"""Sensor entities for Victron MK2 MQTT integration."""

from __future__ import annotations

from collections.abc import Callable
from dataclasses import dataclass
from typing import Any

from homeassistant.components.sensor import SensorEntity, SensorStateClass
from homeassistant.const import (
    EntityCategory,
    PERCENTAGE,
    UnitOfElectricCurrent,
    UnitOfElectricPotential,
    UnitOfFrequency,
)
from homeassistant.core import HomeAssistant

from .const import DATA_BRIDGE, DOMAIN
from .coordinator import VictronMqttBridge
from .entity import VictronMqttEntity


@dataclass(frozen=True)
class MetricDescription:
    """Description for a telemetry-backed sensor."""

    key: str
    name: str
    value_fn: Callable[[VictronMqttBridge], Any]
    unit: str | None = None
    state_class: SensorStateClass | None = SensorStateClass.MEASUREMENT
    entity_category: EntityCategory | None = None


METRICS: tuple[MetricDescription, ...] = (
    MetricDescription(
        key="battery_voltage",
        name="Battery Voltage",
        value_fn=lambda bridge: bridge.metric_float("BatVoltage"),
        unit=UnitOfElectricPotential.VOLT,
    ),
    MetricDescription(
        key="battery_current",
        name="Battery Current",
        value_fn=lambda bridge: bridge.metric_float("BatCurrent"),
        unit=UnitOfElectricCurrent.AMPERE,
    ),
    MetricDescription(
        key="battery_charge",
        name="Battery Charge",
        value_fn=lambda bridge: (
            bridge.metric_float("ChargeState") * 100.0
            if bridge.metric_float("ChargeState") is not None
            else None
        ),
        unit=PERCENTAGE,
    ),
    MetricDescription(
        key="input_voltage",
        name="Input Voltage",
        value_fn=lambda bridge: bridge.metric_float("InVoltage"),
        unit=UnitOfElectricPotential.VOLT,
    ),
    MetricDescription(
        key="input_current",
        name="Input Current",
        value_fn=lambda bridge: bridge.metric_float("InCurrent"),
        unit=UnitOfElectricCurrent.AMPERE,
    ),
    MetricDescription(
        key="input_frequency",
        name="Input Frequency",
        value_fn=lambda bridge: bridge.metric_float("InFrequency"),
        unit=UnitOfFrequency.HERTZ,
    ),
    MetricDescription(
        key="output_voltage",
        name="Output Voltage",
        value_fn=lambda bridge: bridge.metric_float("OutVoltage"),
        unit=UnitOfElectricPotential.VOLT,
    ),
    MetricDescription(
        key="output_current",
        name="Output Current",
        value_fn=lambda bridge: bridge.metric_float("OutCurrent"),
        unit=UnitOfElectricCurrent.AMPERE,
    ),
    MetricDescription(
        key="output_frequency",
        name="Output Frequency",
        value_fn=lambda bridge: bridge.metric_float("OutFrequency"),
        unit=UnitOfFrequency.HERTZ,
    ),
    MetricDescription(
        key="input_power",
        name="Input Power",
        value_fn=lambda bridge: _product(bridge.metric_float("InVoltage"), bridge.metric_float("InCurrent")),
        unit="VA",
    ),
    MetricDescription(
        key="output_power",
        name="Output Power",
        value_fn=lambda bridge: _product(bridge.metric_float("OutVoltage"), bridge.metric_float("OutCurrent")),
        unit="VA",
    ),
    MetricDescription(
        key="last_command_error",
        name="Last Command Error",
        value_fn=lambda bridge: bridge.last_error,
        state_class=None,
        entity_category=EntityCategory.DIAGNOSTIC,
    ),
)


def _product(a: float | None, b: float | None) -> float | None:
    if a is None or b is None:
        return None
    return a * b


async def async_setup_platform(
    hass: HomeAssistant,
    config: dict[str, Any],
    async_add_entities,
    discovery_info: dict[str, Any] | None = None,
) -> None:
    """Set up Victron telemetry sensors."""
    bridge: VictronMqttBridge = hass.data[DOMAIN][DATA_BRIDGE]
    async_add_entities(VictronMetricSensor(bridge, metric) for metric in METRICS)


class VictronMetricSensor(VictronMqttEntity, SensorEntity):
    """Generic telemetry sensor."""

    def __init__(self, bridge: VictronMqttBridge, description: MetricDescription) -> None:
        super().__init__(bridge)
        self.entity_description = description
        self._attr_unique_id = f"{bridge.topic_root}_{description.key}"
        self._attr_name = description.name
        self._attr_native_unit_of_measurement = description.unit
        self._attr_state_class = description.state_class
        self._attr_entity_category = description.entity_category

    @property
    def native_value(self):
        return self.entity_description.value_fn(self.bridge)