app.py

from dotenv import load_dotenv
from flask import Flask,render_template,redirect,request,session
from werkzeug.security import generate_password_hash, check_password_hash
from database import db
from models import User,Task
from waitress import serve
import os

load_dotenv()
app = Flask(__name__)

app.config["SECRET_KEY"] = os.getenv("SECRET_KEY")
app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///taskmanager.db"
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False


db.init_app(app)
    
with app.app_context():
    db.create_all()


@app.route("/")
def home():
    if "user_id" in session:
        return redirect("/dashboard")
    return render_template("home.html")


@app.route("/register", methods=["GET","POST"])
def register():
    if request.method == "POST":
        username = request.form["username"]
        email = request.form["email"]
        password = request.form["password"]

        hashed_password = generate_password_hash(password)

        existing_user = User.query.filter_by(username=username).first()
        existing_email = User.query.filter_by(email=email).first()

        if existing_user or existing_email:
            return render_template("register.html",error ="Username or email already exists",username=username,
            email=email)

        new_user = User(username = username,email=email,password = hashed_password)
        db.session.add(new_user)
        db.session.commit()

        return redirect("/login")
    
    return render_template("register.html")

@app.route("/login", methods = ["GET","POST"])
def login():
    if request.method == "POST":
        email = request.form["email"]
        password = request.form["password"]

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

        if user and check_password_hash(user.password, password):
            session["user_id"] = user.id
            session["username"] = user.username
            return redirect("/dashboard")
        
        return render_template("login.html",error ="Invalid email or password",email=email)
    
    return render_template ("login.html")

@app.route("/dashboard")
def dashboard():
    if "user_id" not in session:
        return redirect("/login")
    
    tasks = Task.query.filter_by(user_id=session["user_id"]).all()
    return render_template("dashboard.html",username=session["username"],tasks=tasks)


@app.route("/logout")
def logout():
    session.pop("user_id",None)
    session.pop("username",None)
    return redirect("/login")

@app.route("/add_task",methods=["GET","POST"])
def add_task():
    if "user_id" not in session:
        return redirect("/login")
    
    if request.method =="POST":
        title = request.form["title"]
        description = request.form["description"]

        new_task=Task(
            title = title,
            description=description,
            user_id=session["user_id"]
        )
    
        db.session.add(new_task)
        db.session.commit()

        return redirect("/dashboard")
    
    return render_template("add_task.html")

@app.route("/edit_task/<int:task_id>", methods=["GET","POST"])
def edit_task(task_id):
    if "user_id" not in session:
        return redirect("/login")
    
    task = Task.query.filter_by(id=task_id,user_id=session["user_id"]).first()

    if not task:
        return "Task not found"
    
    if request.method == "POST":
        task.title = request.form["title"]
        task.description = request.form["description"]
        db.session.commit()
        return redirect("/dashboard")
    
    return render_template("edit_task.html",task=task)

@app.route("/delete_task/<int:task_id>" ,methods=["POST"])
def delete_task(task_id):
    if "user_id" not in session:
        return redirect("/login")
    
    task = Task.query.filter_by(id=task_id,user_id=session["user_id"]).first()

    if not task:
        return "Task not found"
    
    db.session.delete(task)
    db.session.commit()
    return redirect("/dashboard")

@app.route("/complete_task/<int:task_id>",methods=["POST"])
def complete_task(task_id):
    if "user_id" not in session:
        return redirect("/login")
    
    task = Task.query.filter_by(id=task_id,user_id=session["user_id"]).first()

    if not task:
        return "Task not found"
    
    task.status = "Completed"
    db.session.commit()
    return redirect("/dashboard")

@app.after_request
def add_header(response):
    """
    Instructs the browser never to cache pages so the back button 
    won't show protected screens after logout.
    """
    response.headers["Cache-Control"] = "no-store, no-cache, must-revalidate, max-age=0"
    response.headers["Pragma"] = "no-cache"
    response.headers["Expires"] = "0"
    return response


if __name__ == "__main__":
    serve(app, host="0.0.0.0",port=8000)