import io
import qrcode
from reportlab.lib.pagesizes import landscape, A5
from reportlab.pdfgen import canvas
from reportlab.lib import colors
from reportlab.lib.utils import ImageReader

def generate_qr_ticket(ticket_id: int, user_id: int, seat_id: int = 0) -> bytes:
    buffer = io.BytesIO()
    width, height = landscape(A5)
    c = canvas.Canvas(buffer, pagesize=(width, height))

    # Темный фон (под дизайн фронтенда)
    c.setFillColor(colors.HexColor("#121212"))
    c.rect(0, 0, width, height, fill=1, stroke=0)

    # Белая карточка билета
    margin = 20
    c.setFillColor(colors.white)
    c.roundRect(margin, margin, width - 2*margin, height - 2*margin, 10, fill=1, stroke=0)

    # Текст
    c.setFillColor(colors.black)
    c.setFont("Helvetica-Bold", 28)
    c.drawString(margin + 30, height - margin - 50, "EVENT TICKET")

    c.setFont("Helvetica", 14)
    c.drawString(margin + 30, height - margin - 100, f"Ticket ID: {ticket_id}")
    c.drawString(margin + 30, height - margin - 130, f"User ID: {user_id}")
    if seat_id:
        c.drawString(margin + 30, height - margin - 160, f"Seat ID: {seat_id}")

    c.setFont("Helvetica-Oblique", 10)
    c.setFillColor(colors.gray)
    c.drawString(margin + 30, margin + 30, "Scan this QR code at the entrance.")

    # QR-код
    qr = qrcode.QRCode(box_size=5, border=1)
    qr.add_data(f"TICKET:{ticket_id}|USER:{user_id}|SEAT:{seat_id}")
    qr.make(fit=True)
    img = qr.make_image(fill_color="black", back_color="white")
    
    # Буферизация картинки для ReportLab
    img_buffer = io.BytesIO()
    img.save(img_buffer, format="PNG")
    img_buffer.seek(0)
    
    c.drawImage(ImageReader(img_buffer), width - margin - 160, margin + 30, width=130, height=130)

    c.showPage()
    c.save()
    buffer.seek(0)
    return buffer.read()