# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
import functools
import logging
import os
import sys
import time
from collections import Counter
from termcolor import colored


class _ColorfulFormatter(logging.Formatter):
    def __init__(self, *args, **kwargs):
        self._root_name = kwargs.pop("root_name") + "."
        self._abbrev_name = kwargs.pop("abbrev_name", "")
        if len(self._abbrev_name):
            self._abbrev_name = self._abbrev_name + "."
        super(_ColorfulFormatter, self).__init__(*args, **kwargs)

    def formatMessage(self, record):
        record.name = record.name.replace(self._root_name, self._abbrev_name)
        log = super(_ColorfulFormatter, self).formatMessage(record)
        if record.levelno == logging.WARNING:
            prefix = colored("WARNING", "red", attrs=["blink"])
        elif record.levelno == logging.ERROR or record.levelno == logging.CRITICAL:
            prefix = colored("ERROR", "red", attrs=["blink", "underline"])
        else:
            return log
        return prefix + " " + log
    

# so that calling setup_logger multiple times won't add many handlers
@functools.lru_cache()
def setup_logger(
    output=None, distributed_rank=0, *, color=True, name="imagenet", abbrev_name=None
):
    """
    Initialize the detectron2 logger and set its verbosity level to "INFO".
    Args:
        output (str): a file name or a directory to save log. If None, will not save log file.
            If ends with ".txt" or ".log", assumed to be a file name.
            Otherwise, logs will be saved to `output/log.txt`.
        name (str): the root module name of this logger
    Returns:
        logging.Logger: a logger
    """
    logger = logging.getLogger(name)
    logger.setLevel(logging.DEBUG)
    logger.propagate = False

    if abbrev_name is None:
        abbrev_name = name

    plain_formatter = logging.Formatter(
        '[%(asctime)s] %(name)s %(levelname)s: %(message)s',
        datefmt='%m/%d %H:%M:%S'
    )
    # stdout logging: master only
    if distributed_rank == 0:
        ch = logging.StreamHandler(stream=sys.stdout)
        ch.setLevel(logging.DEBUG)
        if color:
            formatter = _ColorfulFormatter(
                colored("[%(asctime)s %(name)s]: ", "green") + "%(message)s",
                datefmt="%m/%d %H:%M:%S",
                root_name=name,
                abbrev_name=str(abbrev_name),
            )
        else:
            formatter = plain_formatter
        ch.setFormatter(formatter)
        logger.addHandler(ch)

    # file logging: all workers
    if output is not None:
        if output.endswith(".txt") or output.endswith(".log"):
            filename = output
        else:
            filename = os.path.join(output, "log.txt")
        if distributed_rank > 0:
            filename = filename + f".rank{distributed_rank}"
        os.makedirs(os.path.dirname(filename), exist_ok=True)

        fh = logging.StreamHandler(_cached_log_stream(filename))
        fh.setLevel(logging.DEBUG)
        fh.setFormatter(plain_formatter)
        logger.addHandler(fh)

    return logger


# cache the opened file object, so that different calls to `setup_logger`
# with the same file name can safely write to the same file.
@functools.lru_cache(maxsize=None)
def _cached_log_stream(filename):
    return open(filename, "a")


"""
Below are some other convenient logging methods.
They are mainly adopted from
https://github.com/abseil/abseil-py/blob/master/absl/logging/__init__.py
"""


def _find_caller():
    """
    Returns:
        str: module name of the caller
        tuple: a hashable key to be used to identify different callers
    """
    frame = sys._getframe(2)
    while frame:
        code = frame.f_code
        if os.path.join("utils", "logger.") not in code.co_filename:
            mod_name = frame.f_globals["__name__"]
            if mod_name == "__main__":
                mod_name = "bridgedepth"
            return mod_name, (code.co_filename, frame.f_lineno, code.co_name)
        frame = frame.f_back


_LOG_COUNTER = Counter()
_LOG_TIMER = {}


def log_every_n_seconds(lvl, msg, n=1, *, name=None):
    """
    Log no more than once per n seconds.

    Args:
        lvl (int): the logging level
        msg (str):
        n (int):
        name (str): name of the logger to use. Will use the caller's module by default.
    """
    caller_module, key = _find_caller()
    last_logged = _LOG_TIMER.get(key, None)
    current_time = time.time()
    if last_logged is None or current_time - last_logged > n:
        logging.getLogger(name or caller_module).log(lvl, msg)
        _LOG_TIMER[key] = current_time