"""Spook - Your homie."""

from __future__ import annotations

from abc import ABC, abstractmethod
from dataclasses import dataclass, field
import importlib
from pathlib import Path
from typing import TYPE_CHECKING, Any, Generic, TypeVar, final

import voluptuous as vol

from homeassistant.const import EVENT_COMPONENT_LOADED, EVENT_CORE_CONFIG_UPDATE
from homeassistant.core import (
    Event,
    HomeAssistant,
    Service,
    ServiceCall,
    ServiceResponse,
    SupportsResponse,
    callback,
)
from homeassistant.exceptions import Unauthorized, UnknownUser
from homeassistant.helpers.entity import Entity
from homeassistant.helpers.entity_component import DATA_INSTANCES, EntityComponent
from homeassistant.helpers.entity_platform import DATA_ENTITY_PLATFORM
from homeassistant.helpers.service import (
    SERVICE_DESCRIPTION_CACHE,
    async_register_admin_service,
    async_set_service_schema,
)
from homeassistant.helpers.translation import (
    _async_get_translations_cache,
    async_get_cached_translations,
    async_get_translations,
)
from homeassistant.loader import async_get_integration
from homeassistant.setup import ATTR_COMPONENT

from .const import DOMAIN, LOGGER
from .core_compat import load_service_descriptions

if TYPE_CHECKING:
    import asyncio
    from collections.abc import Callable
    from types import ModuleType


_EntityT = TypeVar("_EntityT", bound=Entity, default=Entity)
GHOST = "👻"
SERVICE_TRANSLATION_CATEGORY = "services"
SELECTOR_TRANSLATION_CATEGORY = "selector"


class AbstractSpookServiceBase(ABC):
    """Abstract base class to hold a Spook service."""

    hass: HomeAssistant
    domain: str
    service: str
    schema: dict[str | vol.Marker, Any] | None = None

    def __init__(self, hass: HomeAssistant) -> None:
        """Initialize the service."""
        self.hass = hass

    @abstractmethod
    @callback
    def async_register(self) -> bool:
        """Register the service with Home Assistant.

        Returns True when the service was actually registered.
        """
        raise NotImplementedError

    @final
    @callback
    def async_unregister(self) -> None:
        """Unregister the service from Home Assistant."""
        LOGGER.debug(
            "Unregistering Spook service: %s.%s",
            self.domain,
            self.service,
        )

        self.hass.services.async_remove(self.domain, self.service)


class ReplaceExistingService(AbstractSpookServiceBase):
    """Service replaces/may replace an existing service."""

    overriden_service: Service | None = None


class AbstractSpookService(AbstractSpookServiceBase):
    """Abstract class to hold a Spook service."""

    supports_response: SupportsResponse = SupportsResponse.NONE

    @final
    @callback
    def async_register(self) -> bool:
        """Register the service with Home Assistant."""
        # Only register the service if the domain is the spook integration
        # or if the target integration is loaded.
        if self.domain != DOMAIN and self.domain not in self.hass.config.components:
            LOGGER.debug(
                "Not registering Spook %s.%s service, %s is not loaded",
                self.domain,
                self.service,
                self.domain,
            )
            return False

        LOGGER.debug(
            "Registering Spook service: %s.%s",
            self.domain,
            self.service,
        )

        self.hass.services.async_register(
            domain=self.domain,
            service=self.service,
            service_func=self.async_handle_service,
            schema=vol.Schema(self.schema) if self.schema else None,
            supports_response=self.supports_response,
        )

        return True

    @abstractmethod
    async def async_handle_service(self, call: ServiceCall) -> ServiceResponse:
        """Handle the service call."""
        raise NotImplementedError


class AbstractSpookAdminService(AbstractSpookServiceBase):
    """Abstract class to hold a Spook admin service."""

    supports_response: SupportsResponse = SupportsResponse.NONE

    @final
    @callback
    def async_register(self) -> bool:
        """Register the service with Home Assistant."""
        if self.domain != DOMAIN and self.domain not in self.hass.config.components:
            LOGGER.debug(
                "Not registering Spook %s.%s admin service, %s is not loaded",
                self.domain,
                self.service,
                self.domain,
            )
            return False

        LOGGER.debug(
            "Registering Spook admin service: %s.%s",
            self.domain,
            self.service,
        )
        async_register_admin_service(
            hass=self.hass,
            domain=self.domain,
            service=self.service,
            service_func=self.async_handle_service,
            schema=vol.Schema(self.schema) if self.schema else None,
            supports_response=self.supports_response,
        )

        return True

    @abstractmethod
    async def async_handle_service(self, call: ServiceCall) -> None:
        """Handle the service call."""
        raise NotImplementedError


class AbstractSpookEntityService(AbstractSpookServiceBase, Generic[_EntityT]):
    """Abstract class to hold a Spook entity service."""

