# Copyright 2018 ke liang <lokyse@163.com>.
#
# 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.

import sys
import logging
from markerFormatter import MarkerFormatter


class MDCFormatter(MarkerFormatter):
    """
    A custom MDC formatter to prepare Mapped Diagnostic Context
    to enrich log message.
    """

    def __init__(self, fmt=None, mdcfmt=None,
                 datefmt=None, colorfmt=None, style="%"):
        """
        :param fmt: build-in format string contains standard
               Python %-style mapping keys
        :param mdcFmt: mdc format with '{}'-style mapping keys
        :param datefmt: Date format to use
        :param colorfmt: colored output with ANSI escape code on terminal
        :param style: style mapping keys in python3
        """
        if sys.version_info > (3, 2):
            super(MDCFormatter, self).__init__(fmt=fmt,
                                               datefmt=datefmt,
                                               colorfmt=colorfmt,
                                               style=style)
        elif sys.version_info > (2, 7):
            super(MDCFormatter, self).__init__(fmt=fmt,
                                               datefmt=datefmt,
                                               colorfmt=colorfmt)
        else:
            MarkerFormatter.__init__(self, fmt, datefmt, colorfmt)

        self._mdc_tag = "%(mdc)s"
        if self.style == "{":
            self._mdc_tag = "{mdc}"
        elif self.style == "$":
            self._mdc_tag = "${mdc}"

        if mdcfmt:
            self._mdcFmt = mdcfmt
        else:
            self._mdcFmt = '{reqeustID}'

    def _mdcfmtKey(self):
        """
         maximum barce match algorithm to find the mdc key
        :return: key in brace  and key not in brace,such as ({key}, key)
        """

        left = '{'
        right = '}'
        target = self._mdcFmt
        st = []
        keys = []
        for index, v in enumerate(target):
            if v == left:
                st.append(index)
            elif v == right:

                if len(st) == 0:
                    continue

                elif len(st) == 1:
                    start = st.pop()
                    end = index
                    keys.append(target[start:end + 1])
                elif len(st) > 0:
                    st.pop()

        keys = list(filter(lambda x: x[1:-1].strip('\n \t  ') != "", keys))
        words = None
        if keys:
            words = map(lambda x: x[1:-1], keys)

        return keys, words

    def _replaceStr(self, keys):

        fmt = self._mdcFmt
        for i in keys:
            fmt = fmt.replace(i, i[1:-1] + "=" + i)

        return fmt

    def format(self, record):
        """
        Find mdcs in log record extra field, if key form mdcFmt dosen't
        contains mdcs, the values will be empty.
        :param record: the logging record instance
        :return:  string
        for example:
            the mdcs dict in logging record is
            {'key1':'value1','key2':'value2'}
            the mdcFmt is" '{key1} {key3}'
            the output of mdc message: 'key1=value1 key3='

        """
        mdcIndex = self._fmt.find(self._mdc_tag)
        if mdcIndex == -1:
            if sys.version_info > (2, 7):
                return super(MDCFormatter, self).format(record)
            else:
                return MarkerFormatter.format(self, record)

        mdcFmtkeys, mdcFmtWords = self._mdcfmtKey()

        if mdcFmtWords is None:
            self._fmt = self._fmt.replace(self._mdc_tag, "")
            if sys.version_info > (3, 2):
                self._style = logging._STYLES[self.style][0](self._fmt)

            if sys.version_info > (2, 7):
                return super(MDCFormatter, self).format(record)
            else:
                return MarkerFormatter.format(self, record)

        mdc = record.__dict__.get('mdc', None)
        res = {}
        for i in mdcFmtWords:
            if mdc and i in mdc:
                res[i] = mdc[i]
            else:
                res[i] = ""

        del mdc
        try:
            mdcstr = self._replaceStr(keys=mdcFmtkeys).format(**res)
            self._fmt = self._fmt.replace(self._mdc_tag, mdcstr)

            if sys.version_info > (3, 2):
                self._style = logging._STYLES[self.style][0](self._fmt)

            if sys.version_info > (2, 7):
                return super(MDCFormatter, self).format(record)
            else:
                return MarkerFormatter.format(self, record)

        except KeyError as e:
            print("The mdc key %s format is wrong" % str(e))
        except Exception:
            raise