#!/usr/bin/env ruby
# coding: utf-8

require 'treequel'
require 'treequel/model'
require 'treequel/mixins'
require 'treequel/constants'


# Mixin that provides Treequel::Model characteristics to a mixin module.
module Treequel::Model::ObjectClass

	### Extension callback -- add data structures to the extending +mod+.
	### @param [Module] mod  the mixin module to be extended
	def self::extended( mod )
		# mod.instance_variable_set( :@model_directory, nil )
		# mod.instance_variable_set( :@model_bases, [] )
		mod.instance_variable_set( :@model_class, Treequel::Model )
		mod.instance_variable_set( :@model_objectclasses, [] )
		mod.instance_variable_set( :@model_bases, [] )
		super
	end


	### Inclusion callback -- Methods should be applied to the module rather than an instance.
	### Warn the user if they use include() and extend() instead.
	def self::included( mod )
		warn "extending %p rather than appending features to it" % [ mod ]
		mod.extend( self )
	end


	### Declare which Treequel::Model subclasses the mixin will register itself with. If this is
	### used, it should be declared *before* declaring the mixin's bases and/or objectClasses.
	def model_class( mclass=nil )
		if mclass

			# If there were already registered objectclasses, remove them from the previous
			# model class
			unless @model_objectclasses.empty? && @model_bases.empty?
				Treequel.log.warn "%p: model_class should come before model_objectclasses" % [ self ]
				@model_class.unregister_mixin( self )
				mclass.register_mixin( self )
			end
			@model_class = mclass
		end

		return @model_class
	end


	### Set or get objectClasses that the mixin requires. Also registers the mixin with
	### Treequel::Model.
	### 
	### @param [Array<#to_sym>] objectclasses  the objectClasses the mixin will apply to, as an
	###         array of Symbols (or objects that respond to #to_sym)
	### @return [Array<Symbol>] the objectClasses that the module requires
	def model_objectclasses( *objectclasses )
		unless objectclasses.empty?
			@model_objectclasses = objectclasses.map( &:to_sym )
			@model_class.register_mixin( self )
		end
		return @model_objectclasses.dup
	end


	### Set or get base DNs that the mixin applies to.
	def model_bases( *base_dns )
		unless base_dns.empty?
			@model_bases = base_dns.collect {|dn| dn.gsub(/\s+/, '') }
			@model_class.register_mixin( self )
		end

		return @model_bases.dup
	end


	### Return a Branchset (or BranchCollection if the receiver has more than one
	### base) that can be used to search the given +directory+ for entries to which
	### the receiver applies.
	###
	### @param [Treequel::Directory] directory  the directory to search
	### @return [Treequel::Branchset, Treequel::BranchCollection]  the encapsulated search
	def search( directory )
		bases = self.model_bases
		objectclasses = self.model_objectclasses

		raise Treequel::ModelError, "%p has no search criteria defined" % [ self ] if
			bases.empty? && objectclasses.empty?

		Treequel.log.debug "Creating search for %s using model class %p" %
			[ self.name, self.model_class ]

		# Start by making a Branchset or BranchCollection for the mixin's bases. If
		# the mixin doesn't have any bases, just use the base DN of the directory
		# to be searched
		bases = [directory.base_dn] if bases.empty?
		search = bases.
			map {|base| self.model_class.new(directory, base).branchset }.
			inject {|branch1,branch2| branch1 + branch2 }

		Treequel.log.debug "Search branch after applying bases is: %p" % [ search ]

		return self.model_objectclasses.inject( search ) do |branchset, oid|
			Treequel.log.debug "  adding filter for objectClass=%s to %p" % [ oid, branchset ]
			branchset.filter( :objectClass => oid )
		end
	end

end # Treequel::Model::ObjectClass