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

import logging
import re

from email.utils import formataddr
from openerp.http import request

from odoo import _, api, fields, models, modules, SUPERUSER_ID, tools
from odoo.exceptions import UserError, AccessError
from odoo.osv import expression

_logger = logging.getLogger(__name__)
_image_dataurl = re.compile(r'(data:image/[a-z]+?);base64,([a-z0-9+/\n]{3,}=*)\n*([\'"])', re.I)


class Message(models.Model):
    """ Messages model: system notification (replacing res.log notifications),
        comments (OpenChatter discussion) and incoming emails. """
    _name = 'mail.message'
    _description = 'Message'
    _order = 'id desc'
    _rec_name = 'record_name'

    _message_read_limit = 30

    @api.model
    def _get_default_from(self):
        if self.env.user.email:
            return formataddr((self.env.user.name, self.env.user.email))
        raise UserError(_("Unable to send email, please configure the sender's email address."))

    @api.model
    def _get_default_author(self):
        return self.env.user.partner_id

    # content
    subject = fields.Char('Subject')
    date = fields.Datetime('Date', default=fields.Datetime.now)
    body = fields.Html('Contents', default='', sanitize_style=True, strip_classes=True)
    attachment_ids = fields.Many2many(
        'ir.attachment', 'message_attachment_rel',
        'message_id', 'attachment_id',
        string='Attachments',
        help='Attachments are linked to a document through model / res_id and to the message '
             'through this field.')
    parent_id = fields.Many2one(
        'mail.message', 'Parent Message', index=True, ondelete='set null',
        help="Initial thread message.")
    child_ids = fields.One2many('mail.message', 'parent_id', 'Child Messages')
    # related document
    model = fields.Char('Related Document Model', index=True)
    res_id = fields.Integer('Related Document ID', index=True)
    record_name = fields.Char('Message Record Name', help="Name get of the related document.")
    # characteristics
    message_type = fields.Selection([
        ('email', 'Email'),
        ('comment', 'Comment'),
        ('notification', 'System notification')],
        'Type', required=True, default='email',
        help="Message type: email for email message, notification for system "
             "message, comment for other messages such as user replies",
        oldname='type')
    subtype_id = fields.Many2one('mail.message.subtype', 'Subtype', ondelete='set null', index=True)
    mail_activity_type_id = fields.Many2one(
        'mail.activity.type', 'Mail Activity Type',
        index=True, ondelete='set null')
    # origin
    email_from = fields.Char(
        'From', default=_get_default_from,
        help="Email address of the sender. This field is set when no matching partner is found and replaces the author_id field in the chatter.")
    author_id = fields.Many2one(
        'res.partner', 'Author', index=True,
        ondelete='set null', default=_get_default_author,
        help="Author of the message. If not set, email_from may hold an email address that did not match any partner.")
    author_avatar = fields.Binary("Author's avatar", related='author_id.image_small')
    # recipients
    partner_ids = fields.Many2many('res.partner', string='Recipients')
    needaction_partner_ids = fields.Many2many(
        'res.partner', 'mail_message_res_partner_needaction_rel', string='Partners with Need Action')
    needaction = fields.Boolean(
        'Need Action', compute='_get_needaction', search='_search_needaction',
        help='Need Action')
    channel_ids = fields.Many2many(
        'mail.channel', 'mail_message_mail_channel_rel', string='Channels')
    # notifications
    notification_ids = fields.One2many(
        'mail.notification', 'mail_message_id', 'Notifications',
        auto_join=True, copy=False)
    # user interface
    starred_partner_ids = fields.Many2many(
        'res.partner', 'mail_message_res_partner_starred_rel', string='Favorited By')
    starred = fields.Boolean(
        'Starred', compute='_get_starred', search='_search_starred',
        help='Current user has a starred notification linked to this message')
    # tracking
    tracking_value_ids = fields.One2many(
        'mail.tracking.value', 'mail_message_id',
        string='Tracking values',
        groups="base.group_no_one",
        help='Tracked values are stored in a separate model. This field allow to reconstruct '
             'the tracking and to generate statistics on the model.')
    # mail gateway
    no_auto_thread = fields.Boolean(
        'No threading for answers',
        help='Answers do not go in the original document discussion thread. This has an impact on the generated message-id.')
    message_id = fields.Char('Message-Id', help='Message unique identifier', index=True, readonly=1, copy=False)
    reply_to = fields.Char('Reply-To', help='Reply email address. Setting the reply_to bypasses the automatic thread creation.')
    mail_server_id = fields.Many2one('ir.mail_server', 'Outgoing mail server')

    @api.multi
    def _get_needaction(self):
        """ Need action on a mail.message = notified on my channel """
        my_messages = self.env['mail.notification'].sudo().search([
            ('mail_message_id', 'in', self.ids),
            ('res_partner_id', '=', self.env.user.partner_id.id),
            ('is_read', '=', False)]).mapped('mail_message_id')
        for message in self:
            message.needaction = message in my_messages