    platform: str
    required_features: list[int] | None = None
    supports_response: SupportsResponse = SupportsResponse.NONE

    @final
    @callback
    def async_register(self) -> bool:
        """Register the service with Home Assistant."""
        LOGGER.debug(
            "Registering Spook entity service: %s.%s for platform %s",
            self.domain,
            self.service,
            self.platform,
        )

        if not (
            platform := next(
                (
                    platform
                    for platform in self.hass.data.get(DATA_ENTITY_PLATFORM, {}).get(
                        self.domain, []
                    )
                    if platform.domain == self.platform
                ),
                None,
            )
        ):
            msg = (
                f"Could not find platform {self.platform} for domain "
                f"{self.domain} to register service: "
                f"{self.domain}.{self.service}"
            )
            raise RuntimeError(msg)

        platform.async_register_entity_service(
            name=self.service,
            func=self.async_handle_service,
            schema=self.schema,
            required_features=self.required_features,
            supports_response=self.supports_response,
        )

        return True

    @abstractmethod
    async def async_handle_service(
        self,
        entity: _EntityT,
        call: ServiceCall,
    ) -> ServiceResponse:
        """Handle the service call."""
        raise NotImplementedError


class AbstractSpookEntityComponentService(AbstractSpookServiceBase, Generic[_EntityT]):
    """Abstract class to hold a Spook entity component service."""

    required_features: list[int] | None = None
    supports_response: SupportsResponse = SupportsResponse.NONE
    #: For an action that changes how something is set up rather than what it
    #: is doing, which Home Assistant keeps to admins. Automations still pass.
    admin_only: bool = False

    @final
    @callback
    def async_register(self) -> bool:
        """Register the service with Home Assistant."""
        LOGGER.debug(
            "Registering Spook entity component service: %s.%s",
            self.domain,
            self.service,
        )

        # Not every component is there when Spook is. Home Assistant loads
        # calendar and todo only once an integration brings a calendar or a
        # to-do list along, which can be well after Spook, or never. The
        # manager waits for it and registers the action then.
        if self.domain not in self.hass.data.get(DATA_INSTANCES, {}):
            LOGGER.debug(
                "Not registering Spook %s.%s service yet, %s is not loaded",
                self.domain,
                self.service,
                self.domain,
            )
            return False

        component: EntityComponent[Entity] = self.hass.data[DATA_INSTANCES][self.domain]

        component.async_register_entity_service(
            name=self.service,
            func=(
                self._async_handle_service_as_admin
                if self.admin_only
                else self.async_handle_service
            ),
            schema=self.schema,
            required_features=self.required_features,
            supports_response=self.supports_response,
        )

        return True

    async def _async_handle_service_as_admin(
        self,
        entity: _EntityT,
        call: ServiceCall,
    ) -> ServiceResponse:
        """Handle the call, if whoever made it may change how things are set up.

        The same check Home Assistant does for an admin-only entity action. It
        is done here rather than asked of Home Assistant, because the option
        to ask arrived in a later version than the oldest one Spook runs on,
        and passing it there fails registering every one of these actions.
        """
        if call.context.user_id:
            user = await self.hass.auth.async_get_user(call.context.user_id)
            if user is None:
                raise UnknownUser(context=call.context)
            if not user.is_admin:
                raise Unauthorized(context=call.context)

        return await self.async_handle_service(entity, call)

    @abstractmethod
    async def async_handle_service(
        self,
        entity: _EntityT,
        call: ServiceCall,
    ) -> ServiceResponse:
        """Handle the service call."""
        raise NotImplementedError


@dataclass
class SpookServiceManager:
    """Class to manage Spook services."""

    hass: HomeAssistant

    _services: set[AbstractSpookService] = field(default_factory=set)
    _service_schemas: dict[str, Any] = field(default_factory=dict)
    _service_translation_overrides: dict[tuple[str, str, str], str | None] = field(
        default_factory=dict
    )
    # The same, for the option labels of the selectors those actions use.
    _selector_translation_overrides: dict[tuple[str, str, str], str | None] = field(
        default_factory=dict
    )
    # Services for a domain that was not loaded yet, by that domain.
    _waiting_for_domain: dict[str, list[AbstractSpookService]] = field(
        default_factory=dict
    )
    # Everything to undo on unload: the listeners, and any translation
    # injection still on its way.
    _on_unload: list[Callable[[], None]] = field(default_factory=list)

    def __post_init__(self) -> None:
        """Post initialization."""
        LOGGER.debug("Spook service manager initialized")

    async def async_setup(self) -> None:
        """Set up the Spook services."""
        LOGGER.debug("Setting up Spook services")

