"""Home Assistant MQTT Discovery payloads.

Создаём per-instance entities:
  select.cuda_grid_<instance>_layout    — выбор активного layout
  sensor.cuda_grid_<instance>_state     — текущий layout (для UI)
  binary_sensor.cuda_grid_controller_online — availability

См. https://www.home-assistant.io/integrations/mqtt/#mqtt-discovery
"""

from __future__ import annotations

import json
from typing import Any

from .config import HaDiscoveryCfg, InstanceCfg
from .layouts import PREDEFINED_LAYOUTS


def _device_dict(ha: HaDiscoveryCfg) -> dict[str, Any]:
    return {
        "identifiers": [ha.device_identifier],
        "name": ha.device_name,
        "manufacturer": "gx/vf-cuda-grid",
        "model": "cuda-grid-controller",
        "sw_version": "0.1.0",
    }


def availability_topic(prefix_base: str = "cuda_grid") -> str:
    """Где controller публикует online/offline (LWT)."""
    return f"{prefix_base}/state/online"


def discovery_payloads(ha: HaDiscoveryCfg, instances: list[InstanceCfg]) -> list[tuple[str, str]]:
    """Список (discovery_topic, payload_json) для publish при startup."""
    out: list[tuple[str, str]] = []
    avail = availability_topic()

    # Per-instance entities
    for inst in instances:
        # select.layout
        select_topic = f"{ha.prefix}/select/cuda_grid_{inst.name}/layout/config"
        select_payload = {
            "name": f"Layout ({inst.name})",
            "unique_id": f"cuda_grid_{inst.name}_layout_select",
            "command_topic": f"cuda_grid/cmd/{inst.name}/layout/set",
            "state_topic": f"cuda_grid/state/{inst.name}/layout",
            "options": PREDEFINED_LAYOUTS,
            "availability_topic": avail,
            "payload_available": "online",
            "payload_not_available": "offline",
            "device": _device_dict(ha),
        }
        out.append((select_topic, json.dumps(select_payload)))

        # sensor.current_layout (text — duplicate state, удобно для automations)
        sensor_topic = f"{ha.prefix}/sensor/cuda_grid_{inst.name}/current_layout/config"
        sensor_payload = {
            "name": f"Current layout ({inst.name})",
            "unique_id": f"cuda_grid_{inst.name}_layout_sensor",
            "state_topic": f"cuda_grid/state/{inst.name}/layout",
            "availability_topic": avail,
            "payload_available": "online",
            "payload_not_available": "offline",
            "device": _device_dict(ha),
            "icon": "mdi:view-grid",
        }
        out.append((sensor_topic, json.dumps(sensor_payload)))

    # Глобальный availability binary_sensor
    online_topic = f"{ha.prefix}/binary_sensor/cuda_grid_controller/online/config"
    online_payload = {
        "name": "CUDA Grid Controller online",
        "unique_id": "cuda_grid_controller_online",
        "state_topic": avail,
        "payload_on": "online",
        "payload_off": "offline",
        "device_class": "connectivity",
        "device": _device_dict(ha),
    }
    out.append((online_topic, json.dumps(online_payload)))

    return out