# -*- coding: utf-8; -*-

################################################################################

#

#  Rattail -- Retail Software Framework

#

#  This file is part of Rattail.

#

#  Rattail is free software: you can redistribute it and/or modify it under the

#  terms of the GNU General Public License as published by the Free Software

#  Foundation, either version 3 of the License, or (at your option) any later

#  version.

#

#  Rattail is distributed in the hope that it will be useful, but WITHOUT ANY

#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

#  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more

#  details.

#

#  You should have received a copy of the GNU General Public License along with

#  Rattail.  If not, see <http://www.gnu.org/licenses/>.

#

################################################################################

"""

Common email config objects

"""

from __future__ import unicode_literals, absolute_import

import sys

import socket

from traceback import format_exception

import six

from rattail.mail import Email

from rattail.util import load_object

from rattail.core import Object

from rattail.time import make_utc, localtime

class datasync_error_watcher_get_changes(Email):

    """

    When any datasync watcher thread encounters an error trying to get changes,

    this email is sent out.

    """

    default_subject = "Watcher failed to get changes"

    def sample_data(self, request):

        from rattail.datasync import DataSyncWatcher

        try:

            raise RuntimeError("Fake error for preview")

        except:

            exc_type, exc, traceback = sys.exc_info()

        watcher = DataSyncWatcher(self.config, 'test')

        watcher.consumes_self = True

        return {

            'watcher': watcher,

            'error': exc,

            'traceback': ''.join(format_exception(exc_type, exc, traceback)).strip(),

            'datasync_url': '/datasyncchanges',

            'attempts': 2,

        }

class datasync_error_consumer_process_changes(Email):

    """

    When any datasync consumer thread encounters an error trying to process

    changes, this email is sent out.

    """

    default_subject = "Consumer failed to process changes"

    def sample_data(self, request):

        from rattail.datasync import DataSyncWatcher, DataSyncConsumer

        try:

            raise RuntimeError("Fake error for preview")

        except:

            exc_type, exc, traceback = sys.exc_info()

        watcher = DataSyncWatcher(self.config, 'testwatcher')

        consumer = DataSyncConsumer(self.config, 'testconsumer')

        return {

            'watcher': watcher,

            'consumer': consumer,

            'error': exc,

            'attempts': 2,

            'traceback': ''.join(format_exception(exc_type, exc, traceback)).strip(),

            'datasync_url': '/datasync/changes',

        }

class filemon_action_error(Email):

    """

    When any filemon thread encounters an error (and the retry attempts have

    been exhausted) then it will send out this email.

    """

    default_subject = "Error invoking action(s)"

    def sample_data(self, request):

        from rattail.filemon import Action

        action = Action(self.config)

        action.spec = 'rattail.filemon.actions:Action'

        action.retry_delay = 10

        try:

            raise RuntimeError("Fake error for preview")

        except:

            exc_type, exc, traceback = sys.exc_info()

        return {

            'hostname': socket.gethostname(),

            'path': '/tmp/foo.csv',

            'action': action,

            'attempts': 3,

            'error': exc,

            'traceback': ''.join(format_exception(exc_type, exc, traceback)).strip(),

        }

class ImporterEmail(Email):

    """

    Sent when a "version catch-up" import is performed, which involves changes.

    """

    abstract = True

    fallback_key = 'rattail_import_updates'

    handler_spec = None

    def get_handler(self, config):

        return load_object(self.handler_spec)(config)

    def sample_data(self, request):

        handler = self.get_handler(request.rattail_config)

        obj = Object()

        local_data = {

            'foo': 42,

            'bar': True,

            'baz': 'something',

        }

        host_data = {

            'foo': 42,

            'bar': False,

            'baz': 'something else',

        }

        return {

            'host_title': handler.host_title,

            'local_title': handler.local_title,

            'runtime': "1 second",

            'argv': ['bin/rattail', 'import-something'],

            'changes': {

                'Widget': (

                    [],                             # created

                    [(obj, local_data, host_data)], # updated

                    [],                             # deleted

                ),

            },

            'render_record': lambda x: six.text_type(x),

            'max_display': 15,

        }

class rattail_import_versions_updates(Email):

    """

    Sent when a "version catch-up" import is performed, which involves changes.

    """

    fallback_key = 'rattail_import_updates'

    default_subject = "Changes for Rattail -> Rattail (Versions) import"

class upgrade_failure(Email):

    """

    Sent when an app upgrade is attempted, but ultimately failed.

