"""Module to coordinate llm tools."""

from __future__ import annotations

from abc import ABC, abstractmethod
from dataclasses import dataclass
from decimal import Decimal
from enum import Enum
from functools import cache, partial
from typing import Any

import slugify as unicode_slug
import voluptuous as vol

from homeassistant.components.climate.intent import INTENT_GET_TEMPERATURE
from homeassistant.components.conversation.trace import (
    ConversationTraceEventType,
    async_conversation_trace_append,
)
from homeassistant.components.cover.intent import INTENT_CLOSE_COVER, INTENT_OPEN_COVER
from homeassistant.components.homeassistant.exposed_entities import async_should_expose
from homeassistant.components.intent import async_device_supports_timers
from homeassistant.components.weather.intent import INTENT_GET_WEATHER
from homeassistant.core import Context, HomeAssistant, callback
from homeassistant.exceptions import HomeAssistantError
from homeassistant.util import yaml
from homeassistant.util.json import JsonObjectType

from . import (
    area_registry as ar,
    device_registry as dr,
    entity_registry as er,
    floor_registry as fr,
    intent,
    service,
)
from .singleton import singleton

LLM_API_ASSIST = "assist"

BASE_PROMPT = (
    'Current time is {{ now().strftime("%H:%M:%S") }}. '
    'Today\'s date is {{ now().strftime("%Y-%m-%d") }}.\n'
)

DEFAULT_INSTRUCTIONS_PROMPT = """You are a voice assistant for Home Assistant.
Answer questions about the world truthfully.
Answer in plain text. Keep it simple and to the point.
"""


@callback
def async_render_no_api_prompt(hass: HomeAssistant) -> str:
    """Return the prompt to be used when no API is configured.

    No longer used since Home Assistant 2024.7.
    """
    return ""


@singleton("llm")
@callback
def _async_get_apis(hass: HomeAssistant) -> dict[str, API]:
    """Get all the LLM APIs."""
    return {
        LLM_API_ASSIST: AssistAPI(hass=hass),
    }


@callback
def async_register_api(hass: HomeAssistant, api: API) -> None:
    """Register an API to be exposed to LLMs."""
    apis = _async_get_apis(hass)

    if api.id in apis:
        raise HomeAssistantError(f"API {api.id} is already registered")

    apis[api.id] = api


async def async_get_api(
    hass: HomeAssistant, api_id: str, llm_context: LLMContext
) -> APIInstance:
    """Get an API."""
    apis = _async_get_apis(hass)

    if api_id not in apis:
        raise HomeAssistantError(f"API {api_id} not found")

    return await apis[api_id].async_get_api_instance(llm_context)


@callback
def async_get_apis(hass: HomeAssistant) -> list[API]:
    """Get all the LLM APIs."""
    return list(_async_get_apis(hass).values())


@dataclass(slots=True)
class LLMContext:
    """Tool input to be processed."""

    platform: str
    context: Context | None
    user_prompt: str | None
    language: str | None
    assistant: str | None
    device_id: str | None


@dataclass(slots=True)
class ToolInput:
    """Tool input to be processed."""

    tool_name: str
    tool_args: dict[str, Any]


class Tool:
    """LLM Tool base class."""

    name: str
    description: str | None = None
    parameters: vol.Schema = vol.Schema({})

    @abstractmethod
    async def async_call(
        self, hass: HomeAssistant, tool_input: ToolInput, llm_context: LLMContext
    ) -> JsonObjectType:
        """Call the tool."""
        raise NotImplementedError

    def __repr__(self) -> str:
        """Represent a string of a Tool."""
        return f"<{self.__class__.__name__} - {self.name}>"


@dataclass
class APIInstance:
    """Instance of an API to be used by an LLM."""

    api: API
    api_prompt: str
    llm_context: LLMContext
    tools: list[Tool]

    async def async_call_tool(self, tool_input: ToolInput) -> JsonObjectType:
        """Call a LLM tool, validate args and return the response."""
        async_conversation_trace_append(
            ConversationTraceEventType.LLM_TOOL_CALL,
            {"tool_name": tool_input.tool_name, "tool_args": tool_input.tool_args},
        )

        for tool in self.tools:
            if tool.name == tool_input.tool_name:
                break
        else:
            raise HomeAssistantError(f'Tool "{tool_input.tool_name}" not found')

        return await tool.async_call(self.api.hass, tool_input, self.llm_context)


@dataclass(slots=True, kw_only=True)
class API(ABC):
    """An API to expose to LLMs."""

