from dataclasses import dataclass
import logging

from homeassistant.components import sensor
from homeassistant.components.sensor import SensorDeviceClass
from homeassistant.core import HomeAssistant
from homeassistant.helpers.entity import Entity
from homeassistant.helpers.entity_registry import RegistryEntry

from custom_components.powercalc.common import create_source_entity
from custom_components.powercalc.const import (
    CONF_SENSOR_TYPE,
    DATA_CONFIGURED_ENTITIES,
    DATA_ENTITIES,
    DOMAIN,
    ENTRY_DATA_ENERGY_ENTITY,
    ENTRY_DATA_POWER_ENTITY,
    SensorType,
)
from custom_components.powercalc.discovery import get_power_profile_by_source_entity
from custom_components.powercalc.power_profile.power_profile import SUPPORTED_DOMAINS
from custom_components.powercalc.sensors.energy import RealEnergySensor
from custom_components.powercalc.sensors.power import RealPowerSensor
from custom_components.powercalc.sensors.utility_meter import VirtualUtilityMeter

from .filter import CompositeFilter, DomainFilter, EntityFilter, LambdaFilter, get_filtered_entity_list

_LOGGER = logging.getLogger(__name__)


@dataclass(slots=True)
class FindEntitiesResult:
    resolved: list[Entity]
    discoverable: list[str]


async def find_entities(
    hass: HomeAssistant,
    entity_filter: EntityFilter | None = None,
    include_non_powercalc: bool = True,
    exclude_utility_meters: bool = True,
) -> FindEntitiesResult:
    """
    Based on the given entity filter, fetch all power and energy sensors from the HA instance.
    """
    domain_data = hass.data.get(DOMAIN, {})

    source_entity_powercalc_entity_map: dict[str, list[tuple[Entity, bool]]] = domain_data.get(
        DATA_CONFIGURED_ENTITIES,
        {},
    )
    powercalc_entities: dict[str, Entity] = domain_data.get(
        DATA_ENTITIES,
        {},
    )

    resolved_entities: list[Entity] = []
    discoverable_entities: list[str] = []

    source_entities = get_filtered_entity_list(hass, _build_filter(hass, entity_filter, include_non_powercalc))

    if _LOGGER.isEnabledFor(logging.DEBUG):  # pragma: no cover
        _LOGGER.debug("Source entities: %s", [entity.entity_id for entity in source_entities])

    for source_entity in source_entities:
        entity_id = source_entity.entity_id

        mapped = source_entity_powercalc_entity_map.get(entity_id)
        if mapped:
            resolved_entities.extend(entity for entity, _ in mapped)
            continue

        existing = powercalc_entities.get(entity_id)
        if existing:
            resolved_entities.append(existing)
            continue

        real_sensor = _create_real_sensor(source_entity)
        if real_sensor:
            resolved_entities.append(real_sensor)
            continue

        if await _is_discoverable_source_entity(hass, source_entity):
            discoverable_entities.append(entity_id)

    if exclude_utility_meters:
        resolved_entities = [entity for entity in resolved_entities if not isinstance(entity, VirtualUtilityMeter)]

    if _LOGGER.isEnabledFor(logging.DEBUG):  # pragma: no cover
        _LOGGER.debug("Resolved entities: %s", [entity.entity_id for entity in resolved_entities])
        _LOGGER.debug("Discoverable entities: %s", discoverable_entities)

    return FindEntitiesResult(resolved_entities, discoverable_entities)


def _is_source_entity_eligible(
    hass: HomeAssistant,
    source_entity: RegistryEntry,
    include_non_powercalc: bool,
) -> bool:
    """Return whether a registry entity is eligible for Powercalc discovery."""
    if source_entity.platform != DOMAIN:
        return include_non_powercalc or source_entity.domain != sensor.DOMAIN

    # YAML-created Powercalc entities have no config entry and are classified by their runtime type later.
    if source_entity.config_entry_id is None:
        return True

    config_entry = hass.config_entries.async_get_entry(source_entity.config_entry_id)
    if config_entry is None:
        return False

    if config_entry.data.get(CONF_SENSOR_TYPE) == SensorType.GROUP:
        return False

    main_entity_ids = {
        config_entry.data.get(ENTRY_DATA_POWER_ENTITY),
        config_entry.data.get(ENTRY_DATA_ENERGY_ENTITY),
    }
    return source_entity.entity_id in main_entity_ids


def _create_real_sensor(source_entity: RegistryEntry) -> Entity | None:
    if source_entity.domain != sensor.DOMAIN:
        return None

    device_class = source_entity.device_class or source_entity.original_device_class
    if device_class == SensorDeviceClass.POWER:
        return RealPowerSensor(source_entity.entity_id, source_entity.unit_of_measurement)
    if device_class == SensorDeviceClass.ENERGY:
        return RealEnergySensor(source_entity.entity_id)
    return None  # pragma: no cover


async def _is_discoverable_source_entity(hass: HomeAssistant, source_entity: RegistryEntry) -> bool:
    power_profile = await get_power_profile_by_source_entity(
        hass,
        create_source_entity(source_entity.entity_id, hass),
    )
    return bool(
        power_profile
        and not await power_profile.needs_user_configuration
        and power_profile.is_entity_domain_supported(source_entity),
    )


def _build_filter(
    hass: HomeAssistant,
    entity_filter: EntityFilter | None,
    include_non_powercalc: bool,
) -> EntityFilter:
    base_filter = CompositeFilter(
        [
            DomainFilter(SUPPORTED_DOMAINS),
            LambdaFilter(lambda entity: _is_source_entity_eligible(hass, entity, include_non_powercalc)),
            LambdaFilter(lambda entity: entity.platform != "utility_meter"),
            LambdaFilter(lambda entity: not str(entity.unique_id).startswith("powercalc_standby_group")),
            LambdaFilter(lambda entity: "tracked_" not in str(entity.unique_id)),
            LambdaFilter(
                lambda entity: (
                    entity.platform != "tasmota" or not str(entity.entity_id).endswith(("_yesterday", "_today"))
                ),
            ),
        ],
    )
    if not entity_filter:
        return base_filter

    return CompositeFilter([base_filter, entity_filter])