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

import base64
import logging
import re
from uuid import uuid4

from odoo import _, api, fields, models, modules, tools
from odoo.exceptions import UserError, ValidationError
from odoo.osv import expression
from odoo.tools import ormcache, formataddr
from odoo.exceptions import AccessError
from odoo.addons.base.models.ir_model import MODULE_UNINSTALL_FLAG

MODERATION_FIELDS = ['moderation', 'moderator_ids', 'moderation_ids', 'moderation_notify', 'moderation_notify_msg', 'moderation_guidelines', 'moderation_guidelines_msg']
_logger = logging.getLogger(__name__)


class ChannelPartner(models.Model):
    _name = 'mail.channel.partner'
    _description = 'Listeners of a Channel'
    _table = 'mail_channel_partner'
    _rec_name = 'partner_id'

    custom_channel_name = fields.Char('Custom channel name')
    partner_id = fields.Many2one('res.partner', string='Recipient', ondelete='cascade')
    partner_email = fields.Char('Email', related='partner_id.email', readonly=False)
    channel_id = fields.Many2one('mail.channel', string='Channel', ondelete='cascade')
    fetched_message_id = fields.Many2one('mail.message', string='Last Fetched')
    seen_message_id = fields.Many2one('mail.message', string='Last Seen')
    fold_state = fields.Selection([('open', 'Open'), ('folded', 'Folded'), ('closed', 'Closed')], string='Conversation Fold State', default='open')
    is_minimized = fields.Boolean("Conversation is minimized")
    is_pinned = fields.Boolean("Is pinned on the interface", default=True)

    @api.model
    def create(self, vals):
        """Similar access rule as the access rule of the mail channel.

        It can not be implemented in XML, because when the record will be created, the
        partner will be added in the channel and the security rule will always authorize
        the creation.
        """
        if 'channel_id' in vals and not self.env.is_admin():
            channel_id = self.env['mail.channel'].browse(vals['channel_id'])
            if not channel_id._can_invite(vals.get('partner_id')):
                raise AccessError(_('This user can not be added in this channel'))
        return super(ChannelPartner, self).create(vals)

    def write(self, vals):
        if not self.env.is_admin():
            if {'channel_id', 'partner_id', 'partner_email'} & set(vals):
                raise AccessError(_('You can not write on this field'))
        return super(ChannelPartner, self).write(vals)


class Moderation(models.Model):
    _name = 'mail.moderation'
    _description = 'Channel black/white list'

    email = fields.Char(string="Email", index=True, required=True)
    status = fields.Selection([
        ('allow', 'Always Allow'),
        ('ban', 'Permanent Ban')],
        string="Status", required=True)
    channel_id = fields.Many2one('mail.channel', string="Channel", index=True, required=True)

    _sql_constraints = [
        ('channel_email_uniq', 'unique (email,channel_id)', 'The email address must be unique per channel !')
    ]


class Channel(models.Model):
    """ A mail.channel is a discussion group that may behave like a listener
    on documents. """
    _description = 'Discussion Channel'
    _name = 'mail.channel'
    _mail_flat_thread = False
    _mail_post_access = 'read'
    _inherit = ['mail.thread', 'mail.alias.mixin']

    MAX_BOUNCE_LIMIT = 10

    @api.model
    def default_get(self, fields):
        res = super(Channel, self).default_get(fields)
        if not res.get('alias_contact') and (not fields or 'alias_contact' in fields):
            res['alias_contact'] = 'everyone' if res.get('public', 'private') == 'public' else 'followers'
        return res

    def _get_default_image(self):
        image_path = modules.get_module_resource('mail', 'static/src/img', 'groupdefault.png')
        return base64.b64encode(open(image_path, 'rb').read())

