import logging
logger = logging.getLogger("mlagents.envs")

class UnityException(Exception):
    """
    Any error related to ml-agents environment.
    """
    pass

class UnityEnvironmentException(UnityException):
    """
    Related to errors starting and closing environment.
    """
    pass


class UnityActionException(UnityException):
    """
    Related to errors with sending actions.
    """
    pass

class UnityTimeOutException(UnityException):
    """
    Related to errors with communication timeouts.
    """
    def __init__(self, message, log_file_path = None):
        if log_file_path is not None:
            try:
                with open(log_file_path, "r") as f:
                    printing = False
                    unity_error = '\n'
                    for l in f:
                        l=l.strip()
                        if (l == 'Exception') or (l=='Error'):
                            printing = True
                            unity_error += '----------------------\n'
                        if (l == ''):
                            printing = False
                        if printing:
                            unity_error += l + '\n'
                    logger.info(unity_error)
                    logger.error("An error might have occured in the environment. "
                        "You can check the logfile for more information at {}".format(log_file_path))
            except:
                logger.error("An error might have occured in the environment. "
                             "No UnitySDK.log file could be found.")
        super(UnityTimeOutException, self).__init__(message)


class UnityWorkerInUseException(UnityException):
    """
    This error occurs when the port for a certain worker ID is already reserved.
    """

    MESSAGE_TEMPLATE = (
        "Couldn't start socket communication because worker number {} is still in use. "
        "You may need to manually close a previously opened environment "
        "or use a different worker number.")

    def __init__(self, worker_id):
        message = self.MESSAGE_TEMPLATE.format(str(worker_id))
        super(UnityWorkerInUseException, self).__init__(message)