Improve documentation popup in neovim. Fix typo. (#1017)

* Typo fixed

* Improve placement of documentation popup in neovim

If the available space in either side of the completion popup is less
than 3/4 of the required width, then we shall place the documentation
popup below (or above, if necessary) of the completion popup.

Previously, the documentation was just squashed into whatever space was
available. It made documentation undreadable in some cases.

Author: subnut

autoload/lsp/ui/vim/documentation.vim

@@ -31,32 +31,45 @@ function! s:show_documentation(event) abort
 
 
    " Neovim
-   if s:use_nvim_float
+    if s:use_nvim_float
         let l:event = a:event
         let l:event.row = float2nr(l:event.row)
         let l:event.col = float2nr(l:event.col)
 
         let l:buffer = nvim_create_buf(v:false, v:true)
-        let l:curpos = win_screenpos(nvim_get_current_win())[0] + winline() - 1
+        let l:curpos = screenrow()
         let g:lsp_documentation_float_docked = get(g:, 'lsp_documentation_float_docked', 0)
 
+        call setbufvar(l:buffer, 'lsp_syntax_highlights', l:syntax_lines)
+        call setbufvar(l:buffer, 'lsp_do_conceal', 1)
+        call nvim_buf_set_lines(l:buffer, 0, -1, v:false, l:lines)
+        call nvim_buf_set_option(l:buffer, 'readonly', v:true)
+        call nvim_buf_set_option(l:buffer, 'modifiable', v:false)
+        call nvim_buf_set_option(l:buffer, 'filetype', l:ft.'.lsp-hover')
+
+
         if g:lsp_documentation_float_docked
-            let g:lsp_documentation_float_docked_maxheight = get(g:, ':lsp_documentation_float_docked_maxheight', &previewheight)
-            let l:dock_downwards = max([screenrow(), l:curpos]) < (&lines / 2)
+            let g:lsp_documentation_float_docked_maxheight = get(g:, 'lsp_documentation_float_docked_maxheight', &previewheight)
+            let l:dock_downwards = (l:curpos + l:event.height) < (&lines / 2)
             let l:height = min([len(l:data), g:lsp_documentation_float_docked_maxheight])
             let l:width = &columns
             let l:col = 0
             if l:dock_downwards
                 let l:anchor = 'SW'
                 let l:row = &lines - &cmdheight - 1
-                let l:height = min([l:height, &lines - &cmdheight - l:event.row - l:event.height])
+                let l:height = min([l:height, &lines - &cmdheight - l:event.row - l:event.height - 1]) - 1
+                " Extra -1 of height to distinguish between completion popup
+                " and documentation popup
             else " dock upwards
                 let l:anchor = 'NW'
                 let l:row = 0
                 let l:height = min([l:height, l:event.row - 1])
             endif
 
         else " not docked
+            let l:bufferlines = nvim_buf_line_count(l:buffer)
+            let l:maxwidth = max(map(getbufline(l:buffer, 1, '$'), 'strdisplaywidth(v:val)'))
+
             let l:row = l:event['row']
             let l:height = max([&lines - &cmdheight - l:row, &previewheight])
 
@@ -72,36 +85,40 @@ function! s:show_documentation(event) abort
                 let l:width = l:left_area
                 let l:col = l:event.col - 1     " 1 due to padding of completion popup
             endif
+            if l:width < 0.75 * l:maxwidth
+                let l:col = &columns
+                let l:width = l:maxwidth
+                let l:above = l:event.row > &lines - &cmdheight - l:event.row - l:event.height
+                if l:above
+                    let l:anchor = 'SE'
+                    let l:row = l:event.row
+                    let l:height = l:row
+                else
+                    let l:anchor = 'NE'
+                    let l:row = l:event.row + l:event.height
+                    let l:height = &lines - &cmdheight - l:row
+                endif
+            endif
         endif
 
-        call setbufvar(l:buffer, 'lsp_syntax_highlights', l:syntax_lines)
-        call setbufvar(l:buffer, 'lsp_do_conceal', 1)
-
         " add padding on both sides of lines containing text
         for l:index in range(len(l:lines))
             if len(l:lines[l:index]) > 0
                 let l:lines[l:index] = ' ' . l:lines[l:index] . ' '
             endif
         endfor
 
-        call nvim_buf_set_lines(l:buffer, 0, -1, v:false, l:lines)
-        call nvim_buf_set_option(l:buffer, 'readonly', v:true)
-        call nvim_buf_set_option(l:buffer, 'modifiable', v:false)
-        call nvim_buf_set_option(l:buffer, 'filetype', l:ft.'.lsp-hover')
-
         if !g:lsp_documentation_float_docked
-            let l:bufferlines = nvim_buf_line_count(l:buffer)
-            let l:maxwidth = max(map(getbufline(l:buffer, 1, '$'), 'strdisplaywidth(v:val)'))
-            if g:lsp_preview_max_width > 0
-                let l:maxwidth = min([g:lsp_preview_max_width, l:maxwidth])
-            endif
             let l:width = min([float2nr(l:width), l:maxwidth])
             let l:height = min([float2nr(l:height), l:bufferlines])
         endif
         if g:lsp_preview_max_height > 0
             let l:maxheight = g:lsp_preview_max_height
             let l:height = min([l:height, l:maxheight])
         endif
+        if g:lsp_preview_max_width > 0
+            let l:maxwidth = min([g:lsp_preview_max_width, l:width])
+        endif
 
         " Height and width must be atleast 1, otherwise error
         let l:height = (l:height < 1 ? 1 : l:height)