import threading
import time

class Scheduler:
    def __init__(self):
        self.tasks = {}

    def add_task(self, task_name, function, interval):
        """
        Adds a new task to the scheduler.

        Parameters:
            task_name (str): Unique name for the task.
            function (callable): The function to run for this task.
            interval (int): Time in seconds between each execution of the task.
        """
        task = {
            "interval": interval,
            "function": function,
            "stop_event": threading.Event(),
            "thread": threading.Thread(target=self.run_task, args=(task_name,), daemon=True)
        }
        self.tasks[task_name] = task
        task["thread"].start()

    def run_task(self, task_name):
        """
        Executes the task in a loop until its stop event is set.

        Parameters:
            task_name (str): The name of the task to run.
        """
        task = self.tasks[task_name]
        while not task["stop_event"].is_set():
            task["function"]()
            task["stop_event"].wait(task["interval"])

    def stop_task(self, task_name):
        """
        Stops the specified task.

        Parameters:
            task_name (str): The name of the task to stop.
        """
        if task_name in self.tasks:
            self.tasks[task_name]["stop_event"].set()

    def stop_all_tasks(self):
        """
        Stops all tasks managed by the scheduler.
        """
        for task_name in self.tasks.keys():
            self.stop_task(task_name)