    hass: HomeAssistant
    id: str
    name: str

    @abstractmethod
    async def async_get_api_instance(self, llm_context: LLMContext) -> APIInstance:
        """Return the instance of the API."""
        raise NotImplementedError


class IntentTool(Tool):
    """LLM Tool representing an Intent."""

    def __init__(
        self,
        name: str,
        intent_handler: intent.IntentHandler,
    ) -> None:
        """Init the class."""
        self.name = name
        self.description = (
            intent_handler.description or f"Execute Home Assistant {self.name} intent"
        )
        self.extra_slots = None
        if not (slot_schema := intent_handler.slot_schema):
            return

        slot_schema = {**slot_schema}
        extra_slots = set()

        for field in ("preferred_area_id", "preferred_floor_id"):
            if field in slot_schema:
                extra_slots.add(field)
                del slot_schema[field]

        self.parameters = vol.Schema(slot_schema)
        if extra_slots:
            self.extra_slots = extra_slots

    async def async_call(
        self, hass: HomeAssistant, tool_input: ToolInput, llm_context: LLMContext
    ) -> JsonObjectType:
        """Handle the intent."""
        slots = {key: {"value": val} for key, val in tool_input.tool_args.items()}

        if self.extra_slots and llm_context.device_id:
            device_reg = dr.async_get(hass)
            device = device_reg.async_get(llm_context.device_id)

            area: ar.AreaEntry | None = None
            floor: fr.FloorEntry | None = None
            if device:
                area_reg = ar.async_get(hass)
                if device.area_id and (area := area_reg.async_get_area(device.area_id)):
                    if area.floor_id:
                        floor_reg = fr.async_get(hass)
                        floor = floor_reg.async_get_floor(area.floor_id)

            for slot_name, slot_value in (
                ("preferred_area_id", area.id if area else None),
                ("preferred_floor_id", floor.floor_id if floor else None),
            ):
                if slot_value and slot_name in self.extra_slots:
                    slots[slot_name] = {"value": slot_value}

        intent_response = await intent.async_handle(
            hass=hass,
            platform=llm_context.platform,
            intent_type=self.name,
            slots=slots,
            text_input=llm_context.user_prompt,
            context=llm_context.context,
            language=llm_context.language,
            assistant=llm_context.assistant,
            device_id=llm_context.device_id,
        )
        response = intent_response.as_dict()
        del response["language"]
        del response["card"]
        return response


class AssistAPI(API):
    """API exposing Assist API to LLMs."""

    IGNORE_INTENTS = {
        INTENT_GET_TEMPERATURE,
        INTENT_GET_WEATHER,
        INTENT_OPEN_COVER,  # deprecated
        INTENT_CLOSE_COVER,  # deprecated
        intent.INTENT_GET_STATE,
        intent.INTENT_NEVERMIND,
        intent.INTENT_TOGGLE,
    }

    def __init__(self, hass: HomeAssistant) -> None:
        """Init the class."""
        super().__init__(
            hass=hass,
            id=LLM_API_ASSIST,
            name="Assist",
        )
        self.cached_slugify = cache(
            partial(unicode_slug.slugify, separator="_", lowercase=False)
        )

    async def async_get_api_instance(self, llm_context: LLMContext) -> APIInstance:
        """Return the instance of the API."""
        if llm_context.assistant:
            exposed_entities: dict | None = _get_exposed_entities(
                self.hass, llm_context.assistant
            )
        else:
            exposed_entities = None

        return APIInstance(
            api=self,
            api_prompt=self._async_get_api_prompt(llm_context, exposed_entities),
            llm_context=llm_context,
            tools=self._async_get_tools(llm_context, exposed_entities),
        )

    @callback
    def _async_get_api_prompt(
        self, llm_context: LLMContext, exposed_entities: dict | None
    ) -> str:
        """Return the prompt for the API."""
        if not exposed_entities:
            return (
                "Only if the user wants to control a device, tell them to expose entities "
                "to their voice assistant in Home Assistant."
            )

        prompt = [
            (
                "When controlling Home Assistant always call the intent tools. "
                "Use HassTurnOn to lock and HassTurnOff to unlock a lock. "
                "When controlling a device, prefer passing just its name and its domain "
                "(what comes before the dot in its entity id). "
                "When controlling an area, prefer passing just area name and domain."
            )
        ]
        area: ar.AreaEntry | None = None
        floor: fr.FloorEntry | None = None
        if llm_context.device_id:
            device_reg = dr.async_get(self.hass)
            device = device_reg.async_get(llm_context.device_id)

            if device:
                area_reg = ar.async_get(self.hass)
                if device.area_id and (area := area_reg.async_get_area(device.area_id)):
                    floor_reg = fr.async_get(self.hass)
                    if area.floor_id:
                        floor = floor_reg.async_get_floor(area.floor_id)

            extra = "and all generic commands like 'turn on the lights' should target this area."