    """

    default_subject = "Upgrade Failure"

    def sample_data(self, request):

        upgrade = Object(

            description="upgrade to the latest!",

            notes="nothing special",

            executed=make_utc(),

            executed_by="Fred Flintstone",

            exit_code=42,

        )

        return {

            # TODO: first 3 args should be provided by some common logic instead...

            'rattail_config': self.config,

            'localtime': localtime,

            'app_title': self.config.app_title(),

            'upgrade': upgrade,

            'upgrade_url': '#',

        }

class upgrade_success(Email):

    """

    Sent when an app upgrade is performed successfully.

    """

    default_subject = "Upgrade Success"

    def sample_data(self, request):

        upgrade = Object(

            description="upgrade to the latest!",

            notes="nothing special",

            executed=make_utc(),

            executed_by="Fred Flintstone",

            exit_code=0,

        )

        return {

            # TODO: first 3 args should be provided by some common logic instead...

            'rattail_config': self.config,

            'localtime': localtime,

            'app_title': self.config.app_title(),

            'upgrade': upgrade,

            'upgrade_url': '#',

        }

class user_feedback(Email):

    """

    Sent when a user submits a Feedback form from the web UI.

    """

    default_subject = "User Feedback"

    def sample_data(self, request):

        return {

            'user': None,

            'user_name': "Fred Flintstone",

            'referrer': request.route_url('home'),

            'client_ip': '127.0.0.1',

            'message': "Hey there,\n\njust wondered what the heck was going on with this site?  It's crap.\n\nFred",

        }

# -*- coding: utf-8; -*-

################################################################################

#

#  Rattail -- Retail Software Framework

#

#  This file is part of Rattail.

#

#  Rattail is free software: you can redistribute it and/or modify it under the

#  terms of the GNU General Public License as published by the Free Software

#  Foundation, either version 3 of the License, or (at your option) any later

#  version.

#

#  Rattail is distributed in the hope that it will be useful, but WITHOUT ANY

#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

#  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more

#  details.

#

#  You should have received a copy of the GNU General Public License along with

#  Rattail.  If not, see <http://www.gnu.org/licenses/>.

#

################################################################################

"""

Email Framework

"""

from __future__ import unicode_literals, absolute_import

import os

import smtplib

import logging

from email.charset import Charset

from email.message import Message

from email.mime.multipart import MIMEMultipart

from email.mime.application import MIMEApplication

from email.mime.text import MIMEText

import six

from mako.template import Template

from mako.lookup import TemplateLookup

from mako.exceptions import TopLevelLookupException

from rattail import exceptions

from rattail.core import UNSPECIFIED

from rattail.files import resource_path

from rattail.util import import_module_path

from rattail.time import localtime, make_utc

# NOTE: this bit of magic was stolen from Django

# Don't BASE64-encode UTF-8 messages so that we avoid unwanted attention from

# some spam filters.

utf8_charset = Charset('utf-8')

utf8_charset.body_encoding = None  # Python defaults to BASE64

log = logging.getLogger(__name__)

def send_email(config, key, data={}, attachments=[],

               fallback_key=None, default_subject=None,

               enabled=UNSPECIFIED, **kwargs):

    """

    Send an email message of the given type, per config, with the given data

    and/or attachments.

    """

    # TODO: should let config override which handler we use

    handler = EmailHandler(config)

    email = handler.get_email(key, fallback_key=fallback_key,

                              default_subject=default_subject)

    if enabled is UNSPECIFIED:

        enabled = handler.get_enabled(email)

    if enabled:

        kwargs['attachments'] = attachments

        handler.send_message(email, data, **kwargs)

    else:

        log.debug("skipping email of type '%s' per config", key)

# TODO: deprecate / remove this (used only for tailbone preview?)

def deliver_message(config, key, msg, recipients=UNSPECIFIED):

    """

    Deliver an email message using the given SMTP configuration.

