"""UniFi Network entity loader.

Central point to load entities for the different platforms.
Make sure expected clients are available for platforms.
"""
from __future__ import annotations

import asyncio
from collections.abc import Iterable
from datetime import timedelta
from functools import partial
from typing import TYPE_CHECKING

from aiounifi.interfaces.api_handlers import ItemEvent

from homeassistant.const import Platform
from homeassistant.core import callback
from homeassistant.helpers import entity_registry as er
from homeassistant.helpers.dispatcher import async_dispatcher_connect
from homeassistant.helpers.entity_platform import AddEntitiesCallback
from homeassistant.helpers.entity_registry import async_entries_for_config_entry

from ..const import LOGGER, UNIFI_WIRELESS_CLIENTS
from ..entity import UnifiEntity, UnifiEntityDescription

if TYPE_CHECKING:
    from .hub import UnifiHub

CHECK_HEARTBEAT_INTERVAL = timedelta(seconds=1)


class UnifiEntityLoader:
    """UniFi Network integration handling platforms for entity registration."""

    def __init__(self, hub: UnifiHub) -> None:
        """Initialize the UniFi entity loader."""
        self.hub = hub
        self.api_updaters = (
            hub.api.clients.update,
            hub.api.clients_all.update,
            hub.api.devices.update,
            hub.api.dpi_apps.update,
            hub.api.dpi_groups.update,
            hub.api.port_forwarding.update,
            hub.api.sites.update,
            hub.api.system_information.update,
            hub.api.wlans.update,
        )
        self.wireless_clients = hub.hass.data[UNIFI_WIRELESS_CLIENTS]

        self.platforms: list[
            tuple[
                AddEntitiesCallback,
                type[UnifiEntity],
                tuple[UnifiEntityDescription, ...],
                bool,
            ]
        ] = []

        self.known_objects: set[tuple[str, str]] = set()
        """Tuples of entity description key and object ID of loaded entities."""

    async def initialize(self) -> None:
        """Initialize API data and extra client support."""
        await self.refresh_api_data()
        self.restore_inactive_clients()
        self.wireless_clients.update_clients(set(self.hub.api.clients.values()))

    async def refresh_api_data(self) -> None:
        """Refresh API data from network application."""
        results = await asyncio.gather(
            *[update() for update in self.api_updaters],
            return_exceptions=True,
        )
        for result in results:
            if result is not None:
                LOGGER.warning("Exception on update %s", result)

    @callback
    def restore_inactive_clients(self) -> None:
        """Restore inactive clients.

        Provide inactive clients to device tracker and switch platform.
        """
        config = self.hub.config
        macs: list[str] = []
        entity_registry = er.async_get(self.hub.hass)
        for entry in async_entries_for_config_entry(
            entity_registry, config.entry.entry_id
        ):
            if entry.domain == Platform.DEVICE_TRACKER and "-" in entry.unique_id:
                macs.append(entry.unique_id.split("-", 1)[1])

        api = self.hub.api
        for mac in config.option_supported_clients + config.option_block_clients + macs:
            if mac not in api.clients and mac in api.clients_all:
                api.clients.process_raw([dict(api.clients_all[mac].raw)])

    @callback
    def register_platform(
        self,
        async_add_entities: AddEntitiesCallback,
        entity_class: type[UnifiEntity],
        descriptions: tuple[UnifiEntityDescription, ...],
        requires_admin: bool = False,
    ) -> None:
        """Register UniFi entity platforms."""
        self.platforms.append(
            (async_add_entities, entity_class, descriptions, requires_admin)
        )

    @callback
    def load_entities(self) -> None:
        """Populate UniFi platforms with entities."""
        for (
            async_add_entities,
            entity_class,
            descriptions,
            requires_admin,
        ) in self.platforms:
            if requires_admin and not self.hub.is_admin:
                continue
            self._load_entities(entity_class, descriptions, async_add_entities)

    @callback
    def _should_add_entity(
        self, description: UnifiEntityDescription, obj_id: str
    ) -> bool:
        """Check if entity should be added."""
        return bool(
            (description.key, obj_id) not in self.known_objects
            and description.allowed_fn(self.hub, obj_id)
            and description.supported_fn(self.hub, obj_id)
        )

    @callback
    def _load_entities(
        self,
        unifi_platform_entity: type[UnifiEntity],
        descriptions: tuple[UnifiEntityDescription, ...],
        async_add_entities: AddEntitiesCallback,
    ) -> None:
        """Subscribe to UniFi API handlers and create entities."""

        @callback
        def async_load_entities(descriptions: Iterable[UnifiEntityDescription]) -> None:
            """Load and subscribe to UniFi endpoints."""

            @callback
            def _add_unifi_entities() -> None:
                """Add UniFi entity."""
                async_add_entities(
                    unifi_platform_entity(obj_id, self.hub, description)
                    for description in descriptions
                    for obj_id in description.api_handler_fn(self.hub.api)
                    if self._should_add_entity(description, obj_id)
                )

            _add_unifi_entities()

            @callback
            def _create_unifi_entity(
                description: UnifiEntityDescription, event: ItemEvent, obj_id: str
            ) -> None:
                """Create new UniFi entity on event."""
                if self._should_add_entity(description, obj_id):
                    async_add_entities(
                        [unifi_platform_entity(obj_id, self.hub, description)]
                    )

            for description in descriptions:
                description.api_handler_fn(self.hub.api).subscribe(
                    partial(_create_unifi_entity, description), ItemEvent.ADDED
                )

            self.hub.config.entry.async_on_unload(
                async_dispatcher_connect(
                    self.hub.hass,
                    self.hub.signal_options_update,
                    _add_unifi_entities,
                )
            )

        async_load_entities(descriptions)