app.py

from flask import Flask, jsonify, render_template
import joblib, pandas as pd, numpy as np
from datetime import datetime
import psycopg2
from psycopg2 import pool

app = Flask(_name_)

# ---------- Load model bundle ----------
bundle   = joblib.load('gas_danger_model.pkl')
model    = bundle['model']
FEATURES = bundle['features']          # ['Hour', 'Weekday', 'Month', 'Afternoon']

# ---------- PostgreSQL connection pool ----------
PG_POOL = pool.SimpleConnectionPool(
    1, 5,
    user="postgres.czytuqnowdogaowfnfhe",
    password="235711",
    host="aws-0-eu-central-1.pooler.supabase.com",
    port="5432",
    dbname="postgres"
)

# ---------- Per‑gas safety limits ----------
SAFETY_THRESHOLDS = {
    'alcohol': 1000, 'NH3': 25, 'CO': 35, 'CO2': 5000,
    'Toluene': 100, 'acetone': 750, 'lpg': 1000, 'smoke': 1.0
}

# ---------- Helper to fetch latest row ----------
def fetch_latest_reading():
    """
    Returns a dict with keys exactly matching the ones used elsewhere:
    CO2, NH3, alcohol, Toluene, acetone, lpg, CO, smoke, timestamp
    """
    sql = """
        SELECT  co2,
                nh3,
                alcohol,
                toluene,
                acetone,
                lpg,
                co,
                smoke,
                "timestamp"
        FROM    gas_data
        ORDER BY "timestamp" DESC
        LIMIT 1;
    """
    conn = PG_POOL.getconn()
    try:
        with conn.cursor() as cur:
            cur.execute(sql)
            row = cur.fetchone()
            if row is None:
                return None
            raw_keys = ['co2','nh3','alcohol','toluene','acetone',
                        'lpg','co','smoke','timestamp']
            raw = dict(zip(raw_keys, row))
            # Map to mixed‑case keys expected elsewhere
            return {
                'CO2':      raw['co2'],
                'NH3':      raw['nh3'],
                'alcohol':  raw['alcohol'],
                'Toluene':  raw['toluene'],
                'acetone':  raw['acetone'],
                'lpg':      raw['lpg'],
                'CO':       raw['co'],
                'smoke':    raw['smoke'],
                'timestamp':raw['timestamp']
            }
    finally:
        PG_POOL.putconn(conn)

# ---------- Routes ----------
@app.route('/api/predict', methods=['GET'])
def predict():
    current = fetch_latest_reading()
    if current is None:
        return jsonify({'error': 'No rows in gas_data table'}), 404

    ts = current['timestamp']
    now = ts if ts else datetime.now()

    # Add time‑based features
    current.update({
        'Hour': now.hour,
        'Weekday': now.weekday(),
        'Month': now.month,
        'Afternoon': int(12 <= now.hour <= 15)
    })

    # Build feature vector in training order
    X = pd.DataFrame([[current.get(f, np.nan) for f in FEATURES]], columns=FEATURES)
    prob = float(model.predict_proba(X)[0, 1])

    # Per‑gas alert block
    alerts = {
        g: {
            'value': current[g],
            'threshold': thr,
            'status': 'danger' if current[g] > thr else 'safe'
        } for g, thr in SAFETY_THRESHOLDS.items()
    }

    return jsonify({
        'prediction': prob,
        'alerts': alerts,
        'overall_status': 'danger' if prob > 0.4 else 'safe',
        'timestamp': now.isoformat()
    })

@app.route('/')
def dashboard():
    return render_template('dashboard.html')  # supply your own template

if _name_ == '_main_':
    app.run(debug=True, port=5000)