module IRT
  module Session
    extend self

    @@exit_all = false
    def exit_all?
      @@exit_all
    end
    def exit_all=(bool)
      @@exit_all = bool
    end

    def enter(mode, obj=nil)
      IRT.log.print if IRT.tail_on_irt
      ws = obj ? IRB::WorkSpace.new(obj) : IRB.CurrentContext.workspace
      new_irb = IRB::Irb.new(ws)
      IRT.session_no += 1
      main_name = mode == :inspect ?
                    IRB.CurrentContext.current_line.match(/^\s*(?:irb|irt|irt_inspect)\s+(.*)$/).captures[0].strip :
                    new_irb.context.workspace.main.to_s
      main_name = main_name[0..30] + '...' if main_name.size > 30
      new_irb.context.irb_name = "irt##{IRT.session_no}(#{main_name})"
      new_irb.context.irb_path = "(irt##{IRT.session_no})"
      set_binding_file_pointers(new_irb.context) if mode == :binding
      eval_input(new_irb.context, mode)
    end

    def eval_input(new_context, mode)
      new_context.parent_context = IRB.CurrentContext
      new_context.set_last_value( IRB.CurrentContext.last_value ) unless (mode == :inspect || mode == :binding)
      new_context.irt_mode = mode
      new_context.backtrace_map = IRB.CurrentContext.backtrace_map if mode == :interactive
      IRB.conf[:MAIN_CONTEXT] = new_context
      IRT.log.add_hunk
      IRT.log.status << [new_context.irb_name, mode]
      IRT.log.print_status unless mode == :file
      old_trap = trap('SIGINT'){new_context.irb.signal_handle}
      catch(:IRB_EXIT) { new_context.irb.eval_input }
      begin throw(:IRB_EXIT) ; rescue ArgumentError ; end if @@exit_all
    ensure
      IRT::Session.exit unless @@exit_all
      trap 'SIGINT', old_trap if old_trap
    end

    def exit
      exiting_context = IRB.conf[:MAIN_CONTEXT]
      resuming_context = exiting_context.parent_context
      return unless resuming_context
      exiting_mode = exiting_context.irt_mode
      resuming_context.set_last_value( exiting_context.last_value ) \
        unless (exiting_mode == :inspect || exiting_mode == :binding)
      IRB.conf[:MAIN_CONTEXT] = resuming_context
      IRT.log.pop_status
      IRT.log.print_status unless resuming_context.irt_mode == :file
      IRT.log.add_hunk
    end

    def run_file(file_path=IRT.irt_file)
      raise Errno::ENOENT, "No such file or directory - #{file_path}" unless File.exist?(file_path)
      openfile = proc do
        @@exit_all = false
        IRB.conf[:AT_EXIT].pop
        IRT.init_file(file_path)
        irb = IRB::Irb.new(nil, IRT.irt_file.to_s)
        irb.context.irt_mode = :file
        irb.context.irb_path = IRT.irt_file.to_s
        irb.context.irb_name = IRT.irt_file.basename
        IRB.conf[:MAIN_CONTEXT] = irb.context
        begin
          catch(:IRB_EXIT) { irb.eval_input }
        ensure
          IRB.irb_at_exit
        end
      end
      IRB.conf[:AT_EXIT].push(openfile)
      @@exit_all = true
      throw(:IRB_EXIT)
    end


  private

    # used for open the last file for editing
    def set_binding_file_pointers(context)
      caller.each do |c|
        file, line = c.sub(/:in .*$/,'').split(':', 2)
        next if File.expand_path(file).match(/^#{Regexp.quote(IRT.lib_path)}/) # exclude irt internal callers
        context.binding_file = file
        context.binding_line_no = line
        break
      end
    end

  end
end