# Copyright 2015-2019 Camptocamp SA
# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).

import logging
import datetime

from dateutil.relativedelta import relativedelta

from odoo import api, fields, models

_logger = logging.getLogger(__name__)


class FetchmailServer(models.Model):
    """Incoming POP/IMAP mail server account."""
    _inherit = 'fetchmail.server'

    cleanup_days = fields.Integer(
        string='Expiration days',
        help="Number of days before marking an e-mail as read",
    )

    cleanup_folder = fields.Char(
        string='Expiration folder',
        help="Folder where an e-mail marked as read will be moved.",
    )

    purge_days = fields.Integer(
        string='Deletion days',
        help="Number of days before removing an e-mail",
    )

    @property
    def _server_env_fields(self):
        base_fields = super()._server_env_fields
        mail_cleanup_fields = {
            'cleanup_days': {
                'getter': 'getint',
            },
            'purge_days': {
                'getter': 'getint',
            },
            'cleanup_folder': {},
        }
        mail_cleanup_fields.update(base_fields)
        return mail_cleanup_fields

    def _cleanup_fetchmail_server(self, server, imap_server):
        count, failed = 0, 0
        expiration_date = datetime.date.today()
        expiration_date -= relativedelta(days=server.cleanup_days)
        search_text = expiration_date.strftime('(UNSEEN BEFORE %d-%b-%Y)')
        imap_server.select()
        result, data = imap_server.search(None, search_text)
        for num in data[0].split():
            try:
                # Mark message as read
                imap_server.store(num, '+FLAGS', '\\Seen')
                if server.cleanup_folder:
                    # To move a message, you have to COPY
                    # then DELETE the message
                    result = imap_server.copy(num, server.cleanup_folder)
                    if result[0] == 'OK':
                        imap_server.store(num, '+FLAGS', '\\Deleted')
            except Exception:
                _logger.exception(
                    'Failed to cleanup mail from %s server %s.',
                    server.type, server.name)
                failed += 1
            count += 1
        _logger.info(
            'Marked %d email(s) as read on %s server %s;'
            ' %d succeeded, %d failed.', count, server.type,
            server.name, (count - failed), failed)

    def _purge_fetchmail_server(self, server, imap_server):
        # Purging e-mails older than the purge date, if available
        count, failed = 0, 0
        purge_date = datetime.date.today()
        purge_date -= relativedelta(days=server.purge_days)
        search_text = purge_date.strftime('(BEFORE %d-%b-%Y)')
        imap_server.select()
        result, data = imap_server.search(None, search_text)
        for num in data[0].split():
            try:
                # Delete message
                imap_server.store(num, '+FLAGS', '\\Deleted')
            except Exception:
                _logger.exception(
                    'Failed to remove mail from %s server %s.',
                    server.type, server.name)
                failed += 1
            count += 1
        _logger.info(
            'Removed %d email(s) on %s server %s;'
            ' %d succeeded, %d failed.', count, server.type,
            server.name, (count - failed), failed)

    @api.multi
    def fetch_mail(self):
        # Called before the fetch, in order to clean up right before
        # retrieving emails.
        for server in self:
            _logger.info('start cleaning up emails on %s server %s',
                         server.type, server.name)
            imap_server = False
            if server.type == 'imap':
                try:
                    imap_server = server.connect()
                    if server.cleanup_days > 0:
                        self._cleanup_fetchmail_server(server, imap_server)
                    if server.purge_days > 0:
                        self._purge_fetchmail_server(server, imap_server)
                    # Do the final cleanup: delete all messages
                    # flagged as deleted
                    imap_server.expunge()
                except Exception:
                    _logger.exception(
                        'General failure when trying to cleanup'
                        ' mail from %s server %s.',
                        server.type, server.name)
                finally:
                    if imap_server:
                        imap_server.close()
                        imap_server.logout()
        return super().fetch_mail()