# -*- coding: utf-8 -*-
# Part of Odoo. See LICENSE file for full copyright and licensing details.

import logging
from contextlib import contextmanager
from functools import wraps
from requests import HTTPError
import pytz
from dateutil.parser import parse

from odoo import api, fields, models, registry, _
from odoo.tools import ormcache_context
from odoo.exceptions import UserError
from odoo.osv import expression

from odoo.addons.google_calendar.utils.google_event import GoogleEvent
from odoo.addons.google_calendar.utils.google_calendar import GoogleCalendarService
from odoo.addons.google_account.models.google_service import TIMEOUT

_logger = logging.getLogger(__name__)


# API requests are sent to Google Calendar after the current transaction ends.
# This ensures changes are sent to Google only if they really happened in the Odoo database.
# It is particularly important for event creation , otherwise the event might be created
# twice in Google if the first creation crashed in Odoo.
def after_commit(func):
    @wraps(func)
    def wrapped(self, *args, **kwargs):
        dbname = self.env.cr.dbname
        context = self.env.context
        uid = self.env.uid

        if self.env.context.get('no_calendar_sync'):
            return

        @self.env.cr.postcommit.add
        def called_after():
            db_registry = registry(dbname)
            with db_registry.cursor() as cr:
                env = api.Environment(cr, uid, context)
                try:
                    func(self.with_env(env), *args, **kwargs)
                except Exception as e:
                    _logger.warning("Could not sync record now: %s" % self)
                    _logger.exception(e)

    return wrapped

@contextmanager
def google_calendar_token(user):
    yield user._get_google_calendar_token()


class GoogleSync(models.AbstractModel):
    _name = 'google.calendar.sync'
    _description = "Synchronize a record with Google Calendar"

    google_id = fields.Char('Google Calendar Id', copy=False)
    need_sync = fields.Boolean(default=True, copy=False)
    active = fields.Boolean(default=True)

    def write(self, vals):
        google_service = GoogleCalendarService(self.env['google.service'])
        if 'google_id' in vals:
            self._event_ids_from_google_ids.clear_cache(self)
        synced_fields = self._get_google_synced_fields()
        if 'need_sync' not in vals and vals.keys() & synced_fields and not self.env.user.google_synchronization_stopped:
            vals['need_sync'] = True

        result = super().write(vals)
        for record in self.filtered('need_sync'):
            if record.google_id:
                record.with_user(record._get_event_user())._google_patch(google_service, record.google_id, record._google_values(), timeout=3)

        return result

    @api.model_create_multi
    def create(self, vals_list):
        if any(vals.get('google_id') for vals in vals_list):
            self._event_ids_from_google_ids.clear_cache(self)
        if self.env.user.google_synchronization_stopped:
            for vals in vals_list:
                vals.update({'need_sync': False})
        records = super().create(vals_list)

        google_service = GoogleCalendarService(self.env['google.service'])
        records_to_sync = records.filtered(lambda r: r.need_sync and r.active)
        for record in records_to_sync:
            record.with_user(record._get_event_user())._google_insert(google_service, record._google_values(), timeout=3)
        return records

    def unlink(self):
        """We can't delete an event that is also in Google Calendar. Otherwise we would
        have no clue that the event must must deleted from Google Calendar at the next sync.
        """
        synced = self.filtered('google_id')
        # LUL TODO find a way to get rid of this context key
        if self.env.context.get('archive_on_error') and self._active_name:
            synced.write({self._active_name: False})
            self = self - synced
        elif synced:
            # Since we can not delete such an event (see method comment), we archive it.
            # Notice that archiving an event will delete the associated event on Google.
            # Then, since it has been deleted on Google, the event is also deleted on Odoo DB (_sync_google2odoo).
            self.action_archive()
            return True
        return super().unlink()

    def _from_google_ids(self, google_ids):
        if not google_ids:
            return self.browse()
        return self.browse(self._event_ids_from_google_ids(google_ids))

