document.addEventListener('DOMContentLoaded', function () {
    const amountInput = document.getElementById('amount');
    const rateInput = document.getElementById('rate');
    const agreementInput = document.getElementById('agreement');
    const vatAmountOutput = document.getElementById('vatAmount');
    const totalAmountOutput = document.getElementById('totalAmount');
    const netAmountOutput = document.getElementById('netAmount');

    function updateCalculator() {
        const amount = parseFloat(amountInput.value) || 0;
        const rate = parseFloat(rateInput.value) || 0;
        let tax = 0;

        if (amount > 0 && rate > 0) {
            const vatAmount = (amount * rate) / 100;
            const totalAmount = amount + vatAmount;

            vatAmountOutput.textContent = vatAmount.toFixed(2);
            totalAmountOutput.textContent = totalAmount.toFixed(2);

            if (totalAmount > 0) {
                if (totalAmount <= 1000) {
                    tax = totalAmount * 0.10;
                } else if (totalAmount <= 3000) {
                    tax = (1000 * 0.10) + ((totalAmount - 1000) * 0.20);
                } else {
                    tax = (1000 * 0.10) + (2000 * 0.20) + ((totalAmount - 3000) * 0.30);
                }
                const netAmount = totalAmount - tax;
                netAmountOutput.textContent = netAmount.toFixed(2);
            } else {
                netAmountOutput.textContent = '0.00';
            }

        } else {
            vatAmountOutput.textContent = '0.00';
            totalAmountOutput.textContent = '0.00';
            netAmountOutput.textContent = '0.00';
        }
    }

    window.setRate = function(rate) {
        rateInput.value = rate;
        updateCalculator();
    }

    amountInput.addEventListener('input', updateCalculator);
    rateInput.addEventListener('input', updateCalculator);
    agreementInput.addEventListener('change', updateCalculator);

    // Initial calculation
    updateCalculator();
});