main.py

import json
import logging
import os
import uuid
from datetime import datetime
from typing import Any, Dict, List, Optional

import httpx
import uvicorn
from dotenv import load_dotenv
from fastapi import FastAPI, HTTPException, Depends
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from pydantic import BaseModel
from starlette.middleware.cors import CORSMiddleware
from starlette.responses import StreamingResponse, Response

# Configure Logging
logging.basicConfig(
    level=logging.INFO, format="%(asctime)s - %(name)s - %(levelname)s - %(message)s"
)
logger = logging.getLogger(__name__)

# Load Environment Variables
load_dotenv()
app = FastAPI()

# Configuration Constants
BASE_URL = "https://aichatonlineorg.erweima.ai/aichatonline"
APP_SECRET = os.getenv("APP_SECRET", "666")
ACCESS_TOKEN = os.getenv("SD_ACCESS_TOKEN", "")
headers = {
    'accept': '*/*',
    'accept-language': 'zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6',
    'authorization': f'Bearer {ACCESS_TOKEN}',
    'cache-control': 'no-cache',
    'origin': 'chrome-extension://dhoenijjpgpeimemopealfcbiecgceod',
    'pragma': 'no-cache',
    'priority': 'u=1, i',
    'sec-fetch-dest': 'empty',
    'sec-fetch-mode': 'cors',
    'sec-fetch-site': 'none',
    'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36 Edg/129.0.0.0',
}

# Updated ALLOWED_MODELS List (No Duplicates)
ALLOWED_MODELS = [
    {"id": "claude-3.5-sonnet", "name": "Claude 3.5 Sonnet"},
    {"id": "sider", "name": "Sider"},
    {"id": "gpt-4o-mini", "name": "GPT-4o Mini"},
    {"id": "claude-3-haiku", "name": "Claude 3 Haiku"},
    {"id": "claude-3.5-haiku", "name": "Claude 3.5 Haiku"},
    {"id": "gemini-1.5-flash", "name": "Gemini 1.5 Flash"},
    {"id": "llama-3", "name": "Llama 3"},
    {"id": "gpt-4o", "name": "GPT-4o"},
    {"id": "gemini-1.5-pro", "name": "Gemini 1.5 Pro"},
    {"id": "llama-3.1-405b", "name": "Llama 3.1 405b"},
]

# Configure CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # Restrict this to specific origins in production
    allow_credentials=True,
    allow_methods=["*"],  # All methods allowed
    allow_headers=["*"],  # Allow all headers
)

# Security Configuration
security = HTTPBearer()

# Pydantic Models
class Message(BaseModel):
    role: str
    content: str

class ChatRequest(BaseModel):
    model: str
    messages: List[Message]
    stream: Optional[bool] = False

# Utility Functions
def create_chat_completion_data(content: str, model: str, finish_reason: Optional[str] = None) -> Dict[str, Any]:
    return {
        "id": f"chatcmpl-{uuid.uuid4()}",
        "object": "chat.completion.chunk",
        "created": int(datetime.now().timestamp()),
        "model": model,
        "choices": [
            {
                "index": 0,
                "delta": {"content": content, "role": "assistant"},
                "finish_reason": finish_reason,
            }
        ],
        "usage": None,
    }

def verify_app_secret(credentials: HTTPAuthorizationCredentials = Depends(security)):
    if credentials.credentials != APP_SECRET:
        logger.warning(f"Invalid APP_SECRET provided: {credentials.credentials}")
        raise HTTPException(status_code=403, detail="Invalid APP_SECRET")
    logger.info("APP_SECRET verified successfully.")
    return credentials.credentials

# CORS Preflight Options Endpoint
@app.options("/hf/v1/chat/completions")
async def chat_completions_options():
    return Response(
        status_code=200,
        headers={
            "Access-Control-Allow-Origin": "*",
            "Access-Control-Allow-Methods": "POST, OPTIONS",
            "Access-Control-Allow-Headers": "Content-Type, Authorization",
        },
    )

# Replace Escaped Newlines
def replace_escaped_newlines(input_string: str) -> str:
    return input_string.replace("\\n", "\n")

# List Available Models
@app.get("/hf/v1/models")
async def list_models():
    return {"object": "list", "data": ALLOWED_MODELS}

