require 'rdoc/ri/ri_util'
require 'rdoc/ri/ri_formatter'
require 'rdoc/ri/ri_options'


# This is a kind of 'flag' module. If you want to write your
# own 'ri' display module (perhaps because you'r writing
# an IDE or somesuch beast), you simply write a class
# which implements the various 'display' methods in 'DefaultDisplay',
# and include the 'RiDisplay' module in that class. 
#
# To access your class from the command line, you can do
#
#    ruby -r <your source file>  ../ri ....
#
# If folks _really_ want to do this from the command line,
# I'll build an option in

module RiDisplay
  @@display_class = nil

  def RiDisplay.append_features(display_class)
    @@display_class = display_class
  end

  def RiDisplay.new(*args)
    @@display_class.new(*args)
  end
end

######################################################################
#
# A paging display module. Uses the ri_formatter class to do the
# actual presentation
#

class  DefaultDisplay

  include RiDisplay

  def initialize(options)
    @options = options
    @formatter = @options.formatter.new(@options, "     ")
  end    
  
  
  ######################################################################
  
  def display_usage
    page do
      RI::Options::OptionList.usage(short_form=true)
    end
  end


  ######################################################################
  
  def display_method_info(method)
    page do
      @formatter.draw_line(method.full_name)
      display_params(method)
      @formatter.draw_line
      display_flow(method.comment)
      if method.aliases && !method.aliases.empty?
        @formatter.blankline
        aka = "(also known as "
        aka << method.aliases.map {|a| a.name }.join(", ") 
        aka << ")"
        @formatter.wrap(aka)
      end
    end
  end
  
  ######################################################################
  
  def display_class_info(klass, ri_reader)
    page do 
      superclass = klass.superclass_string
      
      if superclass
        superclass = " < " + superclass
      else
        superclass = ""
      end
      
      @formatter.draw_line(klass.display_name + ": " +
                           klass.full_name + superclass)
      
      display_flow(klass.comment)
      @formatter.draw_line 
    
      unless klass.includes.empty?
        @formatter.blankline
        @formatter.display_heading("Includes:", 2, "")
        incs = []
        klass.includes.each do |inc|
          inc_desc = ri_reader.find_class_by_name(inc.name)
          if inc_desc
            str = inc.name + "("
            str << inc_desc.instance_methods.map{|m| m.name}.join(", ")
            str << ")"
            incs << str
          else
            incs << inc.name
          end
      end
        @formatter.wrap(incs.sort.join(', '))
      end
      
      unless klass.constants.empty?
        @formatter.blankline
        @formatter.display_heading("Constants:", 2, "")
        len = 0
        klass.constants.each { |c| len = c.name.length if c.name.length > len }
        len += 2
        klass.constants.each do |c|
          @formatter.wrap(c.value, 
                          @formatter.indent+((c.name+":").ljust(len)))
        end 
      end
      
      unless klass.class_methods.empty?
        @formatter.blankline
        @formatter.display_heading("Class methods:", 2, "")
        @formatter.wrap(klass.class_methods.map{|m| m.name}.sort.join(', '))
      end
      
      unless klass.instance_methods.empty?
        @formatter.blankline
        @formatter.display_heading("Instance methods:", 2, "")
        @formatter.wrap(klass.instance_methods.map{|m| m.name}.sort.join(', '))
      end
      
      unless klass.attributes.empty?
        @formatter.blankline
        @formatter.wrap("Attributes:", "")
        @formatter.wrap(klass.attributes.map{|a| a.name}.sort.join(', '))
      end
    end
  end
  
  ######################################################################
  
  # Display a list of method names
  
  def display_method_list(methods)
    page do
      puts "More than one method matched your request. You can refine"
      puts "your search by asking for information on one of:\n\n"
      @formatter.wrap(methods.map {|m| m.full_name} .join(", "))
    end
  end
  
  ######################################################################
  
  def display_class_list(namespaces)
    page do
      puts "More than one class or module matched your request. You can refine"
      puts "your search by asking for information on one of:\n\n"
      @formatter.wrap(namespaces.map {|m| m.full_name}.join(", "))
    end
  end
  
  ######################################################################

  def list_known_classes(classes)
    if classes.empty?
      warn_no_database
    else
      page do 
        @formatter.draw_line("Known classes and modules")
        @formatter.blankline
        @formatter.wrap(classes.sort.join(", "))
      end
    end
  end

  ######################################################################

  def list_known_names(names)
    if names.empty?
      warn_no_database
    else
      page do 
        names.each {|n| @formatter.raw_print_line(n)}
      end
    end
  end

  ######################################################################

  private

  ######################################################################

  def page
    return yield unless pager = setup_pager
    begin
      save_stdout = STDOUT.clone
      STDOUT.reopen(pager)
      yield
    ensure
      STDOUT.reopen(save_stdout)
      save_stdout.close
      pager.close
    end
  end

  ######################################################################

  def setup_pager
    unless @options.use_stdout
      for pager in [ ENV['PAGER'], "less", "more", 'pager' ].compact.uniq
        return IO.popen(pager, "w") rescue nil
      end
      @options.use_stdout = true
      nil
    end
  end

  ######################################################################
  
  def display_params(method)

    params = method.params

    if params[0,1] == "("
      if method.is_singleton
        params = method.full_name + params
      else
        params = method.name + params
      end
    end
    params.split(/\n/).each do |p|
      @formatter.wrap(p) 
      @formatter.break_to_newline
    end
  end

  ######################################################################
  
  def display_flow(flow)
    if !flow || flow.empty?
      @formatter.wrap("(no description...)")
    else
      @formatter.display_flow(flow)
    end
  end

  ######################################################################
  
  def warn_no_database
    puts "Before using ri, you need to generate documentation"
    puts "using 'rdoc' with the --ri option"
  end
end  # class RiDisplay
