from datetime import datetime
from flask import current_app
from werkzeug.utils import secure_filename
from app import db


class FileMixin:
    '''
    Mixin for db.Model classes. All file related models should use this.
    '''
    creation_date = db.Column(db.DateTime, default=datetime.utcnow)
    filename = db.Column(db.String(255))
    mimetype = db.Column(db.String(255))

    def file_mixin_to_json_serializeable(self, backrefs=False, relationships=False):
        return {
            'creation_date': f'{self.creation_date.isoformat()}Z',
            'filename': self.filename,
            'mimetype': self.mimetype
        }
    
    @classmethod
    def create(cls, file_storage, **kwargs):
        filename = kwargs.pop('filename', file_storage.filename)
        mimetype = kwargs.pop('mimetype', file_storage.mimetype)
        obj = cls(
            filename=secure_filename(filename),
            mimetype=mimetype,
            **kwargs
        )
        db.session.add(obj)
        db.session.flush(objects=[obj])
        db.session.refresh(obj)
        try:
            file_storage.save(obj.path)
        except (AttributeError, OSError) as e:
            current_app.logger.error(e)
            db.session.rollback()
            raise e
        return obj