text: # Copyright (C) 2019 The Electrum developers
  # Distributed under the MIT software license, see the accompanying
  # file LICENCE or http://www.opensource.org/licenses/mit-license.php
  
  import logging
  import datetime
  import sys
  import pathlib
  import os
  import platform
  from typing import Optional
  import copy
  
  
  class LogFormatterForFiles(logging.Formatter):
  
      def formatTime(self, record, datefmt=None):
          # timestamps follow ISO 8601 UTC
          date = datetime.datetime.fromtimestamp(record.created).astimezone(datetime.timezone.utc)
          if not datefmt:
              datefmt = "%Y%m%dT%H%M%S.%fZ"
          return date.strftime(datefmt)
  
      def format(self, record):
          record = _shorten_name_of_logrecord(record)
          return super().format(record)
  
  
  file_formatter = LogFormatterForFiles(fmt="%(asctime)22s | %(levelname)8s | %(name)s | %(message)s")
  
  
  class LogFormatterForConsole(logging.Formatter):
  
      def format(self, record):
          record = _shorten_name_of_logrecord(record)
          return super().format(record)
  
  
  # try to make console log lines short... no timestamp, short levelname, no "electrum."
  console_formatter = LogFormatterForConsole(fmt="%(levelname).1s | %(name)s | %(message)s")
  
  
  def _shorten_name_of_logrecord(record: logging.LogRecord) -> logging.LogRecord:
      record = copy.copy(record)  # avoid mutating arg
      # strip the main module name from the logger name
      if record.name.startswith("electrum."):
          record.name = record.name[9:]
      # manual map to shorten common module names
      record.name = record.name.replace("interface.Interface", "interface", 1)
      record.name = record.name.replace("network.Network", "network", 1)
      record.name = record.name.replace("synchronizer.Synchronizer", "synchronizer", 1)
      record.name = record.name.replace("verifier.SPV", "verifier", 1)
      record.name = record.name.replace("gui.qt.main_window.ElectrumWindow", "gui.qt.main_window", 1)
      return record
  
  
  # enable logs universally (including for other libraries)
  root_logger = logging.getLogger()
  root_logger.setLevel(logging.WARNING)
  
  # log to stderr; by default only WARNING and higher
  console_stderr_handler = logging.StreamHandler(sys.stderr)
  console_stderr_handler.setFormatter(console_formatter)
  console_stderr_handler.setLevel(logging.WARNING)
  root_logger.addHandler(console_stderr_handler)
  
  # creates a logger specifically for electrum library
  electrum_logger = logging.getLogger("electrum")
  electrum_logger.setLevel(logging.DEBUG)
  
  
  def _delete_old_logs(path, keep=10):
      files = sorted(list(pathlib.Path(path).glob("electrum_log_*.log")), reverse=True)
      for f in files[keep:]:
          os.remove(str(f))
  
  
  _logfile_path = None
  def _configure_file_logging(log_directory: pathlib.Path):
      global _logfile_path
      assert _logfile_path is None, 'file logging already initialized'
      log_directory.mkdir(exist_ok=True)
  
      _delete_old_logs(log_directory)
  
      timestamp = datetime.datetime.utcnow().strftime("%Y%m%dT%H%M%SZ")
      PID = os.getpid()
      _logfile_path = log_directory / f"electrum_log_{timestamp}_{PID}.log"
  
      file_handler = logging.FileHandler(_logfile_path)
      file_handler.setFormatter(file_formatter)
      file_handler.setLevel(logging.DEBUG)
      root_logger.addHandler(file_handler)
  
  
  def _configure_verbosity(config):
      verbosity = config.get('verbosity')
      if not verbosity:
          return
      console_stderr_handler.setLevel(logging.DEBUG)
      if verbosity == '*' or not isinstance(verbosity, str):
          return
      # example verbosity:
      #   debug,network=error,interface=error      // effectively blacklists network and interface
      #   warning,network=debug,interface=debug    // effectively whitelists network and interface
      filters = verbosity.split(',')
      for filt in filters:
          if not filt: continue
          items = filt.split('=')
          if len(items) == 1:
              level = items[0]
              electrum_logger.setLevel(level.upper())
          elif len(items) == 2:
              logger_name, level = items
              logger = get_logger(logger_name)
              logger.setLevel(level.upper())
          else:
              raise Exception(f"invalid log filter: {filt}")
  
  
  # --- External API
  
  def get_logger(name: str) -> logging.Logger:
      if name.startswith("electrum."):
          name = name[9:]
      return electrum_logger.getChild(name)
  
  
  _logger = get_logger(__name__)
  _logger.setLevel(logging.INFO)
  
  
  class Logger:
      def __init__(self):
          self.logger = self.__get_logger_for_obj()
  
      def __get_logger_for_obj(self) -> logging.Logger:
          cls = self.__class__
          if cls.__module__:
              name = f"{cls.__module__}.{cls.__name__}"
          else:
              name = cls.__name__
          try:
              diag_name = self.diagnostic_name()
          except Exception as e:
              raise Exception("diagnostic name not yet available?") from e
          if diag_name:
              name += f".[{diag_name}]"
          return get_logger(name)
  
      def diagnostic_name(self):
          return ''
  
  
  def configure_logging(config):
      _configure_verbosity(config)
  
      is_android = 'ANDROID_DATA' in os.environ
      if is_android or config.get('disablefilelogging'):
          pass  # disable file logging
      else:
          log_directory = pathlib.Path(config.path) / "logs"
          _configure_file_logging(log_directory)
  
      # if using kivy, avoid kivy's own logs to get printed twice
      logging.getLogger('kivy').propagate = False
  
      from . import ELECTRUM_VERSION
      _logger.info(f"Electrum version: {ELECTRUM_VERSION} - https://electrum.org - https://github.com/spesmilo/electrum")
      _logger.info(f"Python version: {sys.version}. On platform: {platform.platform()}")
      _logger.info(f"Logging to file: {str(_logfile_path)}")
  
  
  def get_logfile_path() -> Optional[pathlib.Path]:
      return _logfile_path
  