As a 3rd anecdote, I used vim for 10 years as my primary editor and “shell”. Then 10 years ago I learned tmux and fell in love with its window multiplexing. Now I use vim strictly as an editor/splitter. But I use tmux to split my code from my repl window. And maintain multiple windows where I’m working on different projects.

I'm going to try this. I use tmux but the idea of being able to use vim for everything seems nice. If you have tips/suggestions, I'm interested.

For me, some of the things that's really important for a terminal multiplexer include:

1) Keybindings having no conflicts with other terminal applications. For that, vim's default window-management key of <C-w> is unfortunate, as it is very important for delete words in bash and readline. I remap that to <C-@> (CTRL-Space) instead, which is basically used by no terminal program that I am aware of. The other key binding that trips me up are the default vim keybindings to kill the terminal (<C-w><C-c>). If I am midway attempting a window action, but realise something is taking too long and want to stop the job, the keybinding kills my whole shell. If I really want to kill my terminal, I can always issue ZQ or :q! in normal mode.

2) Change my cursor shapes based on which mode I'm in (normal, insert, or terminal/command), which helps me easily tell the mode.

3) Improve the default keybinding for going from terminal back to terminal normal mode. I find the default keybindings <C-\><C-n> and <C-w>N too difficult to type because I need to use this binding very much.

4) Be able to move between windows with the same, consistent set of keybindings no matter which mode I'm in (e.g. not having to go back to normal mode first, from insert or terminal mode). In the same vein, when I land on a buffer I always expect to be in normal mode, so I can start moving around immediately and yank stuff without remembering whether I'm in a terminal or a non-terminal buffer. When I need to manipulate the terminal program I can always `i` or `a`.

I have quite a few other customisations to my vim terminal, but I think these are the most essential ones.

vimrc for 1)

    set termwinkey=<C-@>
    noremap <C-@> <C-w>
    noremap <C-@><CR> <C-w><CR>
    noremap! <C-@> <Esc><C-w>

    noremap <C-@>c <Nop>
    noremap <C-@><C-c> <Nop>
    noremap <C-@><C-q> <Nop>
    noremap! <C-@>c <Nop>
    noremap! <C-@><C-c> <Nop>
    noremap! <C-@><C-q> <Nop>
    tnoremap <C-@>c <Nop>
    tnoremap <C-@><C-c> <Nop>
    tnoremap <C-@><C-q> <Nop>
    noremap <C-@>q <Nop>
    noremap! <C-@>q <Nop>
    tnoremap <C-@>q <Nop>

vimrc for 2) and 3)

    augroup term_normal
     au!      
     autocmd WinNew * let w:winnew = 1
     autocmd CmdlineEnter * let w:outcmd = 0
     autocmd CmdlineLeave * let w:outcmd = 1
     autocmd WinEnter * if exists ('w:winnew') | unlet w:winnew | if (mode() == 't') | call Termcursor () | endif | elseif get(w:, 'outcmd', 1) && (mode() == 't') | call feedkeys("\<C-@>N", "") | endif
     autocmd WinLeave * if (mode() == 't') && (! exists('w:tu')) | call feedkeys("\<C-@>N", 'x') | call Normalcursor () | elseif (mode(1) == 'nt') && (exists('w:tu')) | call feedkeys("i", 'ix') | endif

     tmap <expr> <C-@><C-@> ((mode() == 't') && get(w:, 'outcmd', 1)) ? '<C-@>N' : '<C-@><C-@>'
     augroup end
    
    let &t_SI = "\e[6 q\e]12;#FF00DF\<C-g>"
    let &t_EI = "\e[2 q\e]12;#FF00DF\<C-g>"
    let &t_ti = "\e[4 q\e]12;#FF00DF\<C-g>"
    let &t_te = "\e[2 q\e]12;#FF00DF\<C-g>"
    let &t_Us = "\e[4:2m"
    let &t_ds = "\e[4:4m"
    let &t_Ds = "\e[58:5:4m\e[4:5m"
    
