;
        setValue("refund", refund);
    };
});