def regen_text
    @text = []
    @chunk_lines = []
    @message_lines = []
    @person_lines = []

    prevm = nil
    @thread.each do |m, depth, parent|
      unless m.is_a? Message # handle nil and :fake_root
        @text += chunk_to_lines m, nil, @text.length, depth, parent
        next
      end
      l = @layout[m]

      ## is this still necessary?
      next unless @layout[m].state # skip discarded drafts

      ## build the patina
      text = chunk_to_lines m, l.state, @text.length, depth, parent, l.color, l.star_color

      l.top = @text.length
      l.bot = @text.length + text.length # updated below
      l.prev = prevm
      l.next = nil
      l.depth = depth
      # l.state we preserve
      l.width = 0 # updated below
      @layout[l.prev].next = m if l.prev

      (0 ... text.length).each do |i|
        @chunk_lines[@text.length + i] = m
        @message_lines[@text.length + i] = m
        lw = text[i].flatten.select { |x| x.is_a? String }.map { |x| x.display_length }.sum
      end

      @text += text
      prevm = m
      if l.state != :closed
        m.chunks.each do |c|
          cl = @chunk_layout[c]

          ## set the default state for chunks
          cl.state ||=
            if c.expandable? && c.respond_to?(:initial_state)
              c.initial_state
            else
              :closed
            end

          text = chunk_to_lines c, cl.state, @text.length, depth
          (0 ... text.length).each do |i|
            @chunk_lines[@text.length + i] = c
            @message_lines[@text.length + i] = m
            lw = text[i].flatten.select { |x| x.is_a? String }.map { |x| x.display_length }.sum - (depth * @indent_spaces)
            l.width = lw if lw > l.width
          end
          @text += text
        end
        @layout[m].bot = @text.length
      end
    end
  end
def regen_text
    @text = []
    @chunk_lines = []
    @message_lines = []
    @person_lines = []

    prevm = nil
    @thread.each do |m, depth, parent|
      unless m.is_a? Message # handle nil and :fake_root
        @text += chunk_to_lines m, nil, @text.length, depth, parent
        next
      end
      l = @layout[m]

      ## is this still necessary?
      next unless @layout[m].state # skip discarded drafts

      ## build the patina
      text = chunk_to_lines m, l.state, @text.length, depth, parent, l.color, l.star_color

      l.top = @text.length
      l.bot = @text.length + text.length # updated below
      l.prev = prevm
      l.next = nil
      l.depth = depth
      # l.state we preserve
      l.width = 0 # updated below
      @layout[l.prev].next = m if l.prev

      (0 ... text.length).each do |i|
        @chunk_lines[@text.length + i] = m
        @message_lines[@text.length + i] = m
        lw = text[i].flatten.select { |x| x.is_a? String }.map { |x| x.display_length }.sum
      end

      @text += text
      prevm = m
      if l.state != :closed
        m.chunks.each do |c|
          cl = @chunk_layout[c]

          ## set the default state for chunks
          cl.state ||=
            if c.expandable? && c.respond_to?(:initial_state)
              c.initial_state
            else
              :closed
            end

          text = chunk_to_lines c, cl.state, @text.length, depth
          (0 ... text.length).each do |i|
            @chunk_lines[@text.length + i] = c
            @message_lines[@text.length + i] = m
            lw = text[i].flatten.select { |x| x.is_a? String }.map { |x| x.display_length }.sum - (depth * @indent_spaces)
            l.width = lw if lw > l.width
          end
          @text += text
        end
        @layout[m].bot = @text.length
      end
    end
  end
here we generate the actual content lines. we accumulate
 everything into @text, and we set @chunk_lines and
 @message_lines, and we update @layout.