"""Immich Album Watcher integration for Home Assistant."""

from __future__ import annotations

import logging
from dataclasses import dataclass
from datetime import datetime, time as dt_time

from homeassistant.config_entries import ConfigEntry, ConfigSubentry
from homeassistant.core import HomeAssistant
from homeassistant.helpers.event import async_track_time_change
from homeassistant.util import dt as dt_util

from .const import (
    CONF_ALBUM_ID,
    CONF_ALBUM_NAME,
    CONF_API_KEY,
    CONF_HUB_NAME,
    CONF_IMMICH_URL,
    CONF_SCAN_INTERVAL,
    CONF_TELEGRAM_CACHE_TTL,
    DEFAULT_SCAN_INTERVAL,
    DEFAULT_TELEGRAM_CACHE_TTL,
    DOMAIN,
    PLATFORMS,
)
from .coordinator import ImmichAlbumWatcherCoordinator
from .storage import (
    ImmichAlbumStorage,
    NotificationQueue,
    TelegramFileCache,
    create_notification_queue,
    create_telegram_cache,
)

_LOGGER = logging.getLogger(__name__)


@dataclass
class ImmichHubData:
    """Data for the Immich hub."""

    name: str
    url: str
    api_key: str
    scan_interval: int
    telegram_cache_ttl: int


@dataclass
class ImmichAlbumRuntimeData:
    """Runtime data for an album subentry."""

    coordinator: ImmichAlbumWatcherCoordinator
    album_id: str
    album_name: str


type ImmichConfigEntry = ConfigEntry[ImmichHubData]


async def async_setup_entry(hass: HomeAssistant, entry: ImmichConfigEntry) -> bool:
    """Set up Immich Album Watcher hub from a config entry."""
    hass.data.setdefault(DOMAIN, {})

    hub_name = entry.data.get(CONF_HUB_NAME, "Immich")
    url = entry.data[CONF_IMMICH_URL]
    api_key = entry.data[CONF_API_KEY]
    scan_interval = entry.options.get(CONF_SCAN_INTERVAL, DEFAULT_SCAN_INTERVAL)
    telegram_cache_ttl = entry.options.get(CONF_TELEGRAM_CACHE_TTL, DEFAULT_TELEGRAM_CACHE_TTL)

    # Store hub data
    entry.runtime_data = ImmichHubData(
        name=hub_name,
        url=url,
        api_key=api_key,
        scan_interval=scan_interval,
        telegram_cache_ttl=telegram_cache_ttl,
    )

    # Create storage for persisting album state across restarts
    storage = ImmichAlbumStorage(hass, entry.entry_id)
    await storage.async_load()

    # Create and load Telegram file caches once per hub (shared across all albums)
    # TTL is in hours from config, convert to seconds
    cache_ttl_seconds = telegram_cache_ttl * 60 * 60
    # URL-based cache for non-Immich URLs or URLs without extractable asset IDs
    telegram_cache = create_telegram_cache(hass, entry.entry_id, ttl_seconds=cache_ttl_seconds)
    await telegram_cache.async_load()
    # Asset ID-based cache for Immich URLs — uses thumbhash validation instead of TTL
    telegram_asset_cache = create_telegram_cache(
        hass, f"{entry.entry_id}_assets", use_thumbhash=True
    )
    await telegram_asset_cache.async_load()

    # Create notification queue for quiet hours
    notification_queue = create_notification_queue(hass, entry.entry_id)
    await notification_queue.async_load()

    # Store hub reference
    hass.data[DOMAIN][entry.entry_id] = {
        "hub": entry.runtime_data,
        "subentries": {},
        "storage": storage,
        "telegram_cache": telegram_cache,
        "telegram_asset_cache": telegram_asset_cache,
        "notification_queue": notification_queue,
        "quiet_hours_unsubs": {},  # keyed by "HH:MM" end time
    }

    # Track loaded subentries to detect changes
    hass.data[DOMAIN][entry.entry_id]["loaded_subentries"] = set(entry.subentries.keys())

    # Set up coordinators for all subentries (albums)
    for subentry_id, subentry in entry.subentries.items():
        await _async_setup_subentry_coordinator(hass, entry, subentry)

    # Forward platform setup once - platforms will iterate through subentries
    await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)

    # Check if there are queued notifications from before restart
    if notification_queue.has_pending():
        _register_queue_timers(hass, entry)
        # Process any items whose quiet hours have already ended
        hass.async_create_task(_process_ready_notifications(hass, entry))

    # Register update listener for options and subentry changes
    entry.async_on_unload(entry.add_update_listener(_async_update_listener))

