"""Handle legacy notification platforms."""
from __future__ import annotations

import asyncio
from functools import partial
from typing import Any, cast

from homeassistant.const import CONF_DESCRIPTION, CONF_NAME
from homeassistant.core import HomeAssistant, ServiceCall, callback
from homeassistant.exceptions import HomeAssistantError
from homeassistant.helpers import config_per_platform, discovery, template
from homeassistant.helpers.service import async_set_service_schema
from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType
from homeassistant.loader import async_get_integration, bind_hass
from homeassistant.setup import async_prepare_setup_platform, async_start_setup
from homeassistant.util import slugify
from homeassistant.util.yaml import load_yaml

from .const import (
    ATTR_DATA,
    ATTR_MESSAGE,
    ATTR_TARGET,
    ATTR_TITLE,
    DOMAIN,
    LOGGER,
    NOTIFY_SERVICE_SCHEMA,
    SERVICE_NOTIFY,
)

CONF_FIELDS = "fields"
NOTIFY_SERVICES = "notify_services"


async def async_setup_legacy(hass: HomeAssistant, config: ConfigType) -> None:
    """Set up legacy notify services."""
    hass.data.setdefault(NOTIFY_SERVICES, {})

    async def async_setup_platform(
        integration_name: str,
        p_config: ConfigType | None = None,
        discovery_info: DiscoveryInfoType | None = None,
    ) -> None:
        """Set up a notify platform."""
        if p_config is None:
            p_config = {}

        platform = await async_prepare_setup_platform(
            hass, config, DOMAIN, integration_name
        )

        if platform is None:
            LOGGER.error("Unknown notification service specified")
            return

        full_name = f"{DOMAIN}.{integration_name}"
        LOGGER.info("Setting up %s", full_name)
        with async_start_setup(hass, [full_name]):
            notify_service = None
            try:
                if hasattr(platform, "async_get_service"):
                    notify_service = await platform.async_get_service(
                        hass, p_config, discovery_info
                    )
                elif hasattr(platform, "get_service"):
                    notify_service = await hass.async_add_executor_job(
                        platform.get_service, hass, p_config, discovery_info
                    )
                else:
                    raise HomeAssistantError("Invalid notify platform.")

                if notify_service is None:
                    # Platforms can decide not to create a service based
                    # on discovery data.
                    if discovery_info is None:
                        LOGGER.error(
                            "Failed to initialize notification service %s",
                            integration_name,
                        )
                    return

            except Exception:  # pylint: disable=broad-except
                LOGGER.exception("Error setting up platform %s", integration_name)
                return

            if discovery_info is None:
                discovery_info = {}

            conf_name = p_config.get(CONF_NAME) or discovery_info.get(CONF_NAME)
            target_service_name_prefix = conf_name or integration_name
            service_name = slugify(conf_name or SERVICE_NOTIFY)

            await notify_service.async_setup(
                hass, service_name, target_service_name_prefix
            )
            await notify_service.async_register_services()

            hass.data[NOTIFY_SERVICES].setdefault(integration_name, []).append(
                notify_service
            )
            hass.config.components.add(f"{DOMAIN}.{integration_name}")

    setup_tasks = [
        asyncio.create_task(async_setup_platform(integration_name, p_config))
        for integration_name, p_config in config_per_platform(config, DOMAIN)
        if integration_name is not None
    ]

    if setup_tasks:
        await asyncio.wait(setup_tasks)

    async def async_platform_discovered(
        platform: str, info: DiscoveryInfoType | None
    ) -> None:
        """Handle for discovered platform."""
        await async_setup_platform(platform, discovery_info=info)

    discovery.async_listen_platform(hass, DOMAIN, async_platform_discovered)


@callback
def check_templates_warn(hass: HomeAssistant, tpl: template.Template) -> None:
    """Warn user that passing templates to notify service is deprecated."""
    if tpl.is_static or hass.data.get("notify_template_warned"):
        return

    hass.data["notify_template_warned"] = True
    LOGGER.warning(
        "Passing templates to notify service is deprecated and will be removed in 2021.12. "
        "Automations and scripts handle templates automatically"
    )


@bind_hass
async def async_reload(hass: HomeAssistant, integration_name: str) -> None:
    """Register notify services for an integration."""
    if not _async_integration_has_notify_services(hass, integration_name):
        return

    tasks = [
        notify_service.async_register_services()
        for notify_service in hass.data[NOTIFY_SERVICES][integration_name]
    ]

    await asyncio.gather(*tasks)


@bind_hass
async def async_reset_platform(hass: HomeAssistant, integration_name: str) -> None:
    """Unregister notify services for an integration."""
    if not _async_integration_has_notify_services(hass, integration_name):
        return

    tasks = [
        notify_service.async_unregister_services()
        for notify_service in hass.data[NOTIFY_SERVICES][integration_name]
    ]

    await asyncio.gather(*tasks)

    del hass.data[NOTIFY_SERVICES][integration_name]


def _async_integration_has_notify_services(
    hass: HomeAssistant, integration_name: str
) -> bool:
    """Determine if an integration has notify services registered."""
    if (
        NOTIFY_SERVICES not in hass.data
        or integration_name not in hass.data[NOTIFY_SERVICES]
    ):
        return False

    return True


class BaseNotificationService:
    """An abstract class for notification services."""