        if floor and area:
            prompt.append(f"You are in area {area.name} (floor {floor.name}) {extra}")
        elif area:
            prompt.append(f"You are in area {area.name} {extra}")
        else:
            prompt.append(
                "When a user asks to turn on all devices of a specific type, "
                "ask user to specify an area, unless there is only one device of that type."
            )

        if not llm_context.device_id or not async_device_supports_timers(
            self.hass, llm_context.device_id
        ):
            prompt.append("This device does not support timers.")

        if exposed_entities:
            prompt.append(
                "An overview of the areas and the devices in this smart home:"
            )
            prompt.append(yaml.dump(exposed_entities))

        return "\n".join(prompt)

    @callback
    def _async_get_tools(
        self, llm_context: LLMContext, exposed_entities: dict | None
    ) -> list[Tool]:
        """Return a list of LLM tools."""
        ignore_intents = self.IGNORE_INTENTS
        if not llm_context.device_id or not async_device_supports_timers(
            self.hass, llm_context.device_id
        ):
            ignore_intents = ignore_intents | {
                intent.INTENT_START_TIMER,
                intent.INTENT_CANCEL_TIMER,
                intent.INTENT_INCREASE_TIMER,
                intent.INTENT_DECREASE_TIMER,
                intent.INTENT_PAUSE_TIMER,
                intent.INTENT_UNPAUSE_TIMER,
                intent.INTENT_TIMER_STATUS,
            }

        intent_handlers = [
            intent_handler
            for intent_handler in intent.async_get(self.hass)
            if intent_handler.intent_type not in ignore_intents
        ]

        exposed_domains: set[str] | None = None
        if exposed_entities is not None:
            exposed_domains = {
                entity_id.split(".")[0] for entity_id in exposed_entities
            }
            intent_handlers = [
                intent_handler
                for intent_handler in intent_handlers
                if intent_handler.platforms is None
                or intent_handler.platforms & exposed_domains
            ]

        return [
            IntentTool(self.cached_slugify(intent_handler.intent_type), intent_handler)
            for intent_handler in intent_handlers
        ]


def _get_exposed_entities(
    hass: HomeAssistant, assistant: str
) -> dict[str, dict[str, Any]]:
    """Get exposed entities."""
    area_registry = ar.async_get(hass)
    entity_registry = er.async_get(hass)
    device_registry = dr.async_get(hass)
    interesting_attributes = {
        "temperature",
        "current_temperature",
        "temperature_unit",
        "brightness",
        "humidity",
        "unit_of_measurement",
        "device_class",
        "current_position",
        "percentage",
        "volume_level",
        "media_title",
        "media_artist",
        "media_album_name",
    }

    entities = {}

    for state in hass.states.async_all():
        if not async_should_expose(hass, assistant, state.entity_id):
            continue

        entity_entry = entity_registry.async_get(state.entity_id)
        names = [state.name]
        area_names = []
        description: str | None = None

        if entity_entry is not None:
            names.extend(entity_entry.aliases)
            if entity_entry.area_id and (
                area := area_registry.async_get_area(entity_entry.area_id)
            ):
                # Entity is in area
                area_names.append(area.name)
                area_names.extend(area.aliases)
            elif entity_entry.device_id and (
                device := device_registry.async_get(entity_entry.device_id)
            ):
                # Check device area
                if device.area_id and (
                    area := area_registry.async_get_area(device.area_id)
                ):
                    area_names.append(area.name)
                    area_names.extend(area.aliases)

            if (
                state.domain == "script"
                and entity_entry.unique_id
                and (
                    service_desc := service.async_get_cached_service_description(
                        hass, "script", entity_entry.unique_id
                    )
                )
            ):
                description = service_desc.get("description")

        info: dict[str, Any] = {
            "names": ", ".join(names),
            "state": state.state,
        }

        if description:
            info["description"] = description

        if area_names:
            info["areas"] = ", ".join(area_names)

        if attributes := {
            attr_name: str(attr_value)
            if isinstance(attr_value, (Enum, Decimal))
            else attr_value
            for attr_name, attr_value in state.attributes.items()
            if attr_name in interesting_attributes
        }:
            info["attributes"] = attributes

        entities[state.entity_id] = info

    return entities