    function! Normalcursor ()
     let &t_ve ="\e[2 q\e]12;#FF00DF\<C-g>" 
     let &t_vi ="\e[2 q\e]12;#FF00DF\<C-g>"
     endfunction
    function! Echonormalcursor ()
     call echoraw("\e[2 q\e]12;#FF00DF\<C-g>")
     endfunction
    function! Termcursor ()
     let &t_ve ="\e[4 q\e]12;#FF00DF\<C-g>"
     let &t_vi ="\e[4 q\e]12;#FF00DF\<C-g>"
     endfunction
    function! Echotermcursor ()
     call echoraw("\e[4 q\e]12;#FF00DF\<C-g>")
     endfunction
    
    augroup termcursor
     au!
     autocmd ModeChanged *:n* let &t_ve ="\e[2 q\e]12;#FF00DF\<C-g>"
     autocmd ModeChanged *:n* let &t_vi ="\e[2 q\e]12;#FF00DF\<C-g>"
     autocmd ModeChanged i:* if &t_ve == "" | let &t_ve ="\e[2 q\e]12;#FF00DF\<C-g>" | endif
     autocmd ModeChanged i:* if &t_vi == "" | let &t_vi ="\e[2 q\e]12;#FF00DF\<C-g>" | endif
     autocmd ModeChanged *:i* let &t_ve =""
     autocmd ModeChanged *:i* let &t_vi =""
     autocmd ModeChanged *:t call echoraw("\e[4 q\e]12;#FF00DF\<C-g>")
     autocmd ModeChanged *:t let &t_ve ="\e[4 q\e]12;#FF00DF\<C-g>"
     autocmd ModeChanged *:t let &t_vi ="\e[4 q\e]12;#FF00DF\<C-g>"
     autocmd ModeChanged t:* call echoraw("\e[2 q\e]12;#FF00DF\<C-g>")
     autocmd ModeChanged t:* if (mode(1) != 'ct') | let &t_ve ="\e[2 q\e]12;#FF00DF\<C-g>" | endif
     autocmd ModeChanged t:* if (mode(1) != 'ct') | let &t_vi ="\e[2 q\e]12;#FF00DF\<C-g>" | endif
    
     let g:cmdlinedepth = 0
     autocmd CmdlineEnter * let g:cmdlinedepth = g:cmdlinedepth + 1 | let &t_ve = "\e[4 q\e]12;#FF00DF\<C-g>" | let &t_vi = "\e[4 q\e]12;#FF00DF\<C-g>"
     autocmd CmdlineLeave * let g:cmdlinedepth = g:cmdlinedepth - 1 | if g:cmdlinedepth == 0 | if (mode(1) == 'ct') | call Termcursor () | else | call Normalcursor () | endif | endif
     autocmd CmdwinEnter * let &t_ve ="\e[2 q\e]12;#FF00DF\<C-g>" | let &t_vi ="\e[2 q\e]12;#FF00DF\<C-g>"
     autocmd CmdwinLeave * let &t_ve = "\e[4 q\e]12;#FF00DF\<C-g>" | let &t_vi = "\e[4 q\e]12;#FF00DF\<C-g>"
     
     " autocmd WinEnter * call echoraw("\e[2 q\e]12;#FF00DF\<C-g>")

vimrc for 4)

    vnoremap <C-@>s <C-w>sgv
    vnoremap <C-@>v <C-w>vgv

    nnoremap <expr> <C-@>w '@_' .. ((v:count1 + (winnr() - 1)) % (winnr('$')) + 1) .. '<C-w>w'
    nnoremap <expr> <C-@>W '@_' .. (((- v:count1 + (winnr() - 1)) % (winnr('$')) + winnr('$')) % (winnr('$')) + 1) .. '<C-w>w'
    nnoremap <expr> <C-@>t '@_' .. ((v:count1 - 1) % (winnr('$')) + 1) .. '<C-w>w'
    nnoremap <expr> <C-@>b '@_' .. (((- v:count1) % (winnr('$')) + winnr('$')) % (winnr('$')) + 1) .. '<C-w>w'
    inoremap <C-@><C-@> <C-@>
    map! <C-@>w <Esc><C-@>w
    map! <C-@>W <Esc><C-@>W
    map! <C-@>t <Esc><C-@>t
    map! <C-@>b <Esc><C-@>b
    tmap <C-@>w <C-@>N<C-@>w
    tmap <C-@>W <C-@>N<C-@>W
    tmap <C-@>t <C-@>N<C-@>t
    tmap <C-@>b <C-@>N<C-@>b

