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 typing import Dict
from app.services.message import generate_reply, send_reply, process_message_with_retry
import logging
from datetime import datetime
import time

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
)
logger = logging.getLogger(__name__)
# Initialize FastAPI app
app = FastAPI()

# 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()

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

    processed_count = 0
    error_count = 0
    results = []

    changes = payload.get("entry", [])[0].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")
            
            # Check for duplicate message ID
                # Check for duplicate message
            if message_cache.exists(message_id):
                logger.info(f"Duplicate message detected: {message_id}")
                continue
            
            try:
                    # Process message with retry logic
                    result = await process_message_with_retry(
                        sender_id,
                        content,
                        timestamp
                    )
                    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)
                })

    # Return detailed response
    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")