        # Load service schemas
        integration = await async_get_integration(self.hass, DOMAIN)
        self._service_schemas = await self.hass.async_add_executor_job(
            load_service_descriptions,
            integration,
        )

        modules: list[ModuleType] = []

        def _load_all_service_modules() -> None:
            """Load all service modules."""
            for module_file in Path(__file__).parent.rglob(
                "ectoplasms/*/services/*.py"
            ):
                if module_file.name == "__init__.py":
                    continue
                module_path = str(module_file.relative_to(Path(__file__).parent))[
                    :-3
                ].replace("/", ".")
                modules.append(importlib.import_module(f".{module_path}", __package__))

        await self.hass.async_add_import_executor_job(_load_all_service_modules)

        # Listening starts before anything is parked, and nothing between here
        # and the end of the loop below waits on anything. A domain that loads
        # in the meantime is either there for the loop to register straight
        # away, or loads afterwards with the listener already in place.
        self._on_unload = [
            self.hass.bus.async_listen(
                EVENT_COMPONENT_LOADED,
                self._async_component_loaded,
            ),
            self.hass.bus.async_listen(
                EVENT_CORE_CONFIG_UPDATE,
                self._async_core_config_updated,
            ),
        ]

        for module in modules:
            self._async_setup_service_module(module)

        await self.async_inject_service_translations()

    @callback
    def _async_setup_service_module(self, module: ModuleType) -> None:
        """Set up a single service module, isolating failures.

        A service that fails to set up must not prevent the rest of Spook
        from loading.
        """
        try:
            service = module.SpookService(self.hass)
        # pylint: disable-next=broad-exception-caught
        except Exception:  # noqa: BLE001
            LOGGER.exception(
                "Spook service %s failed to set up and has been skipped; "
                "please report this issue at "
                "https://github.com/frenck/spook/issues",
                module.__name__,
            )
            return

        self._async_setup_service(service, module.__name__)

    @callback
    def _async_setup_service(self, service: AbstractSpookService, name: str) -> None:
        """Register one service, isolating failures.

        One for a domain that is not loaded yet waits for it, and is set up
        through here again once it is.
        """
        try:
            if isinstance(
                service,
                ReplaceExistingService,
            ) and self.hass.services.has_service(service.domain, service.service):
                LOGGER.debug(
                    "Unregistering service that will be overriden service: %s.%s",
                    service.domain,
                    service.service,
                )
                # pylint: disable=protected-access
                service.overriden_service = (
                    self.hass.services._services[service.domain]  # noqa: SLF001
                ).pop(service.service)

            if not self.async_register_service(service):
                self._waiting_for_domain.setdefault(service.domain, []).append(service)
        # pylint: disable-next=broad-exception-caught
        except Exception:  # noqa: BLE001
            # If the service this one overrides was already unregistered,
            # restore it; a failing setup must not silently remove a core
            # service until the next restart.
            if (
                isinstance(service, ReplaceExistingService)
                and service.overriden_service is not None
            ):
                # pylint: disable-next=protected-access
                self.hass.services._services.setdefault(  # noqa: SLF001
                    service.domain,
                    {},
                )[service.service] = service.overriden_service
            LOGGER.exception(
                "Spook service %s failed to set up and has been skipped; "
                "please report this issue at "
                "https://github.com/frenck/spook/issues",
                name,
            )

    @callback
    def _async_component_loaded(self, event: Event) -> None:
        """Register the services that were waiting for this domain."""
        if not (
            waiting := self._waiting_for_domain.pop(event.data[ATTR_COMPONENT], [])
        ):
            return

        for service in waiting:
            self._async_setup_service(service, type(service).__module__)

        # The descriptions went in with the registration, the translations did
        # not: those are injected for every registered service in one go.
        self._async_reinject_service_translations()

    @callback
    def _async_reinject_service_translations(self) -> None:
        """Inject the translations again, in a task unloading cancels.

