local M = {}

function M.compute_lines()
  local help_lines = { "HELP" }
  local help_hl = { { "NvimTreeRootFolder", 0, 0, #help_lines[1] } }
  local mappings = vim.tbl_filter(function(v)
    return (v.cb ~= nil and v.cb ~= "") or (v.action ~= nil and v.action ~= "")
  end, require("nvim-tree.actions").mappings)
  local processed = {}
  for _, b in pairs(mappings) do
    local cb = b.cb
    local key = b.key
    local name
    if cb and cb:sub(1, 35) == require("nvim-tree.config").nvim_tree_callback("test"):sub(1, 35) then
      name = cb:match "'[^']+'[^']*$"
      name = name:match "'[^']+'"
    elseif b.action then
      name = b.action
    else
      name = (b.name ~= nil) and b.name or cb
      name = '"' .. name .. '"'
    end
    table.insert(processed, { key, name, true })
  end
  table.sort(processed, function(a, b)
    return (a[3] == b[3] and (a[2] < b[2] or (a[2] == b[2] and #a[1] < #b[1]))) or (a[3] and not b[3])
  end)

  local num = 0
  for _, val in pairs(processed) do
    local keys = type(val[1]) == "string" and { val[1] } or val[1]
    local map_name = val[2]
    local builtin = val[3]
    for _, key in pairs(keys) do
      num = num + 1
      local bind_string = string.format("%6s : %s", key, map_name)
      table.insert(help_lines, bind_string)

      local hl_len = math.max(6, string.len(key)) + 2
      table.insert(help_hl, { "NvimTreeFolderName", num, 0, hl_len })

      if not builtin then
        table.insert(help_hl, { "NvimTreeFileRenamed", num, hl_len, -1 })
      end
    end
  end
  return help_lines, help_hl
end

return M