"""
LM Studio local LLM client adapter.

Implements the LLMClient protocol for LM Studio's OpenAI-compatible API.
Designed for running local models with configurable endpoint.
"""

import json
import logging
from collections.abc import AsyncIterator
from typing import Any

import httpx

from .base import BaseLLMClient, LLMResponse
from .exceptions import (
    LLMClientError,
    LLMConnectionError,
    LLMResponseParseError,
    LLMServerError,
    LLMStreamError,
    LLMTimeoutError,
)

logger = logging.getLogger(__name__)


class LMStudioClient(BaseLLMClient):
    """
    LM Studio local server client.

    LM Studio provides an OpenAI-compatible API for running local models.
    This client is optimized for local deployment with:
    - No authentication required (local)
    - Configurable base URL
    - No circuit breaker (local server expected to be stable)
    - Longer timeouts for large models
    """

    PROVIDER_NAME = "lmstudio"
    DEFAULT_BASE_URL = "http://localhost:1234/v1"
    DEFAULT_MODEL = "local-model"  # LM Studio uses the loaded model

    def __init__(
        self,
        api_key: str | None = None,  # Not required for local
        model: str | None = None,
        base_url: str | None = None,
        timeout: float = 300.0,  # Long timeout for local inference
        max_retries: int = 2,  # Fewer retries for local
        # Rate limiting
        rate_limit_per_minute: int | None = None,
    ):
        """
        Initialize LM Studio client.

        Args:
            api_key: Not required for local server (ignored)
            model: Model identifier (often ignored by LM Studio, uses loaded model)
            base_url: Local server URL (default: http://localhost:1234/v1)
            timeout: Request timeout in seconds (default longer for local models)
            max_retries: Max retry attempts (fewer for local)
            rate_limit_per_minute: Rate limit for requests per minute (None to disable)
        """
        import os

        # Allow overriding via environment variable
        base_url = base_url or os.environ.get("LMSTUDIO_BASE_URL", self.DEFAULT_BASE_URL)

        super().__init__(
            api_key=api_key or "not-required",  # Placeholder
            model=model or self.DEFAULT_MODEL,
            base_url=base_url,
            timeout=timeout,
            max_retries=max_retries,
            rate_limit_per_minute=rate_limit_per_minute,
        )

        self._client: httpx.AsyncClient | None = None

    async def _get_client(self) -> httpx.AsyncClient:
        """Get or create the HTTP client."""
        if self._client is None or self._client.is_closed:
            headers = {"Content-Type": "application/json"}

            # Add auth header if provided (some local servers may require it)
            if self.api_key and self.api_key != "not-required":
                headers["Authorization"] = f"Bearer {self.api_key}"

            self._client = httpx.AsyncClient(
                base_url=self.base_url,
                headers=headers,
                timeout=httpx.Timeout(self.timeout),
            )
        return self._client

    async def check_health(self) -> bool:
        """
        Check if LM Studio server is running.

        Returns:
            True if server is accessible, False otherwise
        """
        try:
            client = await self._get_client()
            response = await client.get("/models")
            return response.status_code == 200
        except Exception:
            return False

    async def list_models(self) -> list[dict]:
        """
        List available models on the LM Studio server.

        Returns:
            List of model information dicts
        """
        try:
            client = await self._get_client()
            response = await client.get("/models")
            if response.status_code == 200:
                data = response.json()
                return data.get("data", [])
            return []
        except Exception as e:
            logger.warning(f"Failed to list models: {e}")
            return []

    def _handle_error_response(self, response: httpx.Response) -> None:
        """Handle error responses from LM Studio server."""
        status_code = response.status_code

        try:
            error_data = response.json()
            error_message = error_data.get("error", {}).get("message", response.text)
        except Exception:
            error_message = response.text

        if status_code >= 500:
            raise LLMServerError(self.PROVIDER_NAME, status_code, error_message)
        else:
            raise LLMClientError(error_message, self.PROVIDER_NAME, status_code=status_code)

    async def generate(
        self,
        *,
        messages: list[dict] | None = None,
        prompt: str | None = None,
        temperature: float = 0.7,
        max_tokens: int | None = None,
        tools: list[dict] | None = None,
        stream: bool = False,
        stop: list[str] | None = None,
        **kwargs: Any,
    ) -> LLMResponse | AsyncIterator[str]:
        """
        Generate a response from LM Studio local model.

