#!/usr/bin/env python
# -*- encoding: utf-8 -*-

"""Helper functions."""

from functools import wraps

from flask import request
from flask import jsonify

from luncho.server import User


class ForceJSON(object):
    def __init__(self, required=None):
        self.required = required or []

    def __call__(self, func):
        @wraps(func)
        def check_json(*args, **kwargs):
            json = request.get_json(force=True, silent=True)
            if not json:
                return JSONError(400, 'Request MUST be in JSON format')

            # now we have the JSON, let's check if all the fields are here.
            missing = []
            for field in self.required or []:
                if not field in json:
                    missing.append(field)

            if missing:
                return JSONError(400, 'Missing fields', fields=missing)

            return func(*args, **kwargs)
        return check_json


def JSONError(status, message, **kwargs):
    """Generate a JSON error message with the error and extra fields.

    :param status: the HTTP status code for the error
    :type status: int
    :param message: The message in the error
    :type message: str
    :param kwargs: Extra fields to be added in the response. *Note*: `status`
                   and `message` should **NOT** be used.
    :type kwargs: kwargs

    :return: A response with the JSON and the status code."""
    resp = jsonify(status='ERROR',
                   message=message,
                   **kwargs)
    resp.status_code = status
    return resp


def user_or_error(token):
    """Returns a tuple with the user that owns the token and the error. If the
    token is valid, user will have the user object and error will be None; if
    there is something wrong with the token, the user will be None and the
    error will have a Response created with :py:func:`JSONError`.

    :param token: The token received
    :type token: str

    :return: Tuple with the user and the error."""
    user = User.query.filter_by(token=token).first()
    if not user:
        return (None, JSONError(404, 'User not found (via token)'))

    if not user.valid_token(token):
        return (None, JSONError(400, 'Invalid token'))

    return (user, None)