app.py

from flask import Flask, render_template, request, redirect, url_for, flash
from flask_sqlalchemy import SQLAlchemy
from flask_login import LoginManager, UserMixin, login_user, login_required, logout_user, current_user
from werkzeug.security import generate_password_hash, check_password_hash
import os

app = Flask(__name__)
app.config['SECRET_KEY'] = os.urandom(24)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///skillswap.db'
db = SQLAlchemy(app)
login_manager = LoginManager(app)
login_manager.login_view = 'login'

class User(UserMixin, db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)
    password_hash = db.Column(db.String(128))
    skills_to_teach = db.relationship('Skill', backref='teacher', lazy=True, 
                                    foreign_keys='Skill.teacher_id')
    skills_to_learn = db.relationship('Skill', backref='learner', lazy=True,
                                    foreign_keys='Skill.learner_id')

class Skill(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100), nullable=False)
    description = db.Column(db.Text)
    teacher_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    learner_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    status = db.Column(db.String(20), default='available')  # available, matched, completed

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

@app.route('/')
def index():
    skills = Skill.query.filter_by(status='available').all()
    return render_template('index.html', skills=skills)

@app.route('/register', methods=['GET', 'POST'])
def register():
    if request.method == 'POST':
        username = request.form.get('username')
        email = request.form.get('email')
        password = request.form.get('password')
        
        if User.query.filter_by(username=username).first():
            flash('Username already exists')
            return redirect(url_for('register'))
            
        user = User(username=username, email=email)
        user.password_hash = generate_password_hash(password)
        
        db.session.add(user)
        db.session.commit()
        
        return redirect(url_for('login'))
    return render_template('register.html')

@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        username = request.form.get('username')
        password = request.form.get('password')
        user = User.query.filter_by(username=username).first()
        
        if user and check_password_hash(user.password_hash, password):
            login_user(user)
            return redirect(url_for('index'))
        flash('Invalid username or password')
    return render_template('login.html')

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

@app.route('/add_skill', methods=['GET', 'POST'])
@login_required
def add_skill():
    if request.method == 'POST':
        name = request.form.get('name')
        description = request.form.get('description')
        skill_type = request.form.get('type')
        
        skill = Skill(name=name, description=description)
        if skill_type == 'teach':
            skill.teacher_id = current_user.id
        else:
            skill.learner_id = current_user.id
            
        db.session.add(skill)
        db.session.commit()
        return redirect(url_for('profile'))
    return render_template('add_skill.html')

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

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