app.py

import os
from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from typing import List, Literal
import httpx
import logging

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# Read API keys from Hugging Face Secrets
OPENAI_API_KEY = os.environ.get("OPENAI_API_KEY")
HF_TOKEN = os.environ.get("HF_TOKEN")

if not OPENAI_API_KEY:
    logger.warning("OPENAI_API_KEY not set — OpenAI provider will be unavailable")
if not HF_TOKEN:
    logger.warning("HF_TOKEN not set — Hugging Face provider will be unavailable")

# Provider config: each provider has a base URL and a key
PROVIDERS = {
    "openai": {
        "url": "https://api.openai.com/v1/chat/completions",
        "key": OPENAI_API_KEY,
    },
    "hf": {
        "url": "https://router.huggingface.co/v1/chat/completions",
        "key": HF_TOKEN,
    },
}

app = FastAPI(title="Proxy for Unity")

# Enable CORS for Unity WebGL builds
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # In production, specify your domain
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

class Message(BaseModel):
    role: str
    content: str

class ChatRequest(BaseModel):
    model: str
    temperature: float
    messages: List[Message]
    provider: Literal["openai", "hf"] = "openai"  # default keeps existing Unity code working

@app.get("/")
async def root():
    return {
        "status": "running",
        "message": "Proxy Active",
        "providers": {
            "openai": bool(OPENAI_API_KEY),
            "hf": bool(HF_TOKEN),
        },
        "endpoints": {
            "chat": "POST /chat"
        }
    }

@app.post("/chat")
async def proxy_chat(request: ChatRequest):
    provider_config = PROVIDERS.get(request.provider)
    if not provider_config or not provider_config["key"]:
        raise HTTPException(
            status_code=400,
            detail=f"Provider '{request.provider}' is not configured"
        )

    try:
        logger.info(
            f"Provider: {request.provider} | Model: {request.model} | "
            f"Messages: {len(request.messages)}"
        )

        async with httpx.AsyncClient(timeout=60.0) as client:
            response = await client.post(
                provider_config["url"],
                json={
                    "model": request.model,
                    "temperature": request.temperature,
                    "messages": [
                        {"role": msg.role, "content": msg.content}
                        for msg in request.messages
                    ]
                },
                headers={
                    "Authorization": f"Bearer {provider_config['key']}",
                    "Content-Type": "application/json"
                }
            )

            if response.status_code != 200:
                logger.error(f"{request.provider} API error: {response.text}")
                raise HTTPException(
                    status_code=response.status_code,
                    detail=response.text
                )

            result = response.json()
            logger.info(f"Successfully proxied {request.provider} request")
            return result

    except httpx.HTTPError as e:
        logger.error(f"HTTP error: {str(e)}")
        raise HTTPException(status_code=500, detail=f"Proxy error: {str(e)}")
    except Exception as e:
        logger.error(f"Unexpected error: {str(e)}")
        raise HTTPException(status_code=500, detail=f"Server error: {str(e)}")

@app.get("/health")
async def health():
    return {
        "status": "healthy",
        "openai_configured": bool(OPENAI_API_KEY),
        "hf_configured": bool(HF_TOKEN),
    }