"""Authentication and local LLM configuration for MCP Server CLI."""

from typing import Any, Dict, List, Optional
from pydantic import BaseModel
import httpx
import json

from mcp_server_cli.models import LocalLLMConfig


class LLMMessage(BaseModel):
    """A message in an LLM conversation."""

    role: str
    content: str


class LLMChoice(BaseModel):
    """A choice in an LLM response."""

    index: int
    message: LLMMessage
    finish_reason: Optional[str] = None


class LLMResponse(BaseModel):
    """Response from an LLM provider."""

    id: str
    object: str
    created: int
    model: str
    choices: List[LLMChoice]
    usage: Optional[Dict[str, Any]] = None


class ChatCompletionRequest(BaseModel):
    """Request for chat completion."""

    messages: List[Dict[str, str]]
    model: str
    temperature: Optional[float] = None
    max_tokens: Optional[int] = None
    stream: Optional[bool] = False


class LocalLLMClient:
    """Client for interacting with local LLM providers."""

    def __init__(self, config: LocalLLMConfig):
        """Initialize the LLM client.

        Args:
            config: Local LLM configuration.
        """
        self.config = config
        self.base_url = config.base_url.rstrip("/")
        self.model = config.model
        self.timeout = config.timeout

    async def chat_complete(
        self,
        messages: List[Dict[str, str]],
        temperature: Optional[float] = None,
        max_tokens: Optional[int] = None,
        stream: bool = False,
    ) -> LLMResponse:
        """Send a chat completion request to the local LLM.

        Args:
            messages: List of conversation messages.
            temperature: Sampling temperature.
            max_tokens: Maximum tokens to generate.
            stream: Whether to stream the response.

        Returns:
            LLM response with generated text.
        """
        payload = {
            "messages": messages,
            "model": self.model,
            "temperature": temperature or self.config.temperature,
            "max_tokens": max_tokens or self.config.max_tokens,
            "stream": stream,
        }

        async with httpx.AsyncClient(timeout=self.timeout) as client:
            response = await client.post(
                f"{self.base_url}/v1/chat/completions",
                json=payload,
                headers={"Content-Type": "application/json"},
            )
            response.raise_for_status()
            data = response.json()

            return LLMResponse(
                id=data.get("id", "local-llm"),
                object=data.get("object", "chat.completion"),
                created=data.get("created", 0),
                model=data.get("model", self.model),
                choices=[
                    LLMChoice(
                        index=choice.get("index", 0),
                        message=LLMMessage(
                            role=choice.get("message", {}).get("role", "assistant"),
                            content=choice.get("message", {}).get("content", ""),
                        ),
                        finish_reason=choice.get("finish_reason"),
                    )
                    for choice in data.get("choices", [])
                ],
                usage=data.get("usage"),
            )

    async def stream_chat_complete(
        self,
        messages: List[Dict[str, str]],
        temperature: Optional[float] = None,
        max_tokens: Optional[int] = None,
    ):
        """Stream a chat completion from the local LLM.

        Args:
            messages: List of conversation messages.
            temperature: Sampling temperature.
            max_tokens: Maximum tokens to generate.

        Yields:
            Chunks of generated text.
        """
        payload = {
            "messages": messages,
            "model": self.model,
            "temperature": temperature or self.config.temperature,
            "max_tokens": max_tokens or self.config.max_tokens,
            "stream": True,
        }

        async with httpx.AsyncClient(timeout=self.timeout) as client:
            async with client.stream(
                "POST",
                f"{self.base_url}/v1/chat/completions",
                json=payload,
                headers={"Content-Type": "application/json"},
            ) as response:
                async for line in response.aiter_lines():
                    if line.startswith("data: "):
                        data = line[6:]
                        if data == "[DONE]":
                            break
                        try:
                            chunk = json.loads(data)
                            delta = chunk.get("choices", [{}])[0].get("delta", {})
                            content = delta.get("content", "")
                            if content:
                                yield content
                        except json.JSONDecodeError:
                            continue

    async def test_connection(self) -> Dict[str, Any]:
        """Test the connection to the local LLM.

        Returns:
            Dictionary with connection status and details.
        """
        try:
            async with httpx.AsyncClient(timeout=10) as client:
                response = await client.get(f"{self.base_url}/api/tags")
                if response.status_code == 200:
                    return {"status": "connected", "details": response.json()}
        except httpx.RequestError:
            pass

        try:
            async with httpx.AsyncClient(timeout=10) as client:
                response = await client.get(f"{self.base_url}/v1/models")
                if response.status_code == 200:
                    return {"status": "connected", "details": response.json()}
        except httpx.RequestError:
            pass

        return {"status": "failed", "error": "Could not connect to local LLM server"}


class LLMProviderRegistry:
    """Registry for managing LLM providers."""

    def __init__(self):
        """Initialize the provider registry."""
        self._providers: Dict[str, LocalLLMClient] = {}

    def register(self, name: str, client: LocalLLMClient):
        """Register an LLM provider.

        Args:
            name: Provider name.
            client: LLM client instance.
        """
        self._providers[name] = client

    def get(self, name: str) -> Optional[LocalLLMClient]:
        """Get an LLM provider by name.

        Args:
            name: Provider name.

        Returns:
            LLM client or None if not found.
        """
        return self._providers.get(name)

    def list_providers(self) -> List[str]:
        """List all registered provider names.

        Returns:
            List of provider names.
        """
        return list(self._providers.keys())

    def create_default(self, config: LocalLLMConfig) -> LocalLLMClient:
        """Create and register the default LLM provider.

        Args:
            config: Local LLM configuration.

        Returns:
            Created LLM client.
        """
        client = LocalLLMClient(config)
        self.register("default", client)
        return client


def create_llm_client(config: LocalLLMConfig) -> LocalLLMClient:
    """Create an LLM client from configuration.

    Args:
        config: Local LLM configuration.

    Returns:
        Configured LLM client.
    """
    return LocalLLMClient(config)