import json

from bottle import request, response

import model


def missing_attributes(attrs):
    for attr in attrs:
        if attr not in request.json:
            return attr
        else:
            return False


def login():
    missing = missing_attributes(['username', 'password'])
    if missing:
        return bad_request('Missing value for attribute ' + str(missing))
    username = request.json['username']
    password = request.json['password']
    session_id = model.login(username, password)
    if session_id:
        return {'session_id': session_id}
    else:
        return forbidden('Invalid login data')


def register():
    missing = missing_attributes(['username', 'password'])
    if missing:
        return bad_request('Missing value for attribute ' + str(missing))
    username = request.json['username']
    password = request.json['password']
    if model.user_exists(username):
        return forbidden('User already exists.')
    model.register(username, password)
    return {'message': "successfully registered user"}


def not_found(msg=None):
    response.status = 404
    response.content_type = 'application/json'
    if msg is None:
        return json.dumps({"error": "404: Page not found"})
    else:
        return json.dumps({"error": "404: Page not found: " + msg})


def forbidden(msg=None):
    response.status = 403
    response.content_type = 'application/json'
    if msg is None:
        return json.dumps({"error": "403: Forbidden"})
    else:
        return json.dumps({"error": "403: Forbidden: " + msg})


def bad_request(msg=None):
    response.status = 400
    response.content_type = 'application/json'
    if msg is None:
        return json.dumps({"error": "400: Bad request"})
    else:
        return json.dumps({"error": "400: Bad request: " + msg})