import io
import os
import sys
import copy
import json
import socket
import logging
import traceback
from threading import local
from collections import OrderedDict
from contextlib import contextmanager

def json_handler(obj):
  # if isinstance(obj, (datetime.date, datetime.time)):
  #   return obj.isoformat()
  return repr(obj)

def json_robust_dumps(obj):
  return json.dumps(obj, default=json_handler)

class NiceOrderedDict(OrderedDict):
  def __str__(self):
    return json_robust_dumps(self)

class SwagFormatter(logging.Formatter):
  def __init__(self, swaglogger):
    logging.Formatter.__init__(self, None, '%a %b %d %H:%M:%S %Z %Y')

    self.swaglogger = swaglogger
    self.host = socket.gethostname()

  def format_dict(self, record):
    record_dict = NiceOrderedDict()

    if isinstance(record.msg, dict):
      record_dict['msg'] = record.msg
    else:
      try:
        record_dict['msg'] = record.getMessage()
      except (ValueError, TypeError):
        record_dict['msg'] = [record.msg]+record.args

    record_dict['ctx'] = self.swaglogger.get_ctx()

    if record.exc_info:
      record_dict['exc_info'] = self.formatException(record.exc_info)

    record_dict['level'] = record.levelname
    record_dict['levelnum'] = record.levelno
    record_dict['name'] = record.name
    record_dict['filename'] = record.filename
    record_dict['lineno'] = record.lineno
    record_dict['pathname'] = record.pathname
    record_dict['module'] = record.module
    record_dict['funcName'] = record.funcName
    record_dict['host'] = self.host
    record_dict['process'] = record.process
    record_dict['thread'] = record.thread
    record_dict['threadName'] = record.threadName
    record_dict['created'] = record.created

    return record_dict

  def format(self, record):
    return json_robust_dumps(self.format_dict(record))

class SwagErrorFilter(logging.Filter):
  def filter(self, record):
    return record.levelno < logging.ERROR

def _tmpfunc():
  return 0

def _srcfile():
  return os.path.normcase(_tmpfunc.__code__.co_filename)

class SwagLogger(logging.Logger):
  def __init__(self):
    logging.Logger.__init__(self, "swaglog")

    self.global_ctx = {}

    self.log_local = local()
    self.log_local.ctx = {}

  def local_ctx(self):
    try:
      return self.log_local.ctx
    except AttributeError:
      self.log_local.ctx = {}
      return self.log_local.ctx

  def get_ctx(self):
    return dict(self.local_ctx(), **self.global_ctx)

  @contextmanager
  def ctx(self, **kwargs):
    old_ctx = self.local_ctx()
    self.log_local.ctx = copy.copy(old_ctx) or {}
    self.log_local.ctx.update(kwargs)
    try:
      yield
    finally:
      self.log_local.ctx = old_ctx

  def bind(self, **kwargs):
    self.local_ctx().update(kwargs)

  def bind_global(self, **kwargs):
    self.global_ctx.update(kwargs)

  def event(self, event_name, *args, **kwargs):
    evt = NiceOrderedDict()
    evt['event'] = event_name
    if args:
      evt['args'] = args
    evt.update(kwargs)
    ctx = self.get_ctx()
    if ctx:
      evt['ctx'] = self.get_ctx()
    if 'error' in kwargs:
      self.error(evt)
    else:
      self.info(evt)

  def findCaller(self, stack_info=False, stacklevel=1):
    """
    Find the stack frame of the caller so that we can note the source
    file name, line number and function name.
    """
    f = sys._getframe(3)
    #On some versions of IronPython, currentframe() returns None if
    #IronPython isn't run with -X:Frames.
    if f is not None:
        f = f.f_back
    orig_f = f
    while f and stacklevel > 1:
        f = f.f_back
        stacklevel -= 1
    if not f:
        f = orig_f
    rv = "(unknown file)", 0, "(unknown function)", None
    while hasattr(f, "f_code"):
        co = f.f_code
        filename = os.path.normcase(co.co_filename)
        if filename == _srcfile:
            f = f.f_back
            continue
        sinfo = None
        if stack_info:
            sio = io.StringIO()
            sio.write('Stack (most recent call last):\n')
            traceback.print_stack(f, file=sio)
            sinfo = sio.getvalue()
            if sinfo[-1] == '\n':
                sinfo = sinfo[:-1]
            sio.close()
        rv = (co.co_filename, f.f_lineno, co.co_name, sinfo)
        break
    return rv

if __name__ == "__main__":
  log = SwagLogger()

  stdout_handler = logging.StreamHandler(sys.stdout)
  stdout_handler.setLevel(logging.INFO)
  stdout_handler.addFilter(SwagErrorFilter())
  log.addHandler(stdout_handler)

  stderr_handler = logging.StreamHandler(sys.stderr)
  stderr_handler.setLevel(logging.ERROR)
  log.addHandler(stderr_handler)

  log.info("asdasd %s", "a")
  log.info({'wut': 1})
  log.warning("warning")
  log.error("error")
  log.critical("critical")
  log.event("test", x="y")

  with log.ctx():
    stdout_handler.setFormatter(SwagFormatter(log))
    stderr_handler.setFormatter(SwagFormatter(log))
    log.bind(user="some user")
    log.info("in req")
    print("")
    log.warning("warning")
    print("")
    log.error("error")
    print("")
    log.critical("critical")
    print("")
    log.event("do_req", a=1, b="c")