# Chat Completions Endpoint
@app.post("/hf/v1/chat/completions")
async def chat_completions(
    request: ChatRequest, app_secret: str = Depends(verify_app_secret)
):
    logger.info(f"Received chat completion request for model: {request.model}")

    # Validate Selected Model
    if request.model not in [model['id'] for model in ALLOWED_MODELS]:
        allowed = ', '.join(model['id'] for model in ALLOWED_MODELS)
        logger.error(f"Model {request.model} is not allowed.")
        raise HTTPException(
            status_code=400,
            detail=f"Model '{request.model}' is not allowed. Allowed models are: {allowed}",
        )

    logger.info(f"Using model: {request.model}")

    # Generate a UUID
    original_uuid = uuid.uuid4()
    uuid_str = str(original_uuid).replace("-", "")
    logger.debug(f"Generated UUID: {uuid_str}")

    # Prepare JSON Payload for External API
    json_data = {
        'prompt': "\n".join(
            [
                f"{'User' if msg.role == 'user' else 'Assistant'}: {msg.content}"
                for msg in request.messages
            ]
        ),
        'stream': True,
        'app_name': 'ChitChat_Edge_Ext',
        'app_version': '4.26.1',
        'tz_name': 'Asia/Karachi',
        'cid': '',
        'model': request.model,  # Use the selected model directly
        'search': False,
        'auto_search': False,
        'filter_search_history': False,
        'from': 'chat',
        'group_id': 'default',
        'chat_models': [request.model],  # Include the model in chat_models
        'files': [],
        'prompt_template': {
            'key': '',
            'attributes': {
                'lang': 'original',
            },
        },
        'tools': {
            'auto': [
                'search',
                'text_to_image',
                'data_analysis',
            ],
        },
        'extra_info': {
            'origin_url': '',
            'origin_title': '',
        },
    }

    logger.debug(f"JSON Data Sent to External API: {json.dumps(json_data, indent=2)}")

    async def generate():
        async with httpx.AsyncClient() as client:
            try:
                async with client.stream(
                    'POST',
                    'https://sider.ai/api/v2/completion/text',
                    headers=headers,
                    json=json_data,
                    timeout=120.0
                ) as response:
                    response.raise_for_status()
                    async for line in response.aiter_lines():
                        if line and ("[DONE]" not in line):
                            # Assuming the line starts with 'data: ' followed by JSON
                            if line.startswith("data: "):
                                json_line = line[6:]
                                if json_line.startswith("{"):
                                    try:
                                        data = json.loads(json_line)
                                        content = data.get("data", {}).get("text", "")
                                        logger.debug(f"Received content: {content}")
                                        yield f"data: {json.dumps(create_chat_completion_data(content, request.model))}\n\n"
                                    except json.JSONDecodeError as e:
                                        logger.error(f"JSON decode error: {e} - Line: {json_line}")
                    # Send the stop signal
                    yield f"data: {json.dumps(create_chat_completion_data('', request.model, 'stop'))}\n\n"
                    yield "data: [DONE]\n\n"
            except httpx.HTTPStatusError as e:
                logger.error(f"HTTP error occurred: {e} - Response: {e.response.text}")
                raise HTTPException(status_code=e.response.status_code, detail=str(e))
            except httpx.RequestError as e:
                logger.error(f"An error occurred while requesting: {e}")
                raise HTTPException(status_code=500, detail=str(e))

    if request.stream:
        logger.info("Streaming response initiated.")
        return StreamingResponse(generate(), media_type="text/event-stream")
    else:
        logger.info("Non-streaming response initiated.")
        full_response = ""
        async for chunk in generate():
            if chunk.startswith("data: ") and not chunk[6:].startswith("[DONE]"):
                # Parse the JSON part after 'data: '
                try:
                    data = json.loads(chunk[6:])
                    if data["choices"][0]["delta"].get("content"):
                        full_response += data["choices"][0]["delta"]["content"]
                except json.JSONDecodeError:
                    logger.warning(f"Failed to decode JSON from chunk: {chunk}")
        
        # Final Response Structure
        return {
            "id": f"chatcmpl-{uuid.uuid4()}",
            "object": "chat.completion",
            "created": int(datetime.now().timestamp()),
            "model": request.model,
            "choices": [
                {
                    "index": 0,
                    "message": {"role": "assistant", "content": full_response},
                    "finish_reason": "stop",
                }
            ],
            "usage": None,
        }

# Entry Point
if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=7860)