"""
raven.core.processors
~~~~~~~~~~~~~~~~~~~~~

:copyright: (c) 2010-2012 by the Sentry Team, see AUTHORS for more details.
:license: BSD, see LICENSE for more details.
"""
from __future__ import absolute_import

import re

from raven.utils import varmap
from raven.utils import six


class Processor(object):
    def __init__(self, client):
        self.client = client

    def get_data(self, data, **kwargs):
        return

    def process(self, data, **kwargs):
        resp = self.get_data(data, **kwargs)
        if resp:
            data = resp

        if 'stacktrace' in data:
            self.filter_stacktrace(data['stacktrace'])

        if 'exception' in data:
            if 'stacktrace' in data['exception']:
                self.filter_stacktrace(data['exception']['stacktrace'])

        if 'request' in data:
            self.filter_http(data['request'])

        return data

    def filter_stacktrace(self, data):
        pass

    def filter_http(self, data):
        pass


class RemovePostDataProcessor(Processor):
    """
    Removes HTTP post data.
    """
    def filter_http(self, data, **kwargs):
        data.pop('data', None)


class RemoveStackLocalsProcessor(Processor):
    """
    Removes local context variables from stacktraces.
    """
    def filter_stacktrace(self, data, **kwargs):
        for frame in data.get('frames', []):
            frame.pop('vars', None)


class SanitizePasswordsProcessor(Processor):
    """
    Asterisk out things that look like passwords, credit card numbers,
    and API keys in frames, http, and basic extra data.
    """
    MASK = '*' * 8
    FIELDS = frozenset([
        'password', 'secret', 'passwd', 'authorization', 'api_key', 'apikey'
    ])
    VALUES_RE = re.compile(r'^(?:\d[ -]*?){13,16}$')

    def sanitize(self, key, value):
        if value is None:
            return

        if isinstance(value, six.string_types) and self.VALUES_RE.match(value):
            return self.MASK

        if not key:  # key can be a NoneType
            return value

        key = key.lower()
        for field in self.FIELDS:
            if field in key:
                # store mask as a fixed length for security
                return self.MASK
        return value

    def filter_stacktrace(self, data):
        if 'frames' not in data:
            return
        for frame in data['frames']:
            if 'vars' not in frame:
                continue
            frame['vars'] = varmap(self.sanitize, frame['vars'])

    def filter_http(self, data):
        for n in ('data', 'cookies', 'headers', 'env', 'query_string'):
            if n not in data:
                continue

            if isinstance(data[n], six.string_types) and '=' in data[n]:
                # at this point we've assumed it's a standard HTTP query
                querybits = []
                for bit in data[n].split('&'):
                    chunk = bit.split('=')
                    if len(chunk) == 2:
                        querybits.append((chunk[0], self.sanitize(*chunk)))
                    else:
                        querybits.append(chunk)

                data[n] = '&'.join('='.join(k) for k in querybits)
            else:
                data[n] = varmap(self.sanitize, data[n])