feat: add waveform download and storage.

bridges/ach_server.py

@@ -445,8 +445,19 @@ class AchSession:
                 # ── Persist to SQLite DB ─────────────────────────────────────
                 _session_start = datetime.datetime.now()
                 try:
+                    # Build waveform blobs for events that have full raw_samples
+                    _waveform_blobs = {}
+                    for _ev in new_events:
+                        if _ev._waveform_key and _ev.raw_samples:
+                            _blob = _build_waveform_blob(_ev)
+                            if _blob:
+                                _waveform_blobs[_ev._waveform_key.hex()] = _blob
+                    if _waveform_blobs:
+                        log.info("  [DB] waveform blobs prepared: %d", len(_waveform_blobs))
+
                     _ev_ins, _ev_skip = self.db.insert_events(
-                        new_events, serial=serial or self.peer, session_id=None
+                        new_events, serial=serial or self.peer, session_id=None,
+                        waveform_blobs=_waveform_blobs,
                     )
                     _ml_ins, _ml_skip = self.db.insert_monitor_log(
                         new_monitor_entries, session_id=None
@@ -599,6 +610,52 @@ def _event_to_dict(e: Event) -> dict:
     }
 
 
+def _build_waveform_blob(e: Event) -> Optional[str]:
+    """
+    Serialise a downloaded event's full waveform data as a JSON string for
+    storage in the DB waveform_blob column.
+
+    Returns the same shape as GET /device/event/{index}/waveform so the
+    waveform viewer can consume either source without modification.
+    Returns None if the event has no raw_samples (e.g. metadata-only download).
+    """
+    raw = e.raw_samples or {}
+    if not raw:
+        return None
+
+    pv = e.peak_values
+    peak_values = None
+    if pv:
+        peak_values = {
+            "tran":             pv.tran,
+            "vert":             pv.vert,
+            "long":             pv.long,
+            "micl_psi":         pv.micl,
+            "peak_vector_sum":  pv.peak_vector_sum,
+        }
+
+    ts = e.timestamp
+    timestamp_str = (
+        f"{ts.year:04d}-{ts.month:02d}-{ts.day:02d}T"
+        f"{ts.hour:02d}:{ts.minute:02d}:{ts.second:02d}"
+        if ts else None
+    )
+
+    blob = {
+        "index":           e.index,
+        "record_type":     e.record_type,
+        "timestamp":       timestamp_str,
+        "total_samples":   e.total_samples,
+        "pretrig_samples": e.pretrig_samples,
+        "rectime_seconds": e.rectime_seconds,
+        "samples_decoded": len(raw.get("Tran", [])),
+        "sample_rate":     e.sample_rate,
+        "peak_values":     peak_values,
+        "channels":        raw,
+    }
+    return json.dumps(blob)
+
+
 def _monitor_log_entry_to_dict(e: MonitorLogEntry) -> dict:
     return {
         "key":               e.key,