todos.py

import json

FILE_NAME = "todos.json"


def load_tasks():
    try:
        with open(FILE_NAME, "r", encoding="utf-8") as file:
            return json.load(file)
    except FileNotFoundError:
        return []
    except json.JSONDecodeError:
        return []


def save_tasks(tasks):
    with open(FILE_NAME, "w", encoding="utf-8") as file:
        json.dump(tasks, file, indent=2, ensure_ascii=False)


def add_task():
    topic = input("Enter the task topic: ").strip()

    if not topic:
        print("Task topic cannot be empty.")
        return

    tasks = load_tasks()

    if tasks:
        new_id = tasks[-1]["id"] + 1
    else:
        new_id = 1

    new_task = {
        "id": new_id,
        "topic": topic,
        "completed": False
    }

    tasks.append(new_task)
    save_tasks(tasks)
    print(f"Task '{topic}' added successfully.")


def list_tasks():
    tasks = load_tasks()

    if not tasks:
        print("No tasks found.")
        return

    for task in tasks:
        status = "x" if task["completed"] else " "
        print(f"[{status}] {task['id']}. {task['topic']}")


def complete_task():
    tasks = load_tasks()

    list_tasks()
    selected_id = input("Enter the ID of the task to mark as completed: ")

    found = False
    for task in tasks:
        if str(task["id"]) == selected_id:
            task["completed"] = True
            found = True
            break

    if found:
        save_tasks(tasks)
        print(f"Task ID {selected_id} marked as completed.")
    else:
        print(f"Task ID {selected_id} not found.")


def remove_task():
    tasks = load_tasks()

    if not tasks:
        print("No tasks found.")
        return

    list_tasks()
    selected_id = input("Enter the ID of the task to remove: ")

    new_list = [task for task in tasks if str(task["id"]) != selected_id]

    if len(new_list) == len(tasks):
        print(f"Task ID {selected_id} not found.")
    else:
        save_tasks(new_list)
        print(f"Task ID {selected_id} removed successfully.")