let g:NERDTreeShowHidden=1
let g:NERDTreeGitStatusShowIgnored=1

if !&diff
  autocmd StdinReadPre * let s:std_in=1
endif

function NERDTreeInit()
  if !&diff
    let buffer_type = getbufvar(bufnr(), "&filetype")
    if index(g:NERDTreeNoInitFiletypes, buffer_type) == -1
      NERDTree

      if argc() > 0 || exists('s:std_in')
        wincmd p
      endif

      if argc() > 0
        silent NERDTreeFind
        wincmd p
      endif
    endif
  endif
endfunction
autocmd VimEnter * call NERDTreeInit()

autocmd BufWinEnter * if getcmdwintype() == '' | silent NERDTreeMirror | endif
autocmd BufEnter * if winnr('$') == 1 && exists('b:NERDTree') && b:NERDTree.isTabTree() | quit | endif

" set status line on tab switch
function NERDTreeStatusLineTabSwitch()
  " only when in non-meaningful window
  if index(g:NERDTreeStatusLineTabSwitchFiletypes, &filetype) == -1
    return
  endif

  let tab_nr = tabpagenr()
  let buffer_list = tabpagebuflist(tab_nr)

  " default to 2
  let meaningful_window_nr = 2

  for buffer_nr in buffer_list
    let buffer_type = getbufvar(buffer_nr, "&filetype")
    if index(g:NERDTreeStatusLineTabSwitchFiletypes, buffer_type) == -1
      let meaningful_window_nr = bufwinnr(buffer_nr)
      break
    endif
  endfor

  exe meaningful_window_nr .. "wincmd w"
endfunction
autocmd TabLeave * call NERDTreeStatusLineTabSwitch()

map <C-b> <cmd>NERDTreeToggle<CR>