from io import BytesIO
from typing import Optional

from fastapi import HTTPException
from reportlab.lib.units import mm
from reportlab.pdfgen.canvas import Canvas
from reportlab.platypus import Paragraph, SimpleDocTemplate, Frame, PageBreak
from reportlab_qrcode import QRCodeImage
from sqlalchemy import select, func
from sqlalchemy.orm import joinedload, selectinload

from constants import DOMAIN_NAME
from generators.base_pdf_card_generator.base_pdf_card_generator import BasePdfCardGenerator
from models import Deal, ShippingWarehouse, Pallet
from models.shipping import Box


class ShippingQRCodeGenerator(BasePdfCardGenerator):
    async def _get_deal_by_id(self, deal_id: int) -> Optional[Deal]:
        stmt = (
            select(Deal)
            .where(Deal.id == deal_id)
            .options(
                joinedload(Deal.shipping_warehouse),
                selectinload(Deal.pallets),
            )
        )
        deal = (await self._session.execute(stmt)).one_or_none()
        return deal[0] if deal else None

    async def generate_deal(self, deal_id: int) -> BytesIO:
        deal = await self._get_deal_by_id(deal_id)
        if not deal:
            raise HTTPException(status_code=404, detail=f"Сделка с ID {deal_id}a не найдена")

        buffer = BytesIO()
        doc: SimpleDocTemplate = self._create_doc(buffer)

        deal_link = f"{DOMAIN_NAME}/deals/{deal_id}"
        shipping_warehouse = await self._session.get(ShippingWarehouse, deal.shipping_warehouse_id)
        warehouse_name = shipping_warehouse.name if shipping_warehouse else ""

        def on_first_page(canvas: Canvas, doc):
            qr = QRCodeImage(deal_link, size=30 * mm)
            qr.drawOn(canvas, 0, 30)

            deal_id_paragraph = Paragraph(f"ID: {deal_id}", self.small_centered_style)
            deal_name_paragraph = Paragraph(str(deal.name), self.small_centered_style)

            frame = Frame(x1=28 * mm, y1=5 * mm, width=30 * mm, height=30 * mm)
            frame.addFromList([deal_id_paragraph, deal_name_paragraph], canvas)

            warehouse_paragraph = Paragraph(warehouse_name, self.small_centered_style)
            frame = Frame(x1=0 * mm, y1=-7 * mm, width=58 * mm, height=20 * mm)
            frame.addFromList([warehouse_paragraph], canvas)

        empty_paragraph = Paragraph("", self.small_centered_style)
        elements = [empty_paragraph]
        doc.build(elements, on_first_page)

        buffer.seek(0)
        return buffer

    async def generate_pallets(self, deal_id: int):
        deal = await self._get_deal_by_id(deal_id)
        if not deal:
            raise HTTPException(status_code=404, detail=f"Сделка с ID {deal_id}a не найдена")

        buffer = BytesIO()
        doc: SimpleDocTemplate = self._create_doc(buffer)

        shipping_warehouse = await self._session.get(ShippingWarehouse, deal.shipping_warehouse_id)
        warehouse_name = shipping_warehouse.name if shipping_warehouse else ""

        elements = []

        for pallet in deal.pallets:
            elements.append(Paragraph(f"ID: {deal_id}", self.medium_style))
            elements.append(Paragraph(str(deal.name), self.medium_style))
            elements.append(Paragraph(f"Паллет П{pallet.id}", self.medium_style))
            elements.append(Paragraph(warehouse_name, self.medium_style))
            elements.append(PageBreak())

        doc.build(elements)

        buffer.seek(0)
        return buffer

    async def _get_boxes_on_pallets_count(self, deal_id):
        stmt_boxes_on_pallets = (
            select(
                Pallet.id,
                func.count(Box.id).label("box_count"),
            )
            .join(Box, isouter=True)
            .where(Pallet.deal_id == deal_id)
            .group_by(Pallet.id)
        )
        pallets = (await self._session.execute(stmt_boxes_on_pallets)).all()
        return pallets

    async def generate_boxes(self, deal_id: int) -> BytesIO:
        deal = await self._get_deal_by_id(deal_id)
        if not deal:
            raise HTTPException(status_code=404, detail=f"Сделка с ID {deal_id}a не найдена")

        shipping_warehouse = await self._session.get(ShippingWarehouse, deal.shipping_warehouse_id)
        warehouse_name = shipping_warehouse.name if shipping_warehouse else ""

        buffer = BytesIO()
        doc: SimpleDocTemplate = self._create_doc(buffer)

        elements = []

        for box in deal.boxes:
            elements.append(Paragraph(f"ID: {deal_id}", self.medium_style))
            elements.append(Paragraph(str(deal.name), self.medium_style))
            elements.append(Paragraph(f"Короб K{box.id}", self.medium_style))
            elements.append(Paragraph(warehouse_name, self.medium_style))
            elements.append(PageBreak())

        for pallet in deal.pallets:
            for box in pallet.boxes:
                elements.append(Paragraph(f"ID: {deal_id}", self.medium_style))
                elements.append(Paragraph(str(deal.name), self.medium_style))
                box_label = f"Паллет П{pallet.id}, Короб K{box.id}"
                elements.append(Paragraph(box_label, self.medium_style))
                elements.append(Paragraph(warehouse_name, self.medium_style))
                elements.append(PageBreak())

        doc.build(elements)

        buffer.seek(0)
        return buffer