        Args:
            messages: Chat messages in OpenAI format
            prompt: Simple string prompt
            temperature: Sampling temperature
            max_tokens: Maximum tokens to generate
            tools: Tool definitions (limited support in local models)
            stream: If True, returns AsyncIterator
            stop: Stop sequences
            **kwargs: Additional parameters

        Returns:
            LLMResponse or AsyncIterator[str] for streaming
        """
        # Apply rate limiting before proceeding
        await self._apply_rate_limit()

        if stream:
            return self._generate_stream(
                messages=messages,
                prompt=prompt,
                temperature=temperature,
                max_tokens=max_tokens,
                tools=tools,
                stop=stop,
                **kwargs,
            )
        else:
            return await self._generate_non_stream(
                messages=messages,
                prompt=prompt,
                temperature=temperature,
                max_tokens=max_tokens,
                tools=tools,
                stop=stop,
                **kwargs,
            )

    async def _generate_non_stream(
        self,
        *,
        messages: list[dict] | None = None,
        prompt: str | None = None,
        temperature: float = 0.7,
        max_tokens: int | None = None,
        tools: list[dict] | None = None,
        stop: list[str] | None = None,
        **kwargs: Any,
    ) -> LLMResponse:
        """Non-streaming generation."""
        client = await self._get_client()

        # Build request payload (OpenAI-compatible)
        payload = {
            "model": self.model,
            "messages": self._build_messages(messages, prompt),
            "temperature": temperature,
        }

        if max_tokens is not None:
            payload["max_tokens"] = max_tokens
        if stop:
            payload["stop"] = stop

        # Note: most local models don't support tools well
        if tools:
            logger.warning("Tool calling may not be fully supported by local models")
            payload["tools"] = tools

        # Add additional kwargs (e.g., top_p, repeat_penalty)
        for key in ["top_p", "top_k", "repeat_penalty", "presence_penalty", "frequency_penalty"]:
            if key in kwargs:
                payload[key] = kwargs[key]

        # Retry logic for local server
        last_error = None
        for attempt in range(self.max_retries):
            try:
                response = await client.post("/chat/completions", json=payload)

                if response.status_code != 200:
                    self._handle_error_response(response)

                # Parse response
                try:
                    data = response.json()
                    choice = data["choices"][0]
                    message = choice["message"]

                    usage = data.get("usage", {})
                    finish_reason = choice.get("finish_reason", "stop")

                    llm_response = LLMResponse(
                        text=message.get("content", ""),
                        usage=usage,
                        model=data.get("model", self.model),
                        raw_response=data,
                        finish_reason=finish_reason,
                    )

                    self._update_stats(llm_response)
                    return llm_response

                except (KeyError, json.JSONDecodeError) as e:
                    raise LLMResponseParseError(self.PROVIDER_NAME, response.text) from e

            except httpx.TimeoutException:
                last_error = LLMTimeoutError(self.PROVIDER_NAME, self.timeout)
                logger.warning(f"Attempt {attempt + 1} timed out, retrying...")
            except httpx.ConnectError:
                last_error = LLMConnectionError(self.PROVIDER_NAME, self.base_url)
                logger.warning(f"Attempt {attempt + 1} connection failed, retrying...")
            except LLMClientError:
                raise  # Don't retry client errors

        # All retries exhausted
        if last_error:
            raise last_error
        raise LLMConnectionError(self.PROVIDER_NAME, self.base_url)

    async def _generate_stream(
        self,
        *,
        messages: list[dict] | None = None,
        prompt: str | None = None,
        temperature: float = 0.7,
        max_tokens: int | None = None,
        tools: list[dict] | None = None,  # noqa: ARG002
        stop: list[str] | None = None,
        **kwargs: Any,
    ) -> AsyncIterator[str]:
        """Streaming generation."""
        client = await self._get_client()

        # Build request payload
        payload = {
            "model": self.model,
            "messages": self._build_messages(messages, prompt),
            "temperature": temperature,
            "stream": True,
        }

        if max_tokens is not None:
            payload["max_tokens"] = max_tokens
        if stop:
            payload["stop"] = stop

        for key in ["top_p", "top_k", "repeat_penalty"]:
            if key in kwargs:
                payload[key] = kwargs[key]

        async def stream_generator():
            try:
                async with client.stream("POST", "/chat/completions", json=payload) as response:
                    if response.status_code != 200:
                        await response.aread()
                        self._handle_error_response(response)

                    async for line in response.aiter_lines():
                        if line.startswith("data: "):
                            data_str = line[6:]
                            if data_str.strip() == "[DONE]":
                                break

                            try:
                                data = json.loads(data_str)
                                delta = data["choices"][0].get("delta", {})
                                content = delta.get("content", "")
                                if content:
                                    yield content
                            except (json.JSONDecodeError, KeyError):
                                continue

            except httpx.TimeoutException:
                raise LLMTimeoutError(self.PROVIDER_NAME, self.timeout)
            except httpx.ConnectError:
                raise LLMConnectionError(self.PROVIDER_NAME, self.base_url)
            except Exception as e:
                if isinstance(e, LLMClientError):
                    raise
                raise LLMStreamError(self.PROVIDER_NAME, str(e)) from e

        return stream_generator()

    async def close(self) -> None:
        """Close the HTTP client."""
        if self._client and not self._client.is_closed:
            await self._client.aclose()
            self._client = None