"""Shelly PM Mini G3 Parser - extracts power data from MQTT messages."""

from datetime import datetime

import structlog

from exceptions import ParserError

logger = structlog.get_logger()


class ShellyParser:
    """Parser for Shelly PM Mini G3 MQTT Messages."""

    def parse_message(self, topic: str, payload: dict) -> dict | None:
        """
        Parse Shelly MQTT message.

        Args:
            topic: MQTT topic
            payload: Message payload (already JSON parsed)

        Returns:
            Dict with parsed data or None
        """
        try:
            # Only parse status messages
            if "/status/pm1:0" in topic:
                return self._parse_status_message(topic, payload)

            return None

        except Exception as e:
            logger.debug("shelly_parse_error", topic=topic, error=str(e))
            return None

    def _parse_status_message(self, topic: str, data: dict) -> dict | None:
        """
        Parse Shelly PM status message.
        Topic: shaperorigin/status/pm1:0

        Payload format:
        {
            "id": 0,
            "voltage": 230.0,
            "current": 0.217,
            "apower": 50.0,
            "freq": 50.0,
            "aenergy": {"total": 12345.6},
            "temperature": {"tC": 35.2}
        }
        """
        try:
            device_id = self._extract_device_id(topic)

            result = {
                "message_type": "status",
                "device_id": device_id,
                "timestamp": datetime.utcnow().isoformat() + "Z",
                "voltage": data.get("voltage"),
                "current": data.get("current"),
                "apower": data.get("apower", 0),  # Active Power in Watts
                "frequency": data.get("freq"),
                "total_energy": data.get("aenergy", {}).get("total"),
                "temperature": data.get("temperature", {}).get("tC"),
            }

            logger.debug("shelly_parsed_status", device_id=device_id, apower=result["apower"])
            return result

        except Exception as e:
            logger.error("shelly_status_parse_error", error=str(e))
            return None

    def _extract_device_id(self, topic: str) -> str:
        """Extract device ID from topic path."""
        # Example: shaperorigin/status/pm1:0 -> shaperorigin
        parts = topic.split("/")
        if len(parts) > 0:
            return parts[0]
        return "unknown"