from flask import Flask, request, jsonify
from flask_sqlalchemy import SQLAlchemy
from werkzeug.security import generate_password_hash, check_password_hash

app = Flask(__name__)

# Database configuration (SQLite for local testing; replace with MySQL for production)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///users.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)

# User model for database
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80), unique=True, nullable=False)
    password = db.Column(db.String(200), nullable=False)

# Create the database and tables
with app.app_context():
    db.create_all()

@app.route('/login', methods=['POST'])
def login():
    data = request.json
    username = data.get('username')
    password = data.get('password')

    # Find the user in the database
    user = User.query.filter_by(username=username).first()
    if user and check_password_hash(user.password, password):
        return jsonify({"status": "success", "message": f"Welcome, {username}!"})
    return jsonify({"status": "error", "message": "Invalid username or password"}), 401

@app.route('/register', methods=['POST'])
def register():
    data = request.json
    username = data.get('username')
    password = data.get('password')

    # Check if the user already exists
    if User.query.filter_by(username=username).first():
        return jsonify({"status": "error", "message": "Username already exists"}), 400

    # Add the new user to the database
    hashed_password = generate_password_hash(password)
    new_user = User(username=username, password=hashed_password)
    db.session.add(new_user)
    db.session.commit()

    return jsonify({"status": "success", "message": "User registered successfully"})

if __name__ == '__main__':
    app.run(debug=True)