#! /usr/bin/python
# -*- coding: utf-8 -*-

import logging as _logging
import os as _os
import sys as _sys
import threading
import time as _time
from logging import DEBUG, ERROR, FATAL, INFO, WARN

import six

from tensorlayer.decorators import deprecated

__all__ = [
    'DEBUG',
    'debug',
    'ERROR',
    'error',
    'FATAL',
    'fatal',
    'INFO',
    'info',
    'WARN',
    'warning',
    'warn',  # Deprecated
    'set_verbosity',
    'get_verbosity'
]

# Don't use this directly. Use _get_logger() instead.
_logger = None
_logger_lock = threading.Lock()

_level_names = {
    FATAL: 'FATAL',
    ERROR: 'ERROR',
    WARN: 'WARN',
    INFO: 'INFO',
    DEBUG: 'DEBUG',
}


def _get_logger():
    global _logger

    # Use double-checked locking to avoid taking lock unnecessarily.
    if _logger is not None:
        return _logger

    _logger_lock.acquire()

    try:
        if _logger:
            return _logger

        # Scope the TensorFlow logger to not conflict with users' loggers.
        logger = _logging.getLogger('tensorlayer')

        # Don't further configure the TensorFlow logger if the root logger is
        # already configured. This prevents double logging in those cases.
        if not _logging.getLogger().handlers:
            # Determine whether we are in an interactive environment
            # This is only defined in interactive shells.
            if hasattr(_sys, "ps1"):
                _interactive = True
            else:
                _interactive = _sys.flags.interactive

            # If we are in an interactive environment (like Jupyter), set loglevel
            # to INFO and pipe the output to stdout.
            if _interactive:
                logger.setLevel(INFO)
                _logging_target = _sys.stdout
            else:
                _logging_target = _sys.stderr

            # Add the output handler.
            _handler = _logging.StreamHandler(_logging_target)
            _handler.setFormatter(_logging.Formatter('[TL] %(message)s'))
            logger.addHandler(_handler)

        _logger = logger
        return _logger

    finally:
        _logger_lock.release()


def log(level, msg, *args, **kwargs):
    _get_logger().log(level, msg, *args, **kwargs)


def debug(msg, *args, **kwargs):
    _get_logger().debug(msg, *args, **kwargs)


def info(msg, *args, **kwargs):
    _get_logger().info(msg, *args, **kwargs)


def error(msg, *args, **kwargs):
    _get_logger().error("ERROR: %s" % msg, *args, **kwargs)


def fatal(msg, *args, **kwargs):
    _get_logger().fatal("FATAL: %s" % msg, *args, **kwargs)


@deprecated(date="2018-09-30", instructions="This API is deprecated. Please use as `tl.logging.warning`")
def warn(msg, *args, **kwargs):
    warning(msg, *args, **kwargs)


def warning(msg, *args, **kwargs):
    _get_logger().warning("WARNING: %s" % msg, *args, **kwargs)


# Mask to convert integer thread ids to unsigned quantities for logging
# purposes
_THREAD_ID_MASK = 2 * _sys.maxsize + 1

_log_prefix = None  # later set to google2_log_prefix

# Counter to keep track of number of log entries per token.
_log_counter_per_token = {}


def TaskLevelStatusMessage(msg):
    error(msg)


def flush():
    raise NotImplementedError()


def vlog(level, msg, *args, **kwargs):
    _get_logger().log(level, msg, *args, **kwargs)


def _GetNextLogCountPerToken(token):
    """Wrapper for _log_counter_per_token.

    Args:
    token: The token for which to look up the count.

    Returns:
    The number of times this function has been called with
    *token* as an argument (starting at 0)
    """
    global _log_counter_per_token  # pylint: disable=global-variable-not-assigned
    _log_counter_per_token[token] = 1 + _log_counter_per_token.get(token, -1)
    return _log_counter_per_token[token]


def log_every_n(level, msg, n, *args):
    """Log 'msg % args' at level 'level' once per 'n' times.

    Logs the 1st call, (N+1)st call, (2N+1)st call,  etc.
    Not threadsafe.

    Args:
    level: The level at which to log.
    msg: The message to be logged.
    n: The number of times this should be called before it is logged.
    *args: The args to be substituted into the msg.
    """
    count = _GetNextLogCountPerToken(_GetFileAndLine())
    log_if(level, msg, not (count % n), *args)


def log_first_n(level, msg, n, *args):  # pylint: disable=g-bad-name
    """Log 'msg % args' at level 'level' only first 'n' times.

    Not threadsafe.

    Args:
    level: The level at which to log.
    msg: The message to be logged.
    n: The number of times this should be called before it is logged.
    *args: The args to be substituted into the msg.
    """
    count = _GetNextLogCountPerToken(_GetFileAndLine())
    log_if(level, msg, count < n, *args)


def log_if(level, msg, condition, *args):
    """Log 'msg % args' at level 'level' only if condition is fulfilled."""
    if condition:
        vlog(level, msg, *args)


def _GetFileAndLine():
    """Returns (filename, linenumber) for the stack frame."""
    # Use sys._getframe().  This avoids creating a traceback object.
    # pylint: disable=protected-access
    f = _sys._getframe()
    # pylint: enable=protected-access
    our_file = f.f_code.co_filename
    f = f.f_back
    while f:
        code = f.f_code
        if code.co_filename != our_file:
            return (code.co_filename, f.f_lineno)
        f = f.f_back
    return ('<unknown>', 0)


def google2_log_prefix(level, timestamp=None, file_and_line=None):
    """Assemble a logline prefix using the google2 format."""
    # pylint: disable=global-variable-not-assigned
    global _level_names
    # pylint: enable=global-variable-not-assigned

    # Record current time
    now = timestamp or _time.time()
    now_tuple = _time.localtime(now)
    now_microsecond = int(1e6 * (now % 1.0))

    (filename, line) = file_and_line or _GetFileAndLine()
    basename = _os.path.basename(filename)

    # Severity string
    severity = 'I'
    if level in _level_names:
        severity = _level_names[level][0]

    s = '%c%02d%02d %02d: %02d: %02d.%06d %5d %s: %d] ' % (
        severity,
        now_tuple[1],  # month
        now_tuple[2],  # day
        now_tuple[3],  # hour
        now_tuple[4],  # min
        now_tuple[5],  # sec
        now_microsecond,
        _get_thread_id(),
        basename,
        line
    )

    return s


def get_verbosity():
    """Return how much logging output will be produced."""
    return _get_logger().getEffectiveLevel()


def set_verbosity(v):
    """Sets the threshold for what messages will be logged."""
    _get_logger().setLevel(v)


def _get_thread_id():
    """Get id of current thread, suitable for logging as an unsigned quantity."""
    # pylint: disable=protected-access
    thread_id = six.moves._thread.get_ident()
    # pylint:enable=protected-access
    return thread_id & _THREAD_ID_MASK


_log_prefix = google2_log_prefix