    @api.model
    def _search_needaction(self, operator, operand):
        if operator == '=' and operand:
            return ['&', ('notification_ids.res_partner_id', '=', self.env.user.partner_id.id), ('notification_ids.is_read', '=', False)]
        return ['&', ('notification_ids.res_partner_id', '=', self.env.user.partner_id.id), ('notification_ids.is_read', '=', True)]

    @api.depends('starred_partner_ids')
    def _get_starred(self):
        """ Compute if the message is starred by the current user. """
        # TDE FIXME: use SQL
        starred = self.sudo().filtered(lambda msg: self.env.user.partner_id in msg.starred_partner_ids)
        for message in self:
            message.starred = message in starred

    @api.model
    def _search_starred(self, operator, operand):
        if operator == '=' and operand:
            return [('starred_partner_ids', 'in', [self.env.user.partner_id.id])]
        return [('starred_partner_ids', 'not in', [self.env.user.partner_id.id])]

    #------------------------------------------------------
    # Notification API
    #------------------------------------------------------

    @api.model
    def mark_all_as_read(self, channel_ids=None, domain=None):
        """ Remove all needactions of the current partner. If channel_ids is
            given, restrict to messages written in one of those channels. """
        partner_id = self.env.user.partner_id.id
        delete_mode = not self.env.user.share  # delete employee notifs, keep customer ones
        if not domain and delete_mode:
            query = "DELETE FROM mail_message_res_partner_needaction_rel WHERE res_partner_id IN %s"
            args = [(partner_id,)]
            if channel_ids:
                query += """
                    AND mail_message_id in
                        (SELECT mail_message_id
                        FROM mail_message_mail_channel_rel
                        WHERE mail_channel_id in %s)"""
                args += [tuple(channel_ids)]
            query += " RETURNING mail_message_id as id"
            self._cr.execute(query, args)
            self.invalidate_cache()

            ids = [m['id'] for m in self._cr.dictfetchall()]
        else:
            # not really efficient method: it does one db request for the
            # search, and one for each message in the result set to remove the
            # current user from the relation.
            msg_domain = [('needaction_partner_ids', 'in', partner_id)]
            if channel_ids:
                msg_domain += [('channel_ids', 'in', channel_ids)]
            unread_messages = self.search(expression.AND([msg_domain, domain]))
            notifications = self.env['mail.notification'].sudo().search([
                ('mail_message_id', 'in', unread_messages.ids),
                ('res_partner_id', '=', self.env.user.partner_id.id),
                ('is_read', '=', False)])
            if delete_mode:
                notifications.unlink()
            else:
                notifications.write({'is_read': True})
            ids = unread_messages.mapped('id')

        notification = {'type': 'mark_as_read', 'message_ids': ids, 'channel_ids': channel_ids}
        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), notification)

        return ids

    @api.multi
    def mark_as_unread(self, channel_ids=None):
        """ Add needactions to messages for the current partner. """
        partner_id = self.env.user.partner_id.id
        for message in self:
            message.write({'needaction_partner_ids': [(4, partner_id)]})

        ids = [m.id for m in self]
        notification = {'type': 'mark_as_unread', 'message_ids': ids, 'channel_ids': channel_ids}
        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), notification)

    @api.multi
    def set_message_done(self):
        """ Remove the needaction from messages for the current partner. """
        partner_id = self.env.user.partner_id
        delete_mode = not self.env.user.share  # delete employee notifs, keep customer ones

        notifications = self.env['mail.notification'].sudo().search([
            ('mail_message_id', 'in', self.ids),
            ('res_partner_id', '=', partner_id.id),
            ('is_read', '=', False)])

        if not notifications:
            return

        # notifies changes in messages through the bus.  To minimize the number of
        # notifications, we need to group the messages depending on their channel_ids
        groups = []
        messages = notifications.mapped('mail_message_id')
        current_channel_ids = messages[0].channel_ids
        current_group = []
        for record in messages:
            if record.channel_ids == current_channel_ids:
                current_group.append(record.id)
            else:
                groups.append((current_group, current_channel_ids))
                current_group = [record.id]
                current_channel_ids = record.channel_ids

        groups.append((current_group, current_channel_ids))
        current_group = [record.id]
        current_channel_ids = record.channel_ids

        if delete_mode:
            notifications.unlink()
        else:
            notifications.write({'is_read': True})

        for (msg_ids, channel_ids) in groups:
            notification = {'type': 'mark_as_read', 'message_ids': msg_ids, 'channel_ids': [c.id for c in channel_ids]}
            self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', partner_id.id), notification)

