#
#   irb/completor.rb -
#   	$Release Version: 0.9$
#   	$Revision$
#   	$Date$
#   	by Keiju ISHITSUKA(keiju@ishitsuka.com)
#       From Original Idea of shugo@ruby-lang.org
#

require "readline"

module IRB
  module InputCompletor

    @RCS_ID='-$Id$-'

    ReservedWords = [
      "BEGIN", "END",
      "alias", "and",
      "begin", "break",
      "case", "class",
      "def", "defined", "do",
      "else", "elsif", "end", "ensure",
      "false", "for",
      "if", "in",
      "module",
      "next", "nil", "not",
      "or",
      "redo", "rescue", "retry", "return",
      "self", "super",
      "then", "true",
      "undef", "unless", "until",
      "when", "while",
      "yield",
    ]

    CompletionProc = proc { |input|
      bind = IRB.conf[:MAIN_CONTEXT].workspace.binding

#      puts "input: #{input}"

      case input
      when /^(\/[^\/]*\/)\.([^.]*)$/
	# Regexp
	receiver = $1
	message = Regexp.quote($2)

	candidates = Regexp.instance_methods(true)
	select_message(receiver, message, candidates)

      when /^([^\]]*\])\.([^.]*)$/
	# Array
	receiver = $1
	message = Regexp.quote($2)

	candidates = Array.instance_methods(true)
	select_message(receiver, message, candidates)

      when /^([^\}]*\})\.([^.]*)$/
	# Proc or Hash
	receiver = $1
	message = Regexp.quote($2)

	candidates = Proc.instance_methods(true) | Hash.instance_methods(true)
	select_message(receiver, message, candidates)

      when /^(:[^:.]*)$/
 	# Symbol
	if Symbol.respond_to?(:all_symbols)
	  sym = $1
	  candidates = Symbol.all_symbols.collect{|s| ":" + s.id2name}
	  candidates.grep(/^#{sym}/)
	else
	  []
	end

      when /^::([A-Z][^:\.\(]*)$/
	# Absolute Constant or class methods
	receiver = $1
	candidates = Object.constants
	candidates.grep(/^#{receiver}/).collect{|e| "::" + e}

      when /^(((::)?[A-Z][^:.\(]*)+)::?([^:.]*)$/
	# Constant or class methods
	receiver = $1
	message = Regexp.quote($4)
	begin
	  candidates = eval("#{receiver}.constants | #{receiver}.methods", bind)
	rescue Exception
	  candidates = []
	end
	candidates.grep(/^#{message}/).collect{|e| receiver + "::" + e}

      when /^(:[^:.]+)\.([^.]*)$/
	# Symbol
	receiver = $1
	message = Regexp.quote($2)

	candidates = Symbol.instance_methods(true)
	select_message(receiver, message, candidates)

      when /^(-?(0[dbo])?[0-9_]+(\.[0-9_]+)?([eE]-?[0-9]+)?)\.([^.]*)$/
	# Numeric
	receiver = $1
	message = Regexp.quote($5)

	begin
	  candidates = eval(receiver, bind).methods
	rescue Exception
	  candidates = []
	end
	select_message(receiver, message, candidates)

      when /^(-?0x[0-9a-fA-F_]+)\.([^.]*)$/
	# Numeric(0xFFFF)
	receiver = $1
	message = Regexp.quote($2)

	begin
	  candidates = eval(receiver, bind).methods
	rescue Exception
	  candidates = []
	end
	select_message(receiver, message, candidates)

      when /^(\$[^.]*)$/
	candidates = global_variables.grep(Regexp.new(Regexp.quote($1)))

#      when /^(\$?(\.?[^.]+)+)\.([^.]*)$/
      when /^((\.?[^.]+)+)\.([^.]*)$/
	# variable
	receiver = $1
	message = Regexp.quote($3)

	gv = eval("global_variables", bind)
	lv = eval("local_variables", bind)
	cv = eval("self.class.constants", bind)

	if (gv | lv | cv).include?(receiver)
	  # foo.func and foo is local var.
	  candidates = eval("#{receiver}.methods", bind)
	elsif /^[A-Z]/ =~ receiver and /\./ !~ receiver
	  # Foo::Bar.func
	  begin
	    candidates = eval("#{receiver}.methods", bind)
	  rescue Exception
	    candidates = []
	  end
	else
	  # func1.func2
	  candidates = []
	  ObjectSpace.each_object(Module){|m|
	    begin
	      name = m.name
	    rescue Exception
	      name = ""
	    end
	    next if name != "IRB::Context" and
	      /^(IRB|SLex|RubyLex|RubyToken)/ =~ name
	    candidates.concat m.instance_methods(false)
	  }
	  candidates.sort!
	  candidates.uniq!
	end
	select_message(receiver, message, candidates)

      when /^\.([^.]*)$/
	# unknown(maybe String)

	receiver = ""
	message = Regexp.quote($1)

	candidates = String.instance_methods(true)
	select_message(receiver, message, candidates)

      else
	candidates = eval("methods | private_methods | local_variables | self.class.constants", bind)

	(candidates|ReservedWords).grep(/^#{Regexp.quote(input)}/)
      end
    }

    Operators = ["%", "&", "*", "**", "+",  "-",  "/",
      "<", "<<", "<=", "<=>", "==", "===", "=~", ">", ">=", ">>",
      "[]", "[]=", "^",]

    def self.select_message(receiver, message, candidates)
      candidates.grep(/^#{message}/).collect do |e|
	case e
	when /^[a-zA-Z_]/
	  receiver + "." + e
	when /^[0-9]/
	when *Operators
	  #receiver + " " + e
	end
      end
    end
  end
end

if Readline.respond_to?("basic_word_break_characters=")
  Readline.basic_word_break_characters= " \t\n\"\\'`><=;|&{("
end
Readline.completion_append_character = nil
Readline.completion_proc = IRB::InputCompletor::CompletionProc