#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Part of the Reusables package.
#
# Copyright (c) 2014-2020 - Chris Griffith - MIT License
"""
Logging helper functions and common log formats.
"""
from __future__ import absolute_import
import warnings
import logging
import sys
import io
import contextlib
from logging.handlers import RotatingFileHandler, TimedRotatingFileHandler

from reusables.namespace import Namespace
from reusables.shared_variables import sizes
from reusables.wrappers import log_it, log_exception

__all__ = [
    "log_formats",
    "get_logger",
    "setup_logger",
    "get_registered_loggers",
    "get_file_handler",
    "get_stream_handler",
    "add_file_handler",
    "add_stream_handler",
    "add_rotating_file_handler",
    "add_timed_rotating_file_handler",
    "change_logger_levels",
    "remove_all_handlers",
    "remove_file_handlers",
    "remove_stream_handlers",
    "setup_logger",
    "log_it",
    "log_exception",
    "LoggerIOWrapper",
]

log_formats = Namespace(
    {
        "common": "%(asctime)s - %(name)s - %(levelname)s - %(message)s",
        "level_first": "%(levelname)s - %(name)s - %(asctime)s - %(message)s",
        "threaded": "%(relativeCreated)d %(threadName)s : %(message)s",
        "easy_read": "%(asctime)s - %(name)-12s  %(levelname)-8s %(message)s",
        "easy_thread": "%(relativeCreated)8d %(threadName)s : %(name)-12s " "%(levelname)-8s  %(message)s",
        "detailed": "%(asctime)s : %(relativeCreated)5d %(threadName)s : %(name)s " "%(levelname)s %(message)s",
    }
)

if sys.version_info < (2, 7):

    class NullHandler(logging.Handler):
        def emit(self, record):
            pass

    logging.NullHandler = NullHandler


def get_logger(*args, **kwargs):
    """ Depreciated, use setup_logger"""
    warnings.warn("get_logger is changing name to setup_logger", DeprecationWarning)
    return setup_logger(*args, **kwargs)


def get_stream_handler(stream=sys.stderr, level=logging.INFO, log_format=log_formats.easy_read):
    """
    Returns a set up stream handler to add to a logger.

    :param stream: which stream to use, defaults to sys.stderr
    :param level: logging level to set handler at
    :param log_format: formatter to use
    :return: stream handler
    """
    sh = logging.StreamHandler(stream)
    sh.setLevel(level)
    sh.setFormatter(logging.Formatter(log_format))
    return sh


def get_file_handler(
    file_path="out.log",
    level=logging.INFO,
    log_format=log_formats.easy_read,
    handler=logging.FileHandler,
    **handler_kwargs,
):
    """
    Set up a file handler to add to a logger.

    :param file_path: file to write the log to, defaults to out.log
    :param level: logging level to set handler at
    :param log_format: formatter to use
    :param handler: logging handler to use, defaults to FileHandler
    :param handler_kwargs: options to pass to the handler
    :return: handler
    """
    fh = handler(file_path, **handler_kwargs)
    fh.setLevel(level)
    fh.setFormatter(logging.Formatter(log_format))
    return fh


def setup_logger(
    module_name=None,
    level=logging.INFO,
    stream=sys.stderr,
    file_path=None,
    log_format=log_formats.easy_read,
    suppress_warning=True,
):
    """
    Grabs the specified logger and adds wanted handlers to it. Will
    default to adding a stream handler.

    :param module_name: logger name to use
    :param level: logging level to set logger at
    :param stream: stream to log to, or None
    :param file_path: file path to log to, or None
    :param log_format: format to set the handlers to use
    :param suppress_warning: add a NullHandler if no other handler is specified
    :return: configured logger
    """
    new_logger = logging.getLogger(module_name)

    if stream:
        new_logger.addHandler(get_stream_handler(stream, level, log_format))
    elif not file_path and suppress_warning and not new_logger.handlers:
        new_logger.addHandler(logging.NullHandler())

    if file_path:
        new_logger.addHandler(get_file_handler(file_path, level, log_format))
    if level > 0:
        new_logger.setLevel(level)
    return new_logger


def add_stream_handler(logger=None, stream=sys.stderr, level=logging.INFO, log_format=log_formats.easy_read):
    """
    Addes a newly created stream handler to the specified logger

    :param logger: logging name or object to modify, defaults to root logger
    :param stream: which stream to use, defaults to sys.stderr
    :param level: logging level to set handler at
    :param log_format: formatter to use
    """
    if not isinstance(logger, logging.Logger):
        logger = logging.getLogger(logger)

    logger.addHandler(get_stream_handler(stream, level, log_format))


def add_file_handler(logger=None, file_path="out.log", level=logging.INFO, log_format=log_formats.easy_read):
    """
    Addes a newly created file handler to the specified logger

    :param logger: logging name or object to modify, defaults to root logger
    :param file_path: path to file to log to
    :param level: logging level to set handler at
    :param log_format: formatter to use
    """
    if not isinstance(logger, logging.Logger):
        logger = logging.getLogger(logger)

    logger.addHandler(get_file_handler(file_path, level, log_format))


def add_rotating_file_handler(
    logger=None,
    file_path="out.log",
    level=logging.INFO,
    log_format=log_formats.easy_read,
    max_bytes=10 * sizes.mb,
    backup_count=5,
    **handler_kwargs,
):
    """ Adds a rotating file handler to the specified logger.