    @api.model
    def unstar_all(self):
        """ Unstar messages for the current partner. """
        partner_id = self.env.user.partner_id.id

        starred_messages = self.search([('starred_partner_ids', 'in', partner_id)])
        starred_messages.write({'starred_partner_ids': [(3, partner_id)]})

        ids = [m.id for m in starred_messages]
        notification = {'type': 'toggle_star', 'message_ids': ids, 'starred': False}
        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), notification)

    @api.multi
    def toggle_message_starred(self):
        """ Toggle messages as (un)starred. Technically, the notifications related
            to uid are set to (un)starred.
        """
        # a user should always be able to star a message he can read
        self.check_access_rule('read')
        starred = not self.starred
        if starred:
            self.sudo().write({'starred_partner_ids': [(4, self.env.user.partner_id.id)]})
        else:
            self.sudo().write({'starred_partner_ids': [(3, self.env.user.partner_id.id)]})

        notification = {'type': 'toggle_star', 'message_ids': [self.id], 'starred': starred}
        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), notification)

    #------------------------------------------------------
    # Message loading for web interface
    #------------------------------------------------------

    @api.model
    def _message_read_dict_postprocess(self, messages, message_tree):
        """ Post-processing on values given by message_read. This method will
            handle partners in batch to avoid doing numerous queries.

            :param list messages: list of message, as get_dict result
            :param dict message_tree: {[msg.id]: msg browse record as super user}
        """
        # 1. Aggregate partners (author_id and partner_ids), attachments and tracking values
        partners = self.env['res.partner'].sudo()
        attachments = self.env['ir.attachment']
        message_ids = list(message_tree.keys())
        for message in message_tree.values():
            if message.author_id:
                partners |= message.author_id
            if message.subtype_id and message.partner_ids:  # take notified people of message with a subtype
                partners |= message.partner_ids
            elif not message.subtype_id and message.partner_ids:  # take specified people of message without a subtype (log)
                partners |= message.partner_ids
            if message.needaction_partner_ids:  # notified
                partners |= message.needaction_partner_ids
            if message.attachment_ids:
                attachments |= message.attachment_ids
        # Read partners as SUPERUSER -> message being browsed as SUPERUSER it is already the case
        partners_names = partners.name_get()
        partner_tree = dict((partner[0], partner) for partner in partners_names)

        # 2. Attachments as SUPERUSER, because could receive msg and attachments for doc uid cannot see
        attachments_data = attachments.sudo().read(['id', 'datas_fname', 'name', 'mimetype'])
        safari = request and request.httprequest.user_agent.browser == 'safari'
        attachments_tree = dict((attachment['id'], {
            'id': attachment['id'],
            'filename': attachment['datas_fname'],
            'name': attachment['name'],
            'mimetype': 'application/octet-stream' if safari and 'video' in attachment['mimetype'] else attachment['mimetype'],
        }) for attachment in attachments_data)

        # 3. Tracking values
        tracking_values = self.env['mail.tracking.value'].sudo().search([('mail_message_id', 'in', message_ids)])
        message_to_tracking = dict()
        tracking_tree = dict.fromkeys(tracking_values.ids, False)
        for tracking in tracking_values:
            message_to_tracking.setdefault(tracking.mail_message_id.id, list()).append(tracking.id)
            tracking_tree[tracking.id] = {
                'id': tracking.id,
                'changed_field': tracking.field_desc,
                'old_value': tracking.get_old_display_value()[0],
                'new_value': tracking.get_new_display_value()[0],
                'field_type': tracking.field_type,
            }

        # 4. Update message dictionaries
        for message_dict in messages:
            message_id = message_dict.get('id')
            message = message_tree[message_id]
            if message.author_id:
                author = partner_tree[message.author_id.id]
            else:
                author = (0, message.email_from)
            partner_ids = []
            if message.subtype_id:
                partner_ids = [partner_tree[partner.id] for partner in message.partner_ids
                                if partner.id in partner_tree]
            else:
                partner_ids = [partner_tree[partner.id] for partner in message.partner_ids
                                if partner.id in partner_tree]

            customer_email_data = []
            for notification in message.notification_ids.filtered(lambda notif: notif.res_partner_id.partner_share and notif.res_partner_id.active):
                customer_email_data.append((partner_tree[notification.res_partner_id.id][0], partner_tree[notification.res_partner_id.id][1], notification.email_status))

            attachment_ids = []
            for attachment in message.attachment_ids:
                if attachment.id in attachments_tree:
                    attachment_ids.append(attachments_tree[attachment.id])
            tracking_value_ids = []
            for tracking_value_id in message_to_tracking.get(message_id, list()):
                if tracking_value_id in tracking_tree:
                    tracking_value_ids.append(tracking_tree[tracking_value_id])

            message_dict.update({
                'author_id': author,
                'partner_ids': partner_ids,
                'customer_email_status': (all(d[2] == 'sent' for d in customer_email_data) and 'sent') or
                                        (any(d[2] == 'exception' for d in customer_email_data) and 'exception') or 
                                        (any(d[2] == 'bounce' for d in customer_email_data) and 'bounce') or 'ready',
                'customer_email_data': customer_email_data,
                'attachment_ids': attachment_ids,
                'tracking_value_ids': tracking_value_ids,
            })

        return True

    @api.model
    def message_fetch(self, domain, limit=20):
        return self.search(domain, limit=limit).message_format()

