app/main.py

from fastapi import FastAPI, Request, status
from fastapi.responses import JSONResponse
from fastapi.responses import Response
from fastapi.exceptions import HTTPException
from slowapi import Limiter, _rate_limit_exceeded_handler
from slowapi.errors import RateLimitExceeded
from slowapi.util import get_remote_address
from typing import Dict, List
from prometheus_client import Counter, Histogram, start_http_server
from pydantic import BaseModel, ValidationError
from app.services.message import generate_reply, send_reply
import logging
from datetime import datetime
import time
from contextlib import asynccontextmanager
# from app.db.database import create_indexes, init_db
from app.services.webhook_handler import verify_webhook
from app.handlers.message_handler import MessageHandler
from app.handlers.webhook_handler import WebhookHandler
from app.handlers.media_handler import WhatsAppMediaHandler
from app.services.cache import MessageCache
from app.services.chat_manager import ChatManager

from app.utils.load_env import ACCESS_TOKEN

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
)

logger = logging.getLogger(__name__)

# Initialize handlers at startup
message_handler = None
webhook_handler = None


async def setup_message_handler():
    logger = logging.getLogger(__name__)
    message_cache = MessageCache()
    chat_manager = ChatManager()
    media_handler = WhatsAppMediaHandler()
    
    return MessageHandler(
        message_cache=message_cache,
        chat_manager=chat_manager,
        media_handler=media_handler,
        logger=logger
    )
# Initialize FastAPI app
@asynccontextmanager
async def lifespan(app: FastAPI):
   
    
    try:
        # await init_db()

        logger.info("Connected to the MongoDB database!")


        global message_handler, webhook_handler
        message_handler = await setup_message_handler()
        webhook_handler = WebhookHandler(message_handler)
        # collections = app.database.list_collection_names()
        # print(f"Collections in {db_name}: {collections}")
        yield
    except Exception as e:
        logger.error(e)

# Initialize Limiter and Prometheus Metrics
limiter = Limiter(key_func=get_remote_address)
app = FastAPI(lifespan=lifespan)
app.state.limiter = limiter
app.add_exception_handler(RateLimitExceeded, _rate_limit_exceeded_handler)



# app.include_router(users.router, prefix="/users", tags=["Users"])


# Prometheus metrics
webhook_requests = Counter('webhook_requests_total', 'Total webhook requests')
webhook_processing_time = Histogram('webhook_processing_seconds', 'Time spent processing webhook')

# Start Prometheus metrics server on port 8002
# start_http_server(8002)
# Register webhook routes
# app.post("/webhook")(webhook)
# Define Pydantic schema for request validation
class WebhookPayload(BaseModel):
    entry: List[Dict]

@app.post("/webhook")
@limiter.limit("100/minute")
async def webhook(request: Request):
    try:
        payload = await request.json()

        # validated_payload = WebhookPayload(**payload)  # Validate payload
        # logger.info(f"Validated Payload: {validated_payload}")
            
            # Process the webhook payload here
            # For example:
        # results = process_webhook_entries(validated_payload.entry)
        response = await webhook_handler.process_webhook(
            payload=payload,
            access_token=ACCESS_TOKEN
        )
        
        return JSONResponse(
            content=response.__dict__,
            status_code=status.HTTP_200_OK
        )
        
    except ValidationError as ve:
            logger.error(f"Validation error: {ve}")
            return JSONResponse(
                content={"status": "error", "detail": ve.errors()},
                status_code=status.HTTP_422_UNPROCESSABLE_ENTITY
            )
    except Exception as e:
            logger.error(f"Unexpected error: {str(e)}")
            return JSONResponse(
                content={"status": "error", "detail": str(e)},
                status_code=status.HTTP_500_INTERNAL_SERVER_ERROR
            )
    
app.get("/webhook")(verify_webhook)

# Add a route for Prometheus metrics (optional, if not using a separate Prometheus server)
@app.get("/metrics")
async def metrics():
    from prometheus_client import generate_latest
    return Response(content=generate_latest(), media_type="text/plain")
# In-memory cache with timestamp cleanup
# class MessageCache:
#     def __init__(self, max_age_hours: int = 24):
#         self.messages: Dict[str, float] = {}
#         self.max_age_seconds = max_age_hours * 3600

#     def add(self, message_id: str) -> None:
#         self.cleanup()
#         self.messages[message_id] = time.time()

#     def exists(self, message_id: str) -> bool:
#         self.cleanup()
#         return message_id in self.messages

#     def cleanup(self) -> None:
#         current_time = time.time()
#         self.messages = {
#             msg_id: timestamp 
#             for msg_id, timestamp in self.messages.items()
#             if current_time - timestamp < self.max_age_seconds
#         }

# message_cache = MessageCache()
# user_chats = {}

# @app.post("/webhook")
# async def webhook(request: Request):
#     request_id = f"req_{int(time.time()*1000)}"
#     logger.info(f"Processing webhook request {request_id}")
#     payload = await request.json()

#     print("Webhook received:", payload)

#     processed_count = 0
#     error_count = 0
#     results = []

#     entries = payload.get("entry", [])

#     for entry in entries:
#         entry_id = entry.get("id")
#         logger.info(f"Processing entry_id: {entry_id}")

#         changes = entry.get("changes", [])
#         for change in changes:
#             messages = change.get("value", {}).get("messages", [])
#             for message in messages:
#                 message_id = message.get("id")
#                 timestamp = message.get("timestamp")
#                 content = message.get("text", {}).get("body")
#                 sender_id = message.get("from")
#                 msg_type = message.get('type')

#                 # Deduplicate messages based on message_id
#                 if message_cache.exists(message_id):
#                     logger.info(f"Duplicate message detected and skipped: {message_id}")
#                     continue
                
#                 if sender_id not in user_chats:
#                     user_chats[sender_id] = []
#                 user_chats[sender_id].append({
                   
#                     "role": "user",
#                     "content": content
#                 })

#                 history = "".join([f"{item['role']}: {item['content']}\n" for item in user_chats[sender_id]])
#                 print(f"history: {history}")

#                 try:
#                     # Process message with retry logic
#                     result = await process_message_with_retry(
#                         sender_id,content,
#                         history,
#                         timestamp, 
#                     )
#                     user_chats[sender_id].append({
              
#                     "role": "assistant",
#                     "content": result
#                     })

#                     # Add the message ID to the cache
#                     message_cache.add(message_id)
#                     processed_count += 1
#                     results.append(result)
#                 except Exception as e:
#                     error_count += 1
#                     logger.error(
#                         f"Failed to process message {message_id}: {str(e)}",
#                         exc_info=True
#                     )
#                     results.append({
#                         "status": "error",
#                         "message_id": message_id,
#                         "error": str(e)
#                     })

#     response_data = {
#         "request_id": request_id,
#         "processed": processed_count,
#         "errors": error_count,
#         "results": results
#     }

#     logger.info(
#         f"Webhook processing completed - "
#         f"Processed: {processed_count}, Errors: {error_count}"
#     )

#     return JSONResponse(
#         content=response_data,
#         status_code=status.HTTP_200_OK
#     )



# @app.get("/webhook")
# async def verify_webhook(request: Request):
#     mode = request.query_params.get('hub.mode')
#     token = request.query_params.get('hub.verify_token')
#     challenge = request.query_params.get('hub.challenge')

#     # Replace 'your_verification_token' with the token you set in Facebook Business Manager
#     if mode == 'subscribe' and token == 'test':
#            # Return the challenge as plain text
#         return Response(content=challenge, media_type="text/plain")
#     else:
#         raise HTTPException(status_code=403, detail="Verification failed")