import httpx
import logging
import json
from abc import ABC, abstractmethod
from openai import OpenAI
from typing import final
from app.config import settings # <-- Import the centralized settings

# --- 1. Initialize API Clients from Central Config ---
# All environment variable access is now gone from this file.
deepseek_client = OpenAI(api_key=settings.DEEPSEEK_API_KEY, base_url="https://api.deepseek.com")
GEMINI_URL = f"https://generativelanguage.googleapis.com/v1beta/models/{settings.GEMINI_MODEL_NAME}:generateContent?key={settings.GEMINI_API_KEY}"


# --- 2. Provider Interface and Implementations (Unchanged) ---
class LLMProvider(ABC):
    """Abstract base class ('Interface') for all LLM providers."""
    @abstractmethod
    async def generate_response(self, prompt: str) -> str:
        """Generates a response from the LLM."""
        pass

@final
class DeepSeekProvider(LLMProvider):
    """Provider for the DeepSeek API."""
    def __init__(self, model_name: str):
        self.model = model_name

    async def generate_response(self, prompt: str) -> str:
        messages = [{"role": "system", "content": "You are a helpful assistant."}, {"role": "user", "content": prompt}]
        try:
            chat_completion = deepseek_client.chat.completions.create(model=self.model, messages=messages)
            return chat_completion.choices[0].message.content
        except Exception as e:
            logging.error("DeepSeek Provider Error", exc_info=True)
            raise

@final
class GeminiProvider(LLMProvider):
    """Provider for the Google Gemini API."""
    def __init__(self, api_url: str):
        self.url = api_url

    async def generate_response(self, prompt: str) -> str:
        payload = {"contents": [{"parts": [{"text": prompt}]}]}
        headers = {"Content-Type": "application/json"}
        try:
            async with httpx.AsyncClient() as client:
                response = await client.post(self.url, json=payload, headers=headers)
                response.raise_for_status()
                data = response.json()
                return data['candidates'][0]['content']['parts'][0]['text']
        except Exception as e:
            logging.error("Gemini Provider Error", exc_info=True)
            raise

# --- 3. The Factory Function ---
# The dictionary of providers is now built using values from the settings object.
_providers = {
    "deepseek": DeepSeekProvider(model_name=settings.DEEPSEEK_MODEL_NAME),
    "gemini": GeminiProvider(api_url=GEMINI_URL)
}

def get_llm_provider(model_name: str) -> LLMProvider:
    """Factory function to get the appropriate, pre-configured LLM provider."""
    provider = _providers.get(model_name)
    if not provider:
        raise ValueError(f"Unsupported model provider: '{model_name}'. Supported providers are: {list(_providers.keys())}")
    return provider