Samsinite/notify_me

class NotifyMe::Action < ActiveRecord::Base
    self.table_name = "notify_me_actions"

    belongs_to :notification
    belongs_to :commandable,       :polymorphic => true

    validates :notification,       :presence => true
    validates :commandable_type,   :presence => true
    validates :commandable_action, :presence => true
    validate  :validate_uniqness_of_unprocessed_identifiers
    validate  :validate_pressence_of_action

    def validate_uniqness_of_unprocessed_identifiers
        if self.response_identifier != nil
            if NotifyMe::Action.where("response_identifier = ? AND has_been_processed = ?",
                                      self.response_identifier, false).count > 0
                errors.add(:base, "The response_identifier is not unique among unprocessed actions")
            end
        end
    end

    def validate_pressence_of_action
        if self.commandable
            unless self.commandable.respond_to?(self.commandable_action)
                errors.add(:base, "The commandable action #{self.commandable_action} does not exist on the commandable instance")
            end
        else
            begin
                unless self.commandable_type.constantize.respond_to?(self.commandable_action)
                    errors.add(:base, "The commandable action #{self.commandable_action} does not exist on the commandable_type constant")
                end
            rescue NameError
                errors.add(:base, "The commandable_type does not refer to a valid constant")
            end
        end
    end

    def self.process_by_identifier(identifier, *args)
        action = self.where("response_identifier = ? AND has_been_processed = ?",
                            identifier, false).first

        if action
            {:action => action, :rval => action.run_action(*args)}
        else
            nil
        end
    end

    def run_command(*args)
        if self.commandable
            self.commandable.send(self.commandable_action, self, *args)
        else
            self.commandable_type.constantize.send(self.commandable_action, self, *args)
        end
    end

    def run_action(*args)
        rval = run_command(*args)

        self.has_been_processed = true
        self.save!

        return rval
    end
end