src/streamlit_app.py

import streamlit as st
import cv2
from ultralytics import YOLO
import tempfile
import time
from crewai import Agent, Task, Crew
from langchain_groq import ChatGroq

# --- CONFIG ---
st.set_page_config(page_title="CityFlow AI", page_icon="🚦", layout="wide")

# --- SIDEBAR ---
with st.sidebar:
    st.header("🚦 CityFlow Control")
    groq_api_key = st.text_input("Groq API Key", type="password")
    uploaded_file = st.file_uploader("Upload CCTV Footage", type=['mp4', 'mov'])
    confidence = st.slider("Detection Confidence", 0.0, 1.0, 0.3)

# --- MAIN APP ---
st.title("🚦 CityFlow: Autonomous Traffic Management")
st.markdown("Real-time computer vision + Multi-Agent reasoning to optimize traffic flow.")

# Initialize Model (YOLOv8n is small and fast)
@st.cache_resource
def load_model():
    return YOLO('yolov8n.pt')

model = load_model()

# --- THE AGENTS ---
if groq_api_key:
    llm = ChatGroq(temperature=0, model_name="llama-3.3-70b-versatile", groq_api_key=groq_api_key)

    # Agent 1: The Traffic Analyst (Reads the data)
    analyst = Agent(
        role='Traffic Data Analyst',
        goal='Analyze vehicle counts and congestion levels to determine traffic severity.',
        backstory="You are an expert in urban flow. You look at raw numbers (car counts) and decide if it's 'Light', 'Heavy', or 'Gridlock'.",
        llm=llm,
        verbose=False
    )

    # Agent 2: The Signal Controller (Makes the decision)
    controller = Agent(
        role='Signal Control Officer',
        goal='Decide the optimal traffic light duration based on severity.',
        backstory="You control the city lights. If an ambulance is seen, you MUST open the lane. If traffic is heavy, extend Green light duration.",
        llm=llm,
        verbose=False
    )

# --- VIDEO PROCESSING LOOP ---
if uploaded_file and groq_api_key:
    # Save temp file
    tfile = tempfile.NamedTemporaryFile(delete=False)
    tfile.write(uploaded_file.read())
    cap = cv2.VideoCapture(tfile.name)

    col1, col2 = st.columns([2, 1])
    
    with col1:
        st_frame = st.empty()
    
    with col2:
        st_metrics = st.empty()
        st_decision = st.empty()

    frame_count = 0
    
    # Process Video
    while cap.isOpened():
        ret, frame = cap.read()
        if not ret:
            break
            
        frame_count += 1
        
        # Only run AI every 10 frames to keep it fast
        if frame_count % 10 == 0:
            
            # 1. PERCEPTION (YOLO)
            results = model.track(frame, persist=True, conf=confidence)
            
            # Count Vehicles
            car_count = 0
            emergency_count = 0
            
            # Classes: 2=Car, 3=Motorcycle, 5=Bus, 7=Truck
            # We assume class 0 is person, so we filter for vehicles.
            # Note: Standard COCO dataset doesn't distinguish "ambulance", 
            # so we'll simulate emergency logic if we see a Truck (class 7) for this demo.
            
            for result in results:
                boxes = result.boxes
                for box in boxes:
                    cls = int(box.cls[0])
                    if cls in [2, 3, 5, 7]: 
                        car_count += 1
                    if cls == 7: # Simulating "Truck/Emergency" for demo logic
                        emergency_count += 1

            # Draw Boxes on Frame
            res_plotted = results[0].plot()
            
            # 2. REASONING (CrewAI)
            # We pass the real-time data to the agents
            
            task_analyze = Task(
                description=f"Current Status: {car_count} vehicles detected. {emergency_count} heavy/emergency vehicles. Analyze congestion level.",
                agent=analyst,
                expected_output="A short status: 'Light', 'Moderate', 'Critical'."
            )
            
            task_control = Task(
                description="Based on the analysis, decide the Green Light duration (in seconds). If Status is Critical or Emergency detected, set to MAX (60s).",
                agent=controller,
                expected_output="JSON: {'status': '...', 'green_light_duration': 45, 'reason': '...'}"
            )

            # Creating a mini-crew for this single frame decision
            # (In production, you'd run this async, not blocking the video)
            crew = Crew(agents=[analyst, controller], tasks=[task_analyze, task_control])
            decision = crew.kickoff()

            # 3. VISUALIZATION
            st_frame.image(res_plotted, channels="BGR")
            
            st_metrics.metric(label="Vehicles Detected", value=car_count)
            st_metrics.metric(label="Emergency/Heavy", value=emergency_count)
            
            st_decision.info(f"🤖 AI Decision: \n\n{decision}")

    cap.release()