#--
# =============================================================================
# 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'

module Copland

  # This represents a single package in a Repository.
  class Package

    # The Registry instance that contains this package.
    attr_reader :registry

    # The name of this package.
    attr_reader :name

    # The description of the package.
    attr_accessor :description

    # Create a new package associated with the given registry. The package will
    # have the given name. Note: this will _not_ add the package to the
    # registry!
    def initialize( registry, name )
      @registry = registry
      @name = name
      @service_points = Hash.new
      @configuration_points = Hash.new
      @schemas = Hash.new
    end

    # Add the given service point to the package.
    def add_service_point( service_point )
      @service_points[ service_point.name ] = service_point
    end

    # Add the given configuration point to the package.
    def add_configuration_point( configuration_point )
      @configuration_points[ configuration_point.name ] = configuration_point
    end

    # Add the given schema to the package. Note that this requires that the
    # schema have a name. This will also set the schema's +owner+ attribute
    # to the package.
    def add_schema( schema )
      schema.owner = self
      @schemas[ schema.name ] = schema
    end

    # Returns the service point with the given name. If no such service point
    # exists, this returns +nil+.
    def service_point( name )
      @service_points[ name ]
    end

    # This returns the names of all service points in the package.
    def service_points
      @service_points.keys.freeze
    end

    # This instantiates the service point with the given name and returns the
    # resulting service. If the service point does not exist, this will raise
    # a ServicePointNotFound exception.
    #
    # If a block is given, it will be used to initialize the service (but only
    # when the service is created--if the service is a singleton service and
    # it was created previously, the init block will be ignored).
    def service( name, &init )
      point = service_point( name ) or raise ServicePointNotFound, name
      point.instance( &init )
    end

    # Returns +true+ if the named service exists in this package, and +false+
    # otherwise.
    def service_exist?( name )
      return !service_point( name ).nil?
    end

    # This is a convenience method for returning a service with the given name,
    # giving preference when a package is not specified to the service points
    # within the current package.
    def find_service( name, &block )
      Copland::get_possibly_local_service( registry, self, name, &block )
    end

    # This is a convenience method for returning a schema with the given name,
    # giving preference when a package is not specified to the schemas
    # within the current package.
    def find_schema( name )
      find_service( name ) do |pkg, id|
        if pkg.nil?
          raise PackageNotFound, name
        else
          schema = pkg.schema( id )
          raise SchemaNotFound, name unless schema
          return schema
        end
      end
    end

    # Returns the configuration point with the given name, or +nil+ if no such
    # configuration point exists.
    def configuration_point( name )
      @configuration_points[ name ]
    end

    # Returns the names of all configuration points in the package.
    def configuration_points
      @configuration_points.keys.freeze
    end

    # Returns the schema with the given name, or +nil+ if no such schema
    # exists.
    def schema( name )
      @schemas[ name ]
    end

    # Adds a "pending" contribution to the package. When the package is
    # fixated (see #fixate!), the given value will be contributed to the
    # configuration point with the given name. Once the package is
    # fixated, this method will be illegal to invoke.
    def add_pending_contribution( name, value )
      ( @pending_contributions ||= [] ).push :name => name,
                                             :value => value
    end

    # Iterates over each service point in the package.
    def each_service_point( &block )
      @service_points.each_value( &block )
      self
    end

    # Iterates over each configuration point in the package.
    def each_configuration_point( &block )
      @configuration_points.each_value( &block )
    end

    # Iterates over each schema in the package.
    def each_schema( &block )
      @schemas.each_value( &block )
    end

    # Returns the number of service points in the package.
    def service_point_count
      @service_points.size
    end

    # Returns the number of configuration points in the package.
    def configuration_point_count
      @configuration_points.size
    end

    # Returns the number of schemas in the package.
    def schema_count
      @schemas.size
    end

    # Fixates the package. This will, in turn, fixate each configuration and
    # service point in the package. Also, all pending contributions will be
    # contributed to the configuration points they were intended for.
    def fixate!
      extend Fixated

      @schemas.each_value { |schema| schema.fixate! }
      @service_points.each_value { |point| point.fixate! }
      @configuration_points.each_value { |point| point.fixate! }

      if @pending_contributions
        @pending_contributions.each do |value|
          name = value[ :name ]
          contribution = value[ :value ]

          configuration_point = find_service( name ) do |pkg, id|
            raise PackageNotFound, name unless pkg
            pkg.configuration_point( id )
          end

          raise ConfigurationPointNotFound, name unless configuration_point

          contribution.instance_variable_set( :@contributor, self )
          configuration_point.contribute contribution
        end

        remove_instance_variable :@pending_contributions
      end
    end

    # Returns +false+, although when the package is fixated this will be
    # overridden with a method that will return +true+.
    def fixated?
      false
    end

    # This module will be included by the package when it is fixated.
    module Fixated

      # Raises DisallowedOperationException.
      def add_pending_contribution( *args )
        raise DisallowedOperationException,
          "cannot add pending contributions to fixated package"
      end

      # Does nothing.
      def fixate!
        # does nothing
      end

      # Returns +true+.
      def fixated?
        true
      end
    end

  end

end