fix: virtual cursor edge cases (#32)

* perf(Mode): use dedicated virtual cursor namespace

* fix(Mode): virtual cursor stays in inactive buffers when exiting

* fix(Mode): `CursorMoved` not fired as expected

Author: Iron-E

examples/lua/keymaps.lua

@@ -21,6 +21,9 @@ local fooModeKeymaps =
 	zfc = 'q',
 	zff = split_twice,
 	zfo = 'vsplit',
+	e = 'edit foo',
+	p = 'bp',
+	o = 'norm o',
 }
 
 -- enter the mode using the keymaps

lua/libmodal/Mode.lua

@@ -2,23 +2,47 @@ local globals = require 'libmodal.globals'
 local ParseTable = require 'libmodal.collections.ParseTable'
 local utils = require 'libmodal.utils' --- @type libmodal.utils
 
+--- @alias CursorPosition {[1]: integer, [2]: integer} see `nvim_win_get_cursor`
+
 --- @class libmodal.Mode
+--- @field private cursor CursorPosition
 --- @field private flush_input_timer unknown
 --- @field private help? libmodal.utils.Help
---- @field private input libmodal.utils.Var[number]
---- @field private input_bytes? number[] local `input` history
+--- @field private input libmodal.utils.Var[integer]
+--- @field private input_bytes? integer[] local `input` history
 --- @field private instruction fun()|{[string]: fun()|string}
 --- @field private mappings libmodal.collections.ParseTable
 --- @field private modeline string[][]
 --- @field private name string
---- @field private ns number the namespace where cursor highlights are drawn on
 --- @field private popups libmodal.collections.Stack
 --- @field private supress_exit boolean
---- @field public count libmodal.utils.Var[number]
+--- @field private virtual_cursor_autocmd integer
+--- @field public count libmodal.utils.Var[integer]
 --- @field public exit libmodal.utils.Var[boolean]
 --- @field public timeouts? libmodal.utils.Var[boolean]
 local Mode = utils.classes.new()
 
+--- Cursor events triggered by which modes
+local CURSOR_EVENTS_BY_MODE = {
+	CursorMoved = {
+		n = true,
+		V = true,
+		v = true,
+		[utils.api.replace_termcodes '<C-v>'] = true,
+	},
+
+	CursorMovedI = {
+		i = true,
+		R = true,
+	},
+}
+
+--- The namespaces used by modes
+local NS = {
+	--- The virtual cursor namespace. Used to workaround neovim/neovim#20793
+	CURSOR = vim.api.nvim_create_namespace('libmodal-mode-virtual_cursor'),
+}
+
 local HELP_CHAR = '?'
 local TIMEOUT =
 {
@@ -45,7 +69,7 @@ function Mode:execute_instruction(instruction)
 	end
 
 	self.count:set(0)
-	self:redraw_virtual_cursor()
+	self:render_virtual_cursor(0, true)
 end
 
 --- check the user's input against the `self.instruction` mappings to see if there is anything to execute.
@@ -105,9 +129,11 @@ function Mode:check_input_for_mapping()
 end
 
 --- clears the virtual cursor from the screen
+--- @param bufnr integer to clear the cursor on
 --- @private
-function Mode:clear_virt_cursor()
-	vim.api.nvim_buf_clear_namespace(0, self.ns, 0, -1);
+function Mode:clear_virtual_cursor(bufnr)
+	vim.api.nvim_buf_clear_namespace(bufnr, NS.CURSOR, 0, -1);
+
 end
 
 --- enter this mode.
@@ -122,10 +148,22 @@ function Mode:enter()
 	self.count:set(0)
 	self.exit:set(false)
 
