from __future__ import annotations

import logging
from dataclasses import dataclass
from typing import Any

from homeassistant.components.update import UpdateEntity, UpdateEntityFeature
from homeassistant.core import HomeAssistant, callback
from homeassistant.helpers.dispatcher import async_dispatcher_connect
from homeassistant.helpers.entity_platform import AddEntitiesCallback
from homeassistant.helpers.entity import EntityCategory

from .core import DOMAIN, SIGNAL_UPDATED, BCSCore

_LOGGER = logging.getLogger(__name__)


def _pretty_repo_name(core: BCSCore, repo_id: str) -> str:
    """Return a human-friendly name for a repo update entity."""
    try:
        repo = core.get_repo(repo_id)
        if repo and getattr(repo, "name", None):
            name = str(repo.name).strip()
            if name:
                return name
    except Exception:
        pass

    if repo_id.startswith("index:"):
        return f"BCS Index {repo_id.split(':', 1)[1]}"
    if repo_id.startswith("custom:"):
        return f"BCS Custom {repo_id.split(':', 1)[1]}"
    return f"BCS {repo_id}"


@dataclass(frozen=True)
class _RepoKey:
    repo_id: str


class BCSRepoUpdateEntity(UpdateEntity):
    """Update entity representing a BCS-managed repository."""

    _attr_entity_category = EntityCategory.DIAGNOSTIC
    _attr_supported_features = UpdateEntityFeature.INSTALL

    def __init__(self, core: BCSCore, repo_id: str) -> None:
        self._core = core
        self._repo_id = repo_id
        self._in_progress = False

        # Stable unique id (do NOT change)
        self._attr_unique_id = f"{DOMAIN}:{repo_id}"

        self._refresh_display_name()

    def _refresh_display_name(self) -> None:
        pretty = _pretty_repo_name(self._core, self._repo_id)
        self._attr_name = pretty
        self._attr_title = pretty

    @property
    def available(self) -> bool:
        repo = self._core.get_repo(self._repo_id)
        installed = self._core.get_installed(self._repo_id)
        return repo is not None and installed is not None

    @property
    def in_progress(self) -> bool | None:
        return self._in_progress

    @property
    def installed_version(self) -> str | None:
        installed = self._core.get_installed(self._repo_id) or {}
        v = installed.get("installed_version") or installed.get("ref")
        return str(v) if v else None

    @property
    def latest_version(self) -> str | None:
        repo = self._core.get_repo(self._repo_id)
        if not repo:
            return None
        v = getattr(repo, "latest_version", None)
        return str(v) if v else None

    @property
    def update_available(self) -> bool:
        latest = self.latest_version
        installed = self.installed_version
        if not latest or not installed:
            return False
        return latest != installed

    def version_is_newer(self, latest_version: str, installed_version: str) -> bool:
        return latest_version != installed_version

    @property
    def release_url(self) -> str | None:
        repo = self._core.get_repo(self._repo_id)
        return getattr(repo, "url", None) if repo else None

    async def async_install(self, version: str | None, backup: bool, **kwargs: Any) -> None:
        if version is not None:
            _LOGGER.debug("BCS update entity requested specific version=%s (ignored)", version)

        self._in_progress = True
        self.async_write_ha_state()

        try:
            await self._core.update_repo(self._repo_id)
        finally:
            self._in_progress = False
            self.async_write_ha_state()


@callback
def _sync_entities(core: BCSCore, existing: dict[str, BCSRepoUpdateEntity], async_add_entities: AddEntitiesCallback) -> None:
    """Ensure there is one update entity per installed repo AND keep names in sync."""
    installed_map = getattr(core, "_installed_cache", {}) or {}
    new_entities: list[BCSRepoUpdateEntity] = []

    for repo_id, data in installed_map.items():
        if not isinstance(data, dict):
            continue

        if repo_id in existing:
            # IMPORTANT: Update display name after refresh, when repo.name becomes available.
            existing[repo_id]._refresh_display_name()
            continue

        ent = BCSRepoUpdateEntity(core, repo_id)
        existing[repo_id] = ent
        new_entities.append(ent)

    if new_entities:
        async_add_entities(new_entities)

    for ent in existing.values():
        ent.async_write_ha_state()


async def async_setup_platform(
    hass: HomeAssistant,
    config,
    async_add_entities: AddEntitiesCallback,
    discovery_info=None,
):
    """Set up BCS update entities."""
    core: BCSCore | None = hass.data.get(DOMAIN)
    if not core:
        _LOGGER.debug("BCS core not available, skipping update platform setup")
        return

    entities: dict[str, BCSRepoUpdateEntity] = {}

    _sync_entities(core, entities, async_add_entities)

    @callback
    def _handle_update() -> None:
        _sync_entities(core, entities, async_add_entities)

    async_dispatcher_connect(hass, SIGNAL_UPDATED, _handle_update)