document.addEventListener('DOMContentLoaded', function () {
    const orderForm = document.getElementById('orderForm');
    if (!orderForm) return;

    const priceSummary = document.getElementById('price-summary');
    const fileInput = document.getElementById('document');
    const specificReqBtn = document.getElementById('specificReqBtn');

    const basePrices = {
        printType: { 'one-sided': 0.10, 'both-sided': 0.18 },
        color: { 'bw': 0.05, 'color': 0.25 },
        paperSize: { 'a4': 0.02, 'jumbo': 0.05 },
        pagesPerSheet: { '1': 0, '2': 0.01, '4': 0.02 }
    };

    function calculatePrice() {
        const formData = new FormData(orderForm);
        const printType = formData.get('printType');
        const color = formData.get('color');
        const paperSize = formData.get('paperSize');
        const pagesPerSheet = formData.get('pagesPerSheet');
        const quantity = parseInt(formData.get('quantity') || '1', 10);

        let cost = 0;
        cost += basePrices.printType[printType] || 0;
        cost += basePrices.color[color] || 0;
        cost += basePrices.paperSize[paperSize] || 0;
        cost += basePrices.pagesPerSheet[pagesPerSheet] || 0;

        const total = cost * quantity;
        priceSummary.textContent = `$${total.toFixed(2)}`;
    }

    orderForm.addEventListener('change', calculatePrice);
    orderForm.addEventListener('input', calculatePrice);

    orderForm.addEventListener('submit', function(e) {
        if (!fileInput.files || fileInput.files.length === 0) {
            e.preventDefault();
            alert('Please upload a document before submitting.');
            fileInput.focus();
        }
    });

    if (specificReqBtn) {
        specificReqBtn.addEventListener('click', function() {
            alert('Please visit the shop for more specific requirements.');
        });
    }

    calculatePrice();
});