# Redmine - project management software
# Copyright (C) 2006-2009  Jean-Philippe Lang
# Adapted to fit needs for mOTP
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

require_dependency 'token/base'

module Token
  class HashedToken < Base
    # Allow access to the plain value during initial access / creation of the token
    attr_reader :plain_value

    class << self
      def create_and_return_value(user)
        create(user: user).plain_value
      end

      ##
      # Find a token from the token value
      def find_by_plaintext_value(input)
        find_by(value: hash_function(input))
      end
    end

    ##
    # Validate the user input on the token
    # 1. The token is still valid
    # 2. The plain text matches the hash
    def valid_plaintext?(input)
      hashed_input = hash_function(input)
      ActiveSupport::SecurityUtils.secure_compare hashed_input, value
    end

    def self.hash_function(input)
      # Use a fixed salt for hashing token values.
      # We still want to be able to index the hash value for fast lookups,
      # so we need to determine the hash without knowing the associated user (and thus its salt) first.
      Digest::SHA256.hexdigest(input + Rails.application.secrets.fetch(:secret_key_base))
    end
    delegate :hash_function, to: :class

    private

    def initialize_values
      if new_record? && !value.present?
        @plain_value = self.class.generate_token_value
        self.value = hash_function(@plain_value)
      end
    end
  end
end