import sys
import logging
import traceback
import platform

from django.utils.timezone import now
from django.views.debug import get_exception_reporter_filter


class AdminHumbugHandler(logging.Handler):
    """An exception log handler that Humbugs log entries to the Humbug realm.

    If the request is passed as the first argument to the log record,
    request data will be provided in the email report.
    """

    # adapted in part from django/utils/log.py

    def __init__(self):
        logging.Handler.__init__(self)

    def emit(self, record):
        # We have to defer imports to avoid circular imports in settings.py.
        from zephyr.models import Recipient
        from zephyr.lib.actions import internal_send_message

        subject = '%s: %s' % (platform.node(), record.getMessage())
        try:
            request = record.request

            filter = get_exception_reporter_filter(request)
            request_repr = "Request info:\n~~~~\n"
            request_repr += "- path: %s\n" % (request.path,)
            if request.method == "GET":
                request_repr += "- GET: %s\n" % (request.GET,)
            elif request.method == "POST":
                request_repr += "- POST: %s\n" % (filter.get_post_parameters(request),)
            for field in ["REMOTE_ADDR", "QUERY_STRING", "SERVER_NAME"]:
                request_repr += "- %s: \"%s\"\n" % (field, request.META.get(field, "(None)"))
            request_repr += "~~~~"
        except Exception:
            request_repr = "Request repr() unavailable."
        subject = self.format_subject(subject)

        if record.exc_info:
            stack_trace = ''.join(traceback.format_exception(*record.exc_info))
        else:
            stack_trace = 'No stack trace available'

        internal_send_message("humbug+errors@humbughq.com",
                Recipient.STREAM, "devel", subject,
                "~~~~ pytb\n%s\n\n~~~~\n%s" % (stack_trace, request_repr))

    def format_subject(self, subject):
        """
        Escape CR and LF characters, and limit length to MAX_SUBJECT_LENGTH.
        """
        from zephyr.models import MAX_SUBJECT_LENGTH
        formatted_subject = subject.replace('\n', '\\n').replace('\r', '\\r')
        return formatted_subject[:MAX_SUBJECT_LENGTH]