    name = fields.Char('Name', required=True, translate=True)
    active = fields.Boolean(default=True, help="Set active to false to hide the channel without removing it.")
    channel_type = fields.Selection([
        ('chat', 'Chat Discussion'),
        ('channel', 'Channel')],
        'Channel Type', default='channel')
    is_chat = fields.Boolean(string='Is a chat', compute='_compute_is_chat', default=False)
    description = fields.Text('Description')
    uuid = fields.Char('UUID', size=50, index=True, default=lambda self: str(uuid4()), copy=False)
    email_send = fields.Boolean('Send messages by email', default=False)
    # multi users channel
    # depends=['...'] is for `test_mail/tests/common.py`, class Moderation, `setUpClass`
    channel_last_seen_partner_ids = fields.One2many('mail.channel.partner', 'channel_id', string='Last Seen', depends=['channel_partner_ids'])
    channel_partner_ids = fields.Many2many('res.partner', 'mail_channel_partner', 'channel_id', 'partner_id', string='Listeners', depends=['channel_last_seen_partner_ids'])
    channel_message_ids = fields.Many2many('mail.message', 'mail_message_mail_channel_rel')
    is_member = fields.Boolean('Is a member', compute='_compute_is_member')
    # access
    public = fields.Selection([
        ('public', 'Everyone'),
        ('private', 'Invited people only'),
        ('groups', 'Selected group of users')],
        'Privacy', required=True, default='groups',
        help='This group is visible by non members. Invisible groups can add members through the invite button.')
    group_public_id = fields.Many2one('res.groups', string='Authorized Group',
                                      default=lambda self: self.env.ref('base.group_user'))
    group_ids = fields.Many2many(
        'res.groups', string='Auto Subscription',
        help="Members of those groups will automatically added as followers. "
             "Note that they will be able to manage their subscription manually "
             "if necessary.")
    image_128 = fields.Image("Image", max_width=128, max_height=128, default=_get_default_image)
    is_subscribed = fields.Boolean(
        'Is Subscribed', compute='_compute_is_subscribed')
    # moderation
    moderation = fields.Boolean(string='Moderate this channel')
    moderator_ids = fields.Many2many('res.users', 'mail_channel_moderator_rel', string='Moderators')
    is_moderator = fields.Boolean(help="Current user is a moderator of the channel", string='Moderator', compute="_compute_is_moderator")
    moderation_ids = fields.One2many(
        'mail.moderation', 'channel_id', string='Moderated Emails',
        groups="base.group_user")
    moderation_count = fields.Integer(
        string='Moderated emails count', compute='_compute_moderation_count',
        groups="base.group_user")
    moderation_notify = fields.Boolean(string="Automatic notification", help="People receive an automatic notification about their message being waiting for moderation.")
    moderation_notify_msg = fields.Text(string="Notification message")
    moderation_guidelines = fields.Boolean(string="Send guidelines to new subscribers", help="Newcomers on this moderated channel will automatically receive the guidelines.")
    moderation_guidelines_msg = fields.Text(string="Guidelines")

    @api.depends('channel_partner_ids')
    def _compute_is_subscribed(self):
        for channel in self:
            channel.is_subscribed = self.env.user.partner_id in channel.channel_partner_ids

    @api.depends('moderator_ids')
    def _compute_is_moderator(self):
        for channel in self:
            channel.is_moderator = self.env.user in channel.moderator_ids

    @api.depends('moderation_ids')
    def _compute_moderation_count(self):
        read_group_res = self.env['mail.moderation'].read_group([('channel_id', 'in', self.ids)], ['channel_id'], 'channel_id')
        data = dict((res['channel_id'][0], res['channel_id_count']) for res in read_group_res)
        for channel in self:
            channel.moderation_count = data.get(channel.id, 0)

    @api.constrains('moderator_ids')
    def _check_moderator_email(self):
        if any(not moderator.email for channel in self for moderator in channel.moderator_ids):
            raise ValidationError(_("Moderators must have an email address."))

    @api.constrains('moderator_ids', 'channel_partner_ids', 'channel_last_seen_partner_ids')
    def _check_moderator_is_member(self):
        for channel in self:
            if not (channel.mapped('moderator_ids.partner_id') <= channel.sudo().channel_partner_ids):
                raise ValidationError(_("Moderators should be members of the channel they moderate."))

    @api.constrains('moderation', 'email_send')
    def _check_moderation_parameters(self):
        if any(not channel.email_send and channel.moderation for channel in self):
            raise ValidationError(_('Only mailing lists can be moderated.'))

    @api.constrains('moderator_ids')
    def _check_moderator_existence(self):
        if any(not channel.moderator_ids for channel in self if channel.moderation):
            raise ValidationError(_('Moderated channels must have moderators.'))

    def _compute_is_member(self):
        memberships = self.env['mail.channel.partner'].sudo().search([
            ('channel_id', 'in', self.ids),
            ('partner_id', '=', self.env.user.partner_id.id),
            ])
        membership_ids = memberships.mapped('channel_id')
        for record in self:
            record.is_member = record in membership_ids

    def _compute_is_chat(self):
        for record in self:
            if record.channel_type == 'chat':
                record.is_chat = True
            else:
                record.is_chat = False

    @api.onchange('public')
    def _onchange_public(self):
        if self.public != 'public' and self.alias_contact == 'everyone':
            self.alias_contact = 'followers'

    @api.onchange('moderator_ids')
    def _onchange_moderator_ids(self):
        missing_partner_ids = set(self.mapped('moderator_ids.partner_id').ids) - set(self.mapped('channel_last_seen_partner_ids.partner_id').ids)
        if missing_partner_ids:
            self.channel_last_seen_partner_ids = [
                (0, 0, {'partner_id': partner_id})
                for partner_id in missing_partner_ids
            ]

    @api.onchange('email_send')
    def _onchange_email_send(self):
        if not self.email_send:
            self.moderation = False

    @api.onchange('moderation')
    def _onchange_moderation(self):
        if not self.moderation:
            self.moderation_notify = False
            self.moderation_guidelines = False
            self.moderator_ids = False
        else:
            self.moderator_ids |= self.env.user