Some other things I do:

Invoke terminals on directories (instead of netrw). So, I can e.g. sp. to split to a new terminal.

  function! Isdir(dir) abort
   return !empty(a:dir) && (isdirectory(a:dir) ||
    \ (!empty($SYSTEMDRIVE) && isdirectory('/'..tolower($SYSTEMDRIVE[0])..a:dir)))
   endfunction
  
  augroup terminal-explorer
   au!
   au VimEnter * sil! au! FileExplorer *
   au VimEnter * sil! au! Network *
   au VimEnter * sil! au! AuNetrwEvent *
   " au FileType netrw cd % | bw | exe 'terminal ++curwin'
   au BufEnter * if &filetype != 'netrw' && Isdir(expand('%')) | lcd % | exe bufnr("%") ..'bufdo terminal ++curwin' | endif
   augroup end

Make <C-@>m close windows instead:

    noremap <C-@>m <C-w>c
    noremap! <C-@>m <Esc><C-w>c
    tnoremap <C-@>m <C-@>c

Make <C-@>p find the next window if there is no previous window:

    noremap <expr> <silent> <C-@>p ':<C-u>wincmd p <Bar> if win_getid () == ' .. win_getid () .. ' <Bar> wincmd w <Bar> endif <CR>'
    noremap! <expr> <silent> <C-@>p '<Esc>:<C-u>wincmd p <Bar> if win_getid () == ' .. win_getid () .. ' <Bar> wincmd w <Bar> endif <CR>'
    tnoremap <expr> <silent> <C-@>p '<C-@>:<C-u>wincmd p <Bar> if win_getid () == ' .. win_getid () .. ' <Bar> wincmd w <Bar> endif <CR>'

Use <C-@>~. to detach the GNU screen that my vim is running in (I put my vim in a screen with `unbindall` i.e. I use screen merely for keeping my vim alive) (<C-@>~. is in analogy to the SSH quit keybinding <CR>~.).

    noremap <expr> <silent> <C-@>~. ':<C-u>silent !screen -X detach<CR>'
    noremap! <expr> <silent> <C-@>~. '<C-@>:<C-u>silent !screen -X detach<CR>'
    tnoremap <expr> <silent> <C-@>~. '<C-@>:<C-u>silent !screen -X detach<CR>'

With gf and gF, opening files just from a terminal grep is practically more convenient than vim's :grep. For gf in a new tab:

    map <silent> <C-@><C-f> :<C-u>tab split<CR>gf

With terminal multiplexing in vim, you start getting a lot of buffers. You can consider getting a custom tabline. Other tab management features become more important too. You might expect [count]gt to behave just like gt for [count] times:

    nnoremap <expr> gt '@_' .. ((v:count1 + (tabpagenr () - 1)) % (tabpagenr('$') ) + 1) .. 'gt'

For ease of moving to the last tab:

    nnoremap <expr> g<C-t> '@_' .. (((v:count == 0) ? tabpagenr ('$') : v:count)) .. 'gt'

To consistently access the gt family of bindings regardless of mode:

    map <C-@>gt gt
    map <C-@>gT gT
    map <C-@>g<C-t> g<C-t>
    map! <C-@>gt <Esc>gt
    map! <C-@>gT <Esc>gT
    map! <C-@>g<C-t> <Esc>g<C-t>
    tmap <C-@>gt <C-@>Ngt
    tmap <C-@>gT <C-@>NgT
    tmap <C-@>g<C-t> <C-@>Ng<C-t>

When you use <C-w>T a lot to move your windows in to new tabs, you might sometimes want to move them to the previous tab instead of the next one:

    nnoremap <silent> <C-@><C-t> <C-w>T
    nnoremap <silent> <C-@>T <C-w>T:<C-u>tabm -1<CR>

To access these two in any mode consistently:

    map! <C-@><C-t> <Esc><C-@><C-t>
    map! <C-@>T <Esc><C-@>T
    tmap <C-@><C-t> <C-@>N<C-@><C-t>
    tmap <C-@>T <C-@>N<C-@>T

