Show the active step in the status bar and progress on the forecast plot

on_sud_changed() now handles 'Step' messages, showing the step's
description (and clearing it once there's no active step), and tracks
IDLE/DONE <-> running transitions to time a red vertical progress line
on the Automatic tab's forecast - elapsed real time since the brew
started, plotted against the forecast's nominal-schedule time axis so
you can see how actual progress compares to the plan.

client/brewpi_gui.py

@@ -117,6 +117,7 @@ class SudForecastPlot(FigureCanvasQTAgg):
 
 		self.ax = figure.subplots(1, 1)
 		self.line, = self.ax.plot([], [], '-b', linewidth=1.5)
+		self.progress_line = self.ax.axvline(0, color='r', linewidth=1.5, visible=False)
 		self.ax.set_xlabel("t [min]")
 		self.ax.set_ylabel("Temp [°C]")
 		_style_axis(self.ax)
@@ -156,6 +157,15 @@ class SudForecastPlot(FigureCanvasQTAgg):
 		self.figure.tight_layout()
 		self.draw_idle()
 
+	def set_progress(self, t_min):
+		self.progress_line.set_xdata([t_min, t_min])
+		self.progress_line.set_visible(True)
+		self.draw_idle()
+
+	def clear_progress(self):
+		self.progress_line.set_visible(False)
+		self.draw_idle()
+
 
 class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 	def __init__(self):
@@ -170,6 +180,10 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 		self.connected = False
 		self.sud_loaded = False
 		self.sud_state = None
+		# time.monotonic() of the last IDLE/DONE -> running transition, used
+		# to position the forecast plot's progress line; None while not
+		# running.
+		self.sud_start_time = None
 		self.msg_pot = self.msg_dispatch.msgio_get('Pot')
 		self.msg_sensor = self.msg_dispatch.msgio_get('Sensor')
 		self.msg_heater = self.msg_dispatch.msgio_get('Heater')
@@ -253,6 +267,11 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 			self.plot_rate_ist, self.plot_rate_soll,
 			self.plot_power_set, self.plot_power_eff)
 
+		if self.sud_start_time is not None:
+			self.forecast_plot.set_progress((time.monotonic() - self.sud_start_time) / 60.0)
+		else:
+			self.forecast_plot.clear_progress()
+
 	def disconnect(self):
 		# ws_client.disconnect() blocks until the websocket's close handshake
 		# completes (or times out, ~10s if the server doesn't ack promptly),
@@ -274,6 +293,7 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 			# Nothing reported over a dead connection can be trusted anymore.
 			self.sud_loaded = False
 			self.sud_state = None
+			self.sud_start_time = None
 			self.update_sud_actions()
 
 	def update_sud_actions(self):
@@ -425,7 +445,20 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 			elif "Name" in key:
 				self.statusBar().showMessage("Sud schedule updated: {}".format(msg['Name']), 5000)
 			elif "State" in key:
+				running_before = self.sud_state in SUD_RUNNING_STATES
 				self.sud_state = msg['State']
+				running_now = self.sud_state in SUD_RUNNING_STATES
+				if running_now and not running_before:
+					self.sud_start_time = time.monotonic()
+				elif not running_now:
+					self.sud_start_time = None
+			elif "Step" in key:
+				step = msg['Step']
+				descr = step.get('Descr')
+				if descr:
+					self.statusBar().showMessage("Step {}: {}".format(step.get('Index'), descr))
+				else:
+					self.statusBar().clearMessage()
 		self.update_sud_actions()
 
 	def update_sud_forecast(self, doc):