"""Support for bthome event entities."""

from __future__ import annotations

from dataclasses import replace

from homeassistant.components.event import (
    EventDeviceClass,
    EventEntity,
    EventEntityDescription,
)
from homeassistant.config_entries import ConfigEntry
from homeassistant.core import HomeAssistant, callback
from homeassistant.helpers import device_registry as dr, entity_registry as er
from homeassistant.helpers.dispatcher import async_dispatcher_connect
from homeassistant.helpers.entity_platform import AddEntitiesCallback

from . import format_discovered_event_class, format_event_dispatcher_name
from .const import (
    DOMAIN,
    EVENT_CLASS_BUTTON,
    EVENT_CLASS_DIMMER,
    EVENT_PROPERTIES,
    EVENT_TYPE,
    BTHomeBleEvent,
)
from .coordinator import BTHomePassiveBluetoothProcessorCoordinator

DESCRIPTIONS_BY_EVENT_CLASS = {
    EVENT_CLASS_BUTTON: EventEntityDescription(
        key=EVENT_CLASS_BUTTON,
        translation_key="button",
        event_types=[
            "press",
            "double_press",
            "triple_press",
            "long_press",
            "long_double_press",
            "long_triple_press",
        ],
        device_class=EventDeviceClass.BUTTON,
    ),
    EVENT_CLASS_DIMMER: EventEntityDescription(
        key=EVENT_CLASS_DIMMER,
        translation_key="dimmer",
        event_types=["rotate_left", "rotate_right"],
    ),
}


class BTHomeEventEntity(EventEntity):
    """Representation of a BTHome event entity."""

    _attr_should_poll = False
    _attr_has_entity_name = True

    def __init__(
        self,
        address: str,
        event_class: str,
        event: BTHomeBleEvent | None,
    ) -> None:
        """Initialise a BTHome event entity."""
        self._update_signal = format_event_dispatcher_name(address, event_class)
        # event_class is something like "button" or "dimmer"
        # and it maybe postfixed with "_1", "_2", "_3", etc
        # If there is only one button then it will be "button"
        base_event_class, _, postfix = event_class.partition("_")
        base_description = DESCRIPTIONS_BY_EVENT_CLASS[base_event_class]
        self.entity_description = replace(base_description, key=event_class)
        postfix_name = f" {postfix}" if postfix else ""
        self._attr_name = f"{base_event_class.title()}{postfix_name}"
        # Matches logic in PassiveBluetoothProcessorEntity
        self._attr_device_info = dr.DeviceInfo(
            identifiers={(DOMAIN, address)},
            connections={(dr.CONNECTION_BLUETOOTH, address)},
        )
        self._attr_unique_id = f"{address}-{event_class}"
        # If the event is provided then we can set the initial state
        # since the event itself is likely what triggered the creation
        # of this entity. We have to do this at creation time since
        # entities are created dynamically and would otherwise miss
        # the initial state.
        if event:
            self._trigger_event(event[EVENT_TYPE], event[EVENT_PROPERTIES])

    async def async_added_to_hass(self) -> None:
        """Entity added to hass."""
        await super().async_added_to_hass()
        self.async_on_remove(
            async_dispatcher_connect(
                self.hass,
                self._update_signal,
                self._async_handle_event,
            )
        )

    @callback
    def _async_handle_event(self, event: BTHomeBleEvent) -> None:
        self._trigger_event(event[EVENT_TYPE], event[EVENT_PROPERTIES])
        self.async_write_ha_state()


async def async_setup_entry(
    hass: HomeAssistant,
    entry: ConfigEntry,
    async_add_entities: AddEntitiesCallback,
) -> None:
    """Set up BTHome event."""
    coordinator: BTHomePassiveBluetoothProcessorCoordinator = hass.data[DOMAIN][
        entry.entry_id
    ]
    address = coordinator.address
    ent_reg = er.async_get(hass)
    async_add_entities(
        # Matches logic in PassiveBluetoothProcessorEntity
        BTHomeEventEntity(address_event_class[0], address_event_class[2], None)
        for ent_reg_entry in er.async_entries_for_config_entry(ent_reg, entry.entry_id)
        if ent_reg_entry.domain == "event"
        and (address_event_class := ent_reg_entry.unique_id.partition("-"))
    )

    @callback
    def _async_discovered_event_class(event_class: str, event: BTHomeBleEvent) -> None:
        """Handle a newly discovered event class with or without a postfix."""
        async_add_entities([BTHomeEventEntity(address, event_class, event)])

    entry.async_on_unload(
        async_dispatcher_connect(
            hass,
            format_discovered_event_class(address),
            _async_discovered_event_class,
        )
    )