Analogously to gt and gT, sometimes you may want to move your tabs around, or split them:

    function! SSStabmadjust(tabmnum)
     if a:tabmnum < tabpagenr ()
      return a:tabmnum - 1
     else
      return a:tabmnum
      endif
     endfunction

    noremap <silent> <C-@><C-g>s :<C-u>tab split<CR>
    noremap <expr> <silent> <C-@><C-g>t '@_:<C-u>' .. SSStabmadjust ((v:count1 + (tabpagenr () - 1 )) % (tabpagenr('$') ) + 1) .. 'tabm<CR>'
    noremap <expr> <silent> <C-@><C-g>T '@_:<C-u>' .. SSStabmadjust (((- v:count1 + (tabpagenr () - 1 )) % (tabpagenr('$') ) + tabpagenr('$') ) % (tabpagenr('$') ) + 1) .. 'tabm<CR>'
    noremap <expr> <silent> <C-@><C-g><C-t> ':<C-u>' .. ((v:count == 0) ? "" : SSStabmadjust ((v:count % (tabpagenr ('$') )) )) .. 'tabm<CR>'
    map! <C-@><C-g>s <Esc><C-@><C-g>s
    map! <C-@><C-g>t <Esc><C-@><C-g>t
    map! <C-@><C-g>T <Esc><C-@><C-g>T
    map! <C-@><C-g><C-t> <Esc><C-@><C-g><C-t>
    tmap <C-@><C-g>s <C-@>N<C-@><C-g>s
    tmap <C-@><C-g>t <C-@>N<C-@><C-g>t
    tmap <C-@><C-g>T <C-@>N<C-@><C-g>T
    tmap <C-@><C-g><C-t> <C-@>N<C-@><C-g><C-t>

When you get to using [count]g[something] and g[count][something] and <C-@>[count]g[something] etc a lot, you start getting a bit confused about where you need to put the count to make things work. So you can make putting the count anywhere work; now, don't worry and just start pressing g or <C-@>g for window actions, and put a count if you realise you need it:

    map <expr> <C-@>1 Termcountmap(1, "")
    map <expr> <C-@>2 Termcountmap(2, "")
    map <expr> <C-@>3 Termcountmap(3, "")
    map <expr> <C-@>4 Termcountmap(4, "")
    map <expr> <C-@>5 Termcountmap(5, "")
    map <expr> <C-@>6 Termcountmap(6, "")
    map <expr> <C-@>7 Termcountmap(7, "")
    map <expr> <C-@>8 Termcountmap(8, "")
    map <expr> <C-@>9 Termcountmap(9, "")
    map! <expr> <C-@>1 Termcountmap(1, '<Esc>')
    map! <expr> <C-@>2 Termcountmap(2, '<Esc>')
    map! <expr> <C-@>3 Termcountmap(3, '<Esc>')
    map! <expr> <C-@>4 Termcountmap(4, '<Esc>')
    map! <expr> <C-@>5 Termcountmap(5, '<Esc>')
    map! <expr> <C-@>6 Termcountmap(6, '<Esc>')
    map! <expr> <C-@>7 Termcountmap(7, '<Esc>')
    map! <expr> <C-@>8 Termcountmap(8, '<Esc>')
    map! <expr> <C-@>9 Termcountmap(9, '<Esc>')
    tmap <expr> <C-@>1 Termcountmap(1, '<C-@>N')
    tmap <expr> <C-@>2 Termcountmap(2, '<C-@>N')
    tmap <expr> <C-@>3 Termcountmap(3, '<C-@>N')
    tmap <expr> <C-@>4 Termcountmap(4, '<C-@>N')
    tmap <expr> <C-@>5 Termcountmap(5, '<C-@>N')
    tmap <expr> <C-@>6 Termcountmap(6, '<C-@>N')
    tmap <expr> <C-@>7 Termcountmap(7, '<C-@>N')
    tmap <expr> <C-@>8 Termcountmap(8, '<C-@>N')
    tmap <expr> <C-@>9 Termcountmap(9, '<C-@>N')

    function! Termcountmap(initcount, normalkeys)
     let termcount = a:initcount
     while 1
      try
       let char = getchar()
      catch /^Vim:Interrupt$/
       return ""
       endtry
    
