module Sunrise
  module FileUpload
    module ActiveRecord
      def self.included(base)
        base.send :extend, SingletonMethods
      end
      
      module SingletonMethods
        def fileuploads(*args)
          options = args.extract_options!
          
          class_attribute :fileuploads_options, :instance_writer => false
          self.fileuploads_options = options
          
          class_attribute :fileuploads_columns, :instance_writer => false
          self.fileuploads_columns = args.map(&:to_sym)
          
          unless self.is_a?(ClassMethods)
            include InstanceMethods
            extend ClassMethods
            
            attr_accessible :fileupload_guid
            after_save :fileuploads_update, :if => :fileupload_changed?
            
            args.each do |asset|
              accepts_nested_attributes_for asset, :allow_destroy => true
            end
          end
        end
      end
      
      module ClassMethods
        # Update reflection klass by guid
        def fileupload_update(record_id, guid, method)
          klass = fileupload_klass(method)
          klass.update_all(["assetable_id = ?, guid = ?", record_id, nil], ["assetable_type = ? AND guid = ?", name, guid])
        end
        
        # Find asset by guid
        def fileupload_find(method, guid)
          klass = fileupload_klass(method)
          klass.where(:guid => guid).first
        end
        
        protected
          
          def fileupload_klass(method)
            reflections[method.to_sym].klass
          end
      end
      
      module InstanceMethods
        # Generate unique key
        def fileupload_guid
          @fileupload_guid ||= Sunrise::FileUpload.guid
        end
        
        def fileupload_guid=(value)
          @fileupload_changed = true unless value.blank?
          @fileupload_guid = value.blank? ? nil : value
        end
        
        def fileupload_changed?
          @fileupload_changed
        end
        
        def fileupload_multiple?(method)
          association = self.class.reflect_on_association(method)
          association.collection? 
        end
        
        # Find or build new asset object
        def fileupload_asset(method)
          if fileuploads_columns.include?(method.to_sym)
            asset = new_record? ? self.class.fileupload_find(method, fileupload_guid) : send(method)
            asset ||= send("build_#{method}") if respond_to?("build_#{method}")
          end
        end
        
        def fileuploads_columns
          self.class.fileuploads_columns
        end
        
        protected
        
          def fileuploads_update
            fileuploads_columns.each do |method|
              self.class.fileupload_update(id, fileupload_guid, method)
            end
          end
      end
      
    end
  end
end