    @api.multi
    def message_format(self):
        """ Get the message values in the format for web client. Since message values can be broadcasted,
            computed fields MUST NOT BE READ and broadcasted.
            :returns list(dict).
             Example :
                {
                    'body': HTML content of the message
                    'model': u'res.partner',
                    'record_name': u'Agrolait',
                    'attachment_ids': [
                        {
                            'file_type_icon': u'webimage',
                            'id': 45,
                            'name': u'sample.png',
                            'filename': u'sample.png'
                        }
                    ],
                    'needaction_partner_ids': [], # list of partner ids
                    'res_id': 7,
                    'tracking_value_ids': [
                        {
                            'old_value': "",
                            'changed_field': "Customer",
                            'id': 2965,
                            'new_value': "Axelor"
                        }
                    ],
                    'author_id': (3, u'Administrator'),
                    'email_from': 'sacha@pokemon.com' # email address or False
                    'subtype_id': (1, u'Discussions'),
                    'channel_ids': [], # list of channel ids
                    'date': '2015-06-30 08:22:33',
                    'partner_ids': [[7, "Sacha Du Bourg-Palette"]], # list of partner name_get
                    'message_type': u'comment',
                    'id': 59,
                    'subject': False
                    'is_note': True # only if the subtype is internal
                }
        """
        message_values = self.read([
            'id', 'body', 'date', 'author_id', 'email_from',  # base message fields
            'message_type', 'subtype_id', 'subject',  # message specific
            'model', 'res_id', 'record_name',  # document related
            'channel_ids', 'partner_ids',  # recipients
            'starred_partner_ids',  # list of partner ids for whom the message is starred
        ])
        message_tree = dict((m.id, m) for m in self.sudo())
        self._message_read_dict_postprocess(message_values, message_tree)

        # add subtype data (is_note flag, subtype_description). Do it as sudo
        # because portal / public may have to look for internal subtypes
        subtype_ids = [msg['subtype_id'][0] for msg in message_values if msg['subtype_id']]
        subtypes = self.env['mail.message.subtype'].sudo().browse(subtype_ids).read(['internal', 'description'])
        subtypes_dict = dict((subtype['id'], subtype) for subtype in subtypes)

        # fetch notification status
        notif_dict = {}
        notifs = self.env['mail.notification'].sudo().search([('mail_message_id', 'in', list(mid for mid in message_tree)), ('is_read', '=', False)])
        for notif in notifs:
            mid = notif.mail_message_id.id
            if not notif_dict.get(mid):
                notif_dict[mid] = {'partner_id': list()}
            notif_dict[mid]['partner_id'].append(notif.res_partner_id.id)

        for message in message_values:
            message['needaction_partner_ids'] = notif_dict.get(message['id'], dict()).get('partner_id', [])
            message['is_note'] = message['subtype_id'] and subtypes_dict[message['subtype_id'][0]]['internal']
            message['subtype_description'] = message['subtype_id'] and subtypes_dict[message['subtype_id'][0]]['description']
            if message['model'] and self.env[message['model']]._original_module:
                message['module_icon'] = modules.module.get_module_icon(self.env[message['model']]._original_module)
        return message_values

    #------------------------------------------------------
    # mail_message internals
    #------------------------------------------------------

    @api.model_cr
    def init(self):
        self._cr.execute("""SELECT indexname FROM pg_indexes WHERE indexname = 'mail_message_model_res_id_idx'""")
        if not self._cr.fetchone():
            self._cr.execute("""CREATE INDEX mail_message_model_res_id_idx ON mail_message (model, res_id)""")

    @api.model
    def _find_allowed_model_wise(self, doc_model, doc_dict):
        doc_ids = list(doc_dict)
        allowed_doc_ids = self.env[doc_model].with_context(active_test=False).search([('id', 'in', doc_ids)]).ids
        return set([message_id for allowed_doc_id in allowed_doc_ids for message_id in doc_dict[allowed_doc_id]])

    @api.model
    def _find_allowed_doc_ids(self, model_ids):
        IrModelAccess = self.env['ir.model.access']
        allowed_ids = set()
        for doc_model, doc_dict in model_ids.items():
            if not IrModelAccess.check(doc_model, 'read', False):
                continue
            allowed_ids |= self._find_allowed_model_wise(doc_model, doc_dict)
        return allowed_ids

    @api.model
    def _search(self, args, offset=0, limit=None, order=None, count=False, access_rights_uid=None):
        """ Override that adds specific access rights of mail.message, to remove
        ids uid could not see according to our custom rules. Please refer to
        check_access_rule for more details about those rules.

