feat: rewrite ghost text

docs/config.norg

@@ -120,8 +120,8 @@ version: 1.1.1
     virtual text which shows a preview of the entry.
     #tangle
     @code lua
-    --- Whether to show ghost text
-    ---@field ghost_text boolean
+    --- Configuration of ghost text
+    ---@field ghost_text { enabled: boolean, position: "inline"|"overlay" }
     @end
 
 ** Menu

lua/neocomplete/config.lua

@@ -63,7 +63,10 @@ config.defaults = {
             Value = "󰎠",
             Variable = "󰫧",
         },
-        ghost_text = true,
+        ghost_text = {
+            enabled = true,
+            position = "overlay",
+        },
     },
     snippet_expansion = function(snippet_body)
         vim.snippet.expand(snippet_body)

lua/neocomplete/ghost_text.lua

@@ -1,41 +1,66 @@
-local ghost_text = {}
+local Ghost_text = {}
 
-local ns = vim.api.nvim_create_namespace("neocomplete.ghost_text")
+function Ghost_text.new()
+    local self = setmetatable({}, { __index = Ghost_text })
+    self.ns = vim.api.nvim_create_namespace("neocomplete.ghost_text")
+    ---@type neocomplete.entry?
+    self.entry = nil
+    ---@type integer?
+    self.win = nil
+    ---@type integer?
+    self.extmark_id = nil
+    self.config = require("neocomplete.config").options.ui.ghost_text
+    vim.api.nvim_set_decoration_provider(self.ns, {
+        on_win = function(_, win)
+            return win == self.win
+        end,
+        on_line = function()
+            if self.extmark_id then
+                vim.api.nvim_buf_del_extmark(vim.api.nvim_get_current_buf(), self.ns, self.extmark_id)
+                self.extmark_id = nil
+            end
+            if (not self.config.enabled) or not self.entry then
+                return
+            end
+            local word = self.entry:get_insert_word()
+            local offset = self.entry:get_offset()
+            local cursor = vim.api.nvim_win_get_cursor(self.win)
+            local text_after_filter = word:sub(cursor[2] - offset + 1)
+            if self.config.position == "inline" then
+                self.extmark_id =
+                    vim.api.nvim_buf_set_extmark(vim.api.nvim_get_current_buf(), self.ns, cursor[1] - 1, cursor[2], {
+                        virt_text = { { text_after_filter, "@neocomplete.ghost_text" } },
+                        virt_text_pos = "inline",
+                    })
+            elseif self.config.position == "overlay" then
+                self.extmark_id =
+                    vim.api.nvim_buf_set_extmark(vim.api.nvim_get_current_buf(), self.ns, cursor[1] - 1, cursor[2], {
+                        virt_text = { { text_after_filter, "@neocomplete.ghost_text" } },
+                        virt_text_pos = "overlay",
+                        ephemeral = true,
+                    })
+            end
+        end,
+    })
+    return self
+end
 
----@param entry neocomplete.entry
----@param offset integer
-function ghost_text.show(entry, offset)
-    -- TODO: allow multiline text
-    vim.api.nvim_buf_clear_namespace(vim.api.nvim_get_current_buf(), ns, 0, -1)
-    local cursor = vim.api.nvim_win_get_cursor(0)
-    local select_behavior = require("neocomplete.config").options.selection_behavior
-    if select_behavior == "select" then
-        local text = entry:get_insert_text()
-        local text_after_filter = text:sub(offset + 1)
-        vim.api.nvim_buf_set_extmark(vim.api.nvim_get_current_buf(), ns, cursor[1] - 1, cursor[2], {
-            virt_text = { { text_after_filter, "@neocomplete.ghost_text" } },
-            virt_text_pos = "inline",
-        })
-    elseif select_behavior == "insert" then
-        vim.o.ul = vim.o.ul
-        -- TODO: allow going back to original (filter) text
-        local word = entry:get_insert_word()
-        local unblock = require("neocomplete").core:block()
-        -- vim.api.nvim_buf_set_text(0, cursor[1] - 1, cursor[2] - offset, cursor[1] - 1, cursor[2], { word })
-        -- vim.api.nvim_win_set_cursor(0, { cursor[1], cursor[2] - offset + #word })
-        vim.api.nvim_feedkeys(vim.keycode(string.rep("<BS>", offset) .. word), "i", false)
-        unblock()
-        local text = entry:get_insert_text()
-        local text_after_word = text:sub(#word + 1)
-        vim.api.nvim_buf_set_extmark(vim.api.nvim_get_current_buf(), ns, cursor[1] - 1, cursor[2], {
-            virt_text = { { text_after_word, "@neocomplete.ghost_text" } },
-            virt_text_pos = "inline",
-        })
+function Ghost_text:show(entry, window)
+    local changed = self.entry ~= entry
+    self.entry = entry
+    self.win = window
+    if changed then
+        vim.cmd.redraw({ bang = true })
     end
 end
 
