class Byebug::ListCommand

def display_list(b, e, file, current)
  print "[%d, %d] in %s\n", b, e, file
  lines = LineCache::getlines(file,
                              Command.settings[:reload_source_on_change])
  if lines
    return @state.previous_line if b >= lines.size
    e = lines.size if lines.size < e
    [b, 1].max.upto(e) do |n|
      if n > 0 && lines[n-1]
        if n == current
          print "=> %d  %s\n", n, lines[n-1].chomp
        else
          print "   %d  %s\n", n, lines[n-1].chomp
        end
      end
    end
  else
    errmsg "No sourcefile available for %s\n", file
    return @state.previous_line
  end
  return e == lines.size ? @state.previous_line : b
end

def execute
  listsize = Command.settings[:listsize]
  if !@match || !(@match[1] || @match[2])
    b = @state.previous_line ?
    @state.previous_line + listsize : @state.line - (listsize/2)
    e = b + listsize - 1
  elsif @match[1] == '-'
    b = if @state.previous_line
          if  @state.previous_line > 0
            @state.previous_line - listsize
          else
            @state.previous_line
          end
        else
          @state.line - (listsize/2)
        end
    e = b + listsize - 1
  elsif @match[1] == '='
    @state.previous_line = nil
    b = @state.line - (listsize/2)
    e = b + listsize -1
  else
    b, e = @match[2].split(/[-,]/)
    if e
      b = b.to_i
      e = e.to_i
    else
      b = b.to_i - (listsize/2)
      e = b + listsize - 1
    end
  end
  @state.previous_line = display_list(b, e, @state.file, @state.line)
end

def help(cmd)
  %{
    l[ist]\t\tlist forward
    l[ist] -\tlist backward
    l[ist] =\tlist current line
    l[ist] nn-mm\tlist given lines
    * NOTE - to turn on autolist, use 'set autolist'
  }
end

def help_command
  'list'
end

def regexp
  /^\s* l(?:ist)? (?:\s*([-=])|\s+(.+))? $/x
end