#
#   irb/multi-irb.rb - multiple irb module
#   	$Release Version: 0.9.6$
#   	$Revision$
#   	by Keiju ISHITSUKA(keiju@ruby-lang.org)
#
# --
#
#
#
IRB.fail CantShiftToMultiIrbMode unless defined?(Thread)
require "thread"

module IRB
  class JobManager
    @RCS_ID='-$Id$-'

    # Creates a new JobManager object
    def initialize
      # @jobs = [[thread, irb],...]
      @jobs = []
      @current_job = nil
    end

    # The active irb session
    attr_accessor :current_job

    # The total number of irb sessions, used to set +irb_name+ of the current
    # Context.
    def n_jobs
      @jobs.size
    end

    # Returns the thread for the given +key+ object, see #search for more
    # information.
    def thread(key)
      th, = search(key)
      th
    end

    # Returns the irb session for the given +key+ object, see #search for more
    # information.
    def irb(key)
      _, irb = search(key)
      irb
    end

    # Returns the top level thread.
    def main_thread
      @jobs[0][0]
    end

    # Returns the top level irb session.
    def main_irb
      @jobs[0][1]
    end

    # Add the given +irb+ session to the jobs Array.
    def insert(irb)
      @jobs.push [Thread.current, irb]
    end

    # Changes the current active irb session to the given +key+ in the jobs
    # Array.
    #
    # Raises an IrbAlreadyDead exception if the given +key+ is no longer alive.
    #
    # If the given irb session is already active, an IrbSwitchedToCurrentThread
    # exception is raised.
    def switch(key)
      th, irb = search(key)
      IRB.fail IrbAlreadyDead unless th.alive?
      IRB.fail IrbSwitchedToCurrentThread if th == Thread.current
      @current_job = irb
      th.run
      Thread.stop
      @current_job = irb(Thread.current)
    end

    # Terminates the irb sessions specified by the given +keys+.
    #
    # Raises an IrbAlreadyDead exception if one of the given +keys+ is already
    # terminated.
    #
    # See Thread#exit for more information.
    def kill(*keys)
      for key in keys
	th, _ = search(key)
	IRB.fail IrbAlreadyDead unless th.alive?
	th.exit
      end
    end

    # Returns the associated job for the given +key+.
    #
    # If given an Integer, it will return the +key+ index for the jobs Array.
    #
    # When an instance of Irb is given, it will return the irb session
    # associated with +key+.
    #
    # If given an instance of Thread, it will return the associated thread
    # +key+ using Object#=== on the jobs Array.
    #
    # Otherwise returns the irb session with the same top-level binding as the
    # given +key+.
    #
    # Raises a NoSuchJob exception if no job can be found with the given +key+.
    def search(key)
      job = case key
      when Integer
	@jobs[key]
      when Irb
	@jobs.find{|k, v| v.equal?(key)}
      when Thread
	@jobs.assoc(key)
      else
	@jobs.find{|k, v| v.context.main.equal?(key)}
      end
      IRB.fail NoSuchJob, key if job.nil?
      job
    end

    # Deletes the job at the given +key+.
    def delete(key)
      case key
      when Integer
	IRB.fail NoSuchJob, key unless @jobs[key]
	@jobs[key] = nil
      else
	catch(:EXISTS) do
	  @jobs.each_index do
	    |i|
	    if @jobs[i] and (@jobs[i][0] == key ||
			     @jobs[i][1] == key ||
			     @jobs[i][1].context.main.equal?(key))
	      @jobs[i] = nil
	      throw :EXISTS
	    end
	  end
	  IRB.fail NoSuchJob, key
	end
      end
      until assoc = @jobs.pop; end unless @jobs.empty?
      @jobs.push assoc
    end

    # Outputs a list of jobs, see the irb command +irb_jobs+, or +jobs+.
    def inspect
      ary = []
      @jobs.each_index do
	|i|
	th, irb = @jobs[i]
	next if th.nil?

	if th.alive?
	  if th.stop?
	    t_status = "stop"
	  else
	    t_status = "running"
	  end
	else
	  t_status = "exited"
	end
	ary.push format("#%d->%s on %s (%s: %s)",
			i,
			irb.context.irb_name,
			irb.context.main,
			th,
			t_status)
      end
      ary.join("\n")
    end
  end

  @JobManager = JobManager.new

  # The current JobManager in the session
  def IRB.JobManager
    @JobManager
  end

  # The current Context in this session
  def IRB.CurrentContext
    IRB.JobManager.irb(Thread.current).context
  end

  # Creates a new IRB session, see Irb.new.
  #
  # The optional +file+ argument is given to Context.new, along with the
  # workspace created with the remaining arguments, see WorkSpace.new
  def IRB.irb(file = nil, *main)
    workspace = WorkSpace.new(*main)
    parent_thread = Thread.current
    Thread.start do
      begin
	irb = Irb.new(workspace, file)
      rescue
	print "Subirb can't start with context(self): ", workspace.main.inspect, "\n"
	print "return to main irb\n"
	Thread.pass
	Thread.main.wakeup
	Thread.exit
      end
      @CONF[:IRB_RC].call(irb.context) if @CONF[:IRB_RC]
      @JobManager.insert(irb)
      @JobManager.current_job = irb
      begin
	system_exit = false
	catch(:IRB_EXIT) do
	  irb.eval_input
	end
      rescue SystemExit
	system_exit = true
	raise
	#fail
      ensure
	unless system_exit
	  @JobManager.delete(irb)
	  if @JobManager.current_job == irb
	    if parent_thread.alive?
	      @JobManager.current_job = @JobManager.irb(parent_thread)
	      parent_thread.run
	    else
	      @JobManager.current_job = @JobManager.main_irb
	      @JobManager.main_thread.run
	    end
	  end
	end
      end
    end
    Thread.stop
    @JobManager.current_job = @JobManager.irb(Thread.current)
  end

#   class Context
#     def set_last_value(value)
#       @last_value = value
#       @workspace.evaluate "_ = IRB.JobManager.irb(Thread.current).context.last_value"
#       if @eval_history #and !@__.equal?(@last_value)
# 	@eval_history_values.push @line_no, @last_value
# 	@workspace.evaluate "__ = IRB.JobManager.irb(Thread.current).context.instance_eval{@eval_history_values}"
#       end
#       @last_value
#     end
#   end

#  module ExtendCommand
#     def irb_context
#       IRB.JobManager.irb(Thread.current).context
#     end
# #    alias conf irb_context
#   end

  @CONF[:SINGLE_IRB_MODE] = false
  @JobManager.insert(@CONF[:MAIN_CONTEXT].irb)
  @JobManager.current_job = @CONF[:MAIN_CONTEXT].irb

  class Irb
    def signal_handle
      unless @context.ignore_sigint?
	print "\nabort!!\n" if @context.verbose?
	exit
      end

      case @signal_status
      when :IN_INPUT
	print "^C\n"
	IRB.JobManager.thread(self).raise RubyLex::TerminateLineInput
      when :IN_EVAL
	IRB.irb_abort(self)
      when :IN_LOAD
	IRB.irb_abort(self, LoadAbort)
      when :IN_IRB
	# ignore
      else
	# ignore other cases as well
      end
    end
  end

  trap("SIGINT") do
    @JobManager.current_job.signal_handle
    Thread.stop
  end

end