from collections.abc import Callable, Coroutine, Iterable, Iterator
import decimal
from decimal import Decimal
from functools import wraps
import logging
import os.path
import re
from typing import Any, NamedTuple, TypeVar
import uuid

from homeassistant.components.binary_sensor import BinarySensorDeviceClass
from homeassistant.components.sensor import SensorDeviceClass
from homeassistant.const import CONF_UNIQUE_ID
from homeassistant.core import HomeAssistant
from homeassistant.exceptions import TemplateError
from homeassistant.helpers import entity_registry
from homeassistant.helpers.entity_registry import RegistryEntry
from homeassistant.helpers.template import Template
from homeassistant.helpers.typing import ConfigType

from custom_components.powercalc.common import SourceEntity
from custom_components.powercalc.const import (
    DUMMY_ENTITY_ID,
    PLACEHOLDER_ENTITY_BY_DEVICE_CLASS,
    PLACEHOLDER_ENTITY_BY_TRANSLATION_KEY,
    CalculationStrategy,
)
from custom_components.powercalc.power_profile.power_profile import PowerProfile

_LOGGER = logging.getLogger(__name__)

PLACEHOLDER_REGEX = re.compile(r"\[\[\s*([A-Za-z_]\w*(?::[A-Za-z_]\w*)*)\s*\]\]")


def evaluate_power(power: Template | Decimal | float) -> Decimal | None:
    """When power is a template render it."""

    if isinstance(power, Decimal):
        return power

    try:
        if isinstance(power, Template):
            try:
                power = power.async_render()
            except TemplateError as ex:
                _LOGGER.error("Could not render power template %s: %s", power, ex)
                return None
            if power == "unknown":
                return None

        return Decimal(power)  # type: ignore[arg-type]
    except (decimal.DecimalException, ValueError):
        _LOGGER.error("Could not convert power value %s to decimal", power)
        return None


def get_library_path(sub_path: str = "") -> str:
    """Get the path to the library file."""
    base_path = os.path.join(os.path.dirname(__file__), "../../profile_library")
    return f"{base_path}/{sub_path}"


def get_library_json_path() -> str:
    """Get the path to the library.json file."""
    return get_library_path("library.json")


def get_or_create_unique_id(
    sensor_config: ConfigType,
    source_entity: SourceEntity,
    power_profile: PowerProfile | None,
) -> str:
    """Get or create the unique id."""
    unique_id = sensor_config.get(CONF_UNIQUE_ID)
    if unique_id:
        return str(unique_id)

    # For multi-switch and wled strategy we need to use the device id as unique id
    # As we don't want to start a discovery for each switch entity
    if (
        source_entity.device_entry
        and power_profile
        and power_profile.calculation_strategy in [CalculationStrategy.WLED, CalculationStrategy.MULTI_SWITCH]
    ):
        return f"pc_{source_entity.device_entry.id}"

    if source_entity and source_entity.entity_id != DUMMY_ENTITY_ID:
        source_unique_id = source_entity.unique_id or source_entity.entity_id
        # Prefix with pc_ to avoid conflicts with other integrations
        return f"pc_{source_unique_id}"

    return str(uuid.uuid4())


P = TypeVar("P")  # Used for positional and keyword argument types
R = TypeVar("R")  # Used for return type


class RelatedEntityPlaceholderDefinition(NamedTuple):
    prefix: str
    lookup_label: str
    resolver: Callable[[HomeAssistant, SourceEntity, str], str | None]


def make_hashable(arg: Any) -> Any:  # noqa: ANN401
    """Convert unhashable arguments to hashable equivalents."""
    if isinstance(arg, set):
        return frozenset(arg)
    if isinstance(arg, list):
        return tuple(arg)
    if isinstance(arg, dict):
        return frozenset((key, make_hashable(value)) for key, value in arg.items())
    return arg


def async_cache[R](func: Callable[..., Coroutine[Any, Any, R]]) -> Callable[..., Coroutine[Any, Any, R]]:
    """
    A decorator to cache results of an async function based on its arguments.

    Args:
        func: The asynchronous function to decorate.

    Returns:
        A decorated asynchronous function with caching.
    """
    cache: dict[tuple[tuple[Any, ...], frozenset], R] = {}

    @wraps(func)
    async def wrapper(*args: Any, **kwargs: Any) -> R:  # noqa: ANN401
        # Make arguments hashable
        hashable_args = tuple(make_hashable(arg) for arg in args)
        hashable_kwargs = frozenset((key, make_hashable(value)) for key, value in kwargs.items())
        cache_key = (hashable_args, hashable_kwargs)

        if cache_key in cache:
            return cache[cache_key]
        result = await func(*args, **kwargs)
        cache[cache_key] = result
        return result

    return wrapper


def collect_placeholders(data: list | str | dict[str, Any]) -> set[str]:
    found: set[str] = set()
    if isinstance(data, dict):
        for v in data.values():
            found |= collect_placeholders(v)
    elif isinstance(data, list):
        for v in data:
            found |= collect_placeholders(v)
    elif isinstance(data, str):
        found |= set(PLACEHOLDER_REGEX.findall(data))
    return found


