print_stats: stat tracking for virtual sdcard prints in progress

Signed-off-by: Eric Callahan <arksine.code@gmail.com>

klippy/extras/print_stats.py

@@ -0,0 +1,64 @@
+# Virtual SDCard print stat tracking
+#
+# Copyright (C) 2020  Eric Callahan <arksine.code@gmail.com>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+
+class PrintStats:
+    def __init__(self, config):
+        printer = config.get_printer()
+        self.gcode = printer.lookup_object('gcode')
+        self.reactor = printer.get_reactor()
+        self.reset()
+    def _update_filament_usage(self, eventtime):
+        gc_status = self.gcode.get_status(eventtime)
+        cur_epos = gc_status['last_epos']
+        self.filament_used += (cur_epos - self.last_epos) \
+            / gc_status['extrude_factor']
+        self.last_epos = cur_epos
+    def set_current_file(self, filename):
+        self.reset()
+        self.filename = filename
+    def note_start(self):
+        curtime = self.reactor.monotonic()
+        if self.print_start_time is None:
+            self.print_start_time = curtime
+        elif self.last_pause_time is not None:
+            # Update pause time duration
+            pause_duration = curtime - self.last_pause_time
+            self.prev_pause_duration += pause_duration
+            self.last_pause_time = None
+        # Reset last e-position
+        gc_status = self.gcode.get_status(curtime)
+        self.last_epos = gc_status['last_epos']
+    def note_pause(self):
+        if self.last_pause_time is None:
+            curtime = self.reactor.monotonic()
+            self.last_pause_time = curtime
+            # update filament usage
+            self._update_filament_usage(curtime)
+    def reset(self):
+        self.filename = ""
+        self.prev_pause_duration = self.last_epos = 0.
+        self.filament_used = 0.
+        self.print_start_time = self.last_pause_time = None
+    def get_status(self, eventtime):
+        total_duration = 0.
+        time_paused = self.prev_pause_duration
+        if self.print_start_time is not None:
+            if self.last_pause_time is not None:
+                # Calculate the total time spent paused during the print
+                time_paused += eventtime - self.last_pause_time
+            else:
+                # Accumulate filament if not paused
+                self._update_filament_usage(eventtime)
+            total_duration = eventtime - self.print_start_time
+        return {
+            'filename': self.filename,
+            'total_duration': total_duration,
+            'print_duration': total_duration - time_paused,
+            'filament_used': self.filament_used
+        }
+
+def load_config(config):
+    return PrintStats(config)