vimrc: fix dark theme colo,highlights

.vim/vimrc

@@ -37,6 +37,8 @@ call plug#begin()
 " colourschemes
 Plug 'liuchengxu/space-vim-theme'
 Plug 'nikolasvargas/spacemacs-theme'
+" Plug 'romainl/Apprentice'
+" Plug 'arcticicestudio/nord-vim'
 Plug 'cocopon/iceberg.vim'
 Plug 'sainnhe/edge'
 Plug 'chriskempson/base16-vim'
@@ -1171,8 +1173,75 @@ set noscrollbind
 set cmdheight=2               " lines under {status,air}line
 set updatetime=250
 
-set termguicolors
-colo space_vim_theme          " new fav highlighting
+
+if (has('termguicolors'))
+  set termguicolors
+endif
+" let there be light
+" set background=light
+set background=dark
+if &background =~# 'light'
+  " colo default
+  " colo space_vim_theme
+  " colo iceberg
+  " colo edge
+  " colo base16-grayscale-light
+  colo antiphoton
+
+  " proper light only when terminal bg is light
+  " colo bruin
+else
+  " colo spacemacs-theme
+  " colo monotone
+  " colo space_vim_theme
+  colo photon
+
+  " proper dark only when terminal bg is dark
+  " colo bruin
+  " colo monochrome
+endif
+" colo apprentice
+" colo nord
+
+hi CursorLineNR cterm=bold
+hi ALEInfoSign guifg=#616161 ctermfg=59
+hi ALEVirtualTextInfo guifg=#616161 ctermfg=59
+" hi ALEVirtualTextWarning guifg=#5c6370 ctermfg=59
+hi ALEVirtualTextWarning guifg=#616161 ctermfg=59
+" hi ALEVirtualTextError guifg=#7f3963 ctermfg=59
+hi ALEVirtualTextError guifg=#c471a3 ctermfg=59
+hi GitGutterAdd guifg=#32CD32 ctermfg=59
+hi GitGutterDelete guifg=#c471a3 ctermfg=59
+
+" erase most of the background colour in this specific case.
+if g:colors_name =~# 'spacemacs-theme' && &background =~# 'dark'
+  hi Normal ctermbg=NONE guibg=NONE
+  hi LineNr ctermbg=NONE guibg=NONE
+  " hi CursorLineNR cterm=bold
+  hi VertSplit cterm=NONE guibg=NONE
+  hi SignColumn ctermbg=NONE term=standout cterm=NONE guibg=NONE gui=NONE
+  hi GitGutterAdd ctermbg=NONE guibg=NONE cterm=bold gui=bold
+  hi GitGutterChange ctermbg=NONE guibg=NONE cterm=bold gui=bold
+  hi GitGutterDelete ctermbg=NONE guibg=NONE cterm=bold gui=bold
+  hi GitGutterChangeDelete ctermbg=NONE guibg=NONE cterm=bold gui=bold
+
+  " hi GitGutterAddLine ctermbg=NONE guibg=NONE
+  " hi GitGutterChangeLine ctermbg=NONE guibg=NONE
+  " hi GitGutterDeleteLine ctermbg=NONE guibg=NONE
+  " hi GitGutterChangeDeleteLine ctermbg=NONE guibg=NONE
+  " hi SignifySignAdd ctermbg=NONE guibg=NONE
+  " hi SignifySignChange ctermbg=NONE guibg=NONE
+  " hi SignifySignDelete ctermbg=NONE guibg=NONE
+  " hi SignifyChangeDelete ctermbg=NONE guibg=NONE
+  " hi SignifySignDeleteFirstSign ctermbg=NONE guibg=NONE
+
+  hi ALEErrorSign ctermbg=NONE guibg=NONE
+  hi ALEWarningSign ctermbg=NONE guibg=NONE
+  hi Terminal ctermbg=NONE guibg=NONE
+
+endif
+
+
 " compensate for lack of theme italics
 for s in ["Comment", "Constant", "Include", "Define", "Macro", "Delimiter", "Debug", "Identifier", "Boolean", "markdownItalic"]
     execute "hi " s " cterm=italic"