def replace_placeholders(
    data: list | str | dict[str, Any],
    replacements: dict[str, str],
) -> list | str | dict[str, Any]:
    """Replace placeholders in a dictionary with values from a replacement dictionary."""
    if isinstance(data, dict):
        for key, value in data.items():
            data[key] = replace_placeholders(value, replacements)
    elif isinstance(data, list):
        for i in range(len(data)):
            data[i] = replace_placeholders(data[i], replacements)
    elif isinstance(data, str):
        # Use the same regex pattern as PLACEHOLDER_REGEX
        matches = PLACEHOLDER_REGEX.findall(data)
        for match in matches:
            if match in replacements:
                # Replace [[variable]] with its value
                data = data.replace(f"[[{match}]]", str(replacements[match]))
    return data


def iter_related_entity_placeholders(placeholders: Iterable[str]) -> Iterator[str]:
    """Yield placeholders that need lookup against entities on the same device."""
    for placeholder in placeholders:
        if parse_related_entity_placeholder(placeholder):
            yield placeholder


def resolve_related_entity_placeholder(
    hass: HomeAssistant,
    placeholder: str,
    source_entity: SourceEntity | None = None,
) -> str | None:
    """Resolve a single related-entity placeholder against the entity registry."""
    if not source_entity:
        return None

    parsed_placeholder = parse_related_entity_placeholder(placeholder)
    if not parsed_placeholder:
        return None

    definition, lookup_value = parsed_placeholder
    return definition.resolver(hass, source_entity, lookup_value)


def build_related_entity_placeholder_not_found_message(placeholder: str, source_entity_id: str) -> str:
    parsed_placeholder = parse_related_entity_placeholder(placeholder)
    if not parsed_placeholder:
        return f"Could not find related entity for placeholder {placeholder} of entity {source_entity_id}"

    definition, lookup_value = parsed_placeholder
    return f"Could not find related entity for {definition.lookup_label} {lookup_value} of entity {source_entity_id}"


def parse_related_entity_placeholder(placeholder: str) -> tuple[RelatedEntityPlaceholderDefinition, str] | None:
    for definition in RELATED_ENTITY_PLACEHOLDER_DEFINITIONS:
        if placeholder.startswith(definition.prefix):
            return definition, placeholder.removeprefix(definition.prefix)
    return None


def _resolve_related_entity_by_device_class(
    hass: HomeAssistant,
    source_entity: SourceEntity,
    raw_device_class: str,
) -> str | None:
    device_class = _parse_related_entity_device_class(raw_device_class)
    if device_class is None:
        return None
    return get_related_entity_by_device_class(hass, source_entity, device_class)


def _resolve_related_entity_by_translation_key(
    hass: HomeAssistant,
    source_entity: SourceEntity,
    translation_key: str,
) -> str | None:
    return get_related_entity_by_translation_key(hass, source_entity, translation_key)


RELATED_ENTITY_PLACEHOLDER_DEFINITIONS = (
    RelatedEntityPlaceholderDefinition(
        PLACEHOLDER_ENTITY_BY_DEVICE_CLASS,
        "device class",
        _resolve_related_entity_by_device_class,
    ),
    RelatedEntityPlaceholderDefinition(
        PLACEHOLDER_ENTITY_BY_TRANSLATION_KEY,
        "translation key",
        _resolve_related_entity_by_translation_key,
    ),
)


def _parse_related_entity_device_class(raw_device_class: str) -> SensorDeviceClass | BinarySensorDeviceClass | None:
    try:
        return SensorDeviceClass(raw_device_class)
    except ValueError:
        try:
            return BinarySensorDeviceClass(raw_device_class)
        except ValueError:
            return None


def get_related_entity_by_device_class(
    hass: HomeAssistant,
    source_entity: SourceEntity,
    device_class: SensorDeviceClass | BinarySensorDeviceClass,
) -> str | None:
    """Get related entity from same device by device class."""
    return _get_related_entity_for_device(
        hass,
        source_entity=source_entity,
        match_label="device class",
        match_value=device_class,
        matcher=lambda entity_entry: (entity_entry.device_class or entity_entry.original_device_class) == device_class,
    )


def get_related_entity_by_translation_key(
    hass: HomeAssistant,
    source_entity: SourceEntity,
    translation_key: str,
) -> str | None:
    """Get related entity from same device by translation key."""
    return _get_related_entity_for_device(
        hass,
        source_entity=source_entity,
        match_label="translation key",
        match_value=translation_key,
        matcher=lambda entity_entry: entity_entry.translation_key == translation_key,
    )


def _get_related_entity_for_device(
    hass: HomeAssistant,
    source_entity: SourceEntity,
    match_label: str,
    match_value: SensorDeviceClass | BinarySensorDeviceClass | str,
    matcher: Callable[[RegistryEntry], bool],
) -> str | None:
    """Get the first related entity on the same device matching the given predicate."""
    entity_reg = entity_registry.async_get(hass)
    if not source_entity.device_entry:
        _LOGGER.debug("No device_id available, cannot find related entity")
        return None

    related_entities = [
        entity_entry.entity_id
        for entity_entry in entity_registry.async_entries_for_device(entity_reg, source_entity.device_entry.id)
        if matcher(entity_entry)
    ]
    if not related_entities:
        _LOGGER.debug(
            "No related entities found for device %s with %s %s",
            source_entity.device_entry.id,
            match_label,
            match_value,
        )
        return None

    return related_entities[0]