    """

    if recipients is UNSPECIFIED:

        recips = set()

        to = msg.get_all('To')

        if to:

            recips = recips.union(set(to))

        cc = msg.get_all('Cc')

        if cc:

            recips = recips.union(set(cc))

        bcc = msg.get_all('Bcc')

        if bcc:

            recips = recips.union(set(bcc))

    else:

        recips = set(recipients)

    if not recips:

        raise RuntimeError("No recipients for email: {0}".format(repr(msg)))

    server = config.get('rattail.mail', 'smtp.server', default='localhost')

    username = config.get('rattail.mail', 'smtp.username')

    password = config.get('rattail.mail', 'smtp.password')

    if config.getbool('rattail.mail', 'send_feedback_only', usedb=False, default=False):

        send = key == 'user_feedback'

    else:

        send = config.getbool('rattail.mail', 'send_emails', usedb=False, default=True)

    if send:

        log.debug("attempting to send mail of type: %s", key)

        log.debug("connecting to server: %s", server)

        session = smtplib.SMTP(server)

        if username and password:

            result = session.login(username, password)

            log.debug("login() result is: %s", repr(result))

        result = session.sendmail(msg['From'], recips, msg.as_string())

        log.debug("sendmail() result is: %s", repr(result))

        session.quit()

        return True

    log.debug("config says no emails for '%s', but would have sent one to: %s", key, recips)

    return False

class EmailHandler(object):

    """

    Base class and default implementation for email handlers.

    """

    def __init__(self, config):

        self.config = config

        self.enum = self.config.get_enum()

    def get_email(self, key, fallback_key=None, **kwargs):

        """

        Return an email instance of the given type.

        """

        for email in self.iter_emails():

            if email.key == key or email.__name__ == key:

                return email(self.config, key, fallback_key, **kwargs)

        return Email(self.config, key, fallback_key, **kwargs)

    def iter_emails(self):

        """

        Iterate over all available email types.

        """

        for module in self.config.getlist('rattail.mail', 'emails', default=['rattail.emails']):

            module = import_module_path(module)

            for name in dir(module):

                obj = getattr(module, name)

                if (isinstance(obj, type) and issubclass(obj, Email)

                    and not obj.abstract and obj is not Email):

                    yield obj

    def get_enabled(self, email):

        return email.get_enabled()

    def send_message(self, email, data, **kwargs):

        msg = self.make_message(email, data, **kwargs)

        if self.config.getbool('rattail.mail', 'record_attempts', default=False):

            attempt = self.record_attempt(email, msg)

            try:

                self.deliver_message(email, msg)

            except Exception as e:

                self.record_failure(attempt, e)

            else:

                self.record_success(attempt)

        else: # don't record attempts

            self.deliver_message(email, msg)

    def record_attempt(self, email, msg):

        from rattail.db import Session, model

        session = Session()

        attempt = model.EmailAttempt()

        attempt.key = email.key

        attempt.sender = msg['From']

        attempt.to = msg.get_all('To')

        attempt.cc = msg.get_all('Cc')

        attempt.bcc = msg.get_all('Bcc')

        attempt.subject = msg['Subject']

        attempt.sent = make_utc()

        attempt.status_code = self.enum.EMAIL_ATTEMPT_CREATED

        session.add(attempt)

        session.commit()

        session.close()

        # session.expunge(attempt)

        return attempt

    def record_failure(self, attempt, error):

        from rattail.db import Session

        session = Session()

        attempt = session.merge(attempt)

        attempt.status_code = self.enum.EMAIL_ATTEMPT_FAILURE

        attempt.status_text = six.text_type(error)

        session.commit()

        session.close()

    def record_success(self, attempt):

        from rattail.db import Session

        session = Session()

        attempt = session.merge(attempt)

        attempt.status_code = self.enum.EMAIL_ATTEMPT_SUCCESS

        session.commit()

        session.close()

    def make_message(self, email, data, **kwargs):

        context = self.make_context(**data)

        return email.make_message(context, **kwargs)

    def make_context(self, **context):

        context['rattail_config'] = self.config

        context['app_title'] = self.config.app_title(default="Rattail")

        context['localtime'] = localtime

        return context

    def deliver_message(self, email, msg, recipients=UNSPECIFIED):

        """

        Deliver an email message using the given SMTP configuration.

