def generate_invoice_pdf(order_id):
    order = Order.objects.get(id=order_id)
    order_items = OrderItem.objects.select_related("product").filter(order=order)

    buffer = BytesIO()
    p = canvas.Canvas(buffer, pagesize=letter)
    width, height = letter
    y_position = height - 40  # Start position for writing text

    # Company Name
    p.setFont("Helvetica-Bold", 14)
    p.drawString(50, y_position, "Store")
    y_position -= 30

    # Invoice Title
    p.setFont("Helvetica-Bold", 16)
    p.drawString(230, y_position, "Invoice")
    p.line(50, y_position - 5, 550, y_position - 5)  # Horizontal Line
    y_position -= 30

    # Customer & Order Details
    p.setFont("Helvetica", 12)
    details = [
        f"Full Name: {order.full_name}",
        f"Contact: {order.user.profile.phone}",
        f"Order ID: {order.id}",
        f"Order Date: {order.date_ordered.strftime('%B %d, %Y')}",
        f"Payment Method: PayPal",
        f"Total Amount: ${order.amount_paid}",
    ]
    for detail in details:
        p.drawString(50, y_position, detail)
        y_position -= 20

    # Shipping Address Section
    y_position -= 30  # Space before address
    p.setFont("Helvetica-Bold", 12)
    p.drawString(50, y_position, "Shipping Address:")
    y_position -= 20

    p.setFont("Helvetica", 12)
    address_lines = [
        order.address_line_1,
        order.address_line_2 if order.address_line_2 else "",
        f"{order.city}, {order.state} - {order.zip_code}",
        order.country
    ]
    for line in address_lines:
        if line:
            p.drawString(50, y_position, line)
            y_position -= 20

    y_position -= 30  # Space before the table

    # Table Header & Data
    data = [["Product", "Qty", "Unit Price", "Total Price"]]
    for item in order_items:
        data.append([item.product.name, str(item.quantity), f"${item.price}", f"${item.total_price}"])

    # Table Styling
    table = Table(data, colWidths=[200, 70, 100, 100])
    table.setStyle(TableStyle([
        ("BACKGROUND", (0, 0), (-1, 0), colors.grey),
        ("TEXTCOLOR", (0, 0), (-1, 0), colors.whitesmoke),
        ("ALIGN", (0, 0), (-1, -1), "CENTER"),
        ("FONTNAME", (0, 0), (-1, 0), "Helvetica-Bold"),
        ("BOTTOMPADDING", (0, 0), (-1, 0), 10),
        ("GRID", (0, 0), (-1, -1), 1, colors.black),
    ]))

    # Dynamic Table Handling
    max_rows_per_page = 10  # Adjust as needed
    header = data[0]  # Table header
    rows = data[1:]  # Table rows

    while rows:
        rows_to_draw = rows[:max_rows_per_page]  # Get rows that fit on this page
        rows = rows[max_rows_per_page:]  # Remaining rows for next page

        # Create table for this page
        page_data = [header] + rows_to_draw
        table = Table(page_data, colWidths=[200, 70, 100, 100])
        table.setStyle(TableStyle([
            ("BACKGROUND", (0, 0), (-1, 0), colors.grey),
            ("TEXTCOLOR", (0, 0), (-1, 0), colors.whitesmoke),
            ("ALIGN", (0, 0), (-1, -1), "CENTER"),
            ("FONTNAME", (0, 0), (-1, 0), "Helvetica-Bold"),
            ("BOTTOMPADDING", (0, 0), (-1, 0), 10),
            ("GRID", (0, 0), (-1, -1), 1, colors.black),
        ]))

        # Check if table fits, otherwise create a new page
        if y_position - (len(rows_to_draw) * 20) < 100:
            p.showPage()  # Create a new page
            y_position = height - 40  # Reset position

        table.wrapOn(p, width, height)
        table.drawOn(p, 50, y_position - (len(rows_to_draw) * 20))
        y_position -= (len(rows_to_draw) * 20 + 30)

    # Net Total at the bottom of the last page
    p.setFont("Helvetica-Bold", 14)
    p.drawString(400, y_position, "Net Total:")
    p.drawString(470, y_position, f"${order.amount_paid}")

    # Footer
    p.setFont("Helvetica", 10)
    p.drawString(50, 30, "Thank you for shopping with us!")
    p.drawString(50, 15, "For any queries, contact [email protected]")

    p.showPage()
    p.save()

    buffer.seek(0)
    return buffer.getvalue()