"""
Notification image serving module.

Serves chart PNG images generated by notification runners.
Images are stored in /tmp/ by the notify-runner process.
"""

import logging
import re
from pathlib import Path

from flask import Blueprint, abort, send_file

from .config import Config

logger = logging.getLogger(__name__)

images_bp = Blueprint("images", __name__)

VALID_FILENAME_PATTERN = re.compile(r"^[a-zA-Z0-9_\-]+\.png$")


@images_bp.route("/api/notifications/images/<filename>")
def serve_notification_image(filename: str):
    """Serve a notification chart image from the temp directory."""
    if not VALID_FILENAME_PATTERN.match(filename):
        abort(404)

    file_path = Path(Config.NOTIFICATION_IMAGES_DIR) / filename
    if not file_path.is_file():
        abort(404)

    response = send_file(file_path, mimetype="image/png")
    response.headers["Cache-Control"] = "no-cache"
    return response