# frozen_string_literal: true

require 'bcrypt'

module OmniAuth
  module Identity
    # This is lightly edited from Rails 6.1 code and is used if
    # the version of ActiveModel that's being used does not
    # include SecurePassword. The only difference is that instead of
    # using ActiveSupport::Concern, it checks to see if there is already
    # a has_secure_password method.
    module SecurePassword
      def self.included(base)
        base.extend ClassMethods unless base.respond_to?(:has_secure_password)
      end

      # BCrypt hash function can handle maximum 72 bytes, and if we pass
      # password of length more than 72 bytes it ignores extra characters.
      # Hence need to put a restriction on password length.
      MAX_PASSWORD_LENGTH_ALLOWED = 72

      class << self
        attr_accessor :min_cost # :nodoc:
      end
      self.min_cost = false

      module ClassMethods
        # Adds methods to set and authenticate against a BCrypt password.
        # This mechanism requires you to have a +XXX_digest+ attribute.
        # Where +XXX+ is the attribute name of your desired password.
        #
        # The following validations are added automatically:
        # * Password must be present on creation
        # * Password length should be less than or equal to 72 bytes
        # * Confirmation of password (using a +XXX_confirmation+ attribute)
        #
        # If confirmation validation is not needed, simply leave out the
        # value for +XXX_confirmation+ (i.e. don't provide a form field for
        # it). When this attribute has a +nil+ value, the validation will not be
        # triggered.
        #
        # For further customizability, it is possible to suppress the default
        # validations by passing <tt>validations: false</tt> as an argument.
        #
        # Add bcrypt (~> 3.1.7) to Gemfile to use #has_secure_password:
        #
        #   gem 'bcrypt', '~> 3.1.7'
        #
        # Example using Active Record (which automatically includes ActiveModel::SecurePassword):
        #
        #   # Schema: User(name:string, password_digest:string, recovery_password_digest:string)
        #   class User < ActiveRecord::Base
        #     has_secure_password
        #     has_secure_password :recovery_password, validations: false
        #   end
        #
        #   user = User.new(name: 'david', password: '', password_confirmation: 'nomatch')
        #   user.save                                                  # => false, password required
        #   user.password = 'mUc3m00RsqyRe'
        #   user.save                                                  # => false, confirmation doesn't match
        #   user.password_confirmation = 'mUc3m00RsqyRe'
        #   user.save                                                  # => true
        #   user.recovery_password = "42password"
        #   user.recovery_password_digest                              # => "$2a$04$iOfhwahFymCs5weB3BNH/uXkTG65HR.qpW.bNhEjFP3ftli3o5DQC"
        #   user.save                                                  # => true
        #   user.authenticate('notright')                              # => false
        #   user.authenticate('mUc3m00RsqyRe')                         # => user
        #   user.authenticate_recovery_password('42password')          # => user
        #   User.find_by(name: 'david')&.authenticate('notright')      # => false
        #   User.find_by(name: 'david')&.authenticate('mUc3m00RsqyRe') # => user
        def has_secure_password(attribute = :password, validations: true)
          # Load bcrypt gem only when has_secure_password is used.
          # This is to avoid ActiveModel (and by extension the entire framework)
          # being dependent on a binary library.
          begin
            require 'bcrypt'
          rescue LoadError
            warn "You don't have bcrypt installed in your application. Please add it to your Gemfile and run bundle install"
            raise
          end

          include InstanceMethodsOnActivation.new(attribute)

          if validations
            include ActiveModel::Validations

            # This ensures the model has a password by checking whether the password_digest
            # is present, so that this works with both new and existing records. However,
            # when there is an error, the message is added to the password attribute instead
            # so that the error message will make sense to the end-user.
            validate do |record|
              record.errors.add(attribute, :blank) unless record.public_send("#{attribute}_digest").present?
            end

            validates_length_of attribute, maximum: ActiveModel::SecurePassword::MAX_PASSWORD_LENGTH_ALLOWED
            validates_confirmation_of attribute, allow_blank: true
          end
        end
      end

      class InstanceMethodsOnActivation < Module
        def initialize(attribute)
          attr_reader attribute

          define_method("#{attribute}=") do |unencrypted_password|
            if unencrypted_password.nil?
              public_send("#{attribute}_digest=", nil)
            elsif !unencrypted_password.empty?
              instance_variable_set("@#{attribute}", unencrypted_password)
              cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST : BCrypt::Engine.cost
              public_send("#{attribute}_digest=", BCrypt::Password.create(unencrypted_password, cost: cost))
            end
          end

          define_method("#{attribute}_confirmation=") do |unencrypted_password|
            instance_variable_set("@#{attribute}_confirmation", unencrypted_password)
          end

          # Returns +self+ if the password is correct, otherwise +false+.
          #
          #   class User < ActiveRecord::Base
          #     has_secure_password validations: false
          #   end
          #
          #   user = User.new(name: 'david', password: 'mUc3m00RsqyRe')
          #   user.save
          #   user.authenticate_password('notright')      # => false
          #   user.authenticate_password('mUc3m00RsqyRe') # => user
          define_method("authenticate_#{attribute}") do |unencrypted_password|
            attribute_digest = public_send("#{attribute}_digest")
            BCrypt::Password.new(attribute_digest).is_password?(unencrypted_password) && self
          end

          alias_method :authenticate, :authenticate_password if attribute == :password
        end
      end
    end
  end
end