    # While not purely typed, it makes typehinting more useful for us
    # and removes the need for constant None checks or asserts.
    hass: HomeAssistant = None  # type: ignore

    # Name => target
    registered_targets: dict[str, str]

    def send_message(self, message: str, **kwargs: Any) -> None:
        """Send a message.

        kwargs can contain ATTR_TITLE to specify a title.
        """
        raise NotImplementedError()

    async def async_send_message(self, message: str, **kwargs: Any) -> None:
        """Send a message.

        kwargs can contain ATTR_TITLE to specify a title.
        """
        await self.hass.async_add_executor_job(
            partial(self.send_message, message, **kwargs)
        )

    async def _async_notify_message_service(self, service: ServiceCall) -> None:
        """Handle sending notification message service calls."""
        kwargs = {}
        message = service.data[ATTR_MESSAGE]

        if title := service.data.get(ATTR_TITLE):
            check_templates_warn(self.hass, title)
            title.hass = self.hass
            kwargs[ATTR_TITLE] = title.async_render(parse_result=False)

        if self.registered_targets.get(service.service) is not None:
            kwargs[ATTR_TARGET] = [self.registered_targets[service.service]]
        elif service.data.get(ATTR_TARGET) is not None:
            kwargs[ATTR_TARGET] = service.data.get(ATTR_TARGET)

        check_templates_warn(self.hass, message)
        message.hass = self.hass
        kwargs[ATTR_MESSAGE] = message.async_render(parse_result=False)
        kwargs[ATTR_DATA] = service.data.get(ATTR_DATA)

        await self.async_send_message(**kwargs)

    async def async_setup(
        self,
        hass: HomeAssistant,
        service_name: str,
        target_service_name_prefix: str,
    ) -> None:
        """Store the data for the notify service."""
        # pylint: disable=attribute-defined-outside-init
        self.hass = hass
        self._service_name = service_name
        self._target_service_name_prefix = target_service_name_prefix
        self.registered_targets = {}

        # Load service descriptions from notify/services.yaml
        integration = await async_get_integration(hass, DOMAIN)
        services_yaml = integration.file_path / "services.yaml"
        self.services_dict = cast(
            dict, await hass.async_add_executor_job(load_yaml, str(services_yaml))
        )

    async def async_register_services(self) -> None:
        """Create or update the notify services."""
        if hasattr(self, "targets"):
            stale_targets = set(self.registered_targets)

            for name, target in self.targets.items():  # type: ignore
                target_name = slugify(f"{self._target_service_name_prefix}_{name}")
                if target_name in stale_targets:
                    stale_targets.remove(target_name)
                if (
                    target_name in self.registered_targets
                    and target == self.registered_targets[target_name]
                ):
                    continue
                self.registered_targets[target_name] = target
                self.hass.services.async_register(
                    DOMAIN,
                    target_name,
                    self._async_notify_message_service,
                    schema=NOTIFY_SERVICE_SCHEMA,
                )
                # Register the service description
                service_desc = {
                    CONF_NAME: f"Send a notification via {target_name}",
                    CONF_DESCRIPTION: f"Sends a notification message using the {target_name} integration.",
                    CONF_FIELDS: self.services_dict[SERVICE_NOTIFY][CONF_FIELDS],
                }
                async_set_service_schema(self.hass, DOMAIN, target_name, service_desc)

            for stale_target_name in stale_targets:
                del self.registered_targets[stale_target_name]
                self.hass.services.async_remove(
                    DOMAIN,
                    stale_target_name,
                )

        if self.hass.services.has_service(DOMAIN, self._service_name):
            return

        self.hass.services.async_register(
            DOMAIN,
            self._service_name,
            self._async_notify_message_service,
            schema=NOTIFY_SERVICE_SCHEMA,
        )

        # Register the service description
        service_desc = {
            CONF_NAME: f"Send a notification with {self._service_name}",
            CONF_DESCRIPTION: f"Sends a notification message using the {self._service_name} service.",
            CONF_FIELDS: self.services_dict[SERVICE_NOTIFY][CONF_FIELDS],
        }
        async_set_service_schema(self.hass, DOMAIN, self._service_name, service_desc)

    async def async_unregister_services(self) -> None:
        """Unregister the notify services."""
        if self.registered_targets:
            remove_targets = set(self.registered_targets)
            for remove_target_name in remove_targets:
                del self.registered_targets[remove_target_name]
                self.hass.services.async_remove(
                    DOMAIN,
                    remove_target_name,
                )

        if not self.hass.services.has_service(DOMAIN, self._service_name):
            return

        self.hass.services.async_remove(
            DOMAIN,
            self._service_name,
        )