-function ghost_text.hide()
-    vim.api.nvim_buf_clear_namespace(vim.api.nvim_get_current_buf(), ns, 0, -1)
+function Ghost_text:hide()
+    self.entry = nil
+    self.win = nil
+    if self.extmark_id then
+        vim.api.nvim_buf_del_extmark(vim.api.nvim_get_current_buf(), self.ns, self.extmark_id)
+        self.extmark_id = nil
+    end
 end
 
-return ghost_text
+return Ghost_text

lua/neocomplete/menu/draw.lua

@@ -112,6 +112,6 @@ return function(self)
     end
 
     if entry and self.config.ui.ghost_text then
-        require("neocomplete.ghost_text").show(entry, #prefix)
+        -- require("neocomplete.ghost_text").show(entry, #prefix)
     end
 end

lua/neocomplete/menu/init.lua

@@ -13,6 +13,7 @@ function Menu.new()
     self.index = 0
     self.menu_window = require("neocomplete.utils.window").new()
     self.docs_window = require("neocomplete.utils.window").new()
+    self.ghost_text = require("neocomplete.ghost_text").new()
     return self
 end
 
@@ -33,7 +34,7 @@ end
 function Menu.close(self)
     self.menu_window:close()
     self.docs_window:close()
-    require("neocomplete.ghost_text").hide()
+    self.ghost_text:hide()
 end
 
 ---@param menu neocomplete.menu
@@ -126,6 +127,7 @@ function Menu:select_next(count)
     draw_docs(self, self:get_active_entry(), self.config.ui.docs_view)
     self:draw()
     self.menu_window:draw_scrollbar()
+    self.ghost_text:show(self:get_active_entry(), vim.api.nvim_get_current_win())
 end
 
 function Menu:select_prev(count)
@@ -138,6 +140,7 @@ function Menu:select_prev(count)
     draw_docs(self, self:get_active_entry(), self.config.ui.docs_view)
     self:draw()
     self.menu_window:draw_scrollbar()
+    self.ghost_text:show(self:get_active_entry(), vim.api.nvim_get_current_win())
 end
 
 function Menu:open(entries, offset)
@@ -154,6 +157,7 @@ function Menu:open(entries, offset)
     self:draw()
     self.menu_window:draw_scrollbar()
     self.menu_window:set_scroll(self.index, -1)
+    self.ghost_text:show(self:get_active_entry(), vim.api.nvim_get_current_win())
 end
 
 function Menu:get_active_entry()

lua/neocomplete/types/config.lua

@@ -18,8 +18,8 @@
 ---@field docs_view neocomplete.config.ui.docs
 --- The icons for the different compltion item kinds
 ---@field type_icons neocomplete.config.ui.type_icons
---- Whether to show ghost text
----@field ghost_text boolean
+--- Configuration of ghost text
+---@field ghost_text { enabled: boolean, position: "inline"|"overlay" }
 --- Configuration of the completion menu of neocomplete.nvim
 ---@class neocomplete.config.ui.menu
 --- Maximum height of the menu