    @api.model
    @ormcache_context('google_ids', keys=('active_test',))
    def _event_ids_from_google_ids(self, google_ids):
        return self.search([('google_id', 'in', google_ids)]).ids

    def _sync_odoo2google(self, google_service: GoogleCalendarService):
        if not self:
            return
        if self._active_name:
            records_to_sync = self.filtered(self._active_name)
        else:
            records_to_sync = self
        cancelled_records = self - records_to_sync

        updated_records = records_to_sync.filtered('google_id')
        new_records = records_to_sync - updated_records
        for record in cancelled_records.filtered(lambda e: e.google_id and e.need_sync):
            record.with_user(record._get_event_user())._google_delete(google_service, record.google_id)
        for record in new_records:
            record.with_user(record._get_event_user())._google_insert(google_service, record._google_values())
        for record in updated_records:
            record.with_user(record._get_event_user())._google_patch(google_service, record.google_id, record._google_values())

    def _cancel(self):
        self.google_id = False
        self.unlink()

    @api.model
    def _sync_google2odoo(self, google_events: GoogleEvent, default_reminders=()):
        """Synchronize Google recurrences in Odoo. Creates new recurrences, updates
        existing ones.

        :param google_recurrences: Google recurrences to synchronize in Odoo
        :return: synchronized odoo recurrences
        """
        existing = google_events.exists(self.env)
        new = google_events - existing - google_events.cancelled()

        odoo_values = [
            dict(self._odoo_values(e, default_reminders), need_sync=False)
            for e in new
        ]
        new_odoo = self.with_context(dont_notify=True)._create_from_google(new, odoo_values)
        cancelled = existing.cancelled()
        cancelled_odoo = self.browse(cancelled.odoo_ids(self.env))
        cancelled_odoo._cancel()
        synced_records = new_odoo + cancelled_odoo
        for gevent in existing - cancelled:
            # Last updated wins.
            # This could be dangerous if google server time and odoo server time are different
            updated = parse(gevent.updated)
            odoo_record = self.browse(gevent.odoo_id(self.env))
            # Migration from 13.4 does not fill write_date. Therefore, we force the update from Google.
            if not odoo_record.write_date or updated >= pytz.utc.localize(odoo_record.write_date):
                vals = dict(self._odoo_values(gevent, default_reminders), need_sync=False)
                odoo_record.with_context(dont_notify=True)._write_from_google(gevent, vals)
                synced_records |= odoo_record

        return synced_records

    def _google_error_handling(self, http_error):
        # We only handle the most problematic errors of sync events.
        if http_error.response.status_code in (403, 400):
            response = http_error.response.json()
            if not self.exists():
                reason = "Google gave the following explanation: %s" % response['error'].get('message')
                error_log = "Error while syncing record. It does not exists anymore in the database. %s" % reason
                _logger.error(error_log)
                return 

            if self._name == 'calendar.event':
                start = self.start and self.start.strftime('%Y-%m-%d at %H:%M') or _("undefined time")
                event_ids = self.id
                name = self.name
                error_log = "Error while syncing event: "
                event = self
            else:
                # calendar recurrence is triggering the error
                event = self.base_event_id or self._get_first_event(include_outliers=True)
                start = event.start and event.start.strftime('%Y-%m-%d at %H:%M') or _("undefined time")
                event_ids = _("%(id)s and %(length)s following", id=event.id, length=len(self.calendar_event_ids.ids))
                name = event.name
                # prevent to sync other events
                self.calendar_event_ids.need_sync = False
                error_log = "Error while syncing recurrence [{id} - {name} - {rrule}]: ".format(id=self.id, name=self.name, rrule=self.rrule)

            # We don't have right access on the event or the request paramaters were bad.
            # https://developers.google.com/calendar/v3/errors#403_forbidden_for_non-organizer
            if http_error.response.status_code == 403 and "forbiddenForNonOrganizer" in http_error.response.text:
                reason = _("you don't seem to have permission to modify this event on Google Calendar")
            else:
                reason = _("Google gave the following explanation: %s", response['error'].get('message'))

            error_log += "The event (%(id)s - %(name)s at %(start)s) could not be synced. It will not be synced while " \
                         "it is not updated. Reason: %(reason)s" % {'id': event_ids, 'start': start, 'name': name,
                                                                    'reason': reason}
            _logger.warning(error_log)

            body = _(
                "The following event could not be synced with Google Calendar. </br>"
                "It will not be synced as long at it is not updated.</br>"
                "%(reason)s", reason=reason)

            if event:
                event.message_post(
                    body=body,
                    message_type='comment',
                    subtype_xmlid='mail.mt_note',
                )

