app.py

from flask import Flask, render_template, redirect, url_for, flash
from flask_login import LoginManager, UserMixin, login_user, login_required, logout_user, current_user
from flask_wtf import FlaskForm
from flask_sqlalchemy import SQLAlchemy
from wtforms import StringField, PasswordField, SubmitField
from wtforms.validators import DataRequired, Length, EqualTo

app = Flask(__name__)
app.config['SECRET_KEY'] = 'seu_segredo_aqui'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///site.db'  # SQLite database
db = SQLAlchemy(app)

class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(20), unique=True, nullable=False)
    password = db.Column(db.String(60), nullable=False)

login_manager = LoginManager(app)
login_manager.login_view = 'login'

@login_manager.user_loader
def load_user(user_id):
    return User.query.get(int(user_id))

class LoginForm(FlaskForm):
    username = StringField('Username', validators=[DataRequired()])
    password = PasswordField('Password', validators=[DataRequired()])
    submit = SubmitField('Login')

class RegistrationForm(FlaskForm):
    username = StringField('Username', validators=[DataRequired(), Length(min=4, max=20)])
    password = PasswordField('Password', validators=[DataRequired(), Length(min=6)])
    confirm_password = PasswordField('Confirm Password', validators=[DataRequired(), EqualTo('password')])
    submit = SubmitField('Register')

@app.route('/')
@login_required
def home():
    return render_template('home.html', username=current_user.username)

@app.route('/login', methods=['GET', 'POST'])
def login():
    form = LoginForm()
    if form.validate_on_submit():
        user = User.query.filter_by(username=form.username.data).first()
        if user and user.password == form.password.data:
            login_user(user)
            return redirect(url_for('home'))
        else:
            flash('Invalid username or password', 'error')
    return render_template('login.html', form=form)

@app.route('/logout')
@login_required
def logout():
    logout_user()
    return redirect(url_for('login'))

@app.route('/register', methods=['GET', 'POST'])
def register():
    form = RegistrationForm()
    if form.validate_on_submit():
        existing_user = User.query.filter_by(username=form.username.data).first()
        if not existing_user:
            new_user = User(username=form.username.data, password=form.password.data)
            db.session.add(new_user)
            db.session.commit()
            flash('Registration successful! Please log in.', 'success')
            return redirect(url_for('login'))
        else:
            flash('Username already exists. Please choose another one.', 'error')
    return render_template('register.html', form=form)

if __name__ == '__main__':
    with app.app_context():
        db.create_all()
    app.run(debug=True)