        Injecting waits on loading translations before it writes anything.
        Left running through an unload, it would write Spook's strings back
        for actions that were just taken away, after unload put the originals
        back.
        """
        task = self.hass.async_create_task(
            self.async_inject_service_translations(),
            "Inject Spook service translations",
        )
        self._on_unload.append(task.cancel)

        @callback
        def _finished(_task: asyncio.Task[None]) -> None:
            # Already gone when unloading cleared the list and cancelled it.
            if task.cancel in self._on_unload:
                self._on_unload.remove(task.cancel)

        task.add_done_callback(_finished)

    @callback
    def async_register_service(self, service: AbstractSpookService) -> bool:
        """Register a Spook service.

        Returns False when the domain it belongs to is not loaded (yet).
        """
        # A service aimed at an integration that is not set up never lands in
        # Home Assistant. Injecting a description for it would then describe
        # an action that does not exist, which core refuses with a KeyError.
        if not service.async_register():
            return False

        self._services.add(service)

        # Override service description with Spook's if the service is not
        # for the Spook integration.
        if service.domain != DOMAIN and (
            service_schema := self._service_schemas.get(
                f"{service.domain}_{service.service}",
            )
        ):
            LOGGER.debug(
                "Injecting Spook service schema for: %s.%s",
                service.domain,
                service.service,
            )
            async_set_service_schema(
                self.hass,
                domain=service.domain,
                service=service.service,
                schema=service_schema,
            )

        return True

    @callback
    def _service_schema_key(self, service: AbstractSpookService) -> str:
        """Return the services.yaml key for a Spook service."""
        if service.domain == DOMAIN:
            return service.service
        return f"{service.domain}_{service.service}"

    @callback
    def _service_translation_strings(
        self,
        service: AbstractSpookService,
        cached_spook_translations: dict[str, str],
    ) -> dict[str, str]:
        """Return service translation strings mapped to the target domain."""
        schema_key = self._service_schema_key(service)
        spook_prefix = f"component.{DOMAIN}.services.{schema_key}."
        target_prefix = f"component.{service.domain}.services.{service.service}."

        return {
            f"{target_prefix}{key.removeprefix(spook_prefix)}": (
                f"{value} {GHOST}"
                if key == f"{spook_prefix}name" and GHOST not in value
                else value
            )
            for key, value in cached_spook_translations.items()
            if key.startswith(spook_prefix)
        }

    @callback
    def _translation_component_cache(
        self,
        language: str,
        domain: str,
        *,
        create: bool = False,
        category: str = SERVICE_TRANSLATION_CATEGORY,
    ) -> dict[str, str] | None:
        """Return the Home Assistant translation cache for a component."""
        translations_cache = _async_get_translations_cache(self.hass)

        try:
            cache = translations_cache.cache_data.cache
        except AttributeError:
            LOGGER.warning(
                "Unable to access Home Assistant's translation cache, "
                "skipping Spook service translation update"
            )
            return None

        if not isinstance(cache, dict):
            LOGGER.warning(
                "Home Assistant's translation cache has an unexpected structure, "
                "skipping Spook service translation update"
            )
            return None

        if create:
            return (
                cache.setdefault(language, {})
                .setdefault(category, {})
                .setdefault(domain, {})
            )

        return cache.get(language, {}).get(category, {}).get(domain)

    @callback
    def _inject_service_translation_strings(
        self,
        service: AbstractSpookService,
        cached_spook_translations: dict[str, str],
    ) -> None:
        """Inject service translation strings into Home Assistant's cache."""
        language = self.hass.config.language
        component_cache = self._translation_component_cache(
            language,
            service.domain,
            create=True,
        )
        if component_cache is None:
            return

        cached_translations = async_get_cached_translations(
            self.hass,
            language,
            SERVICE_TRANSLATION_CATEGORY,
            service.domain,
        )

        for key, value in self._service_translation_strings(
            service,
            cached_spook_translations,
        ).items():
            self._service_translation_overrides.setdefault(
                (language, service.domain, key), cached_translations.get(key)
            )
            component_cache[key] = value

    @callback
    def _selector_translation_keys(self, service: AbstractSpookService) -> set[str]:
        """Return the selector translation keys a Spook service's fields use."""
        schema = self._service_schemas.get(self._service_schema_key(service)) or {}
        keys: set[str] = set()
        for field_schema in (schema.get("fields") or {}).values():
            for selector_config in (
                (field_schema or {}).get("selector") or {}
            ).values():
                if isinstance(selector_config, dict) and (
                    key := selector_config.get("translation_key")
                ):
                    keys.add(key)
        return keys

    @callback
    def _inject_selector_translation_strings(
        self,
        service: AbstractSpookService,
        cached_spook_translations: dict[str, str],
    ) -> None:
        """Inject the option labels of a Spook service's selectors.

