require "devise_sms_activable/hooks"

module Devise
  module Models
    # SmsActivable is responsible to verify if an account is already confirmed to
    # sign in, and to send sms with confirmation instructions.
    # Confirmation instructions are sent to the user phone after creating a
    # record and when manually requested by a new confirmation instruction request.
    #
    # == Options
    #
    # Confirmable adds the following options to devise_for:
    #
    #   * +sms_confirm_within+: the time you want to allow the user to access his account
    #     before confirming it. After this period, the user access is denied. You can
    #     use this to let your user access some features of your application without
    #     confirming the account, but blocking it after a certain period (ie 7 days).
    #     By default confirm_within is 0 days, so the user must confirm before entering.
    #     If you want to allow user to use parts of the site and block others override sms_confirmation_required? 
    #     and check manually on selected pages using the require_sms_activated! helper or sms_confirmed? property on record
    #
    # == Examples
    #
    #   User.find(1).sms_confirm!      # returns true unless it's already confirmed
    #   User.find(1).sms_confirmed?    # true/false
    #   User.find(1).send_sms_token # manually send token
    #
    module SmsActivable
      extend ActiveSupport::Concern

      included do
        before_create :generate_sms_token, :if => :sms_confirmation_required?
        after_create  :resend_sms_token, :if => :sms_confirmation_required?
      end

      # Confirm a user by setting it's sms_confirmed_at to actual time. If the user
      # is already confirmed, add en error to email field
      def confirm_sms!
        unless_sms_confirmed do
          self.sms_confirmation_token = nil
          self.sms_confirmed_at = Time.now
          save(:validate => false)
        end
      end

      # Verifies whether a user is sms-confirmed or not
      def confirmed_sms?
        !!sms_confirmed_at
      end

      # Send confirmation token by sms
      def send_sms_token
        if(self.phone?)
          generate_sms_token! if self.generate_sms_token.nil?
          ::Devise.sms_sender.send_sms(self.phone, I18n.t(:"devise.sms_activations.sms_body", :sms_confirmation_token => self.sms_confirmation_token, :default => self.sms_confirmation_token))
        else
          self.errors.add(:sms_confirmation_token, :no_phone_associated)
          false
        end
      end

      # Resend sms confirmation token. This method does not need to generate a new token.
      def resend_sms_token
        unless_sms_confirmed { send_sms_token }
      end

      # Overwrites active? from Devise::Models::Activatable for sms confirmation
      # by verifying whether a user is active to sign in or not. If the user
      # is already confirmed, it should never be blocked. Otherwise we need to
      # calculate if the confirm time has not expired for this user.

      def active?
        super && !sms_confirmation_required? || confirmed_sms? || confirmation_sms_period_valid?
      end

      # The message to be shown if the account is inactive.
      def inactive_message
        !confirmed_sms? ? I18n.t(:"devise.sms_activations.unconfirmed_sms") : super
      end

      # If you don't want confirmation to be sent on create, neither a code
      # to be generated, call skip_sms_confirmation!
      def skip_sms_confirmation!
        self.sms_confirmed_at = Time.now
      end

      protected

        # Callback to overwrite if an sms confirmation is required or not.
        def sms_confirmation_required?
          !confirmed_sms?
        end

        # Checks if the confirmation for the user is within the limit time.
        # We do this by calculating if the difference between today and the
        # confirmation sent date does not exceed the confirm in time configured.
        # Confirm_in is a model configuration, must always be an integer value.
        #
        # Example:
        #
        #   # sms_confirm_within = 1.day and sms_confirmation_sent_at = today
        #   confirmation_period_valid?   # returns true
        #
        #   # sms_confirm_within = 5.days and sms_confirmation_sent_at = 4.days.ago
        #   confirmation_period_valid?   # returns true
        #
        #   # sms_confirm_within = 5.days and sms_confirmation_sent_at = 5.days.ago
        #   confirmation_period_valid?   # returns false
        #
        #   # sms_confirm_within = 0.days
        #   confirmation_period_valid?   # will always return false
        #
        def confirmation_sms_period_valid?
          confirmation_sms_sent_at && confirmation_sms_sent_at.utc >= self.class.sms_confirm_within.ago
        end

        # Checks whether the record is confirmed or not, yielding to the block
        # if it's already confirmed, otherwise adds an error to email.
        def unless_sms_confirmed
          unless confirmed_sms?
            yield
          else
            self.errors.add(:sms_confirmation_token, :sms_already_confirmed)
            false
          end
        end

        # Generates a new random token for confirmation, and stores the time
        # this token is being generated
        def generate_sms_token
          self.sms_confirmed_at = nil
          self.sms_confirmation_token = self.class.sms_confirmation_token
          self.confirmation_sms_sent_at = Time.now.utc
        end

        def generate_sms_token!
          generate_sms_token && save(:validate => false)
        end

        module ClassMethods
          # Attempt to find a user by it's email. If a record is found, send a new
          # sms token instructions to it. If not user is found, returns a new user
          # with an email not found error.
          # Options must contain the user email
          def send_sms_token(attributes={})
            sms_confirmable = find_or_initialize_with_errors(sms_confirmation_keys, attributes, :not_found)
            sms_confirmable.resend_sms_token if sms_confirmable.persisted?
            sms_confirmable
          end

          # Find a user by it's sms confirmation token and try to confirm it.
          # If no user is found, returns a new user with an error.
          # If the user is already confirmed, create an error for the user
          # Options must have the sms_confirmation_token
          def confirm_by_sms_token(sms_confirmation_token)
            sms_confirmable = find_or_initialize_with_error_by(:sms_confirmation_token, sms_confirmation_token)
            sms_confirmable.confirm_sms! if sms_confirmable.persisted?
            sms_confirmable
          end

          # Generates a small token that can be used conveniently on SMS's.
          # The token is 5 chars long and uppercased.

          def generate_small_token(column)
            loop do
              token = Devise.friendly_token[0,5].upcase
              break token unless to_adapter.find_first({ column => token })
            end
          end

          # Generate an sms token checking if one does not already exist in the database.
          def sms_confirmation_token
            generate_small_token(:sms_confirmation_token)
          end

          Devise::Models.config(self, :sms_confirm_within, :sms_confirmation_keys)
        end
    end
  end
end