import json
from functools import wraps
from flask import redirect, request, current_app
import re

jsonp_validator = re.compile("^[a-zA-Z0-9_\-.]{1,128}$")


def jsonp(f):
    """Wraps JSONified output for JSONP"""
    @wraps(f)
    def decorated_function(*args, **kwargs):
        callback = request.args.get('callback', False)
        if callback and jsonp_validator.match(callback):
            content = str(callback) + '(' + str(f(*args, **kwargs).data) + ')'
            return current_app.response_class(
                content, mimetype='application/javascript')
        else:
            return f(*args, **kwargs)
    return decorated_function