Files
bambuddy/backend
maziggy a53dc20ca3 fix(usage-tracker): split mid-print AMS-Backup spool switch correctly (#1771)
Reporter forcefully started a print needing ~260 g with 180 g on the
  first spool and a backup spool in the AMS. Printer correctly consumed
  spool 1, AMS Backup switched, spool 2 finished the print. Bambuddy
  attributed all 260 g to spool 2 -- spool 1 untouched in inventory.

  Two stacking bugs produced the exact "all to second spool" symptom for
  prints without per-layer 3MF gcode data:

  1. bambu_mqtt.py:2135 wrote state.total_layers = int(data["total_layer_num"])
     unconditionally. P1S firmware pushes total_layer_num=0 at print end
     (same reset pattern other models do for layer_num / progress). The
     unconditional write clobbered the slicer's actual total to 0 before
     the usage tracker read it.

  2. usage_tracker.py:1129-1137 linear-fallback dumped EVERYTHING onto the
     last segment when total_layers was 0:
       if total_layers > 0:
           segment_grams = total_weight * (seg_end_layer - seg_start_layer) / total_layers
       else:
           segment_grams = 0.0   # <- entire print weight ends up on last segment

     Path 2 (AMS remain% delta) couldn't recover because (a) the emptied
     spool reported remain=-1 and (b) Bug-A had already added the second
     spool's key to handled_trays, suppressing the Path 2 lookup.

  Fix:

  - bambu_mqtt.py: only overwrite state.total_layers when the incoming
    value is positive (mirror of the existing _last_valid_layer_num
    pattern at line 2127). Explicit reset on new print start at
    _handle_print_start so the previous print's total can't bleed in.

  - usage_tracker.py: cascade the linear-fallback denominator -
    state.total_layers, then last_layer_num (already threaded in for
    the last_progress fallback), then equal-split as a bounded fence.
    Equal-split is still wrong but never dumps the whole print on the
    last segment, which was strictly worse.
2026-06-20 12:26:31 +02:00
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