        Non employees users see only message with subtype (aka do not see
        internal logs).

        After having received ids of a classic search, keep only:
        - if author_id == pid, uid is the author, OR
        - uid belongs to a notified channel, OR
        - uid is in the specified recipients, OR
        - uid has a notification on the message, OR
        - uid have read access to the related document is model, res_id
        - otherwise: remove the id
        """
        # Rules do not apply to administrator
        if self._uid == SUPERUSER_ID:
            return super(Message, self)._search(
                args, offset=offset, limit=limit, order=order,
                count=count, access_rights_uid=access_rights_uid)
        # Non-employee see only messages with a subtype (aka, no internal logs)
        if not self.env['res.users'].has_group('base.group_user'):
            args = ['&', '&', ('subtype_id', '!=', False), ('subtype_id.internal', '=', False)] + list(args)
        # Perform a super with count as False, to have the ids, not a counter
        ids = super(Message, self)._search(
            args, offset=offset, limit=limit, order=order,
            count=False, access_rights_uid=access_rights_uid)
        if not ids and count:
            return 0
        elif not ids:
            return ids

        pid = self.env.user.partner_id.id
        author_ids, partner_ids, channel_ids, allowed_ids = set([]), set([]), set([]), set([])
        model_ids = {}

        # check read access rights before checking the actual rules on the given ids
        super(Message, self.sudo(access_rights_uid or self._uid)).check_access_rights('read')

        self._cr.execute("""
            SELECT DISTINCT m.id, m.model, m.res_id, m.author_id,
                            COALESCE(partner_rel.res_partner_id, needaction_rel.res_partner_id),
                            channel_partner.channel_id as channel_id
            FROM "%s" m
            LEFT JOIN "mail_message_res_partner_rel" partner_rel
            ON partner_rel.mail_message_id = m.id AND partner_rel.res_partner_id = %%(pid)s
            LEFT JOIN "mail_message_res_partner_needaction_rel" needaction_rel
            ON needaction_rel.mail_message_id = m.id AND needaction_rel.res_partner_id = %%(pid)s
            LEFT JOIN "mail_message_mail_channel_rel" channel_rel
            ON channel_rel.mail_message_id = m.id
            LEFT JOIN "mail_channel" channel
            ON channel.id = channel_rel.mail_channel_id
            LEFT JOIN "mail_channel_partner" channel_partner
            ON channel_partner.channel_id = channel.id AND channel_partner.partner_id = %%(pid)s
            WHERE m.id = ANY (%%(ids)s)""" % self._table, dict(pid=pid, ids=ids))
        for id, rmod, rid, author_id, partner_id, channel_id in self._cr.fetchall():
            if author_id == pid:
                author_ids.add(id)
            elif partner_id == pid:
                partner_ids.add(id)
            elif channel_id:
                channel_ids.add(id)
            elif rmod and rid:
                model_ids.setdefault(rmod, {}).setdefault(rid, set()).add(id)

        allowed_ids = self._find_allowed_doc_ids(model_ids)

        final_ids = author_ids | partner_ids | channel_ids | allowed_ids

        if count:
            return len(final_ids)
        else:
            # re-construct a list based on ids, because set did not keep the original order
            id_list = [id for id in ids if id in final_ids]
            return id_list

    @api.multi
    def check_access_rule(self, operation):
        """ Access rules of mail.message:
            - read: if
                - author_id == pid, uid is the author OR
                - uid is in the recipients (partner_ids) OR
                - uid has been notified (needaction) OR
                - uid is member of a listern channel (channel_ids.partner_ids) OR
                - uid have read access to the related document if model, res_id
                - otherwise: raise
            - create: if
                - no model, no res_id (private message) OR
                - pid in message_follower_ids if model, res_id OR
                - uid can read the parent OR
                - uid have write or create access on the related document if model, res_id, OR
                - otherwise: raise
            - write: if
                - author_id == pid, uid is the author, OR
                - uid is in the recipients (partner_ids) OR
                - uid has write or create access on the related document if model, res_id
                - otherwise: raise
            - unlink: if
                - uid has write or create access on the related document if model, res_id
                - otherwise: raise

