# -*- coding: utf-8 -*-
# Copyright 2016 Jairo Llopis <jairo.llopis@tecnativa.com>
# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).

import hmac
import hashlib
from openerp import api, models
from openerp.exceptions import AccessDenied
from openerp.tools import consteq


class MailMassMailing(models.Model):
    _inherit = "mail.mass_mailing"

    @api.multi
    def _unsubscribe_token(self, res_id, compare=None):
        """Generate a secure hash for this mailing list and parameters.
        This is appended to the unsubscription URL and then checked at
        unsubscription time to ensure no malicious unsubscriptions are
        performed.

        :param int res_id:
            ID of the resource that will be unsubscribed.

        :param str compare:
            Received token to be compared with the good one.

        :raise AccessDenied:
            Will happen if you provide :param:`compare` and it does not match
            the good token.
        """
        secret = self.env["ir.config_parameter"].sudo().get_param(
            "database.secret")
        key = (self.env.cr.dbname, self.id, int(res_id))
        token = hmac.new(str(secret), repr(key), hashlib.sha512).hexdigest()
        if compare is not None and not consteq(token, str(compare)):
            raise AccessDenied()
        return token

    def update_opt_out(self, email, res_ids, value):
        """Save unsubscription reason when opting out from mailing."""
        self.ensure_one()
        action = "unsubscription" if value else "subscription"
        records = self.env[self.mailing_model].browse(res_ids)
        previous = self.env["mail.unsubscription"].search(limit=1, args=[
            ("mass_mailing_id", "=", self.id),
            ("email", "=", email),
            ("action", "=", action),
        ])
        for one in records:
            # Store action only when something changed, or there was no
            # previous subscription record
            if one.opt_out != value or (action == "subscription" and
                                        not previous):
                # reason_id and details are expected from the context
                self.env["mail.unsubscription"].create({
                    "email": email,
                    "mass_mailing_id": self.id,
                    "unsubscriber_id": "%s,%d" % (one._name, one.id),
                    "action": action,
                })
        return super(MailMassMailing, self).update_opt_out(
            email, res_ids, value)