WIP: ALEFindReferences: add -fzf flag to show output in fzf

autoload/ale/references.vim

@@ -1,4 +1,6 @@
 let g:ale_default_navigation = get(g:, 'ale_default_navigation', 'buffer')
+let g:ale_references_show_contents = get(g:, 'ale_references_show_contents', 1)
+let g:ale_references_use_fzf = get(g:, 'ale_references_use_fzf', 0)
 
 let s:references_map = {}
 
@@ -67,48 +69,160 @@ function! ale#references#HandleTSServerResponse(conn_id, response) abort
 endfunction
 
 function! ale#references#FormatLSPResponseItem(response_item, options) abort
+    let l:line_text = ''
+
+    let l:line= a:response_item.range.start.line
+    let l:col = a:response_item.range.start.character
+    let l:filename = ale#util#ToResource(a:response_item.uri)
+
+    if get(a:options, 'show_contents') == 1
+        try
+            let l:line_text = substitute(readfile(l:filename)[l:line], '^\s*\(.\{-}\)\s*$', '\1', '')
+        catch
+            " This happens in tests
+        endtry
+    endif
+
+    if get(a:options, 'use_fzf') == 1
+        let l:filename = ale#util#ToResource(a:response_item.uri)
+        let l:nline = a:response_item.range.start.line + 1
+        let l:ncol = a:response_item.range.start.character + 1
+
+        " grep-style output (filename:line:col:text) so that fzf can properly
+        " show matches and previews using ':' as delimiter
+        return l:filename . ':' . l:nline . ":" . l:ncol . ":" . l:line_text
+    endif
+
     if get(a:options, 'open_in') is# 'quickfix'
         return {
-        \ 'filename': ale#util#ToResource(a:response_item.uri),
+        \ 'filename': l:filename,
         \ 'lnum': a:response_item.range.start.line + 1,
         \ 'col': a:response_item.range.start.character + 1,
+        \ 'text': l:line_text,
         \}
     else
         return {
-        \ 'filename': ale#util#ToResource(a:response_item.uri),
-        \ 'line': a:response_item.range.start.line + 1,
-        \ 'column': a:response_item.range.start.character + 1,
+        \ 'filename': l:filename,
+        \ 'line': l:line + 1,
+        \ 'column': l:col + 1,
+        \ 'match': l:line_text,
         \}
     endif
 endfunction
 
-function! ale#references#HandleLSPResponse(conn_id, response) abort
-    if has_key(a:response, 'id')
-    \&& has_key(s:references_map, a:response.id)
-        let l:options = remove(s:references_map, a:response.id)
-
-        " The result can be a Dictionary item, a List of the same, or null.
-        let l:result = get(a:response, 'result', [])
-        let l:item_list = []
-
-        if type(l:result) is v:t_list
-            for l:response_item in l:result
-                call add(l:item_list,
-                \ ale#references#FormatLSPResponseItem(l:response_item, l:options)
-                \)
-            endfor
+function! ale#references#ShowInFzf(item_list, options) abort
+    let name = "LSP References"
+    let capname = "References"
+    let items = copy(a:item_list)
+    let cwd = getcwd() " no-custom-checks
+    let sep = has('win32') ? '\' : '/'
+
+    function! s:relative_paths(line) closure
+        return substitute(a:line, '^' . cwd . sep, '', '')
+    endfunction
+
+    if get(a:options, 'use_relative_paths')
+        let items = map(filter(items, 'len(v:val)'), 's:relative_paths(v:val)')
+    endif
+
+    let start_query = ''
+    let fzf_options = {
+    \ 'source':  items,
+    \ 'options': ['--prompt', name.'> ', '--query', start_query,
+    \             '--multi', '--bind', 'alt-a:select-all,alt-d:deselect-all',
+    \             '--delimiter', ':', '--preview-window', '+{2}/2']
+    \}
+
+    call add(fzf_options['options'], '--highlight-line') " this only works for more recent fzf versions (TODO: handle version check?)
+
+    " wrap with #with_preview and #fzfwrap before adding the sinklist,
+    " otherwise --expect options are not added
+    let opts_with_preview = fzf#vim#with_preview(fzf_options)
+    let bang = 0 " TODO: handle bang
+    let wrapped = fzf#wrap(name, opts_with_preview, bang)
+
+    call remove(wrapped, 'sink*') " remove the default sinklist to add in our custom sinklist
+
+    function! wrapped.sinklist(lines) closure
+        if len(a:lines) <2
+            return
         endif
+        let cmd = a:lines[0]
+        function! s:references_to_qf(line) closure
+            " mimics ag_to_qf in fzf.vim
+            let parts = matchlist(a:line, '\(.\{-}\)\s*:\s*\(\d\+\)\%(\s*:\s*\(\d\+\)\)\?\%(\s*:\(.*\)\)\?')
+            let filename = &acd ? fnamemodify(parts[1], ':p') : parts[1]
+            return {'filename': filename, 'lnum': parts[2], 'col': parts[3], 'text': parts[4]}
+        endfunction
 
