api/websocket.py

import json
import base64
import cv2
import numpy as np
import asyncio
from fastapi import WebSocket, WebSocketDisconnect
from services.vision import process_frame_synchronous
from services.attendance import mark_attendance
from core.state import active_connections

async def websocket_endpoint(websocket: WebSocket):
    """
    Hard-Locked WebSocket Connection with Visual Debugging.
    Returns crops and bounding boxes alongside the Truth Report.
    """
    await websocket.accept()
    active_connections.append(websocket)
    
    try:
        while True:
            data = await websocket.receive_text()
            payload = json.loads(data)
            
            if payload.get("type") == "heartbeat":
                await websocket.send_json({"type": "heartbeat_ack"})
                continue
            
            if payload.get("type") == "frame":
                encoded_data = payload["image"].split(',')[1]
                nparr = np.frombuffer(base64.b64decode(encoded_data), np.uint8)
                frame = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
                
                report, stats = await asyncio.to_thread(process_frame_synchronous, frame)
                
                results_summary = []
                # Prepare visual data for frontend
                client_faces = []
                
                for face in report:
                    name = face["name"]
                    score = face["score"]
                    status = face["status"]
                    
                    # Store data for drawing boxes and showing crops
                    client_faces.append({
                        "name": name,
                        "score": score,
                        "status": status,
                        "box": face["box"],
                        "crop": face["crop_b64"]
                    })
                    
                    if status == "match":
                        # Business Logic: Mark Attendance
                        status_db, time_str = mark_attendance(name)
                        results_summary.append(f"✅ {name} ({score}%)")
                        
                        # Push to session attendance list
                        await websocket.send_json({
                            "type": "attendance",
                            "name": name,
                            "time": time_str or "Just Now",
                            "status": "success"
                        })
                    else:
                        results_summary.append(f"❌ {name} ({score}%)")

                # Detailed Terminal Output
                debug_msg = f"Faces: {stats['detected']} | "
                debug_msg += " | ".join(results_summary) if results_summary else "No faces found."

                # Send frame processing result back to browser
                await websocket.send_json({
                    "type": "ready", 
                    "debug": debug_msg,
                    "faces": client_faces # ALL visual debug data included here
                })
                
    except WebSocketDisconnect:
        if websocket in active_connections:
            active_connections.remove(websocket)