class SignupHandler(Handler):
    def get(self):
        self.render("signup_form.html")

    def post(self):
        have_error = False
        self.user_username = self.request.get('username')
        self.user_password = self.request.get('password')
        self.user_verify = self.request.get('verify')
        self.user_email = self.request.get('email')

        check_username = valid_helpers.valid_username(self.user_username)
        check_password = valid_helpers.valid_password(self.user_password)
        check_verify = valid_helpers.valid_verify(self.user_verify, self.user_password)
        check_email = valid_helpers.valid_email(self.user_email)

        params = dict(user_username = self.user_username, user_email = self.user_email)

        if not(check_username):
            params['error_username'] = "That's not a valid username."
            have_error = True
        if not(check_password):
            params['error_password'] = "That wasn't a valid password."
            have_error = True
        if not(check_verify):
            params['error_verify'] = "Your passwords didn't match."
            have_error = True
        if not(check_email):
            params['error_email'] = "That's not a valid email."
            have_error = True
        if not have_error:
            existing_user = User.by_name(self.user_username)
            if existing_user:
                params['error_username'] = "This user already exists"
                have_error = True

        if have_error:
            self.render("signup_form.html", **params)
        else:
            self.done()