    @after_commit
    def _google_delete(self, google_service: GoogleCalendarService, google_id, timeout=TIMEOUT):
        with google_calendar_token(self.env.user.sudo()) as token:
            if token:
                google_service.delete(google_id, token=token, timeout=timeout)
                # When the record has been deleted on our side, we need to delete it on google but we don't want
                # to raise an error because the record don't exists anymore.
                self.exists().with_context(dont_notify=True).need_sync = False

    @after_commit
    def _google_patch(self, google_service: GoogleCalendarService, google_id, values, timeout=TIMEOUT):
        with google_calendar_token(self.env.user.sudo()) as token:
            if token:
                try:
                    google_service.patch(google_id, values, token=token, timeout=timeout)
                except HTTPError as e:
                    if e.response.status_code in (400, 403):
                        self._google_error_handling(e)
                self.exists().with_context(dont_notify=True).need_sync = False

    @after_commit
    def _google_insert(self, google_service: GoogleCalendarService, values, timeout=TIMEOUT):
        if not values:
            return
        with google_calendar_token(self.env.user.sudo()) as token:
            if token:
                try:
                    send_updates = self._context.get('send_updates', True)
                    google_service.google_service = google_service.google_service.with_context(send_updates=send_updates)
                    google_id = google_service.insert(values, token=token, timeout=timeout)
                    # Everything went smoothly
                    self.with_context(dont_notify=True).write({
                        'google_id': google_id,
                        'need_sync': False,
                    })
                except HTTPError as e:
                    if e.response.status_code in (400, 403):
                        self._google_error_handling(e)
                        self.with_context(dont_notify=True).need_sync = False

    def _get_records_to_sync(self, full_sync=False):
        """Return records that should be synced from Odoo to Google

        :param full_sync: If True, all events attended by the user are returned
        :return: events
        """
        domain = self._get_sync_domain()
        if not full_sync:
            is_active_clause = (self._active_name, '=', True) if self._active_name else expression.TRUE_LEAF
            domain = expression.AND([domain, [
                '|',
                    '&', ('google_id', '=', False), is_active_clause,
                    ('need_sync', '=', True),
            ]])
        # We want to limit to 200 event sync per transaction, it shouldn't be a problem for the day to day
        # but it allows to run the first synchro within an acceptable time without timeout.
        # If there is a lot of event to synchronize to google the first time,
        # they will be synchronized eventually with the cron running few times a day
        return self.with_context(active_test=False).search(domain, limit=200)

    def _write_from_google(self, gevent, vals):
        self.write(vals)

    @api.model
    def _create_from_google(self, gevents, vals_list):
        return self.create(vals_list)

    @api.model
    def _odoo_values(self, google_event: GoogleEvent, default_reminders=()):
        """Implements this method to return a dict of Odoo values corresponding
        to the Google event given as parameter
        :return: dict of Odoo formatted values
        """
        raise NotImplementedError()

    def _google_values(self):
        """Implements this method to return a dict with values formatted
        according to the Google Calendar API
        :return: dict of Google formatted values
        """
        raise NotImplementedError()

    def _get_sync_domain(self):
        """Return a domain used to search records to synchronize.
        e.g. return a domain to synchronize records owned by the current user.
        """
        raise NotImplementedError()

    def _get_google_synced_fields(self):
        """Return a set of field names. Changing one of these fields
        marks the record to be re-synchronized.
        """
        raise NotImplementedError()

    @api.model
    def _restart_google_sync(self):
        """ Turns on the google synchronization for all the events of
        a given user.
        """
        raise NotImplementedError()

    def _get_event_user(self):
        """ Return the correct user to send the request to Google.
        It's possible that a user creates an event and sets another user as the organizer. Using self.env.user will
        cause some issues, and It might not be possible to use this user for sending the request, so this method gets
        the appropriate user accordingly.
        """
        raise NotImplementedError()