nnoremap <silent> <F5> :Fern . -reveal=% -drawer -toggle<CR>

function! s:init_fern() abort
  setlocal nonumber norelativenumber

  nmap <buffer><expr>
    \ <Plug>(fern-my-expand-or-collapse)
    \ fern#smart#leaf(
    \   "\<Plug>(fern-action-collapse)",
    \   "\<Plug>(fern-action-expand)",
    \   "\<Plug>(fern-action-collapse)",
    \ )

    nmap <buffer><expr>
    \ <Plug>(fern-my-open-expand-collapse)
    \ fern#smart#leaf(
    \   "\<Plug>(fern-action-open:select)",
    \   "\<Plug>(fern-action-expand)",
    \   "\<Plug>(fern-action-collapse)",
    \ )

  nmap <buffer> H <Plug>(fern-action-open:split)
  nmap <buffer> V <Plug>(fern-action-open:vsplit)
  nmap <buffer> t <Plug>(fern-action-open:tabedit)
  nmap <buffer> r <Plug>(fern-action-rename)
  nmap <buffer> R <Plug>(fern-action-reload)
  nmap <buffer> N <Plug>(fern-action-new-file)
  nmap <buffer> K <Plug>(fern-action-new-dir)
  nmap <buffer> c <Plug>(fern-action-copy)
  nmap <buffer> m <Plug>(fern-action-move)
  nmap <buffer> h <Plug>(fern-action-hidden:toggle)
  nmap <buffer> C <Plug>(fern-action-clipboard-copy)
  nmap <buffer> M <Plug>(fern-action-clipboard-move)
  nmap <buffer> P <Plug>(fern-action-clipboard-paste)
  nmap <buffer> D <Plug>(fern-action-remove)
  nmap <buffer> <BS> <Plug>(fern-action-leave)
  nmap <buffer> <space> <Plug>(fern-action-mark-toggle)
  nmap <buffer> <CR> <Plug>(fern-my-open-expand-collapse)
  nmap <buffer><nowait> o <Plug>(fern-my-expand-or-collapse)
endfunction

augroup fern-custom
  autocmd! *
  autocmd FileType fern call s:init_fern()
augroup END