        Specific case: non employee users see only messages with subtype (aka do
        not see internal logs).
        """
        def _generate_model_record_ids(msg_val, msg_ids):
            """ :param model_record_ids: {'model': {'res_id': (msg_id, msg_id)}, ... }
                :param message_values: {'msg_id': {'model': .., 'res_id': .., 'author_id': ..}}
            """
            model_record_ids = {}
            for id in msg_ids:
                vals = msg_val.get(id, {})
                if vals.get('model') and vals.get('res_id'):
                    model_record_ids.setdefault(vals['model'], set()).add(vals['res_id'])
            return model_record_ids

        if self._uid == SUPERUSER_ID:
            return
        # Non employees see only messages with a subtype (aka, not internal logs)
        if not self.env['res.users'].has_group('base.group_user'):
            self._cr.execute('''SELECT DISTINCT message.id, message.subtype_id, subtype.internal
                                FROM "%s" AS message
                                LEFT JOIN "mail_message_subtype" as subtype
                                ON message.subtype_id = subtype.id
                                WHERE message.message_type = %%s AND (message.subtype_id IS NULL OR subtype.internal IS TRUE) AND message.id = ANY (%%s)''' % (self._table), ('comment', self.ids,))
            if self._cr.fetchall():
                raise AccessError(
                    _('The requested operation cannot be completed due to security restrictions. Please contact your system administrator.\n\n(Document type: %s, Operation: %s)') %
                    (self._description, operation))

        # Read mail_message.ids to have their values
        message_values = dict((res_id, {}) for res_id in self.ids)

        if operation in ['read', 'write']:
            self._cr.execute("""
                SELECT DISTINCT m.id, m.model, m.res_id, m.author_id, m.parent_id,
                                COALESCE(partner_rel.res_partner_id, needaction_rel.res_partner_id),
                                channel_partner.channel_id as channel_id
                FROM "%s" m
                LEFT JOIN "mail_message_res_partner_rel" partner_rel
                ON partner_rel.mail_message_id = m.id AND partner_rel.res_partner_id = %%(pid)s
                LEFT JOIN "mail_message_res_partner_needaction_rel" needaction_rel
                ON needaction_rel.mail_message_id = m.id AND needaction_rel.res_partner_id = %%(pid)s
                LEFT JOIN "mail_message_mail_channel_rel" channel_rel
                ON channel_rel.mail_message_id = m.id
                LEFT JOIN "mail_channel" channel
                ON channel.id = channel_rel.mail_channel_id
                LEFT JOIN "mail_channel_partner" channel_partner
                ON channel_partner.channel_id = channel.id AND channel_partner.partner_id = %%(pid)s
                WHERE m.id = ANY (%%(ids)s)""" % self._table, dict(pid=self.env.user.partner_id.id, ids=self.ids))
            for mid, rmod, rid, author_id, parent_id, partner_id, channel_id in self._cr.fetchall():
                message_values[mid] = {
                    'model': rmod,
                    'res_id': rid,
                    'author_id': author_id,
                    'parent_id': parent_id,
                    'notified': any((message_values[mid].get('notified'), partner_id, channel_id))
                }
        else:
            self._cr.execute("""SELECT DISTINCT id, model, res_id, author_id, parent_id FROM "%s" WHERE id = ANY (%%s)""" % self._table, (self.ids,))
            for mid, rmod, rid, author_id, parent_id in self._cr.fetchall():
                message_values[mid] = {'model': rmod, 'res_id': rid, 'author_id': author_id, 'parent_id': parent_id}

        # Author condition (READ, WRITE, CREATE (private))
        author_ids = []
        if operation == 'read' or operation == 'write':
            author_ids = [mid for mid, message in message_values.items()
                          if message.get('author_id') and message.get('author_id') == self.env.user.partner_id.id]
        elif operation == 'create':
            author_ids = [mid for mid, message in message_values.items()
                          if not message.get('model') and not message.get('res_id')]

        # Parent condition, for create (check for received notifications for the created message parent)
        notified_ids = []
        if operation == 'create':
            # TDE: probably clean me
            parent_ids = [message.get('parent_id') for message in message_values.values()
                          if message.get('parent_id')]
            self._cr.execute("""SELECT DISTINCT m.id, partner_rel.res_partner_id, channel_partner.partner_id FROM "%s" m
                LEFT JOIN "mail_message_res_partner_rel" partner_rel
                ON partner_rel.mail_message_id = m.id AND partner_rel.res_partner_id = (%%s)
                LEFT JOIN "mail_message_mail_channel_rel" channel_rel
                ON channel_rel.mail_message_id = m.id
                LEFT JOIN "mail_channel" channel
                ON channel.id = channel_rel.mail_channel_id
                LEFT JOIN "mail_channel_partner" channel_partner
                ON channel_partner.channel_id = channel.id AND channel_partner.partner_id = (%%s)
                WHERE m.id = ANY (%%s)""" % self._table, (self.env.user.partner_id.id, self.env.user.partner_id.id, parent_ids,))
            not_parent_ids = [mid[0] for mid in self._cr.fetchall() if any([mid[1], mid[2]])]
            notified_ids += [mid for mid, message in message_values.items()
                             if message.get('parent_id') in not_parent_ids]