    _LOGGER.info(
        "Immich Album Watcher hub set up successfully with %d albums",
        len(entry.subentries),
    )

    return True


async def _async_setup_subentry_coordinator(
    hass: HomeAssistant, entry: ImmichConfigEntry, subentry: ConfigSubentry
) -> None:
    """Set up coordinator for an album subentry."""
    hub_data: ImmichHubData = entry.runtime_data
    album_id = subentry.data[CONF_ALBUM_ID]
    album_name = subentry.data.get(CONF_ALBUM_NAME, "Unknown Album")
    storage: ImmichAlbumStorage = hass.data[DOMAIN][entry.entry_id]["storage"]
    telegram_cache: TelegramFileCache = hass.data[DOMAIN][entry.entry_id]["telegram_cache"]
    telegram_asset_cache: TelegramFileCache = hass.data[DOMAIN][entry.entry_id]["telegram_asset_cache"]

    _LOGGER.debug("Setting up coordinator for album: %s (%s)", album_name, album_id)

    # Create coordinator for this album
    coordinator = ImmichAlbumWatcherCoordinator(
        hass,
        url=hub_data.url,
        api_key=hub_data.api_key,
        album_id=album_id,
        album_name=album_name,
        scan_interval=hub_data.scan_interval,
        hub_name=hub_data.name,
        storage=storage,
        telegram_cache=telegram_cache,
        telegram_asset_cache=telegram_asset_cache,
    )

    # Load persisted state before first refresh to detect changes during downtime
    await coordinator.async_load_persisted_state()

    # Fetch initial data
    await coordinator.async_config_entry_first_refresh()

    # Store subentry runtime data
    subentry_data = ImmichAlbumRuntimeData(
        coordinator=coordinator,
        album_id=album_id,
        album_name=album_name,
    )
    hass.data[DOMAIN][entry.entry_id]["subentries"][subentry.subentry_id] = subentry_data

    _LOGGER.info("Coordinator for album '%s' set up successfully", album_name)


def _is_quiet_hours(start_str: str, end_str: str) -> bool:
    """Check if current time is within quiet hours."""
    if not start_str or not end_str:
        return False

    try:
        now = dt_util.now().time()
        start_time = dt_time.fromisoformat(start_str)
        end_time = dt_time.fromisoformat(end_str)
    except ValueError:
        return False

    if start_time <= end_time:
        return start_time <= now < end_time
    else:
        # Crosses midnight (e.g., 22:00 - 08:00)
        return now >= start_time or now < end_time


def _register_queue_timers(hass: HomeAssistant, entry: ImmichConfigEntry) -> None:
    """Register timers for each unique quiet_hours_end in the queue."""
    entry_data = hass.data[DOMAIN][entry.entry_id]
    queue: NotificationQueue = entry_data["notification_queue"]
    unsubs: dict[str, list] = entry_data["quiet_hours_unsubs"]

    # Collect unique end times from queued items
    end_times: set[str] = set()
    for item in queue.get_all():
        end_str = item.get("params", {}).get("quiet_hours_end", "")
        if end_str:
            end_times.add(end_str)

    for end_str in end_times:
        if end_str in unsubs:
            continue  # Timer already registered for this end time

        try:
            end_time = dt_time.fromisoformat(end_str)
        except ValueError:
            _LOGGER.warning("Invalid quiet hours end time in queue: %s", end_str)
            continue

        async def _on_quiet_hours_end(_now: datetime, _end_str: str = end_str) -> None:
            """Handle quiet hours end — process matching queued notifications."""
            _LOGGER.info("Quiet hours ended (%s), processing queued notifications", _end_str)
            await _process_notifications_for_end_time(hass, entry, _end_str)

        unsub = async_track_time_change(
            hass, _on_quiet_hours_end, hour=end_time.hour, minute=end_time.minute, second=0
        )
        unsubs[end_str] = unsub
        entry.async_on_unload(unsub)

        _LOGGER.debug("Registered quiet hours timer for %s", end_str)


def _unregister_queue_timer(hass: HomeAssistant, entry: ImmichConfigEntry, end_str: str) -> None:
    """Unregister a quiet hours timer if no more items need it."""
    entry_data = hass.data[DOMAIN][entry.entry_id]
    queue: NotificationQueue = entry_data["notification_queue"]
    unsubs: dict[str, list] = entry_data["quiet_hours_unsubs"]

    # Check if any remaining items still use this end time
    for item in queue.get_all():
        if item.get("params", {}).get("quiet_hours_end", "") == end_str:
            return  # Still needed

    unsub = unsubs.pop(end_str, None)
    if unsub:
        unsub()
        _LOGGER.debug("Unregistered quiet hours timer for %s (no more items)", end_str)


async def _process_ready_notifications(
    hass: HomeAssistant, entry: ImmichConfigEntry
) -> None:
    """Process queued notifications whose quiet hours have already ended."""
    entry_data = hass.data[DOMAIN].get(entry.entry_id)
    if not entry_data:
        return

    queue: NotificationQueue = entry_data["notification_queue"]
    items = queue.get_all()
    if not items:
        return

