module Rubyfocus
	# The Searchable module allows you to easily search arrays of items by
	# effectively supplying find and select methods. Passing a hash to either
	# of these methods allows you to search by given properties - for example:
	# 
	#   data_store.find(name: "Foobar")
	#
	# Is basically the same as:
	#
	# 	data_store.find{ |o| o.name == "Foobard" }
	#
	# If you pass +find+ or +select+ a String or Fixnum, it will look for objects
	# whose +id+ equals this value.
	#
	# You should ensure that your class' +array+ method is overwritten to point
	# to the appriopriate array.
	module Searchable
		# This method will return only the *first* object that matches the given
		# criteria, or +nil+ if no object is found.
		def find(arg=nil, &blck)
			fs_block = find_select_block(arg) || blck
			if fs_block
				return array.find(&fs_block)
			else
				raise ArgumentError, "ItemArray#find called with #{arg.class} argument."
			end
		end

		# This method will return an array of all objects that match the given
		# criteria, or +[]+ if no object is found.
		def select(arg=nil, &blck)
			fs_block = find_select_block(arg) || blck
			if fs_block
				return array.select(&fs_block)
			else
				raise ArgumentError, "ItemArray#select called with #{arg.class} argument."
			end
		end

		# This method should be overriden
		def array
			raise RuntimeError, "Method #{self.class}#array has not been implemented!"
		end

		private
		# This method determines the correct block to use in find or select operations
		def find_select_block(arg)
			case arg
			when Fixnum # ID
				string_id = arg.to_s
				Proc.new{ |item| item.id == string_id }
			when String
				Proc.new{ |item| item.id == arg }
			when Hash
				Proc.new{ |item| arg.all?{ |k,v| item.send(k) == v } }
			else
				nil
			end
		end
	end


	# A sample class, SearchableArray, is basically a wrapper around a standard array
	class SearchableArray
		include Searchable
		attr_reader :array

		# Takes the same arguments as the array it wraps
		def initialize(*args, &blck)
		  @array = Array.new(*args, &blck)
		end

		# In all other respects, it's an array - handily governed by this method
		def method_missing meth, *args, &blck
			if @array.respond_to?(meth)
				@array.send(meth, *args, &blck)
			else
				super(meth, *args, &blck)
			end
		end
	end
end