        """

        if recipients is UNSPECIFIED:

            recips = set()

            to = msg.get_all('To')

            if to:

                recips = recips.union(set(to))

            cc = msg.get_all('Cc')

            if cc:

                recips = recips.union(set(cc))

            bcc = msg.get_all('Bcc')

            if bcc:

                recips = recips.union(set(bcc))

        else:

            recips = set(recipients)

        if not recips:

            raise RuntimeError("No recipients for email: {0}".format(repr(msg)))

        server = self.config.get('rattail.mail', 'smtp.server', default='localhost')

        username = self.config.get('rattail.mail', 'smtp.username')

        password = self.config.get('rattail.mail', 'smtp.password')

        if self.config.getbool('rattail.mail', 'send_feedback_only', usedb=False, default=False):

            send = email.key == 'user_feedback'

        else:

            send = self.config.getbool('rattail.mail', 'send_emails', usedb=False, default=True)

        if send:

            log.debug("attempting to send mail of type: %s", email.key)

            log.debug("connecting to server: %s", server)

            session = smtplib.SMTP(server)

            if username and password:

                result = session.login(username, password)

                log.debug("login() result is: %s", repr(result))

            result = session.sendmail(msg['From'], recips, msg.as_string())

            log.debug("sendmail() result is: %s", repr(result))

            session.quit()

            return True

        log.debug("config says no emails for '%s', but would have sent one to: %s", email.key, recips)

        return False

class Email(object):

    # Note: The docstring of an email is leveraged by code, hence this odd one.

    """

    (This email has no description.)

    """

    key = None

    fallback_key = None

    abstract = False

    default_prefix = "[rattail]"

    default_subject = "Automated message"

    # Whether or not the email's :attr:`to` attribute is dynamically determined

    # at run-time, i.e. via some logic other than typical reading from config.

    dynamic_to = False

    dynamic_to_help = None

    def __init__(self, config, key=None, fallback_key=None, default_subject=None):

        self.config = config

        self.enum = config.get_enum()

        if key:

            self.key = key

        elif not self.key:

            self.key = self.__class__.__name__

            if self.key == 'Email':

                raise exceptions.ConfigurationError("Email instance has no key: {0}".format(repr(self)))

        if fallback_key:

            self.fallback_key = fallback_key

        if default_subject:

            self.default_subject = default_subject

        templates = config.getlist('rattail.mail', 'templates')

        if templates:

            templates = [resource_path(p) for p in templates]

        self.templates = TemplateLookup(directories=templates)

    def sample_data(self, request):

        return {}

    def get_enabled(self):

        """

        Get the enabled flag for the email's message type.

        """

        enabled = self.config.getbool('rattail.mail', '{0}.enabled'.format(self.key))

        if enabled is not None:

            return enabled

        enabled = self.config.getbool('rattail.mail', 'default.enabled')

        if enabled is not None:

            return enabled

        return self.config.getbool('rattail.mail', 'send_emails', default=True)

    def get_sender(self):

        """

        Returns the value for the message's ``From:`` header.

        :rtype: str

        """

        sender = self.config.get('rattail.mail', '{0}.from'.format(self.key))

        if not sender:

            sender = self.config.get('rattail.mail', 'default.from')

            if not sender:

                raise exceptions.SenderNotFound(self.key)

        return sender

    def get_replyto(self):

        """

        Get the Reply-To address for the message.

        """

        replyto = self.config.get('rattail.mail', '{0}.replyto'.format(self.key))

        if not replyto:

            replyto = self.config.get('rattail.mail', 'default.replyto')

        return replyto

    def get_recips(self, type_='to'):

        """

        Returns a list of recipients of the given type for the message.

        :param type_: Must be one of: ``('to', 'cc', 'bcc')``.

        :rtype: list

        """

        try:

            if type_.lower() not in ('to', 'cc', 'bcc'):

                raise Exception

        except:

            raise ValueError("Recipient type must be one of ('to', 'cc', 'bcc'); "

                             "not: {0}".format(repr(type_)))

        type_ = type_.lower()

        recips = self.config.getlist('rattail.mail', '{0}.{1}'.format(self.key, type_))

        if not recips:

            recips = self.config.getlist('rattail.mail', 'default.{0}'.format(type_))

        return recips

    def get_prefix(self, data={}, magic=True):

        """

        Returns a string to be used as the subject prefix for the message.

        :rtype: str

        """

        prefix = self.config.get('rattail.mail', '{0}.prefix'.format(self.key))

        if not prefix:

            prefix = self.config.get('rattail.mail', 'default.prefix')

        prefix = prefix or self.default_prefix

        if magic and not self.config.production():

            prefix = "[STAGE] {}".format(prefix)

        return prefix

    def get_subject(self, data={}, render=True, template=UNSPECIFIED):

        """

        Returns the base value for the message's subject header, i.e. minus

        prefix.

