feat: connect/disconnect, track user pos

added a jank timer poller to check if promise for workspace event is
done

lua/codemp/utils.lua

@@ -16,6 +16,19 @@ local function color(x)
 	return available_colors[ math.fmod(math.abs(native.hash(x)), #available_colors) + 1 ]
 end
 
+local function async_poller(generator, callback)
+	local promise = nil
+	local timer = vim.loop.new_timer()
+	timer:start(500, 500, function()
+		if promise == nil then promise = generator() end
+		if promise.ready then
+			callback(promise:await())
+			promise = nil
+		end
+	end)
+
+end
+
 ---@param first integer
 ---@param last integer
 ---@return integer, integer, integer, integer
@@ -193,4 +206,5 @@ return {
 	hash = native.hash,
 	available_colors = available_colors,
 	color = color,
+	poller = async_poller,
 }

lua/codemp/workspace.lua

@@ -2,6 +2,12 @@ local utils = require('codemp.utils')
 local buffers = require('codemp.buffers')
 local session = require('codemp.session')
 
+---@class UserHighlight
+---@field ns integer namespace to use for this user
+---@field hi string color for user to use
+---@field pos [integer, integer] cursor start position of this user
+
+---@type table<string, UserHighlight>
 local user_hl = {}
 
 local function fetch_workspaces_list()
@@ -50,12 +56,16 @@ local function register_cursor_handler(ws)
 		while true do
 			local event = controller:try_recv():await()
 			if event == nil then break end
-			if user_hl[event.user] == nil then
-				user_hl[event.user] = {
+			local user = event.user -- do it on separate line so language server understands that it wont be nil
+			if user ~= nil then
+				if user_hl[user] == nil then
+					user_hl[user] = {
 						ns = vim.api.nvim_create_namespace("codemp-cursor-" .. event.user),
 						hi = utils.color(event.user),
+						pos = { 0, 0 },
 					}
 				end
+				user_hl[user].pos = event.start
 				local old_buffer = buffers.users[event.user]
 				if old_buffer ~= nil then
 					local old_buffer_id = buffers.map_rev[old_buffer]
@@ -78,6 +88,7 @@ local function register_cursor_handler(ws)
 					require('codemp.window').update() -- redraw user positions
 				end
 			end
+		end
 	end))
 	controller:callback(function (_controller) async:send() end)
 end
@@ -90,20 +101,29 @@ local function join(workspace)
 	print(" >< joined workspace " .. ws.name)
 	register_cursor_callback(ws)
 	register_cursor_handler(ws)
-
-	-- TODO this is temporary and ad-hoc
-	-- ws:callback(function (event)
-	-- 	if event.type == "leave" then
-	-- 		if buffers.users[event.value] ~= nil then
-	-- 			vim.schedule(function ()
-	-- 				vim.api.nvim_buf_clear_namespace(buffers.users[event.value], user_hl[event.value].ns, 0, -1)
-	-- 				buffers.users[event.value] = nil
-	-- 				user_hl[event.value] = nil
-	-- 			end)
-	-- 		end
-	-- 	end
-	-- 	vim.schedule(function() require('codemp.window').update() end)
-	-- end)
+	utils.poller(
+		function() return ws:event() end,
+		function(event)
+			if event.type == "leave" then
+				if buffers.users[event.value] ~= nil then
+					vim.schedule(function ()
+						local buf_name = buffers.users[event.value]
+						vim.api.nvim_buf_clear_namespace(buffers.map_rev[buf_name], user_hl[event.value].ns, 0, -1)
+						buffers.users[event.value] = nil
+						user_hl[event.value] = nil
+					end)
+				end
+			elseif event.type == "join" then
+				buffers.users[event.value] = ""
+				user_hl[event.value] = {
+					ns = vim.api.nvim_create_namespace("codemp-cursor-" .. event.value),
+					hi = utils.color(event.value),
+					pos = { 0, 0 },
+				}
+			end
+			vim.schedule(function() require('codemp.window').update() end)
+		end
+	)
 
 	session.workspace = ws
 	require('codemp.window').update()