unless defined?(Viget::ForeignKeyMigrations)
  require 'rubygems'
  require 'activerecord'
  
  module Viget
    module ForeignKeyMigrations
      # :stopdoc:
      VERSION = '0.3.2'
      LIBPATH = ::File.expand_path(::File.dirname(__FILE__)) + ::File::SEPARATOR
      PATH = ::File.dirname(LIBPATH) + ::File::SEPARATOR
      # :startdoc:
 
      # Returns the version string for the library.
      #
      def self.version
        VERSION
      end
 
      # Returns the library path for the module. If any arguments are given,
      # they will be joined to the end of the libray path using
      # <tt>File.join</tt>.
      #
      def self.libpath( *args )
        args.empty? ? LIBPATH : ::File.join(LIBPATH, *args)
      end
 
      # Returns the lpath for the module. If any arguments are given,
      # they will be joined to the end of the path using
      # <tt>File.join</tt>.
      #
      def self.path( *args )
        args.empty? ? PATH : ::File.join(PATH, *args)
      end
 
      # Utility method used to rquire all files ending in .rb that lie in the
      # directory below this file that has the same name as the filename passed
      # in. Optionally, a specific _directory_ name can be passed in such that
      # the _filename_ does not have to be equivalent to the directory.
      #
      def self.require_all_libs_relative_to( fname, dir = nil )
        dir ||= ::File.basename(fname, '.*')
        search_me = ::File.expand_path(::File.join(::File.dirname(fname), dir, '**', '*.rb'))
 
        Dir.glob(search_me).sort.each {|rb| require rb}
      end
 
    end
 
    module_name = 'ActiveRecord::ConnectionAdapters'
    adapter_names = [ 'MysqlAdapter', 'PostgreSQLAdapter', 'SQLiteAdapter', 'SQLite3Adapter' ]
    adapter_names.each do |name|
      filename = name.downcase.sub(/adapter$/, '_adapter')
      begin
        require "#{module_name.underscore}/#{filename}"
      rescue LoadError
        nil
      end
    end
 
    ForeignKeyMigrations.require_all_libs_relative_to __FILE__
    
    ActiveRecord::ConnectionAdapters::AbstractAdapter.send(:include, Viget::ForeignKeyMigrations::SchemaStatements)
    ActiveRecord::ConnectionAdapters::TableDefinition.send(:include, Viget::ForeignKeyMigrations::TableDefinition)
 
    # Enable foreign key migration support for the following databases.
    adapter_names.each do |adapter_name|
      if module_name.constantize.const_defined?(adapter_name)
        adapter = "#{module_name}::#{adapter_name}".constantize
        adapter.send(:include, Viget::ForeignKeyMigrations::DatabaseSupport)
      end  
    end
  end  
end  # unless defined?
 
true