module Neo4j
  module Rails
    module Finders
      extend ActiveSupport::Concern

      included do
        rule(:_all, :functions => Neo4j::Rule::Functions::Count.new)
      end

      module ClassMethods
        # overwrite the index method to add find_by_xxx class methods
        def index(*args)
          field = args.first
          module_eval <<-RUBY, __FILE__, __LINE__
						def self.all_by_#{field}(value)
							find_with_indexer("#{field}: \\"\#{value}\\"")
						end
						
						def self.find_by_#{field}(value)
							all_by_#{field}(value).first
						end
          RUBY

          super
        end

        # load an id or array of ids from the database
        def load(*ids)
          result = ids.map { |id| Neo4j::Node.load(id) }
          if ids.length == 1
            result.first
          else
            result
          end
        end

        # Behave like the ActiveRecord query interface
        #
        # === Example
        #
        #   Handle Model.find(params[:id])
        #   Model.find
        #   Model.find(:first)
        #   Model.find("1")
        #   Model.find(1)
        #   Model.find("name: test")
        #   Model.find(:name => "test")
        #   Model.find(:first, "name: test")
        #   Model.find(:first, { :name => "test" })
        #   Model.find(:first, :conditions => "name: test")
        #   Model.find(:first, :conditions => { :name => "test" })
        #   Model.find(:all, "name: test")
        #   Model.find(:all, { :name => "test" })
        #   Model.find(:all, :conditions => "name: test")
        #   Model.find(:all, :conditions => { :name => "test" })
        #
        def find(*args)
          case args.first
            when :all, :first
              kind = args.shift
              send(kind, *args)
            when "0", 0
              nil
            else
              if ((args.first.is_a?(Integer) || args.first.is_a?(String)) && args.first.to_i > 0)
                find_with_ids(*args)
              else
                first(*args)
              end
          end
        end

        def all(*args)
          if !conditions_in?(*args)
            # use the _all rule to recover all the stored instances of this node
            _all
          else
            # handle the special case of a search by id
            ids = ids_in(args.first)
            if ids
              [find_with_ids(ids)].flatten
            else
              find_with_indexer(*args)
            end
          end
        end

        def first(*args)
          all(*args).first
        end

        def last(*args)
          a = all(*args)
          a.empty? ? nil : a[a.size - 1]
        end

        def count
          all.size
        end

        # Call this method if you are using Neo4j::Rails::Model outside rails
        # This method is automatically called by rails to close all lucene connections.
        def close_lucene_connections
          Thread.current[:neo4j_lucene_connection].each {|hits| hits.close} if Thread.current[:neo4j_lucene_connection]
          Thread.current[:neo4j_lucene_connection] = nil
        end

        protected

        def ids_in(arg)
          return nil unless arg.is_a?(Hash)
          condition = arg[:conditions].present? ? arg[:conditions] : arg
          condition.is_a?(Hash) && condition[:id]
        end


        def conditions_in?(*args)
          return false if args.empty?

          # does it contain an string, which will be treated like a condition ?
          return true if args.find { |a| a.is_a?(String) }

          # does it contain an empty conditions param ?
          hash = args.find { |a| a.is_a?(Hash) }
          if hash
            return false if hash.include?(:conditions) && hash[:conditions].empty?

            # does it contain only paging or sorting params ?
            !hash.except(:sort, :page, :per_page).empty?
          else
            return false
          end
        end

        def find_with_ids(*args)
          result = load(*args.map { |p| p.to_i })
          if result.is_a?(Array)
            result = result.select { |r| r.is_a? self }
          else
            result = nil unless result.is_a? self
          end
          result
        end

        def find_with_indexer(*args)
          hits                                     = _indexer.find(*args)
          # We need to save this so that the Rack Neo4j::Rails:LuceneConnection::Closer can close it
          Thread.current[:neo4j_lucene_connection] ||= []
          Thread.current[:neo4j_lucene_connection] << hits
          hits
        end
      end
    end
  end
end