-        if empty(l:item_list)
-            call ale#util#Execute('echom ''No references found.''')
-        else
-            if get(l:options, 'open_in') is# 'quickfix'
-                call setqflist([], 'r')
-                call setqflist(l:item_list, 'a')
-                call ale#util#Execute('cc 1')
-            else
-                call ale#preview#ShowSelection(l:item_list, l:options)
+        let references = map(filter(a:lines[1:], 'len(v:val)'), 's:references_to_qf(v:val)')
+
+        if empty(references)
+            return
+        endif
+
+        if get(a:options, 'open_in') is# 'quickfix'
+            call setqflist([], 'r')
+            call setqflist(references, 'a')
+            echomsg 'a:lines[1]=' . string(a:lines[1:])
+            call ale#util#Execute('cc 1')
+        endif
+
+        function! s:action(key, file)
+            " copied from fzf.vim
+            let default_action = {
+              \ 'ctrl-t': 'tab split',
+              \ 'ctrl-x': 'split',
+              \ 'ctrl-v': 'vsplit' }
+
+            let fzf_actions = get(g:, 'fzf_action', default_action)
+            let Cmd = get(fzf_actions, a:key, 'edit')
+
+            let cursor_cmd = escape("call cursor(" . a:file['lnum'] . "," . a:file['col'] . ")", ' ')
+            let fullcmd = Cmd . " +" . cursor_cmd . " " . fnameescape(a:file['filename'])
+            silent keepjumps keepalt execute fullcmd
+        endfunction
+
+        return map(references, 's:action(cmd, v:val)')
+    endfunction
+
+    call fzf#run(wrapped)
+endfunction
+
+function! ale#references#HandleLSPResponse(conn_id, response) abort
+    if ! (has_key(a:response, 'id') && has_key(s:references_map, a:response.id))
+        return
+    endif
+
+    let l:options = remove(s:references_map, a:response.id)
+
+    " The result can be a Dictionary item, a List of the same, or null.
+    let l:result = get(a:response, 'result', [])
+    let l:item_list = []
+
+    if type(l:result) is v:t_list
+        for l:response_item in l:result
+            call add(l:item_list,
+            \ ale#references#FormatLSPResponseItem(l:response_item, l:options)
+            \)
+        endfor
+    endif
+
+    if empty(l:item_list)
+        call ale#util#Execute('echom ''No references found.''')
+    else
+        if get(l:options, 'use_fzf') == 1
+            if !exists('*fzf#run')
+                throw "fzf#run function not found. You also need Vim plugin from the main fzf repository (i.e. junegunn/fzf *and* junegunn/fzf.vim)"
             endif
+
+            call ale#references#ShowInFzf(l:item_list, l:options)
+        elseif get(l:options, 'open_in') is# 'quickfix'
+            call setqflist([], 'r')
+            call setqflist(l:item_list, 'a')
+            call ale#util#Execute('cc 1')
+        else
+            call ale#preview#ShowSelection(l:item_list, l:options)
         endif
     endif
 endfunction
@@ -147,6 +261,8 @@ function! s:OnReady(line, column, options, linter, lsp_details) abort
     let s:references_map[l:request_id] = {
     \ 'use_relative_paths': has_key(a:options, 'use_relative_paths') ? a:options.use_relative_paths : 0,
     \ 'open_in': get(a:options, 'open_in', 'current-buffer'),
+    \ 'show_contents': a:options.show_contents,
+    \ 'use_fzf': get(a:options, 'use_fzf', g:ale_references_use_fzf),
     \}
 endfunction
 
@@ -165,6 +281,8 @@ function! ale#references#Find(...) abort
                 let l:options.open_in = 'vsplit'
             elseif l:option is? '-quickfix'
                 let l:options.open_in = 'quickfix'
+            elseif l:option is? '-fzf'
+                let l:options.use_fzf = 1
             endif
         endfor
     endif
@@ -177,6 +295,10 @@ function! ale#references#Find(...) abort
         endif
     endif
 
+    if !has_key(l:options, 'show_contents')
+        let l:options.show_contents = ale#Var(bufnr(''), 'references_show_contents')
+    endif
+
     let l:buffer = bufnr('')
     let [l:line, l:column] = getpos('.')[1:2]
     let l:column = min([l:column, len(getline(l:line))])