#!/usr/bin/env python3
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"""Defines the interfaces for the communication and its child processes"""

import time
from abc import ABC, abstractmethod
from multiprocessing import Process
from typing import Any

from ..helpers.click_helpers import recho
from ..helpers.logger import get_listener, logger
from .parameter import ComControl


class ComInterface:
    """Base class for communication interfaces.
    Manages process control, logging, and process lifecycle for communication backends.
    """

    def __init__(self, name: str) -> None:
        """Initializes the communication interface.

        Args:
            name (str): Name of the communication interface instance.
        """
        self.name = name
        self.control = ComControl(log_level=logger.level)
        self._processes: dict[str, ProcessInterface] = {}
        # Listener is used to log messages received from other processes via
        # the control.logger queue. Without Listener and logging.QueueHandler,
        # two logging messages would be printed simultaneously.
        self.log_listener = get_listener(self.control.logger)

    def start(self) -> None:
        """Starts all managed processes and waits until they are ready.
        Also starts the logging listener.

        Raises:
            ChildProcessError: If a process terminates during initialization.
        """
        self.log_listener.start()
        if self._processes:
            for x in self._processes.values():
                # If more than one process is needed for communication, the
                # ready event must be reset, otherwise not all processes are started
                if x.control.ready.is_set():
                    x.control.ready.clear()
                logger.debug("Start: %s", x)
                x.start()
                while not x.control.ready.is_set():
                    if x.control.shutdown.is_set():
                        error_text = (
                            f"Process {x.name} terminated during initialization."
                        )
                        raise ChildProcessError(error_text)
                    time.sleep(0.1)
        else:
            recho("No process available")

    def shutdown(self, block: bool = False, timeout: int | None = None) -> None:
        """Signals all processes to shut down and optionally waits until they have finished.

        Args:
            block (bool): If True, blocks until all processes have terminated
                or timeout is reached.
            timeout (int | None): Maximum time to wait in seconds if blocking.
                None means indefinite.
        """
        self.control.shutdown.set()
        start_time = time.time()
        if block:
            while True:
                if not self.is_alive():
                    break
                if timeout and (time.time() - start_time) > timeout:
                    break

    def is_alive(self, process_name: str | None = None) -> bool:
        """Checks whether the managed process or all processes are still alive.

        Args:
            process_name (str | None): Name of the process to check. If None, checks all.

        Returns:
            bool: True if the specified process (or all) is alive, False otherwise.
        """
        if not self._processes:
            return False
        if process_name is None:
            return all(x.is_alive() for x in self._processes.values())
        return self._processes[process_name].is_alive()


class ProcessInterface(Process, ABC):
    """Abstract base class for communication processes.
    Provides shutdown signaling and enforces implementation of the run method.
    """

    name: str
    control: ComControl
    parameter: Any

    def shutdown(self) -> None:
        """Signals the process to shut down by setting the shutdown event."""
        self.control.shutdown.set()

    @abstractmethod
    def run(self) -> None:
        """Main process logic. Must be implemented by subclasses."""