import re
from decimal import Decimal

from fastapi import APIRouter, File, UploadFile
from pydantic import BaseModel

router = APIRouter(prefix="/ocr", tags=["ocr"])


class ReceiptSuggestion(BaseModel):
    total_cost: Decimal | None = None
    liters: Decimal | None = None
    price_per_liter: Decimal | None = None
    station: str | None = None
    confidence: float
    message: str


@router.post("/fuel-receipt", response_model=ReceiptSuggestion)
async def scan_fuel_receipt(file: UploadFile = File(...)) -> ReceiptSuggestion:
    content = await file.read()
    text = content.decode("utf-8", errors="ignore")
    numbers = [Decimal(item.replace(",", ".")) for item in re.findall(r"\d+[,.]\d+|\d+", text)]
    total = max(numbers) if numbers else None
    liters = next((item for item in numbers if Decimal("5") <= item <= Decimal("120")), None)
    price = None
    if total and liters and liters:
        price = (total / liters).quantize(Decimal("0.01"))

    return ReceiptSuggestion(
        total_cost=total,
        liters=liters,
        price_per_liter=price,
        station=None,
        confidence=0.35 if numbers else 0,
        message=(
            "OCR-модуль готов к подключению движка распознавания. Сейчас извлекаю числа из текстового слоя/имени файла."
            if numbers
            else "Не удалось распознать чек. Можно заполнить поля вручную, а OCR-движок подключить отдельным сервисом."
        ),
    )