[nvim] Change fzf to use floating window

By default fzf now uses a floating window covering most of the editor
screen real estate. It can still be full screened with a bang.

Floating window can be made optional with fzf layout options, but for
now I will try it for all fzf searches to get a feel for the positives
and negatives.

nvim/.config/nvim/plugin/fzf.vim

@@ -1,7 +1,5 @@
 " PLUGIN: fzf.vim
 " set some fzf defaults
-" windows drops down from above, 40% of the screen
-let g:fzf_layout = { 'up': '~40%' }
 " any Fzf command is prefixed with Fzf
 " this groups them nicely together, and avoids confusion when suddenly :Buffer
 " or :Files would appear as a command otherwise
@@ -13,6 +11,7 @@ let g:fzf_colors =
   \ 'hl':      ['fg', 'Comment'],
   \ 'fg+':     ['fg', 'CursorLine', 'CursorColumn', 'Normal'],
   \ 'bg+':     ['bg', 'CursorLine', 'CursorColumn'],
+  \ 'gutter':  ['bg', 'Normal'],
   \ 'hl+':     ['fg', 'Statement'],
   \ 'info':    ['fg', 'PreProc'],
   \ 'border':  ['fg', 'Ignore'],
@@ -30,5 +29,37 @@ let g:fzf_action = {
 " FzfRg but also search through hidden files
 command! -bang -nargs=* FzfRgHidden
   \ call fzf#vim#grep(
-  \   'rg --column --line-number --no-heading --color=always --smart-case --hidden '.shellescape(<q-args>), 1,
+  \   "rg --column --line-number --no-heading --color=always --smart-case --hidden --glob '!.git' ".shellescape(<q-args>), 1,
   \   fzf#vim#with_preview(), <bang>0)
+
+" make fzf use the nvim floating window globally. (weee, technology!)
+"
+let $FZF_DEFAULT_OPTS="--layout=reverse --margin=1,2"
+" to use fzf in a floating window only conditionally, the best approach would
+" probably be call fzf#run(fzf#wrap({ 'window': 'call FloatingFZF()' })) for
+" every command we want to floatize
+let g:fzf_layout = { 'window': 'call FloatingFZF()' }
+
+function! FloatingFZF()
+  " create a minimal nofile scratch buffer
+  let buf = nvim_create_buf(v:false, v:true)
+  call setbufvar(buf, '&signcolumn', 'no')
+
+  " this should probably change depending on fzf command
+  let height = float2nr(50)
+  let width = float2nr(200)
+  " center the window in editor
+  let horizontal = float2nr((&columns - width) / 2)
+  let vertical = float2nr((&lines - height) / 2)
+
+  let opts = {
+        \ 'relative': 'editor',
+        \ 'row': vertical,
+        \ 'col': horizontal,
+        \ 'width': width,
+        \ 'height': height,
+        \ 'style': 'minimal'
+        \ }
+
+  call nvim_open_win(buf, v:true, opts)
+endfunction