        # Recipients condition, for read and write (partner_ids) and create (message_follower_ids)
        other_ids = set(self.ids).difference(set(author_ids), set(notified_ids))
        model_record_ids = _generate_model_record_ids(message_values, other_ids)
        if operation in ['read', 'write']:
            notified_ids = [mid for mid, message in message_values.items() if message.get('notified')]
        elif operation == 'create':
            for doc_model, doc_ids in model_record_ids.items():
                followers = self.env['mail.followers'].sudo().search([
                    ('res_model', '=', doc_model),
                    ('res_id', 'in', list(doc_ids)),
                    ('partner_id', '=', self.env.user.partner_id.id),
                    ])
                fol_mids = [follower.res_id for follower in followers]
                notified_ids += [mid for mid, message in message_values.items()
                                 if message.get('model') == doc_model and message.get('res_id') in fol_mids]

        # CRUD: Access rights related to the document
        other_ids = other_ids.difference(set(notified_ids))
        model_record_ids = _generate_model_record_ids(message_values, other_ids)
        document_related_ids = []
        for model, doc_ids in model_record_ids.items():
            DocumentModel = self.env[model]
            mids = DocumentModel.browse(doc_ids).exists()
            if hasattr(DocumentModel, 'check_mail_message_access'):
                DocumentModel.check_mail_message_access(mids.ids, operation)  # ?? mids ?
            else:
                self.env['mail.thread'].check_mail_message_access(mids.ids, operation, model_name=model)
            document_related_ids += [mid for mid, message in message_values.items()
                                     if message.get('model') == model and message.get('res_id') in mids.ids]

        # Calculate remaining ids: if not void, raise an error
        other_ids = other_ids.difference(set(document_related_ids))
        if not (other_ids and self.browse(other_ids).exists()):
            return
        raise AccessError(
            _('The requested operation cannot be completed due to security restrictions. Please contact your system administrator.\n\n(Document type: %s, Operation: %s)') %
            (self._description, operation))

    @api.model
    def _get_record_name(self, values):
        """ Return the related document name, using name_get. It is done using
            SUPERUSER_ID, to be sure to have the record name correctly stored. """
        model = values.get('model', self.env.context.get('default_model'))
        res_id = values.get('res_id', self.env.context.get('default_res_id'))
        if not model or not res_id or model not in self.env:
            return False
        return self.env[model].sudo().browse(res_id).name_get()[0][1]

    @api.model
    def _get_reply_to(self, values):
        """ Return a specific reply_to: alias of the document through
        message_get_reply_to or take the email_from """
        model, res_id, email_from = values.get('model', self._context.get('default_model')), values.get('res_id', self._context.get('default_res_id')), values.get('email_from')  # ctx values / defualt_get res ?
        if model and hasattr(self.env[model], 'message_get_reply_to'):
            # return self.env[model].browse(res_id).message_get_reply_to([res_id], default=email_from)[res_id]
            return self.env[model].message_get_reply_to([res_id], default=email_from)[res_id]
        else:
            # return self.env['mail.thread'].message_get_reply_to(default=email_from)[None]
            return self.env['mail.thread'].message_get_reply_to([None], default=email_from)[None]

    @api.model
    def _get_message_id(self, values):
        if values.get('no_auto_thread', False) is True:
            message_id = tools.generate_tracking_message_id('reply_to')
        elif values.get('res_id') and values.get('model'):
            message_id = tools.generate_tracking_message_id('%(res_id)s-%(model)s' % values)
        else:
            message_id = tools.generate_tracking_message_id('private')
        return message_id

    @api.multi
    def _invalidate_documents(self):
        """ Invalidate the cache of the documents followed by ``self``. """
        for record in self:
            if record.model and record.res_id:
                self.env[record.model].invalidate_cache(ids=[record.res_id])

    @api.model
    def create(self, values):
        # coming from mail.js that does not have pid in its values
        if self.env.context.get('default_starred'):
            self = self.with_context({'default_starred_partner_ids': [(4, self.env.user.partner_id.id)]})

        if 'email_from' not in values:  # needed to compute reply_to
            values['email_from'] = self._get_default_from()
        if not values.get('message_id'):
            values['message_id'] = self._get_message_id(values)
        if 'reply_to' not in values:
            values['reply_to'] = self._get_reply_to(values)
        if 'record_name' not in values and 'default_record_name' not in self.env.context:
            values['record_name'] = self._get_record_name(values)

        if 'attachment_ids' not in values:
            values.setdefault('attachment_ids', [])

        # extract base64 images
        if 'body' in values:
            Attachments = self.env['ir.attachment']
            data_to_url = {}
            def base64_to_boundary(match):
                key = match.group(2)
                if not data_to_url.get(key):
                    name = 'image%s' % len(data_to_url)
                    attachment = Attachments.create({
                        'name': name,
                        'datas': match.group(2),
                        'datas_fname': name,
                        'res_model': 'mail.message',
                    })
                    attachment.generate_access_token()
                    values['attachment_ids'].append((4, attachment.id))
                    data_to_url[key] = ['/web/image/%s?access_token=%s' % (attachment.id, attachment.access_token), name]
                return '%s%s alt="%s"' % (data_to_url[key][0], match.group(3), data_to_url[key][1])
            values['body'] = _image_dataurl.sub(base64_to_boundary, tools.ustr(values['body']))

