#--
# =============================================================================
# Copyright (c) 2004, Jamis Buck (jgb3@email.byu.edu)
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# 
#     * Redistributions of source code must retain the above copyright notice,
#       this list of conditions and the following disclaimer.
# 
#     * Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
# 
#     * The names of its contributors may not be used to endorse or promote
#       products derived from this software without specific prior written
#       permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
# =============================================================================
#++

require 'copland/errors'
require 'copland/utils'
require 'singleton'

module Copland
  module Implementation

    # This is the implementation of the BuilderFactory service. It constructs
    # service implementations and wires services together automatically, as
    # determined by their dependencies in the configuration files.
    class BuilderFactory

      # This is the list of patterns that are recognized as "setter" methods.
      # These are used when determining how to set properties.
      SETTERS = [ "%s=", "set_%s" ]
      
      # This is the factory method used to construct new services. Based
      # on the +parms+ argument, the new service is instantiated, initialized,
      # and returned.
      def create_instance( point, parms )
        ensure_log( point )

        klass = Copland::get_class( parms['class'] )

        args = ( parms['parameters'] || [] )

        if klass.include?( Singleton )
          if args.length > 0
            raise CoplandException,
              "Singleton instances cannot have constructor parameters"
          end
          obj = klass.instance
        else
          obj = klass.new( *args )
        end

        if parms['properties']
          parms['properties'].each_pair do |name, value|
            catch( :property_set ) do
              SETTERS.each do |pattern|
                setter = pattern % name
                if obj.respond_to?( setter )
                  obj.__send__( setter, value )
                  throw :property_set
                end
              end

              @log.warn "no setter for #{name.inspect} found on " +
                        "#{klass} (#{point.full_name})"
              obj.instance_variable_set "@#{name}".intern, value
            end
          end
        end

        if parms['invoke']
          parms['invoke'].each_pair do |name, value|
            obj.__send__( name, *( value || [] ) )
          end
        end

        initialize_method = parms[ 'initialize-method' ] ||
          "initialize_service"

        if obj.respond_to?( initialize_method )
          obj.__send__( initialize_method )
        end

        return obj
      end

      def ensure_log( point )
        return if @log
        @log = point.owner.registry.logs.get( "copland.BuilderFactory" )
      end

    end

  end
end