      if type(char) == 0
       let char = nr2char(char)
       endif
    
      if char == '0'
       let termcount = termcount * 10
      elseif char == '1'
       let termcount = termcount * 10 + 1
      elseif char == '2'
       let termcount = termcount * 10 + 2
      elseif char == '3'
       let termcount = termcount * 10 + 3
      elseif char == '4'
       let termcount = termcount * 10 + 4
      elseif char == '5'
       let termcount = termcount * 10 + 5
      elseif char == '6'
       let termcount = termcount * 10 + 6
      elseif char == '7'
       let termcount = termcount * 10 + 7
      elseif char == '8'
       let termcount = termcount * 10 + 8
      elseif char == '9'
       let termcount = termcount * 10 + 9
      elseif char == 'g'
       return a:normalkeys .. termcount .. 'g'
      elseif char == "\<C-g>"
       return a:normalkeys .. termcount .. "\<C-@>\<C-g>"
      elseif char == 'w'
       return a:normalkeys .. termcount .. "\<C-@>w"
      elseif char == 'W'
       return a:normalkeys .. termcount .. "\<C-@>W"
      elseif char == 't'
       return a:normalkeys .. termcount .. "\<C-@>t"
      elseif char == 'b'
       return a:normalkeys .. termcount .. "\<C-@>b"
      else
       return a:normalkeys .. ":\<C-u>" .. termcount .. ' wincmd ' .. char .. "\<CR>\<C-l>"
       endif
    
      endwhile
     endfunction
    
    map <expr> g<C-@> <C-@>g
    
    map <expr> g1 Prefixcountmap (v:count * 10 + 1, "", 'g')
    map <expr> g2 Prefixcountmap (v:count * 10 + 2, "", 'g')
    map <expr> g3 Prefixcountmap (v:count * 10 + 3, "", 'g')
    map <expr> g4 Prefixcountmap (v:count * 10 + 4, "", 'g')
    map <expr> g5 Prefixcountmap (v:count * 10 + 5, "", 'g')
    map <expr> g6 Prefixcountmap (v:count * 10 + 6, "", 'g')
    map <expr> g7 Prefixcountmap (v:count * 10 + 7, "", 'g')
    map <expr> g8 Prefixcountmap (v:count * 10 + 8, "", 'g')
    map <expr> g9 Prefixcountmap (v:count * 10 + 9, "", 'g')
    tmap <expr> <c-@>g1 Prefixcountmap (v:count * 10 + 1, '<c-@>n', 'g')
    tmap <expr> <c-@>g2 Prefixcountmap (v:count * 10 + 2, '<c-@>n', 'g')
    tmap <expr> <c-@>g3 Prefixcountmap (v:count * 10 + 3, '<c-@>n', 'g')
    tmap <expr> <c-@>g4 Prefixcountmap (v:count * 10 + 4, '<c-@>n', 'g')
    tmap <expr> <c-@>g5 Prefixcountmap (v:count * 10 + 5, '<c-@>n', 'g')
    tmap <expr> <c-@>g6 Prefixcountmap (v:count * 10 + 6, '<c-@>n', 'g')
    tmap <expr> <c-@>g7 Prefixcountmap (v:count * 10 + 7, '<c-@>n', 'g')
    tmap <expr> <c-@>g8 Prefixcountmap (v:count * 10 + 8, '<c-@>n', 'g')
    tmap <expr> <c-@>g9 Prefixcountmap (v:count * 10 + 9, '<c-@>n', 'g')
    