    # Find items whose quiet hours have ended
    ready_indices = []
    for i, item in enumerate(items):
        params = item.get("params", {})
        start_str = params.get("quiet_hours_start", "")
        end_str = params.get("quiet_hours_end", "")
        if not _is_quiet_hours(start_str, end_str):
            ready_indices.append(i)

    if not ready_indices:
        return

    _LOGGER.info("Found %d queued notifications ready to send (quiet hours ended)", len(ready_indices))
    await _send_queued_items(hass, entry, ready_indices)


async def _process_notifications_for_end_time(
    hass: HomeAssistant, entry: ImmichConfigEntry, end_str: str
) -> None:
    """Process queued notifications matching a specific quiet_hours_end time."""
    entry_data = hass.data[DOMAIN].get(entry.entry_id)
    if not entry_data:
        return

    queue: NotificationQueue = entry_data["notification_queue"]
    items = queue.get_all()
    if not items:
        return

    # Find items matching this end time that are no longer in quiet hours
    matching_indices = []
    for i, item in enumerate(items):
        params = item.get("params", {})
        if params.get("quiet_hours_end", "") == end_str:
            start_str = params.get("quiet_hours_start", "")
            if not _is_quiet_hours(start_str, end_str):
                matching_indices.append(i)

    if not matching_indices:
        return

    _LOGGER.info("Processing %d queued notifications for quiet hours end %s", len(matching_indices), end_str)
    await _send_queued_items(hass, entry, matching_indices)

    # Clean up timer if no more items need it
    _unregister_queue_timer(hass, entry, end_str)


async def _send_queued_items(
    hass: HomeAssistant, entry: ImmichConfigEntry, indices: list[int]
) -> None:
    """Send specific queued notifications by index and remove them from the queue."""
    import asyncio
    from homeassistant.helpers import entity_registry as er

    entry_data = hass.data[DOMAIN].get(entry.entry_id)
    if not entry_data:
        return

    queue: NotificationQueue = entry_data["notification_queue"]

    # Find a fallback sensor entity
    ent_reg = er.async_get(hass)
    fallback_entity_id = None
    for ent in er.async_entries_for_config_entry(ent_reg, entry.entry_id):
        if ent.domain == "sensor":
            fallback_entity_id = ent.entity_id
            break

    if not fallback_entity_id:
        _LOGGER.warning("No sensor entity found to process notification queue")
        return

    items = queue.get_all()
    sent_count = 0
    for i in indices:
        if i >= len(items):
            continue
        params = dict(items[i].get("params", {}))
        try:
            target_entity_id = params.pop("entity_id", None) or fallback_entity_id
            # Remove quiet hours params so the replay doesn't re-queue
            params.pop("quiet_hours_start", None)
            params.pop("quiet_hours_end", None)
            await hass.services.async_call(
                DOMAIN,
                "send_telegram_notification",
                params,
                target={"entity_id": target_entity_id},
                blocking=True,
            )
            sent_count += 1
        except Exception:
            _LOGGER.exception("Failed to send queued notification %d", i + 1)

        # Small delay between notifications to avoid rate limiting
        await asyncio.sleep(1)

    # Remove sent items from queue (in reverse order to preserve indices)
    await queue.async_remove_indices(sorted(indices, reverse=True))
    _LOGGER.info("Sent %d/%d queued notifications", sent_count, len(indices))


async def _async_update_listener(
    hass: HomeAssistant, entry: ImmichConfigEntry
) -> None:
    """Handle config entry updates (options or subentry changes)."""
    entry_data = hass.data[DOMAIN][entry.entry_id]
    loaded_subentries = entry_data.get("loaded_subentries", set())
    current_subentries = set(entry.subentries.keys())

    # Check if subentries changed
    if loaded_subentries != current_subentries:
        _LOGGER.info(
            "Subentries changed (loaded: %d, current: %d), reloading entry",
            len(loaded_subentries),
            len(current_subentries),
        )
        await hass.config_entries.async_reload(entry.entry_id)
        return

    # Handle options-only update
    new_interval = entry.options.get(CONF_SCAN_INTERVAL, DEFAULT_SCAN_INTERVAL)

    # Update hub data
    entry.runtime_data.scan_interval = new_interval

    # Update all subentry coordinators
    subentries_data = entry_data["subentries"]
    for subentry_data in subentries_data.values():
        subentry_data.coordinator.update_scan_interval(new_interval)

    _LOGGER.info("Updated hub options (scan_interval=%d)", new_interval)


async def async_unload_entry(hass: HomeAssistant, entry: ImmichConfigEntry) -> bool:
    """Unload a config entry."""
    # Cancel all quiet hours timers
    entry_data = hass.data[DOMAIN].get(entry.entry_id, {})
    for unsub in entry_data.get("quiet_hours_unsubs", {}).values():
        unsub()

    # Unload all platforms
    unload_ok = await hass.config_entries.async_unload_platforms(entry, PLATFORMS)

    if unload_ok:
        # Clean up hub data
        hass.data[DOMAIN].pop(entry.entry_id, None)
        _LOGGER.info("Immich Album Watcher hub unloaded")

    return unload_ok