# app.py
from flask import Flask, request, jsonify, session, redirect, url_for
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy.exc import IntegrityError
import bcrypt

app = Flask(__name__)
app.secret_key = 'supersecretkey'

@app.route('/')
def home():
    return "Welcome to the Home Page!"

# Configure PostgreSQL database
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://app_user:your_password@localhost/app_db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)

# User model for SQLAlchemy
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80), unique=True, nullable=False)
    password_hash = db.Column(db.String(120), nullable=False)

    def set_password(self, password):
        """Hash the password and store the hash."""
        self.password_hash = bcrypt.hashpw(password.encode('utf-8'), bcrypt.gensalt()).decode('utf-8')

    def check_password(self, password):
        """Check if the password matches the stored hash."""
        return bcrypt.checkpw(password.encode('utf-8'), self.password_hash.encode('utf-8'))

# Routes
@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        username = request.form['username']
        password = request.form['password']
        
        # Authenticate user (add your logic here)
        user = User.query.filter_by(username=username).first()
        
        if user and user.password == password:
            session['user_id'] = user.id
            return redirect(url_for('welcome'))
        else:
            return 'Invalid username or password'
    
    return '''
        <form method="POST">
            <input type="text" name="username" placeholder="Username"/>
            <input type="password" name="password" placeholder="Password"/>
            <input type="submit" value="Login"/>
        </form>
    '''

@app.route('/welcome')
def welcome():
    if 'user_id' in session:
        return 'Welcome to the landing page!'
    else:
        return redirect(url_for('login'))

@app.route('/admin/users', methods=['GET', 'POST', 'DELETE', 'PUT'])
def manage_users():
    if 'user_id' not in session:
        return redirect(url_for('login'))

    # 1. List all users (GET request)
    if request.method == 'GET':
        users = User.query.all()
        return jsonify([{'id': u.id, 'username': u.username} for u in users])

    # 2. Create a new user (POST request)
    elif request.method == 'POST':
        data = request.form
        username = data.get('username')
        password = data.get('password')

        if username and password:
            new_user = User(username=username)
            new_user.set_password(password)  # Hash the password before storing
            db.session.add(new_user)
            db.session.commit()
            return jsonify({'message': 'User created successfully'}), 201
        return jsonify({'message': 'Username and password required'}), 400

    # 3. Delete a user (DELETE request)
    elif request.method == 'DELETE':
        data = request.form
        username = data.get('username')

        user = User.query.filter_by(username=username).first()
        if user:
            db.session.delete(user)
            db.session.commit()
            return jsonify({'message': 'User deleted successfully'}), 200
        return jsonify({'message': 'User not found'}), 404

    # 4. Modify a user (PUT request)
    elif request.method == 'PUT':
        data = request.form
        username = data.get('username')
        new_username = data.get('new_username')
        new_password = data.get('new_password')

        user = User.query.filter_by(username=username).first()

        if user:
            if new_username:
                user.username = new_username
            if new_password:
                user.set_password(new_password)  # Hash the new password before storing
            db.session.commit()
            return jsonify({'message': 'User updated successfully'}), 200
        return jsonify({'message': 'User not found'}), 404

@app.route('/reset_user')
def reset_user():
    # Define the old username and the new user credentials
    old_username = 'old_username'  # Change this to the current username
    new_username = 'newuser'
    new_password = 'newpassword123'
    
    # Find and delete the old user if they exist
    old_user = User.query.filter_by(username=old_username).first()
    if old_user:
        db.session.delete(old_user)
        db.session.commit()

    # Create a new user with the new username and hashed password
    new_user = User(username=new_username)
    new_user.set_password(new_password)  # Hash the new password
    db.session.add(new_user)
    db.session.commit()

    return f"User '{new_username}' created with password '{new_password}'"


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