    :param logger: logging name or object to modify, defaults to root logger
    :param file_path: path to file to log to
    :param level: logging level to set handler at
    :param log_format: log formatter
    :param max_bytes: Max file size in bytes before rotating
    :param backup_count: Number of backup files
    :param handler_kwargs: options to pass to the handler
    """
    if not isinstance(logger, logging.Logger):
        logger = logging.getLogger(logger)

    logger.addHandler(
        get_file_handler(
            file_path,
            level,
            log_format,
            handler=RotatingFileHandler,
            maxBytes=max_bytes,
            backupCount=backup_count,
            **handler_kwargs,
        )
    )


def add_timed_rotating_file_handler(
    logger=None,
    file_path="out.log",
    level=logging.INFO,
    log_format=log_formats.easy_read,
    when="w0",
    interval=1,
    backup_count=5,
    **handler_kwargs,
):
    """ Adds a timed rotating file handler to the specified logger.
    Defaults to weekly rotation, with 5 backups.

    :param logger: logging name or object to modify, defaults to root logger
    :param file_path: path to file to log to
    :param level: logging level to set handler at
    :param log_format: log formatter
    :param when:
    :param interval:
    :param backup_count: Number of backup files
    :param handler_kwargs: options to pass to the handler
    """
    if not isinstance(logger, logging.Logger):
        logger = logging.getLogger(logger)

    logger.addHandler(
        get_file_handler(
            file_path,
            level,
            log_format,
            handler=TimedRotatingFileHandler,
            when=when,
            interval=interval,
            backupCount=backup_count,
            **handler_kwargs,
        )
    )


def remove_stream_handlers(logger=None):
    """
    Remove only stream handlers from the specified logger

    :param logger: logging name or object to modify, defaults to root logger
    """
    if not isinstance(logger, logging.Logger):
        logger = logging.getLogger(logger)

    new_handlers = []
    for handler in logger.handlers:
        # FileHandler is a subclass of StreamHandler so
        # 'if not a StreamHandler' does not work
        if (
            isinstance(handler, logging.FileHandler)
            or isinstance(handler, logging.NullHandler)
            or (isinstance(handler, logging.Handler) and not isinstance(handler, logging.StreamHandler))
        ):
            new_handlers.append(handler)
    logger.handlers = new_handlers


def remove_file_handlers(logger=None):
    """
    Remove only file handlers from the specified logger. Will go through
    and close each handler for safety.

    :param logger: logging name or object to modify, defaults to root logger
    """
    if not isinstance(logger, logging.Logger):
        logger = logging.getLogger(logger)

    new_handlers = []
    for handler in logger.handlers:
        if isinstance(handler, logging.FileHandler):
            handler.close()
        else:
            new_handlers.append(handler)
    logger.handlers = new_handlers


def remove_all_handlers(logger=None):
    """
    Safely remove all handlers from the logger

    :param logger: logging name or object to modify, defaults to root logger
    """
    if not isinstance(logger, logging.Logger):
        logger = logging.getLogger(logger)

    remove_file_handlers(logger)
    logger.handlers = []


def change_logger_levels(logger=None, level=logging.DEBUG):
    """
    Go through the logger and handlers and update their levels to the
    one specified.

    :param logger: logging name or object to modify, defaults to root logger
    :param level: logging level to set at (10=Debug, 20=Info, 30=Warn, 40=Error)
    """
    if not isinstance(logger, logging.Logger):
        logger = logging.getLogger(logger)

    logger.setLevel(level)
    for handler in logger.handlers:
        handler.level = level


def get_registered_loggers(hide_children=False, hide_reusables=False):
    """
    Find the names of all loggers currently registered

    :param hide_children: only return top level logger names
    :param hide_reusables: hide the reusables loggers
    :return: list of logger names
    """

    return [
        logger
        for logger in logging.Logger.manager.loggerDict.keys()
        if not (hide_reusables and "reusables" in logger) and not (hide_children and "." in logger)
    ]


class LoggerIOWrapper(io.IOBase):
    """
    A wrapper around logging.Logger in order to set the logger as a standard stream
    such as redirecting the sys.stdout input like so
    sys.stdout = LoggerIOWrapper(logging.getLogger(__name__))

    :param logger: logger to log the messages to.
    :type logger: logging.Logger
    """

    def __init__(self, logger):
        super().__init__()
        self.logger = logger

    def close(self):
        handlers = (h for h in self.logger.handlers if isinstance(h, logging.FileHandler))
        if handlers:
            for h in handlers:
                h.stream.close()

    def fileno(self):
        for handle in self.logger.handlers:
            with contextlib.suppress(OSError):
                return handle.stream.fileno()
        raise OSError()

    def write(self, message, *args, level=logging.DEBUG, exc_info=False):
        self.logger.log(level, message, *args, exc_info=exc_info)

    def writeable(self):
        return True

    def readable(self):
        return False
