"""File upload: images and documents, max 10MB."""
import os
import uuid
from flask import current_app
from werkzeug.utils import secure_filename

ALLOWED_IMAGE_EXT = {"png", "jpg", "jpeg", "gif", "webp"}
ALLOWED_DOC_EXT = {"pdf", "doc", "docx", "txt", "md"}
MAX_SIZE = 10 * 1024 * 1024


class FileService:
    @staticmethod
    def save_upload(file, subdir="uploads"):
        if not file or not file.filename:
            return None
        filename = secure_filename(file.filename)
        if not filename:
            filename = str(uuid.uuid4())
        ext = filename.rsplit(".", 1)[-1].lower() if "." in filename else ""
        if ext not in ALLOWED_IMAGE_EXT and ext not in ALLOWED_DOC_EXT:
            return None
        upload_root = current_app.config.get("UPLOAD_FOLDER", "/tmp/chat_uploads")
        dest_dir = os.path.join(upload_root, subdir)
        os.makedirs(dest_dir, exist_ok=True)
        unique = "{}_{}".format(uuid.uuid4().hex, filename)
        path = os.path.join(dest_dir, unique)
        file.save(path)
        if os.path.getsize(path) > MAX_SIZE:
            os.remove(path)
            return None
        return (os.path.join(subdir, unique), path)