        :rtype: str

        """

        if template is UNSPECIFIED:

            template = self.config.get('rattail.mail', '{}.subject'.format(self.key),

                                       default=self.default_subject)

            if not template:

                template = self.config.get('rattail.mail', 'default.subject')

        if template and render:

            return Template(template).render(**data)

        return template

    def get_complete_subject(self, data={}, render=True, prefix=UNSPECIFIED, template=UNSPECIFIED):

        """

        Returns the value for the message's ``Subject:`` header, i.e. the base

        subject with the prefix applied.  Note that config may provide the

        complete subject also, in which case the prefix and base subject are

        not considered.

        :rtype: str

        """

        if prefix is UNSPECIFIED:

            prefix = self.get_prefix(data)

        prefix = (prefix or "").rstrip()

        if prefix:

            prefix = "{} ".format(prefix)

        return "{}{}".format(prefix, self.get_subject(data, render=render, template=template))

    def get_template(self, type_):

        """

        Locate and return the Mako email template of the given type

        (e.g. 'html'), or ``None`` if no such template can be found.

        """

        try:

            return self.templates.get_template('{0}.{1}.mako'.format(self.key, type_))

        except TopLevelLookupException:

            if self.fallback_key:

                try:

                    return self.templates.get_template('{0}.{1}.mako'.format(self.fallback_key, type_))

                except TopLevelLookupException:

                    pass

    def normalize_attachments(self, attachments):

        normalized = []

        for attachment in attachments:

            if isinstance(attachment, six.string_types):

                attachment = self.normalize_attachment(attachment)

            normalized.append(attachment)

        return normalized

    ATTACHMENT_MIME_MAP = {

        '.doc': 'application/msword',

        '.pdf': 'pdf',

        '.xls': 'vnd.ms-excel',

    }

    def normalize_attachment(self, path):

        root, ext = os.path.splitext(path)

        ext = ext.lower()

        if ext == '.csv':

            with open(path, 'rb') as f:

                part = MIMEText(f.read(), 'csv', 'utf_8')

            filename = os.path.basename(path)

            part.add_header('Content-Disposition', 'attachment; filename="{}"'.format(filename))

            return part

        else:

            mimetype = self.ATTACHMENT_MIME_MAP.get(ext)

            if mimetype:

                with open(path, 'rb') as f:

                    part = MIMEApplication(f.read(), mimetype)

                filename = os.path.basename(path)

                part.add_header('Content-Disposition', 'attachment; filename="{}"'.format(filename))

                return part

        raise ValueError("Magic is not (yet) supported, please construct your own attachments for file: {}".format(path))

    def make_message(self, data={}, attachments=[], inlines=[],

                     subject_prefix=UNSPECIFIED, subject_template=UNSPECIFIED,

                     sender=UNSPECIFIED, replyto=UNSPECIFIED,

                     to=UNSPECIFIED, cc=UNSPECIFIED, bcc=UNSPECIFIED):

        """

        Returns a proper email ``Message`` instance which may be sent via SMTP.

        """

        txt_template = self.get_template('txt')

        html_template = self.get_template('html')

        attachments = self.normalize_attachments(attachments)

        # TODO: provide more defaults?

        data.setdefault('six', six)

        if txt_template and html_template:

            txt_part = MIMEText(txt_template.render(**data), _charset='utf_8')

            html_part = MIMEText(html_template.render(**data), _subtype='html', _charset='utf_8')

            if inlines:

                html_part = MIMEMultipart(_subtype='related', _subparts=[html_part] + inlines)

            msg = MIMEMultipart(_subtype='alternative', _subparts=[txt_part, html_part])

            if attachments:

                msg = MIMEMultipart(_subtype='mixed', _subparts=[msg] + attachments)

        elif txt_template:

            msg = MIMEText(txt_template.render(**data), _charset='utf_8')

            if attachments:

                msg = MIMEMultipart(_subtype='mixed', _subparts=[msg] + attachments)

        elif html_template:

            msg = SafeMIMEText(html_template.render(**data), 'html', utf8_charset)

            if inlines:

                msg = MIMEMultipart(_subtype='related', _subparts=[msg] + inlines)

            if attachments:

                msg = MIMEMultipart(_subtype='mixed', _subparts=[msg] + attachments)

        else:

            raise exceptions.MailTemplateNotFound(self.key)