    map <expr> <C-@><C-g>1 Prefixcountmap (v:count * 10 + 1, "", '<C-@><C-g>')
    map <expr> <C-@><C-g>2 Prefixcountmap (v:count * 10 + 2, "", '<C-@><C-g>')
    map <expr> <C-@><C-g>3 Prefixcountmap (v:count * 10 + 3, "", '<C-@><C-g>')
    map <expr> <C-@><C-g>4 Prefixcountmap (v:count * 10 + 4, "", '<C-@><C-g>')
    map <expr> <C-@><C-g>5 Prefixcountmap (v:count * 10 + 5, "", '<C-@><C-g>')
    map <expr> <C-@><C-g>6 Prefixcountmap (v:count * 10 + 6, "", '<C-@><C-g>')
    map <expr> <C-@><C-g>7 Prefixcountmap (v:count * 10 + 7, "", '<C-@><C-g>')
    map <expr> <C-@><C-g>8 Prefixcountmap (v:count * 10 + 8, "", '<C-@><C-g>')
    map <expr> <C-@><C-g>9 Prefixcountmap (v:count * 10 + 9, "", '<C-@><C-g>')
    map! <expr> <C-@><C-g>1 Prefixcountmap (v:count * 10 + 1, '<Esc>', '<C-@><C-g>')
    map! <expr> <C-@><C-g>2 Prefixcountmap (v:count * 10 + 2, '<Esc>', '<C-@><C-g>')
    map! <expr> <C-@><C-g>3 Prefixcountmap (v:count * 10 + 3, '<Esc>', '<C-@><C-g>')
    map! <expr> <C-@><C-g>4 Prefixcountmap (v:count * 10 + 4, '<Esc>', '<C-@><C-g>')
    map! <expr> <C-@><C-g>5 Prefixcountmap (v:count * 10 + 5, '<Esc>', '<C-@><C-g>')
    map! <expr> <C-@><C-g>6 Prefixcountmap (v:count * 10 + 6, '<Esc>', '<C-@><C-g>')
    map! <expr> <C-@><C-g>7 Prefixcountmap (v:count * 10 + 7, '<Esc>', '<C-@><C-g>')
    map! <expr> <C-@><C-g>8 Prefixcountmap (v:count * 10 + 8, '<Esc>', '<C-@><C-g>')
    map! <expr> <C-@><C-g>9 Prefixcountmap (v:count * 10 + 9, '<Esc>', '<C-@><C-g>')
    tmap <expr> <C-@><C-g>1 Prefixcountmap (v:count * 10 + 1, '<C-@>N', '<C-@><C-g>')
    tmap <expr> <C-@><C-g>2 Prefixcountmap (v:count * 10 + 2, '<C-@>N', '<C-@><C-g>')
    tmap <expr> <C-@><C-g>3 Prefixcountmap (v:count * 10 + 3, '<C-@>N', '<C-@><C-g>')
    tmap <expr> <C-@><C-g>4 Prefixcountmap (v:count * 10 + 4, '<C-@>N', '<C-@><C-g>')
    tmap <expr> <C-@><C-g>5 Prefixcountmap (v:count * 10 + 5, '<C-@>N', '<C-@><C-g>')
    tmap <expr> <C-@><C-g>6 Prefixcountmap (v:count * 10 + 6, '<C-@>N', '<C-@><C-g>')
    tmap <expr> <C-@><C-g>7 Prefixcountmap (v:count * 10 + 7, '<C-@>N', '<C-@><C-g>')
    tmap <expr> <C-@><C-g>8 Prefixcountmap (v:count * 10 + 8, '<C-@>N', '<C-@><C-g>')
    tmap <expr> <C-@><C-g>9 Prefixcountmap (v:count * 10 + 9, '<C-@>N', '<C-@><C-g>')
    
    function! Prefixcountmap(initcount, prefix, countprefix)
     let termcount = a:initcount
     while 1
      try
       let char = getchar()
      catch /^Vim:Interrupt$/
       return ""
       endtry
    
      if type(char) == 0
       let char = nr2char(char)
       endif
    
      if char == '0'
       let termcount = termcount * 10
      elseif char == '1'
       let termcount = termcount * 10 + 1
      elseif char == '2'
       let termcount = termcount * 10 + 2
      elseif char == '3'
       let termcount = termcount * 10 + 3
      elseif char == '4'
       let termcount = termcount * 10 + 4
      elseif char == '5'
       let termcount = termcount * 10 + 5
      elseif char == '6'
       let termcount = termcount * 10 + 6
      elseif char == '7'
       let termcount = termcount * 10 + 7
      elseif char == '8'
       let termcount = termcount * 10 + 8
      elseif char == '9'
       let termcount = termcount * 10 + 9
      else
       return a:prefix .. termcount .. a:countprefix .. char
       endif
    
      endwhile
     endfunction

(equivalently, if you use screen; the key point is the \eP and the \e\\ between which the real xterm escape codes go, or else screen will eat your escape codes which will never see the light of day)