        Home Assistant looks a selector's labels up under the domain the action
        belongs to, `component.todo.selector...` for a `todo` action, and Spook
        keeps them under its own. Without this, the options show as their raw
        values.
        """
        if not (keys := self._selector_translation_keys(service)):
            return

        language = self.hass.config.language
        component_cache = self._translation_component_cache(
            language,
            service.domain,
            create=True,
            category=SELECTOR_TRANSLATION_CATEGORY,
        )
        if component_cache is None:
            return

        cached_translations = async_get_cached_translations(
            self.hass,
            language,
            SELECTOR_TRANSLATION_CATEGORY,
            service.domain,
        )

        for key in keys:
            spook_prefix = f"component.{DOMAIN}.selector.{key}."
            target_prefix = f"component.{service.domain}.selector.{key}."
            for spook_key, value in cached_spook_translations.items():
                if not spook_key.startswith(spook_prefix):
                    continue
                target_key = f"{target_prefix}{spook_key.removeprefix(spook_prefix)}"
                self._selector_translation_overrides.setdefault(
                    (language, service.domain, target_key),
                    cached_translations.get(target_key),
                )
                component_cache[target_key] = value

    async def async_inject_service_translations(self) -> None:
        """Inject Spook service strings into Home Assistant translations."""
        services = [
            service
            for service in self._services
            if self._service_schema_key(service) in self._service_schemas
        ]

        if not services:
            return

        await async_get_translations(
            self.hass,
            self.hass.config.language,
            SERVICE_TRANSLATION_CATEGORY,
            {DOMAIN, *(service.domain for service in services)},
        )
        cached_spook_translations = async_get_cached_translations(
            self.hass,
            self.hass.config.language,
            SERVICE_TRANSLATION_CATEGORY,
            DOMAIN,
        )

        for service in services:
            self._inject_service_translation_strings(
                service,
                cached_spook_translations,
            )

        domains = {DOMAIN, *(service.domain for service in services)}
        await async_get_translations(
            self.hass,
            self.hass.config.language,
            SELECTOR_TRANSLATION_CATEGORY,
            domains,
        )
        cached_spook_selector_translations = async_get_cached_translations(
            self.hass,
            self.hass.config.language,
            SELECTOR_TRANSLATION_CATEGORY,
            DOMAIN,
        )
        for service in services:
            self._inject_selector_translation_strings(
                service,
                cached_spook_selector_translations,
            )

    @callback
    def _async_core_config_updated(self, event: Event) -> None:
        """Re-inject service translations when the language changes."""
        if "language" not in event.data:
            return
        self._async_reinject_service_translations()

    @callback
    def async_clear_service_translation_overrides(self) -> None:
        """Restore translation strings that were overridden by Spook."""
        self._restore(self._service_translation_overrides, SERVICE_TRANSLATION_CATEGORY)
        self._restore(
            self._selector_translation_overrides, SELECTOR_TRANSLATION_CATEGORY
        )

    @callback
    def _restore(
        self,
        overrides: dict[tuple[str, str, str], str | None],
        category: str,
    ) -> None:
        """Put back what Spook overrode, and take away what it only added."""
        for (language, domain, key), original_value in overrides.items():
            component_cache = self._translation_component_cache(
                language, domain, category=category
            )
            if component_cache is None:
                continue

            if original_value is None:
                component_cache.pop(key, None)
            else:
                component_cache[key] = original_value

        overrides.clear()

    @callback
    def async_on_unload(self) -> None:
        """Tear down the Spook services."""
        LOGGER.debug("Tearing down Spook services")
        # A copy, as cancelling a finished injection takes it off the list.
        for undo in list(self._on_unload):
            undo()
        self._on_unload.clear()
        self._waiting_for_domain.clear()

        for service in self._services:
            LOGGER.debug(
                "Unregistering service: %s.%s",
                service.domain,
                service.service,
            )
            service.async_unregister()

            if (
                isinstance(service, ReplaceExistingService)
                and service.overriden_service
            ):
                LOGGER.debug(
                    "Restoring service that was overriden previously: %s.%s",
                    service.domain,
                    service.service,
                )

                # pylint: disable-next=protected-access
                self.hass.services._services.setdefault(  # noqa: SLF001
                    service.domain,
                    {},
                )[service.service] = service.overriden_service

                # Flush service description schema cache
                self.hass.data.pop(SERVICE_DESCRIPTION_CACHE, None)

        self.async_clear_service_translation_overrides()