initial commit

hameter/meter.py

@@ -0,0 +1,92 @@
+"""Meter data model and rtlamr output parsing."""
+
+import json
+import logging
+from dataclasses import dataclass
+from datetime import datetime, timezone
+from typing import Optional
+
+from hameter.config import MeterConfig
+
+logger = logging.getLogger(__name__)
+
+# Map rtlamr message Type to the field containing the meter ID.
+PROTOCOL_ID_FIELDS: dict[str, str] = {
+    "SCM": "ID",
+    "SCM+": "EndpointID",
+    "IDM": "ERTSerialNumber",
+    "NetIDM": "ERTSerialNumber",
+    "R900": "ID",
+    "R900BCD": "ID",
+}
+
+# Map rtlamr message Type to the field containing the consumption value.
+PROTOCOL_CONSUMPTION_FIELDS: dict[str, str] = {
+    "SCM": "Consumption",
+    "SCM+": "Consumption",
+    "IDM": "LastConsumptionCount",
+    "NetIDM": "LastConsumptionCount",
+    "R900": "Consumption",
+    "R900BCD": "Consumption",
+}
+
+
+@dataclass
+class MeterReading:
+    meter_id: int
+    protocol: str
+    raw_consumption: int
+    calibrated_consumption: float
+    timestamp: str
+    raw_message: dict
+
+
+def parse_rtlamr_line(
+    line: str,
+    meters: dict[int, MeterConfig],
+) -> Optional[MeterReading]:
+    """Parse a single JSON line from rtlamr stdout.
+
+    Args:
+        line: Raw JSON string from rtlamr.
+        meters: Dict mapping meter ID to config. If empty, accept all meters
+                (discovery mode).
+
+    Returns:
+        MeterReading if the line matches a configured meter (or any meter in
+        discovery mode), otherwise None.
+    """
+    data = json.loads(line)
+    msg_type = data.get("Type", "")
+    message = data.get("Message", {})
+
+    id_field = PROTOCOL_ID_FIELDS.get(msg_type)
+    consumption_field = PROTOCOL_CONSUMPTION_FIELDS.get(msg_type)
+
+    if not id_field or not consumption_field:
+        return None
+
+    meter_id = int(message.get(id_field, 0))
+    if meter_id == 0:
+        return None
+
+    raw_consumption = int(message.get(consumption_field, 0))
+
+    # Filter: if meters dict is populated, only accept configured meters.
+    if meters and meter_id not in meters:
+        return None
+
+    meter_cfg = meters.get(meter_id)
+    multiplier = meter_cfg.multiplier if meter_cfg else 1.0
+    calibrated = raw_consumption * multiplier
+
+    timestamp = data.get("Time") or datetime.now(timezone.utc).isoformat()
+
+    return MeterReading(
+        meter_id=meter_id,
+        protocol=msg_type,
+        raw_consumption=raw_consumption,
+        calibrated_consumption=round(calibrated, 4),
+        timestamp=timestamp,
+        raw_message=message,
+    )