import functools
import logging
import os
import sys
import threading
from logging import CRITICAL  # NOQA
from logging import DEBUG  # NOQA
from logging import ERROR  # NOQA
from logging import FATAL  # NOQA
from logging import INFO  # NOQA
from logging import NOTSET  # NOQA
from logging import WARN  # NOQA
from logging import WARNING  # NOQA
from typing import Optional


_lock = threading.Lock()
_default_handler: Optional[logging.Handler] = None

log_levels = {
    "debug": logging.DEBUG,
    "info": logging.INFO,
    "warning": logging.WARNING,
    "error": logging.ERROR,
    "critical": logging.CRITICAL,
}

_default_log_level = logging.WARNING

_tqdm_active = True


def _get_default_logging_level():
    """
    If M4_VERBOSITY env var is set to one of the valid choices return that as the new default level. If it is
    not - fall back to `_default_log_level`
    """
    env_level_str = os.getenv("M4_VERBOSITY", None)
    if env_level_str:
        if env_level_str in log_levels:
            return log_levels[env_level_str]
        else:
            logging.getLogger().warning(
                f"Unknown option M4_VERBOSITY={env_level_str}, has to be one of: { ', '.join(log_levels.keys()) }"
            )
    return _default_log_level


def _get_library_name() -> str:
    return __name__.split(".")[0]


def _get_library_root_logger() -> logging.Logger:
    return logging.getLogger(_get_library_name())


def _configure_library_root_logger() -> None:
    global _default_handler

    with _lock:
        if _default_handler:
            # This library has already configured the library root logger.
            return
        _default_handler = logging.StreamHandler()  # Set sys.stderr as stream.
        _default_handler.flush = sys.stderr.flush

        # Apply our default configuration to the library root logger.
        library_root_logger = _get_library_root_logger()
        library_root_logger.addHandler(_default_handler)
        library_root_logger.setLevel(_get_default_logging_level())
        library_root_logger.propagate = False


def _reset_library_root_logger() -> None:
    global _default_handler

    with _lock:
        if not _default_handler:
            return

        library_root_logger = _get_library_root_logger()
        library_root_logger.removeHandler(_default_handler)
        library_root_logger.setLevel(logging.NOTSET)
        _default_handler = None


def get_log_levels_dict():
    return log_levels


def get_logger(name: Optional[str] = None) -> logging.Logger:
    """
    Return a logger with the specified name.

    This function is not supposed to be directly accessed unless you are writing a custom m4 module.
    """

    if name is None:
        name = _get_library_name()

    _configure_library_root_logger()
    return logging.getLogger(name)


def get_verbosity() -> int:
    """
    Return the current level for the 🤗 M4's root logger as an int.

    Returns:
        `int`: The logging level.

    <Tip>

    🤗 M4 has following logging levels:

    - 50: `m4.logging.CRITICAL` or `m4.logging.FATAL`
    - 40: `m4.logging.ERROR`
    - 30: `m4.logging.WARNING` or `m4.logging.WARN`
    - 20: `m4.logging.INFO`
    - 10: `m4.logging.DEBUG`

    </Tip>"""

    _configure_library_root_logger()
    return _get_library_root_logger().getEffectiveLevel()


def set_verbosity(verbosity: int) -> None:
    """
    Set the verbosity level for the 🤗 M4's root logger.

    Args:
        verbosity (`int`):
            Logging level, e.g., one of:

            - `m4.logging.CRITICAL` or `m4.logging.FATAL`
            - `m4.logging.ERROR`
            - `m4.logging.WARNING` or `m4.logging.WARN`
            - `m4.logging.INFO`
            - `m4.logging.DEBUG`
    """

    _configure_library_root_logger()
    _get_library_root_logger().setLevel(verbosity)


def set_verbosity_info():
    """Set the verbosity to the `INFO` level."""
    return set_verbosity(INFO)


def set_verbosity_warning():
    """Set the verbosity to the `WARNING` level."""
    return set_verbosity(WARNING)


def set_verbosity_debug():
    """Set the verbosity to the `DEBUG` level."""
    return set_verbosity(DEBUG)


def set_verbosity_error():
    """Set the verbosity to the `ERROR` level."""
    return set_verbosity(ERROR)


def disable_default_handler() -> None:
    """Disable the default handler of the HuggingFace M4's root logger."""

    _configure_library_root_logger()

    assert _default_handler is not None
    _get_library_root_logger().removeHandler(_default_handler)


def enable_default_handler() -> None:
    """Enable the default handler of the HuggingFace M4's root logger."""

    _configure_library_root_logger()

    assert _default_handler is not None
    _get_library_root_logger().addHandler(_default_handler)


def add_handler(handler: logging.Handler) -> None:
    """adds a handler to the HuggingFace M4's root logger."""

    _configure_library_root_logger()

    assert handler is not None
    _get_library_root_logger().addHandler(handler)


def remove_handler(handler: logging.Handler) -> None:
    """removes given handler from the HuggingFace M4's root logger."""

    _configure_library_root_logger()

    assert handler is not None and handler not in _get_library_root_logger().handlers
    _get_library_root_logger().removeHandler(handler)


def disable_propagation() -> None:
    """
    Disable propagation of the library log outputs. Note that log propagation is disabled by default.
    """

    _configure_library_root_logger()
    _get_library_root_logger().propagate = False


def enable_propagation() -> None:
    """
    Enable propagation of the library log outputs. Please disable the HuggingFace M4's default handler to
    prevent double logging if the root logger has been configured.
    """

    _configure_library_root_logger()
    _get_library_root_logger().propagate = True


def enable_explicit_format() -> None:
    """
    Enable explicit formatting for every HuggingFace M4's logger. The explicit formatter is as follows:
    ```
        [LEVELNAME|FILENAME|LINE NUMBER] TIME >> MESSAGE
    ```
    All handlers currently bound to the root logger are affected by this method.
    """
    handlers = _get_library_root_logger().handlers

    for handler in handlers:
        formatter = logging.Formatter("[%(levelname)s|%(filename)s:%(lineno)s] %(asctime)s >> %(message)s")
        handler.setFormatter(formatter)


def reset_format() -> None:
    """
    Resets the formatting for HuggingFace M4's loggers.

    All handlers currently bound to the root logger are affected by this method.
    """
    handlers = _get_library_root_logger().handlers

    for handler in handlers:
        handler.setFormatter(None)


@functools.lru_cache(None)
def warning_once(self, *args, **kwargs):
    """
    This method is identical to `logger.warning()`, but will emit the warning with the same message only once

    Note: The cache is for the function arguments, so 2 different callers using the same arguments
    will hit the cache. The assumption here is that all warning messages are unique across the code.
    If they aren't then need to switch to another type of cache that includes the caller frame
    information in the hashing function.
    """
    self.warning(*args, **kwargs)


logging.Logger.warning_once = warning_once