"""Email backend that writes messages to a file."""

import datetime

import os

from django.conf import settings

from django.core.exceptions import ImproperlyConfigured

from django.core.mail.backends.console import EmailBackend as ConsoleEmailBackend

class EmailBackend(ConsoleEmailBackend):

    def __init__(self, *args, **kwargs):

        self._fname = None

        if 'file_path' in kwargs:

            self.file_path = kwargs.pop('file_path')

        else:

            self.file_path = getattr(settings, 'EMAIL_FILE_PATH',None)

        # Make sure self.file_path is a string.

        if not isinstance(self.file_path, basestring):

            raise ImproperlyConfigured('Path for saving emails is invalid: %r' % self.file_path)

        self.file_path = os.path.abspath(self.file_path)

        # Make sure that self.file_path is an directory if it exists.

        if os.path.exists(self.file_path) and not os.path.isdir(self.file_path):

            raise ImproperlyConfigured('Path for saving email messages exists, but is not a directory: %s' % self.file_path)

        # Try to create it, if it not exists.

        elif not os.path.exists(self.file_path):

            try:

                os.makedirs(self.file_path)

            except OSError, err:

                raise ImproperlyConfigured('Could not create directory for saving email messages: %s (%s)' % (self.file_path, err))

        # Make sure that self.file_path is writable.

        if not os.access(self.file_path, os.W_OK):

            raise ImproperlyConfigured('Could not write to directory: %s' % self.file_path)

        # Finally, call super().

        # Since we're using the console-based backend as a base,

        # force the stream to be None, so we don't default to stdout

        kwargs['stream'] = None

        super(EmailBackend, self).__init__(*args, **kwargs)

    def _get_filename(self):

        """Return a unique file name."""

        if self._fname is None:

            timestamp = datetime.datetime.now().strftime("%Y%m%d-%H%M%S")

            fname = "%s-%s.log" % (timestamp, abs(id(self)))

            self._fname = os.path.join(self.file_path, fname)

        return self._fname

    def open(self):

        if self.stream is None:

            self.stream = open(self._get_filename(), 'a')

            return True

        return False

    def close(self):

        try:

            if self.stream is not None:

                self.stream.close()

        finally:

            self.stream = None