module Vool
  class MethodStatement < Statement
    attr_reader :name, :args , :body , :clazz

    def initialize( name , args , body)
      @name , @args , @body = name , args , body
      unless( body.is_a?(ScopeStatement))
        @body = ScopeStatement.new([])
        @body.statements << body if body
      end

    end

    # compile to mom instructions. methods themselves do no result in instructions (yet)
    # instead the resulting instruction tree is saved into the method object that
    #  represents the method
    def to_mom( _ )
      method = @clazz.get_method( @name )
      @body.to_mom(method)
    end

    def collect(arr)
      @body.collect(arr)
      super
    end

    def set_class(clazz)
      @clazz = clazz
    end

    def create_objects
      args_type = make_type
      frame_type = make_frame
      method = Parfait::VoolMethod.new(name , args_type , frame_type , body )
      @clazz.add_method( method )
      typed_method = method.create_parfait_method(clazz.instance_type)
      compiler = Risc::MethodCompiler.new( typed_method ).init_method
      head = @body.to_mom( method ).flatten
      compiler.add_mom(head)
    end

    private

    def make_type(  )
      type_hash = {}
      @args.each {|arg| type_hash[arg] = :Object }
      Parfait::NamedList.type_for( type_hash )
    end

    def make_frame
      type_hash = {}
      vars = []
      @body.collect([]).each { |node| node.add_local(vars) }
      vars.each { |var| type_hash[var] = :Object }
      Parfait::NamedList.type_for( type_hash )
    end

  end
end