# Handles a method definition
class YARD::Handlers::Ruby::MethodHandler < YARD::Handlers::Ruby::Base
  handles :def, :defs
  
  process do
    nobj = namespace
    mscope = scope
    if statement.type == :defs
      if statement[0][0].type == :ident
        raise YARD::Parser::UndocumentableError, 'method defined on object instance'
      end
      meth = statement[2][0]
      nobj = P(namespace, statement[0].source) if statement[0][0].type == :const
      args = format_args(statement[3])
      blk = statement[4]
      mscope = :class
    else
      meth = statement[0][0]
      args = format_args(statement[1])
      blk = statement[2]
    end
    
    nobj = P(namespace, nobj.value) while nobj.type == :constant
    obj = register MethodObject.new(nobj, meth, mscope) do |o| 
      o.visibility = visibility 
      o.source = statement.source
      o.signature = method_signature(meth)
      o.explicit = true
      o.parameters = args
    end
    if mscope == :instance && meth == "initialize"
      unless obj.has_tag?(:return)
        obj.docstring.add_tag(YARD::Tags::Tag.new(:return, 
          "a new instance of #{namespace.name}", namespace.name.to_s))
      end
    elsif mscope == :class && obj.docstring.blank? && %w(inherited included 
        extended method_added method_removed method_undefined).include?(meth)
      obj.docstring.add_tag(YARD::Tags::Tag.new(:private, nil))
    elsif meth.to_s =~ /\?$/
      if obj.tag(:return) && (obj.tag(:return).types || []).empty?
        obj.tag(:return).types = ['Boolean']
      elsif obj.tag(:return).nil?
        obj.docstring.add_tag(YARD::Tags::Tag.new(:return, "", "Boolean"))
      end
    end
    
    if obj.has_tag?(:option)
      # create the options parameter if its missing
      obj.tags(:option).each do |option|
        expected_param = option.name
        unless obj.tags(:param).find {|x| x.name == expected_param }
          new_tag = YARD::Tags::Tag.new(:param, "a customizable set of options", "Hash", expected_param)
          obj.docstring.add_tag(new_tag)
        end
      end
    end
    
    if info = obj.attr_info
      if meth.to_s =~ /=$/ # writer
        info[:write] = obj if info[:read]
      else
        info[:read] = obj if info[:write]
      end
    end
    
    parse_block(blk, :owner => obj) # mainly for yield/exceptions
  end
  
  def format_args(args)
    args = args.jump(:params)
    params = []
    params += args.required_params.map {|a| [a.source, nil] } if args.required_params
    params += args.optional_params.map {|a| [a[0].source, a[1].source] } if args.optional_params
    params << ["*" + args.splat_param.source, nil] if args.splat_param
    params += args.required_end_params.map {|a| [a.source, nil] } if args.required_end_params
    params << ["&" + args.block_param.source, nil] if args.block_param
    params
  end
  
  def method_signature(method_name)
    if statement[1]
      "def #{method_name}(#{statement[1].jump(:params).source})"
    else
      "def #{method_name}"
    end
  end
end