ToDoList.py

import json
import os

class ToDoList:
    def __init__(self, filename='todo_list.json'):
        self.filename = filename
        self.tasks = self.load_tasks()

    def load_tasks(self):
        if os.path.exists(self.filename):
            with open(self.filename, 'r') as file:
                return json.load(file)
        return []

    def save_tasks(self):
        with open(self.filename, 'w') as file:
            json.dump(self.tasks, file)

    def add_task(self, task, due_date, priority):
        self.tasks.append({'task': task, 'due_date': due_date, 'priority': priority, 'completed': False})
        self.save_tasks()
        print(f'Task "{task}" with due date "{due_date}" and priority "{priority}" added to the list.')

    def view_tasks(self):
        if not self.tasks:
            print("No tasks in the list.")
            return
        for index, task in enumerate(self.tasks):
            status = "✓" if task['completed'] else "✗"
            print(f"{index + 1}. [{status}] {task['task']} (Due: {task['due_date']}, Priority: {task['priority']})")

    def update_task(self, index, new_task, new_due_date, new_priority):
        if 0 <= index < len(self.tasks):
            self.tasks[index]['task'] = new_task
            self.tasks[index]['due_date'] = new_due_date
            self.tasks[index]['priority'] = new_priority
            self.save_tasks()
            print(f'Task {index + 1} updated to "{new_task}" with due date "{new_due_date}" and priority "{new_priority}".')
        else:
            print("Invalid task number.")

    def delete_task(self, index):
        if 0 <= index < len(self.tasks):
            removed_task = self.tasks.pop(index)
            self.save_tasks()
            print(f'Task "{removed_task["task"]}" removed from the list.')
        else:
            print("Invalid task number.")

    def mark_completed(self, index):
        if 0 <= index < len(self.tasks):
            self.tasks[index]['completed'] = True
            self.save_tasks()
            print(f'Task {index + 1} marked as completed.')
        else:
            print("Invalid task number.")

def main():
    todo_list = ToDoList()
    
    while True:
        print("\nTo-Do List Menu:")
        print("1. Add Task")
        print("2. View Tasks")
        print("3. Update Task")
        print("4. Delete Task")
        print("5. Mark Task as Completed")
        print("6. Exit")
        
        choice = input("Choose an option (1-6): ")
        
        if choice == '1':
            task = input("Enter the task: ")
            due_date = input("Enter the due date (YYYY-MM-DD): ")
            priority = input("Enter the priority (High, Medium, Low): ")
            todo_list.add_task(task, due_date, priority)
        elif choice == '2':
            todo_list.view_tasks()
        elif choice == '3':
            todo_list.view_tasks()
            index = int(input("Enter the task number to update: ")) - 1
            new_task = input("Enter the new task: ")
            new_due_date = input("Enter the new due date (YYYY-MM-DD): ")
            new_priority = input("Enter the new priority (High, Medium, Low): ")
            todo_list.update_task(index, new_task, new_due_date, new_priority)
        elif choice == '4':
            todo_list.view_tasks()
            index = int(input("Enter the task number to delete: ")) - 1
            todo_list.delete_task(index)
        elif choice == '5':
            todo_list.view_tasks()
            index = int(input("Enter the task number to mark as completed: ")) - 1
            todo_list.mark_completed(index)
        elif choice == '6':
            print("Exiting the To-Do List application.")
            break
        else:
            print("Invalid choice. Please try again.")

if __name__ == "__main__":
    main()