sort 'buffers' by 'lastused' (closes #208)

also changes buffers preview to read lines from the buffer instead
of attaching the exisiting buffer to the preview window, the former
turned out to changed the 'lastused' field of the buffer which was
undesireable for buffer sorting.

lua/fzf-lua/path.lua

@@ -166,12 +166,20 @@ function M.entry_to_file(entry, cwd)
     file = M.join({cwd, file})
     stripped = M.join({cwd, stripped})
   end
+  local terminal
+  if bufnr then
+    terminal = utils.is_term_buffer(bufnr)
+    if terminal then
+      file, line = stripped:match("(.*):(%d+)$")
+    end
+  end
   return {
     stripped = stripped,
-    bufnr = bufnr,
+    bufnr = tonumber(bufnr),
+    terminal = terminal,
     path = file,
-    line = line or 1,
-    col  = col or 1,
+    line = tonumber(line) or 1,
+    col  = tonumber(col) or 1,
   }
 end
 

lua/fzf-lua/previewer/builtin.lua

@@ -112,6 +112,7 @@ function Previewer.base:clear_preview_buf()
     end
   end
   self.preview_bufnr = nil
+  self.preview_isterm = nil
   self.preview_bufloaded = nil
   return retbuf
 end
@@ -142,12 +143,8 @@ function Previewer.base:display_entry(entry_str)
     -- specialized previewer populate function
     self:populate_preview_buf(entry_str)
 
-    -- is the preview a terminal buffer (alternative way)
-    --[[ local is_terminal =
-      vim.fn.getwininfo(self.win.preview_winid)[1].terminal == 1 ]]
-
     -- set preview window options
-    if not utils.is_term_buffer(self.preview_bufnr) then
+    if not self.preview_isterm then
       self:set_winopts(self.win.preview_winid)
     end
 
@@ -205,7 +202,10 @@ function Previewer.base:scroll(direction)
       utils.zz()
     end)
   else
-    if utils.is_term_buffer(self.preview_bufnr) then
+    -- DO NOT NEED THIS WORKAROUND
+    -- since we are no longer setting the terminal buffer
+    -- directly into the preview window we can scroll norally
+    --[[ if self.preview_isterm then
       -- can't use ":norm!" with terminal buffers due to:
       -- 'Vim(normal):Can't re-enter normal mode from terminal mode'
       -- https://github.com/neovim/neovim/issues/4895#issuecomment-303073838
@@ -216,7 +216,7 @@ function Previewer.base:scroll(direction)
       utils.feed_keys_termcodes((':noa lua vim.api.nvim_win_call(' ..
         '%d, function() vim.cmd("norm! <C-v>%s") vim.cmd("startinsert") end)<CR>'):
         format(tonumber(preview_winid), input))
-    else
+    else --]]
       -- local input = direction > 0 and [[]] or [[]]
       -- local input = direction > 0 and [[]] or [[]]
       -- ^D = 0x04, ^U = 0x15 ('g8' on char to display)
@@ -225,7 +225,7 @@ function Previewer.base:scroll(direction)
         vim.cmd([[norm! ]] .. input)
         utils.zz()
       end)
-    end
+    -- end
   end
   self.win:update_scrollbar()
 end
@@ -241,9 +241,6 @@ end
 
 function Previewer.buffer_or_file:parse_entry(entry_str)
   local entry = path.entry_to_file(entry_str, self.opts.cwd)
-  if entry.bufnr and utils.is_term_buffer(entry.bufnr) then
-    entry.line = tonumber(entry_str:match(":(%d+)$"))
-  end
   return entry
 end
 
@@ -252,12 +249,21 @@ function Previewer.buffer_or_file:populate_preview_buf(entry_str)
   local entry = self:parse_entry(entry_str)
   if vim.tbl_isempty(entry) then return end
   if entry.bufnr and api.nvim_buf_is_loaded(entry.bufnr) then
-    -- must convert to number or our backup will have conflicting keys
-    local bufnr = tonumber(entry.bufnr)
-    -- display the buffer in the preview
-    api.nvim_win_set_buf(self.win.preview_winid, bufnr)
-    -- store current preview buffer
-    self.preview_bufnr = bufnr
+    -- WE NO LONGER REUSE THE CURRENT BUFFER (except for term)
+    -- this changes the buffer's 'getbufinfo[1].lastused'
+    -- which messes up our `buffers()` sort
+    self.preview_isterm = entry.terminal
+    --[[ if self.preview_isterm then
+      -- display the buffer in the preview
+      api.nvim_win_set_buf(self.win.preview_winid, entry.bufnr)
+      -- store current preview buffer
+      self.preview_bufnr = entry.bufnr
+    else --]]
+      -- mark the buffer for unloading the next call
+      self.preview_bufloaded = true
+      local lines = vim.api.nvim_buf_get_lines(entry.bufnr, 0, -1, false)
+      vim.api.nvim_buf_set_lines(self.preview_bufnr, 0, -1, false, lines)
+    -- end
     self:preview_buf_post(entry)
   elseif entry.uri then
     -- LSP 'jdt://' entries, see issue #195

lua/fzf-lua/providers/buffers.lua

@@ -80,13 +80,16 @@ local make_buffer_entries = function(opts, bufnrs, tabnr, curbuf)
       end
     end
 
-    if opts.sort_lastused and (flag == "#" or flag == "%") then
-      if flag == "%" then header_line = true end
-      local idx = ((buffers[1] ~= nil and buffers[1].flag == "%") and 2 or 1)
-      table.insert(buffers, idx, element)
-    else
-      table.insert(buffers, element)
+    if opts.sort_lastused and flag == "%" then
+      header_line = true
     end
+
+    table.insert(buffers, element)
+  end
+  if opts.sort_lastused then
+    table.sort(buffers, function(a, b)
+      return a.info.lastused > b.info.lastused
+    end)
   end
   return buffers, header_line
 end