# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from ._base import Config
from synapse.util.logcontext import LoggingContextFilter
from twisted.logger import globalLogBeginner, STDLibLogObserver
import logging
import logging.config
import yaml
from string import Template
import os
import signal


DEFAULT_LOG_CONFIG = Template("""
version: 1

formatters:
  precise:
   format: '%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s\
- %(message)s'

filters:
  context:
    (): synapse.util.logcontext.LoggingContextFilter
    request: ""

handlers:
  file:
    class: logging.handlers.RotatingFileHandler
    formatter: precise
    filename: ${log_file}
    maxBytes: 104857600
    backupCount: 10
    filters: [context]
    level: INFO
  console:
    class: logging.StreamHandler
    formatter: precise
    filters: [context]

loggers:
    synapse:
        level: INFO

    synapse.storage.SQL:
        level: INFO

root:
    level: INFO
    handlers: [file, console]
""")


class LoggingConfig(Config):

    def read_config(self, config):
        self.verbosity = config.get("verbose", 0)
        self.log_config = self.abspath(config.get("log_config"))
        self.log_file = self.abspath(config.get("log_file"))

    def default_config(self, config_dir_path, server_name, **kwargs):
        log_file = self.abspath("homeserver.log")
        log_config = self.abspath(
            os.path.join(config_dir_path, server_name + ".log.config")
        )
        return """
        # Logging verbosity level.
        verbose: 0

        # File to write logging to
        log_file: "%(log_file)s"

        # A yaml python logging config file
        log_config: "%(log_config)s"
        """ % locals()

    def read_arguments(self, args):
        if args.verbose is not None:
            self.verbosity = args.verbose
        if args.log_config is not None:
            self.log_config = args.log_config
        if args.log_file is not None:
            self.log_file = args.log_file

    def add_arguments(cls, parser):
        logging_group = parser.add_argument_group("logging")
        logging_group.add_argument(
            '-v', '--verbose', dest="verbose", action='count',
            help="The verbosity level."
        )
        logging_group.add_argument(
            '-f', '--log-file', dest="log_file",
            help="File to log to."
        )
        logging_group.add_argument(
            '--log-config', dest="log_config", default=None,
            help="Python logging config file"
        )

    def generate_files(self, config):
        log_config = config.get("log_config")
        if log_config and not os.path.exists(log_config):
            with open(log_config, "wb") as log_config_file:
                log_config_file.write(
                    DEFAULT_LOG_CONFIG.substitute(log_file=config["log_file"])
                )

    def setup_logging(self):
        setup_logging(self.log_config, self.log_file, self.verbosity)


def setup_logging(log_config=None, log_file=None, verbosity=None):
    log_format = (
        "%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s"
        " - %(message)s"
    )
    if log_config is None:

        level = logging.INFO
        level_for_storage = logging.INFO
        if verbosity:
            level = logging.DEBUG
            if verbosity > 1:
                level_for_storage = logging.DEBUG

        # FIXME: we need a logging.WARN for a -q quiet option
        logger = logging.getLogger('')
        logger.setLevel(level)

        logging.getLogger('synapse.storage').setLevel(level_for_storage)

        formatter = logging.Formatter(log_format)
        if log_file:
            # TODO: Customisable file size / backup count
            handler = logging.handlers.RotatingFileHandler(
                log_file, maxBytes=(1000 * 1000 * 100), backupCount=3
            )

            def sighup(signum, stack):
                logger.info("Closing log file due to SIGHUP")
                handler.doRollover()
                logger.info("Opened new log file due to SIGHUP")

            # TODO(paul): obviously this is a terrible mechanism for
            #   stealing SIGHUP, because it means no other part of synapse
            #   can use it instead. If we want to catch SIGHUP anywhere
            #   else as well, I'd suggest we find a nicer way to broadcast
            #   it around.
            if getattr(signal, "SIGHUP"):
                signal.signal(signal.SIGHUP, sighup)
        else:
            handler = logging.StreamHandler()
        handler.setFormatter(formatter)

        handler.addFilter(LoggingContextFilter(request=""))

        logger.addHandler(handler)
    else:
        with open(log_config, 'r') as f:
            logging.config.dictConfig(yaml.load(f))

    # It's critical to point twisted's internal logging somewhere, otherwise it
    # stacks up and leaks kup to 64K object;
    # see: https://twistedmatrix.com/trac/ticket/8164
    #
    # Routing to the python logging framework could be a performance problem if
    # the handlers blocked for a long time as python.logging is a blocking API
    # see https://twistedmatrix.com/documents/current/core/howto/logger.html
    # filed as https://github.com/matrix-org/synapse/issues/1727
    #
    # However this may not be too much of a problem if we are just writing to a file.
    observer = STDLibLogObserver()
    globalLogBeginner.beginLoggingTo([observer])