-	--- HACK: https://github.com/neovim/neovim/issues/20793
+	--- HACK: neovim/neovim#20793
 	vim.api.nvim_command 'highlight Cursor blend=100'
 	vim.schedule(function() vim.opt.guicursor:append { 'a:Cursor/lCursor' } end)
-	self:render_virt_cursor()
+	self.cursor = self:cursor_in(0)
+	self:render_virtual_cursor(0)
+
+	do
+		local augroup = vim.api.nvim_create_augroup('libmodal-mode-' .. self.name, { clear = false })
+		self.virtual_cursor_autocmd = vim.api.nvim_create_autocmd('BufLeave', {
+			callback = function(ev)
+				local bufnr = ev.buf
+				self:clear_virtual_cursor(bufnr)
+			end,
+			group = augroup,
+		})
+	end
 
 	self.previous_mode_name = vim.g.libmodalActiveModeName
 	vim.g.libmodalActiveModeName = self.name
@@ -194,19 +232,37 @@ function Mode:get_user_input()
 	end
 end
 
---- clears and then renders the virtual cursor
---- @private
-function Mode:redraw_virtual_cursor()
-	self:clear_virt_cursor()
-	self:render_virt_cursor()
+--- @param winid integer
+--- @return CursorPosition line_and_col
+function Mode:cursor_in(winid)
+	local cursor = vim.api.nvim_win_get_cursor(winid)
+	cursor[1] = cursor[1] - 1 -- win_get_cursor returns +1 for our purpose
+	return cursor
 end
 
 --- render the virtual cursor using extmarks
+--- @param winid integer
+--- @param clear? boolean if true, clear other virtual cursors before rendering the new one
 --- @private
-function Mode:render_virt_cursor()
-	local line_nr, col_nr = unpack(vim.api.nvim_win_get_cursor(0))
-	line_nr = line_nr - 1 -- win_get_cursor returns +1 for our purpose
-	vim.highlight.range(0, self.ns, 'Cursor', { line_nr, col_nr }, { line_nr, col_nr + 1 }, {})
+function Mode:render_virtual_cursor(winid, clear)
+	local bufnr = vim.api.nvim_win_get_buf(winid)
+	if clear then
+		self:clear_virtual_cursor(bufnr)
+	end
+
+	local cursor = self:cursor_in(winid)
+	vim.highlight.range(bufnr, NS.CURSOR, 'Cursor', cursor, cursor, { inclusive = true })
+
+	if not vim.deep_equal(self.cursor, cursor) then
+		local mode = vim.api.nvim_get_mode().mode
+		if CURSOR_EVENTS_BY_MODE.CursorMoved[mode] then
+			vim.api.nvim_exec_autocmds('CursorMoved', {})
+		elseif CURSOR_EVENTS_BY_MODE.CursorMovedI[mode] then
+			vim.api.nvim_exec_autocmds('CursorMovedI', {})
+		end
+
+		self.cursor = cursor
+	end
 end
 
 --- show the mode indicator, if it is enabled
@@ -234,18 +290,20 @@ end
 --- @private
 --- @return nil
 function Mode:tear_down()
+	--- HACK: neovim/neovim#20793
+	self:clear_virtual_cursor(0)
+	vim.schedule(function() vim.opt.guicursor:remove { 'a:Cursor/lCursor' } end)
+	vim.api.nvim_command 'highlight Cursor blend=0'
+	vim.api.nvim_del_autocmd(self.virtual_cursor_autocmd)
+	self.cursor = nil
+
 	if type(self.instruction) == 'table' then
 		self.flush_input_timer:stop()
 		self.input_bytes = nil
 
 		self.popups:pop():close()
 	end
 
-	--- HACK: https://github.com/neovim/neovim/issues/20793
-	self:clear_virt_cursor()
-	vim.schedule(function() vim.opt.guicursor:remove { 'a:Cursor/lCursor' } end)
-	vim.api.nvim_command 'highlight Cursor blend=0'
-
 	if self.previous_mode_name and #vim.trim(self.previous_mode_name) < 1 then
 		vim.g.libmodalActiveModeName = nil
 	else
@@ -272,7 +330,6 @@ function Mode.new(name, instruction, supress_exit)
 			input = utils.Var.new(name, 'input'),
 			instruction = instruction,
 			name = name,
-			ns = vim.api.nvim_create_namespace('libmodal' .. name),
 			modeline = {{'-- ' .. name .. ' --', 'LibmodalPrompt'}},
 		},
 		Mode