""" powermon / outputformats / hass.py

LOCAL PATCH (g) — see ../Install.md §5(g). Original behavior preserved
except for these changes (all aimed at cleaner HA-frontend rendering and
correct long-term-statistics behavior):

  - Removed `last_reset` from discovery payload. That field is HA-spec
    for `state_class: total` cumulative counters; setting it on
    `measurement` sensors causes HA to warn and ignore. Upstream emits
    `str(datetime.now())` on every discovery — meaningless timestamp
    that fires a state-class warning per entity per startup.

  - Removed `force_update: "true"` default. Upstream forces a recorder
    write on every state publish even if the value hasn't changed,
    bloating the HA history database with hundreds of duplicate rows
    per day per slowly-changing entity. HA defaults are correct.

  - Added `suggested_display_precision` based on unit. Without this,
    HA's voltage/current/temperature device classes round to integers
    in the frontend (e.g. `52.5 V` displays as `52 V`).

  - Default `state_class: measurement` for numeric sensors when the
    protocol definition didn't supply one. Without state_class, HA
    excludes the sensor from long-term statistics, the Energy
    dashboard, and the standard "show this as a trend" graph.
"""
import json as js
import logging

from powermon.commands.command import Command
from powermon.commands.reading import Reading
from powermon.commands.result import Result
from powermon.outputformats.abstractformat import AbstractFormat

log = logging.getLogger("hass")


# Suggested decimal places per unit for the HA frontend. Keys must match
# whatever powermon's reading_definitions emit as the unit string (the
# value the BMS / inverter parser sets as `data_unit`).
_PRECISION_BY_UNIT: dict[str, int] = {
    "V":   1,
    "mV":  0,
    "A":   1,
    "mA":  0,
    "W":   0,
    "VA":  0,
    "Hz":  1,
    "%":   0,
    "°C":  0,
    "Ah":  1,
    "Wh":  0,
    "kWh": 1,
    "ms":  0,
    "s":   0,
}


class Hass(AbstractFormat):
    """ formatter to generate home assistant auto config mqtt messages """
    def __init__(self, config):
        super().__init__(config)
        self.name = "hass"
        self.discovery_prefix = config.get("discovery_prefix", "homeassistant")
        self.entity_id_prefix = config.get("entity_id_prefix", None)

    def __str__(self):
        return f"{self.name}: generates Home Assistant auto config and update mqtt messages"

    def get_options(self):
        """ return a dict of all options and defaults """
        extra_options = {"discovery_prefix": "homeassistant", "entity_id_prefix": None}
        options = super().get_options()
        options.update(extra_options)
        return options

    def format(self, command: Command, result: Result, device_info) -> list:
        log.info("Using output formatter: %s", self.name)

        config_msgs = []
        value_msgs = []

        _result = []
        if result.readings is None:
            return _result
        display_data: list[Reading] = self.format_and_filter_data(result)
        log.debug("displayData: %s", display_data)

        for response in display_data:
            data_name = self.format_key(response.data_name)
            value = response.data_value
            unit = response.data_unit
            icon = response.icon
            device_class = response.device_class
            state_class = response.state_class

            if unit == "bool" or value == "enabled" or value == "disabled":
                component = "binary_sensor"
            else:
                component = "sensor"

            if component == "binary_sensor":
                if value == 0 or value == "0" or value == "disabled":
                    value = "OFF"
                elif value == 1 or value == "1" or value == "enabled":
                    value = "ON"

            if self.entity_id_prefix is None:
                object_id = f"{data_name}".lower().replace(" ", "_")
                name = f"{data_name}"
            else:
                object_id = f"{self.entity_id_prefix}_{data_name}".lower().replace(" ", "_")
                name = f"{self.entity_id_prefix} {data_name}"

            topic_base = f"{self.discovery_prefix}/{component}/{object_id}".replace(" ", "_")
            topic = f"{topic_base}/config"
            state_topic = f"{topic_base}/state"

            payload = {
                "name": f"{name}",
                "state_topic": f"{state_topic}",
                "unique_id": f"{object_id}_{device_info.serial_number}",
                # PATCH (g): removed `force_update: "true"` and `last_reset`
            }

            payload["device"] = {
                "name": device_info.name,
                "identifiers": [device_info.serial_number],
                "model": device_info.model,
                "manufacturer": device_info.manufacturer,
            }

            if unit and unit != "bool":
                payload["unit_of_measurement"] = f"{unit}"

            if icon:
                payload.update({"icon": icon})

            if device_class:
                payload["device_class"] = device_class

            # PATCH (g): default state_class to "measurement" for numeric
            # sensors that don't have one set in the reading definition.
            # Required for HA long-term statistics / Energy dashboard wiring.
            if not state_class and component == "sensor" and isinstance(value, (int, float)):
                state_class = "measurement"
            if state_class:
                payload["state_class"] = state_class

            # PATCH (g): emit suggested_display_precision so HA frontend
            # renders the correct decimal count instead of rounding voltages
            # / currents / etc. to integers per device_class default.
            if component == "sensor" and unit in _PRECISION_BY_UNIT:
                payload["suggested_display_precision"] = _PRECISION_BY_UNIT[unit]

            payloads = js.dumps(payload)
            msg = {"topic": topic, "payload": payloads}
            config_msgs.append(msg)

            msg = {"topic": state_topic, "payload": value}
            value_msgs.append(msg)

        # order value msgs after config to allow HA time to build entity before state data arrives
        return config_msgs + value_msgs