overleaf/services/web/public/coffee/ide/online-users/OnlineUsersManager.coffee

define [
	"libs/md5"
], () ->
	class OnlineUsersManager
		constructor: (@ide, @$scope) ->
			@$scope.onlineUsers = {}
			@$scope.onlineUserCursorHighlights = {}

			@$scope.$on "cursor:editor:update", (event, position) =>
				@sendCursorPositionUpdate(position)

			@ide.socket.on "clientTracking.clientUpdated", (client) =>
				if client.id != @ide.socket.socket.sessionid # Check it's not me!
					@$scope.$apply () =>
						@$scope.onlineUsers[client.id] = client
						@updateCursorHighlights()

			@ide.socket.on "clientTracking.clientDisconnected", (client_id) =>
				@$scope.$apply () =>
					delete @$scope.onlineUsers[client_id]
					@updateCursorHighlights()

		updateCursorHighlights: () ->
			console.log "UPDATING CURSOR HIGHLIGHTS"
			@$scope.onlineUserCursorHighlights = {}
			for client_id, client of @$scope.onlineUsers
				doc_id = client.doc_id
				continue if !doc_id?
				@$scope.onlineUserCursorHighlights[doc_id] ||= []
				@$scope.onlineUserCursorHighlights[doc_id].push {
					label: client.name
					cursor:
						row: client.row
						column: client.column
					hue: @getHueForUserId(client.user_id)
				}

		UPDATE_INTERVAL: 500
		sendCursorPositionUpdate: (position) ->
			if !@cursorUpdateTimeout?
				@cursorUpdateTimeout = setTimeout ()=>
					doc_id   = @$scope.editor.open_doc_id

					@ide.socket.emit "clientTracking.updatePosition", {
						row: position.row
						column: position.column
						doc_id: doc_id
					}

					delete @cursorUpdateTimeout
				, @UPDATE_INTERVAL

		OWN_HUE: 200 # We will always appear as this color to ourselves
		ANONYMOUS_HUE: 100
		getHueForUserId: (user_id) ->
			if !user_id? or user_id == "anonymous-user"
				return @ANONYMOUS_HUE

			if window.user.id == user_id
				return @OWN_HUE

			hash = CryptoJS.MD5(user_id)
			hue = parseInt(hash.toString().slice(0,8), 16) % 320
			# Avoid 20 degrees either side of the personal hue
			if hue > @OWNER_HUE - 20
				hue = hue + 40
			return hue