from flask_wtf import FlaskForm
from werkzeug.utils import secure_filename
from wtforms import FileField, SubmitField, ValidationError
from wtforms.validators import DataRequired


class ImportResultsForm(FlaskForm):
    '''
    Form used to import one result json file.
    '''
    file = FileField('File', validators=[DataRequired()])
    submit = SubmitField()

    def validate_file(self, field):
        if not field.data.filename.lower().endswith('.json'):
            raise ValidationError('File does not have an approved extension: '
                                  '.json')
        field.data.filename = secure_filename(field.data.filename)