"""Home Assistant discovery and legacy slot-publication helpers."""

from __future__ import annotations

import json
from dataclasses import dataclass
from typing import Any, Callable, Iterable

from .config import HomeAssistantConfig
from .contracts import LEGACY_STATE_QOS, LEGACY_STATE_RETAIN, SLOT_IDS, Topics


Publish = Callable[..., Any]


HA_DEVICE = {
    "identifiers": ["ytplayer-controller"],
    "name": "YouTube Controller",
    "manufacturer": "River of Glory",
    "model": "YT Controller",
}


@dataclass(frozen=True)
class SlotAnnouncement:
    slot: int
    title: str
    state: str
    count: int
    items: tuple[str, ...] = ()


def discovery_messages(
    topics: Topics,
    config: HomeAssistantConfig,
) -> Iterable[tuple[str, str, int, bool]]:
    """Yield the existing thirty discovery documents unchanged."""

    for slot in SLOT_IDS:
        base = topics.slot_base(slot)
        object_id = f"yt_slot_{slot}"
        entities = (
            (
                "title",
                {
                    "name": f"YT Slot {slot} Title",
                    "state_topic": f"{base}/title",
                    "unique_id": f"{object_id}_title",
                    "icon": "mdi:playlist-music",
                    "device": HA_DEVICE,
                },
            ),
            (
                "state",
                {
                    "name": f"YT Slot {slot} State",
                    "state_topic": f"{base}/state",
                    "unique_id": f"{object_id}_state",
                    "icon": "mdi:circle-small",
                    "device": HA_DEVICE,
                },
            ),
            (
                "count",
                {
                    "name": f"YT Slot {slot} Count",
                    "state_topic": f"{base}/count",
                    "unique_id": f"{object_id}_count",
                    "icon": "mdi:numeric",
                    "device": HA_DEVICE,
                },
            ),
        )
        for suffix, payload in entities:
            yield (
                f"{config.discovery_prefix}/sensor/{object_id}_{suffix}/config",
                json.dumps(payload),
                LEGACY_STATE_QOS,
                LEGACY_STATE_RETAIN,
            )


def slot_messages(
    announcement: SlotAnnouncement,
    topics: Topics,
    *,
    clear_items_through: int = 0,
) -> Iterable[tuple[str, str, int, bool]]:
    """Yield retained legacy slot topics, including stale item cleanup."""

    base = topics.slot_base(announcement.slot)
    yield f"{base}/title", announcement.title, LEGACY_STATE_QOS, LEGACY_STATE_RETAIN
    yield f"{base}/state", announcement.state, LEGACY_STATE_QOS, LEGACY_STATE_RETAIN
    yield f"{base}/count", str(announcement.count), LEGACY_STATE_QOS, LEGACY_STATE_RETAIN
    for index, title in enumerate(announcement.items, start=1):
        yield f"{base}/items/{index}", title, LEGACY_STATE_QOS, LEGACY_STATE_RETAIN
    for index in range(len(announcement.items) + 1, clear_items_through + 1):
        yield f"{base}/items/{index}", "", LEGACY_STATE_QOS, LEGACY_STATE_RETAIN