    augroup term_normal
     au!      
     autocmd WinNew * let w:winnew = 1
     autocmd CmdlineEnter * let w:outcmd = 0
     autocmd CmdlineLeave * let w:outcmd = 1
     autocmd WinEnter * if exists ('w:winnew') | unlet w:winnew | if (mode() == 't') | call Termcursor () | endif | elseif get(w:, 'outcmd', 1) && (mode() == 't') | call feedkeys("\<C-@>N", "") | endif
     autocmd WinLeave * if (mode() == 't') && (! exists('w:tu')) | call feedkeys("\<C-@>N", 'x') | call Normalcursor () | elseif (mode(1) == 'nt') && (exists('w:tu')) | call feedkeys("i", 'ix') | endif
    
     tmap <expr> <C-@><C-@> ((mode() == 't') && get(w:, 'outcmd', 1)) ? '<C-@>N' : '<C-@><C-@>'
     augroup end
    
    let &t_SI = "\eP\e[6 q\e]12;#FF00DF\<C-g>\e\\"
    let &t_EI = "\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\"
    let &t_ti = "\eP\e[4 q\e]12;#FF00DF\<C-g>\e\\"
    let &t_te = "\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\"
    let &t_Us = "\eP\e[4:2m\e\\"
    let &t_ds = "\eP\e[4:4m\e\\"
    let &t_Ds = "\eP\e[58:5:3m\e[4:5m\e\\"
    
    function! Normalcursor ()
     let &t_ve ="\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\" 
     let &t_vi ="\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\"
     endfunction
    function! Echonormalcursor ()
     call echoraw("\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\")
     endfunction
    function! Termcursor ()
     let &t_ve ="\eP\e[4 q\e]12;#FF00DF\<C-g>\e\\"
     let &t_vi ="\eP\e[4 q\e]12;#FF00DF\<C-g>\e\\"
     endfunction
    function! Echotermcursor ()
     call echoraw("\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\")
     endfunction
    
    augroup termcursor
     au!
     autocmd ModeChanged *:n* let &t_ve ="\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\"
     autocmd ModeChanged *:n* let &t_vi ="\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\"
     autocmd ModeChanged i:* if &t_ve == "" | let &t_ve ="\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\" | endif
     autocmd ModeChanged i:* if &t_vi == "" | let &t_vi ="\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\" | endif
     autocmd ModeChanged *:i* let &t_ve =""
     autocmd ModeChanged *:i* let &t_vi =""
     autocmd ModeChanged *:t call echoraw("\eP\e[4 q\e]12;#FF00DF\<C-g>\e\\")
     autocmd ModeChanged *:t let &t_ve ="\eP\e[4 q\e]12;#FF00DF\<C-g>\e\\"
     autocmd ModeChanged *:t let &t_vi ="\eP\e[4 q\e]12;#FF00DF\<C-g>\e\\"
     autocmd ModeChanged t:* call echoraw("\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\")
     autocmd ModeChanged t:* if (mode(1) != 'ct') | let &t_ve ="\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\" | endif
     autocmd ModeChanged t:* if (mode(1) != 'ct') | let &t_vi ="\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\" | endif
     
     " TODO -- doesnt restore from redraw?
     let g:cmdlinedepth = 0
     autocmd CmdlineEnter * let g:cmdlinedepth = g:cmdlinedepth + 1 | let &t_ve = "\eP\e[4 q\e]12;#FF00DF\<C-g>\e\\" | let &t_vi = "\eP\e[4 q\e]12;#FF00DF\<C-g>\e\\"
     autocmd CmdlineLeave * let g:cmdlinedepth = g:cmdlinedepth - 1 | if g:cmdlinedepth == 0 | if (mode(1) == 'ct') | call Termcursor () | else | call Normalcursor () | endif | endif
     autocmd CmdwinEnter * let &t_ve ="\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\" | let &t_vi ="\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\"
     autocmd CmdwinLeave * let &t_ve = "\eP\e[4 q\e]12;#FF00DF\<C-g>\e\\" | let &t_vi = "\eP\e[4 q\e]12;#FF00DF\<C-g>\e\\"
    
     " autocmd WinEnter * call echoraw("\eP\e[2 q\e]12;#FF00DF\<C-g>\e\\")
     augroup end

thanks for the reply and tips, lots of useful information in there.