# Released under the MIT License. See LICENSE for details.
#
"""Common errors and related functionality."""
from __future__ import annotations

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    pass


class CleanError(Exception):
    """An error that can be presented to the user as a simple message.

    These errors should be completely self-explanatory, to the point where
    a traceback or other context would not be useful.

    A CleanError with no message can be used to inform a script to fail
    without printing any message.

    This should generally be limited to errors that will *always* be
    presented to the user (such as those in high level tool code).
    Exceptions that may be caught and handled by other code should use
    more descriptive exception types.
    """

    def pretty_print(self, flush: bool = False) -> None:
        """Print the error to stdout, using red colored output if available.

        If the error has an empty message, prints nothing (not even a newline).
        """
        from efro.terminal import Clr
        errstr = str(self)
        if errstr:
            print(f'{Clr.SRED}{errstr}{Clr.RST}', flush=flush)


class CommunicationError(Exception):
    """A communication related error has occurred.

    This covers anything network-related going wrong in the sending
    of data or receiving of a response. This error does not imply
    that data was not received on the other end; only that a full
    acknowledgement round trip was not completed.

    These errors should be gracefully handled whenever possible, as
    occasional network outages are generally unavoidable.
    """


class RemoteError(Exception):
    """An error occurred on the other end of some connection.

    This occurs when communication succeeds but another type of error
    occurs remotely. The error string can consist of a remote stack
    trace or a simple message depending on the context.

    Communication systems should raise more specific error types when
    more introspection/control is needed; this is intended somewhat as
    a catch-all.
    """

    def __str__(self) -> str:
        s = ''.join(str(arg) for arg in self.args)
        return f'Remote Exception Follows:\n{s}'


class IntegrityError(ValueError):
    """Data has been tampered with or corrupted in some form."""


def is_urllib_network_error(exc: BaseException) -> bool:
    """Is the provided exception from urllib a network-related error?

    This should be passed an exception which resulted from opening or
    reading a urllib Request. It returns True for any errors that could
    conceivably arise due to unavailable/poor network connections,
    firewall/connectivity issues, etc. These issues can often be safely
    ignored or presented to the user as general 'network-unavailable'
    states.
    """
    import urllib.error
    import http.client
    import errno
    import socket
    if isinstance(
            exc,
        (urllib.error.URLError, ConnectionError, http.client.IncompleteRead,
         http.client.BadStatusLine, socket.timeout)):
        # Special case: although an HTTPError is a subclass of URLError,
        # we don't return True for it. It means we have successfully
        # communicated with the server but what we are asking for is
        # not there/etc.
        if isinstance(exc, urllib.error.HTTPError):
            return False
        return True
    if isinstance(exc, OSError):
        if exc.errno == 10051:  # Windows unreachable network error.
            return True
        if exc.errno in {
                errno.ETIMEDOUT,
                errno.EHOSTUNREACH,
                errno.ENETUNREACH,
        }:
            return True
    return False


def is_udp_network_error(exc: BaseException) -> bool:
    """Is the provided exception a network-related error?

    This should be passed an exception which resulted from creating and
    using a socket.SOCK_DGRAM type socket. It should return True for any
    errors that could conceivably arise due to unavailable/poor network
    connections, firewall/connectivity issues, etc. These issues can often
    be safely ignored or presented to the user as general
    'network-unavailable' states.
    """
    import errno
    if isinstance(exc, ConnectionRefusedError):
        return True
    if isinstance(exc, OSError):
        if exc.errno == 10051:  # Windows unreachable network error.
            return True
        if exc.errno in {
                errno.EADDRNOTAVAIL,
                errno.ETIMEDOUT,
                errno.EHOSTUNREACH,
                errno.ENETUNREACH,
                errno.EINVAL,
                errno.EPERM,
                errno.EACCES,
                # Windows 'invalid argument' error.
                10022,
                # Windows 'a socket operation was attempted to'
                #         'an unreachable network' error.
                10051,
        }:
            return True
    return False


def is_asyncio_streams_network_error(exc: BaseException) -> bool:
    """Is the provided exception a network-related error?

    This should be passed an exception which resulted from creating and
    using asyncio streams. It should return True for any errors that could
    conceivably arise due to unavailable/poor network connections,
    firewall/connectivity issues, etc. These issues can often be safely
    ignored or presented to the user as general 'connection-lost' events.
    """
    import errno
    import ssl

    if isinstance(exc, (
            ConnectionError,
            TimeoutError,
            EOFError,
    )):
        return True

    # Also some specific errno ones.
    if isinstance(exc, OSError):
        if exc.errno == 10051:  # Windows unreachable network error.
            return True
        if exc.errno in {
                errno.ETIMEDOUT,
                errno.EHOSTUNREACH,
                errno.ENETUNREACH,
        }:
            return True

    # Am occasionally getting a specific SSL error on shutdown which I
    # believe is harmless (APPLICATION_DATA_AFTER_CLOSE_NOTIFY).
    # It sounds like it may soon be ignored by Python (as of March 2022).
    # Let's still complain, however, if we get any SSL errors besides
    # this one. https://bugs.python.org/issue39951
    if isinstance(exc, ssl.SSLError):
        if 'APPLICATION_DATA_AFTER_CLOSE_NOTIFY' in str(exc):
            return True

    return False