app/services/qr_generator_service.py

from __future__ import annotations

import urllib.parse
from typing import Any, Dict, List

from app.core.logger import get_logger

logger = get_logger(__name__)

QR_CODE_BASE_URL = "https://api.qrserver.com/v1/create-qr-code/"
DEFAULT_SIZE = "300x300"
MAX_DATA_LENGTH = 2048
MAX_ITEMS = 500


class QRGeneratorError(Exception):
    pass


class QRGeneratorService:

    def generate_bulk(
        self,
        data_list: List[str],
        size: str = DEFAULT_SIZE,
    ) -> List[Dict[str, Any]]:
        results: List[Dict[str, Any]] = []
        for idx, data in enumerate(data_list):
            try:
                self._validate_data(data)
                qr_url = self._build_qr_url(data, size)
                results.append({
                    "index": idx,
                    "data": data,
                    "qr_image_url": qr_url,
                    "error": None,
                })
            except QRGeneratorError as e:
                results.append({
                    "index": idx,
                    "data": data,
                    "qr_image_url": None,
                    "error": str(e),
                })
        return results

    @staticmethod
    def _validate_data(data: str) -> None:
        if not data or not isinstance(data, str):
            raise QRGeneratorError("Data must be a non-empty string")
        if len(data) > MAX_DATA_LENGTH:
            raise QRGeneratorError(
                f"Data exceeds max length of {MAX_DATA_LENGTH} characters"
            )

    @staticmethod
    def _build_qr_url(data: str, size: str) -> str:
        encoded = urllib.parse.quote(data, safe="")
        return f"{QR_CODE_BASE_URL}?size={size}&data={encoded}"