task_cli.py

import sys
import json
import os
from datetime import datetime

DB_FILE = 'tasks_db.json'

def load_tasks():
    if not os.path.exists(DB_FILE):
        return []
    try:
        with open(DB_FILE, 'r') as f:
            return json.load(f)
    except (json.JSONDecodeError, IOError):
        return []

def save_tasks(tasks):
    with open(DB_FILE, 'w') as f:
        json.dump(tasks, f, indent=4)

def add_task(description):
    tasks = load_tasks()
    now = datetime.now().isoformat()
    new_task = {
        'id': max([t['id'] for t in tasks], default=0) + 1,
        'description': description,
        'status': 'todo',
        'createdAt': now,
        'updatedAt': now
    }
    tasks.append(new_task)
    save_tasks(tasks)
    print(f"Task added successfully (ID: {new_task['id']})")

def update_task(task_id, description):
    tasks = load_tasks()
    for t in tasks:
        if t['id'] == task_id:
            t['description'] = description
            t['updatedAt'] = datetime.now().isoformat()
            save_tasks(tasks)
            print(f"Task {task_id} updated.")
            return
    print("Task not found.")

def change_status(task_id, status):
    tasks = load_tasks()
    for t in tasks:
        if t['id'] == task_id:
            t['status'] = status
            t['updatedAt'] = datetime.now().isoformat()
            save_tasks(tasks)
            print(f"Task {task_id} marked as {status}.")
            return
    print("Task not found.")

def delete_task(task_id):
    tasks = load_tasks()
    new_tasks = [t for t in tasks if t['id'] != task_id]
    if len(new_tasks) < len(tasks):
        save_tasks(new_tasks)
        print(f"Task {task_id} deleted.")
    else:
        print("Task not found.")

def list_tasks(status_filter=None):
    tasks = load_tasks()
    filtered = [t for t in tasks if status_filter is None or t['status'] == status_filter]
    if not filtered:
        print("No tasks found.")
        return
    for t in filtered:
        print(f"[{t['id']}] {t['description']} | Status: {t['status']}")

def main():
    if len(sys.argv) < 2: return
    cmd = sys.argv[1]
    
    try:
        if cmd == 'add': add_task(" ".join(sys.argv[2:]))
        elif cmd == 'update': update_task(int(sys.argv[2]), " ".join(sys.argv[3:]))
        elif cmd == 'delete': delete_task(int(sys.argv[2]))
        elif cmd == 'mark-in-progress': change_status(int(sys.argv[2]), 'in-progress')
        elif cmd == 'mark-done': change_status(int(sys.argv[2]), 'done')
        elif cmd == 'list':
            status = sys.argv[2] if len(sys.argv) > 2 else None
            list_tasks(status)
    except (IndexError, ValueError):
        print("Usage error. Check your arguments.")

if __name__ == '__main__':
    main()