local handler = function(virtText, lnum, endLnum, width, truncate)
  local newVirtText = {}
  local suffix = (" 󰡏 %d "):format(endLnum - lnum)
  local sufWidth = vim.fn.strdisplaywidth(suffix)
  local targetWidth = width - sufWidth
  local curWidth = 0
  for _, chunk in ipairs(virtText) do
    local chunkText = chunk[1]
    local chunkWidth = vim.fn.strdisplaywidth(chunkText)
    if targetWidth > curWidth + chunkWidth then
      table.insert(newVirtText, chunk)
    else
      chunkText = truncate(chunkText, targetWidth - curWidth)
      local hlGroup = chunk[2]
      table.insert(newVirtText, { chunkText, hlGroup })
      chunkWidth = vim.fn.strdisplaywidth(chunkText)
      -- str width returned from truncate() may less than 2nd argument, need padding
      if curWidth + chunkWidth < targetWidth then
        suffix = suffix .. (" "):rep(targetWidth - curWidth - chunkWidth)
      end
      break
    end
    curWidth = curWidth + chunkWidth
  end
  table.insert(newVirtText, { suffix, "MoreMsg" })
  return newVirtText
end

require("ufo").setup {
  fold_virt_text_handler = handler,
  close_fold_kinds = {},
  -- close_fold_kinds = { "imports", "comment" },
  provider_selector = function(bufnr, filetype, buftype)
    -- if you prefer treesitter provider rather than lsp,
    -- return ftMap[filetype] or {'treesitter', 'indent'}
    -- return ftMap[filetype]
    return { "treesitter", "indent" }

    -- refer to ./doc/example.lua for detail
  end,

  preview = {
    win_config = {
      border = { "", "─", "", "", "", "─", "", "" },
      winhighlight = "Normal:Folded",
      winblend = 0,
    },
    mappings = {
      scrollU = "<M-k>",
      scrollD = "<M-j>",
      jumpTop = "[",
      jumpBot = "]",
    },
  },
}

-- return M
