require 'P4'

module Commands
  module Init
    # Base class of 'initializers'.
    #
    # This actually acts more as a registry of defined classes.
    class InitModel
      # Child classes should define this number greater than one. 0 should be
      # reserved for a single system settings instance.
      def rank
        1
      end

      # It's likely that the main child class will handle overriding this method.
      # Our default method does nothing.
      def execute(p4)
      end

      #========================================================================
      # Ok, the real business starts here.
      #
      # Don't even think about overriding the following rules
      #========================================================================

      class << self
        attr_accessor :model_classes
      end

      # The registered set of non-abstract model classes.
      #
      @model_classes = []

      @inheritable_attributes ||= [:inheritable_attributes]

      # A lot of our settings are actually class instance variables, which
      # can be overridden. This allows the child classes that depend on these
      # values to define what they are.
      def self.inheritable_attributes(*args)
        @inheritable_attributes += args
        args.each do |arg|
          class_eval %(
          class << self; attr_accessor :#{arg} end
        )
        end
        @inheritable_attributes
      end

      def self.inherited(subclass)
        # Copy 'down' any inheritable attribute to the new child class
        @inheritable_attributes.each do |inheritable_attribute|
          instance_var = "@#{inheritable_attribute}"
          subclass.instance_variable_set(instance_var, instance_variable_get(instance_var))
        end

        if subclass.respond_to?(:abstract) && subclass.send(:abstract)
          InitModel.model_classes.push(subclass)
        end
      end

      def self.run(p4port)
        system_settings = nil
        super_user = nil
        models = []

        InitModel.model_classes.each do |model|
          if model <= DefaultSuperUser
            # do nothing
          elsif model <= SystemSettingsModel
            system_settings = model.new
          elsif !super_user and model <= UserModel and model.super
            super_user = model.new
          else
            models << model.new
          end
        end

        if !super_user
          super_user = DefaultSuperUser.new
        end

        models.sort! { |a, b| a.rank <=> b.rank }

        # Clear out any P4 Environment variables
        ENV.keys.select { |x| x =~ /^P4/ }.each { |x| ENV.delete(x) }

        p4 = P4.new
        p4.port = p4port
        p4.connect
        p4.exception_level = P4::RAISE_ERRORS

        system_settings.execute(p4, super_user)

        models.each { |m| m.execute(p4, models, super_user) }
      end
    end
  end
end