        # delegate creation of tracking after the create as sudo to avoid access rights issues
        tracking_values_cmd = values.pop('tracking_value_ids', False)
        message = super(Message, self).create(values)
        if tracking_values_cmd:
            message.sudo().write({'tracking_value_ids': tracking_values_cmd})

        message._invalidate_documents()

        if not self.env.context.get('message_create_from_mail_mail'):
            message._notify(force_send=self.env.context.get('mail_notify_force_send', True),
                            user_signature=self.env.context.get('mail_notify_user_signature', True))
        return message

    @api.multi
    def read(self, fields=None, load='_classic_read'):
        """ Override to explicitely call check_access_rule, that is not called
            by the ORM. It instead directly fetches ir.rules and apply them. """
        self.check_access_rule('read')
        return super(Message, self).read(fields=fields, load=load)

    @api.multi
    def write(self, vals):
        if 'model' in vals or 'res_id' in vals:
            self._invalidate_documents()
        res = super(Message, self).write(vals)
        self._invalidate_documents()
        return res

    @api.multi
    def unlink(self):
        # cascade-delete attachments that are directly attached to the message (should only happen
        # for mail.messages that act as parent for a standalone mail.mail record).
        self.check_access_rule('unlink')
        self.mapped('attachment_ids').filtered(
            lambda attach: attach.res_model == self._name and (attach.res_id in self.ids or attach.res_id == 0)
        ).unlink()
        self._invalidate_documents()
        return super(Message, self).unlink()

    #------------------------------------------------------
    # Messaging API
    #------------------------------------------------------

    @api.multi
    def _notify(self, force_send=False, send_after_commit=True, user_signature=True):
        """ Compute recipients to notify based on specified recipients and document
        followers. Delegate notification to partners to send emails and bus notifications
        and to channels to broadcast messages on channels """
        group_user = self.env.ref('base.group_user')
        # have a sudoed copy to manipulate partners (public can go here with website modules like forum / blog / ... )
        self_sudo = self.sudo()

        self.ensure_one()
        partners_sudo = self_sudo.partner_ids
        channels_sudo = self_sudo.channel_ids

        # all followers of the mail.message document have to be added as partners and notified
        # and filter to employees only if the subtype is internal
        if self_sudo.subtype_id and self.model and self.res_id:
            followers = self_sudo.env['mail.followers'].search([
                ('res_model', '=', self.model),
                ('res_id', '=', self.res_id),
                ('subtype_ids', 'in', self_sudo.subtype_id.id),
            ])
            if self_sudo.subtype_id.internal:
                followers = followers.filtered(lambda fol: fol.channel_id or (fol.partner_id.user_ids and group_user in fol.partner_id.user_ids[0].mapped('groups_id')))
            channels_sudo |= followers.mapped('channel_id')
            partners_sudo |= followers.mapped('partner_id')

        # remove author from notified partners
        if not self._context.get('mail_notify_author', False) and self_sudo.author_id:
            partners_sudo = partners_sudo - self_sudo.author_id

        # update message, with maybe custom values
        message_values = {}
        if channels_sudo:
            message_values['channel_ids'] = [(6, 0, channels_sudo.ids)]
        if partners_sudo:
            message_values['needaction_partner_ids'] = [(6, 0, partners_sudo.ids)]
        if self.model and self.res_id and hasattr(self.env[self.model], 'message_get_message_notify_values'):
            message_values.update(self.env[self.model].browse(self.res_id).message_get_message_notify_values(self, message_values))
        if message_values:
            self.write(message_values)

        # notify partners and channels
        # those methods are called as SUPERUSER because portal users posting messages
        # have no access to partner model. Maybe propagating a real uid could be necessary.
        email_channels = channels_sudo.filtered(lambda channel: channel.email_send)
        notif_partners = partners_sudo.filtered(lambda partner: 'inbox' in partner.mapped('user_ids.notification_type'))
        if email_channels or partners_sudo - notif_partners:
            partners_sudo.search([
                '|',
                ('id', 'in', (partners_sudo - notif_partners).ids),
                ('channel_ids', 'in', email_channels.ids),
                ('email', '!=', self_sudo.author_id.email or self_sudo.email_from),
            ])._notify(self, force_send=force_send, send_after_commit=send_after_commit, user_signature=user_signature)

        notif_partners._notify_by_chat(self)

        channels_sudo._notify(self)

        # Discard cache, because child / parent allow reading and therefore
        # change access rights.
        if self.parent_id:
            self.parent_id.invalidate_cache()

        return True