from flask import Flask, render_template, request, redirect, url_for, jsonify
from flask_sqlalchemy import SQLAlchemy
from flask_socketio import SocketIO, emit
from datetime import datetime, timedelta

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///tasks.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)
socketio = SocketIO(app)

# Database models
class Task(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100), nullable=False)
    priority = db.Column(db.String(1), nullable=False)  # A, B, C, or D
    duration = db.Column(db.Integer, nullable=False)  # Duration in minutes
    status = db.Column(db.String(10), default='pending')
    due_date = db.Column(db.Date, nullable=True)  # Due date for the task
    completed_at = db.Column(db.DateTime, nullable=True)  # Timestamp for when the task was completed

def format_duration(minutes):
    """Convert duration in minutes to 'H M' format."""
    hours = minutes // 60
    remaining_minutes = minutes % 60
    if hours > 0:
        return f"{hours}H {remaining_minutes}M" if remaining_minutes > 0 else f"{hours}H"
    return f"{remaining_minutes}M"

@app.context_processor
def utility_processor():
    return dict(format_duration=format_duration)

def cleanup_completed_tasks():
    """Remove tasks that have been completed for more than 1 hour."""
    expiration_time = datetime.utcnow() - timedelta(hours=1)
    old_tasks = Task.query.filter(Task.status == 'completed', Task.completed_at < expiration_time).all()
    for task in old_tasks:
        db.session.delete(task)
    db.session.commit()

# Routes
@app.route('/')
def index():
    cleanup_completed_tasks()  # Remove old completed tasks

    # Get the sorting parameter from the query string (default is "priority")
    sort_by = request.args.get('sort_by', 'priority')

    # Dynamically sort tasks based on the parameter
    if sort_by == 'priority':
        tasks = Task.query.filter(Task.status == 'pending').order_by(Task.priority).all()
    elif sort_by == 'due_date':
        tasks = Task.query.filter(Task.status == 'pending').order_by(Task.due_date).all()
    elif sort_by == 'duration':
        tasks = Task.query.filter(Task.status == 'pending').order_by(Task.duration).all()
    else:
        tasks = Task.query.filter(Task.status == 'pending').all()  # Default: no sorting

    return render_template('index.html', tasks=tasks, sort_by=sort_by)

@app.route('/add_task', methods=['POST'])
def add_task():
    name = request.form['name']
    priority = request.form['priority']
    duration_input = request.form['duration']
    due_date_input = request.form['due_date']

    # Parse duration (e.g., "10M" -> 10 minutes, "2H" -> 120 minutes)
    if duration_input.endswith('M'):
        duration = int(duration_input[:-1])  # Extract the number before 'M'
    elif duration_input.endswith('H'):
        duration = int(duration_input[:-1]) * 60  # Convert hours to minutes
    else:
        return "Invalid duration format. Use 'M' for minutes or 'H' for hours.", 400

    # Parse due date (e.g., "2025-03-30")
    try:
        due_date = datetime.strptime(due_date_input, '%Y-%m-%d').date() if due_date_input else None
    except ValueError:
        return "Invalid due date format. Use 'YYYY-MM-DD'.", 400

    # Create and save the new task
    new_task = Task(name=name, priority=priority, duration=duration, due_date=due_date)
    db.session.add(new_task)
    db.session.commit()

    # Emit the new task to connected clients
    socketio.emit('task_update', {
        'action': 'add',
        'task': {
            'id': new_task.id,
            'name': name,
            'priority': priority,
            'duration': duration,
            'due_date': due_date_input,
            'status': 'pending'
        }
    })
    return redirect(url_for('index'))

@app.route('/complete_task/<int:task_id>')
def complete_task(task_id):
    task = Task.query.get(task_id)
    if task:
        task.status = 'completed'
        task.completed_at = datetime.utcnow()  # Store the timestamp in UTC
        db.session.commit()
        socketio.emit('task_update', {'action': 'complete', 'task_id': task_id})
    return redirect(url_for('index'))

@app.route('/completed_tasks')
def completed_tasks():
    cleanup_completed_tasks()  # Remove old completed tasks

    # Get the sorting parameter from the query string (default is "completed_at")
    sort_by = request.args.get('sort_by', 'completed_at')

    # Dynamically sort tasks based on the parameter
    if sort_by == 'priority':
        tasks = Task.query.filter(Task.status == 'completed').order_by(Task.priority).all()
    elif sort_by == 'due_date':
        tasks = Task.query.filter(Task.status == 'completed').order_by(Task.due_date).all()
    elif sort_by == 'duration':
        tasks = Task.query.filter(Task.status == 'completed').order_by(Task.duration).all()
    elif sort_by == 'completed_at':
        tasks = Task.query.filter(Task.status == 'completed').order_by(Task.completed_at.desc()).all()
    else:
        tasks = Task.query.filter(Task.status == 'completed').all()  # Default: no sorting

    return render_template('completed_tasks.html', tasks=tasks, sort_by=sort_by)

if __name__ == '__main__':
    with app.app_context():
        # Create database tables within the app context
        db.create_all()
    socketio.run(app, debug=True)