    @api.model
    def create(self, vals):
        # ensure image at quick create
        if not vals.get('image_128'):
            defaults = self.default_get(['image_128'])
            vals['image_128'] = defaults['image_128']

        current_partner = self.env.user.partner_id.id
        # always add current user to new channel, go through
        # channel_last_seen_partner_ids otherwise in v14 the channel is not
        # visible for the user (because is_pinned is false and taken in account)
        if 'channel_partner_ids' in vals:
            vals['channel_partner_ids'] = [
                entry
                for entry in vals['channel_partner_ids']
                if entry[0] != 4 or entry[1] != current_partner
            ]
        membership = vals.setdefault('channel_last_seen_partner_ids', [])
        if all(entry[0] != 0 or entry[2].get('partner_id') != current_partner for entry in membership):
            membership.append((0, False, {'partner_id': current_partner}))

        visibility_default = self._fields['public'].default(self)
        visibility = vals.pop('public', visibility_default)
        vals['public'] = 'public'
        # Create channel and alias
        channel = super(Channel, self.with_context(
            mail_create_nolog=True, mail_create_nosubscribe=True)
        ).create(vals)
        if visibility != 'public':
            channel.sudo().public = visibility

        if vals.get('group_ids'):
            channel._subscribe_users()

        # make channel listen itself: posting on a channel notifies the channel
        if not self._context.get('mail_channel_noautofollow'):
            channel.message_subscribe(channel_ids=[channel.id])

        return channel

    def unlink(self):
        # Delete mail.channel
        try:
            all_emp_group = self.env.ref('mail.channel_all_employees')
        except ValueError:
            all_emp_group = None
        if all_emp_group and all_emp_group in self and not self._context.get(MODULE_UNINSTALL_FLAG):
            raise UserError(_('You cannot delete those groups, as the Whole Company group is required by other modules.'))
        return super(Channel, self).unlink()

    def write(self, vals):
        # First checks if user tries to modify moderation fields and has not the right to do it.
        if any(key for key in MODERATION_FIELDS if vals.get(key)) and any(self.env.user not in channel.moderator_ids for channel in self if channel.moderation):
            if not self.env.user.has_group('base.group_system'):
                raise UserError(_("You do not have the rights to modify fields related to moderation on one of the channels you are modifying."))

        result = super(Channel, self).write(vals)

        if vals.get('group_ids'):
            self._subscribe_users()

        # avoid keeping messages to moderate and accept them
        if vals.get('moderation') is False:
            self.env['mail.message'].search([
                ('moderation_status', '=', 'pending_moderation'),
                ('model', '=', 'mail.channel'),
                ('res_id', 'in', self.ids)
            ])._moderate_accept()

        return result

    def _alias_get_creation_values(self):
        values = super(Channel, self)._alias_get_creation_values()
        values['alias_model_id'] = self.env['ir.model']._get('mail.channel').id
        if self.id:
            values['alias_force_thread_id'] = self.id
        return values

    def _subscribe_users(self):
        to_create = []
        for mail_channel in self:
            partners_to_add = mail_channel.group_ids.users.partner_id - mail_channel.channel_partner_ids
            to_create += [{
                'channel_id': mail_channel.id,
                'partner_id': partner.id,
            } for partner in partners_to_add]

        self.env['mail.channel.partner'].create(to_create)

    def action_follow(self):
        self.ensure_one()
        channel_partner = self.mapped('channel_last_seen_partner_ids').filtered(lambda cp: cp.partner_id == self.env.user.partner_id)
        if not channel_partner:
            return self.write({'channel_last_seen_partner_ids': [(0, 0, {'partner_id': self.env.user.partner_id.id})]})
        return False

    def action_unfollow(self):
        return self._action_unfollow(self.env.user.partner_id)

    def _action_unfollow(self, partner):
        channel_info = self.channel_info('unsubscribe')[0]  # must be computed before leaving the channel (access rights)
        result = self.write({'channel_partner_ids': [(3, partner.id)]})
        # side effect of unsubscribe that wasn't taken into account because
        # channel_info is called before actually unpinning the channel
        channel_info['is_pinned'] = False
        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', partner.id), channel_info)
        if not self.email_send:
            notification = _('<div class="o_mail_notification">left <a href="#" class="o_channel_redirect" data-oe-id="%s">#%s</a></div>') % (self.id, self.name,)
            # post 'channel left' message as root since the partner just unsubscribed from the channel
            self.sudo().message_post(body=notification, subtype_xmlid="mail.mt_comment", author_id=partner.id)
        return result

    def _notify_get_groups(self):
        """ All recipients of a message on a channel are considered as partners.
        This means they will receive a minimal email, without a link to access
        in the backend. Mailing lists should indeed send minimal emails to avoid
        the noise. """
        groups = super(Channel, self)._notify_get_groups()
        for (index, (group_name, group_func, group_data)) in enumerate(groups):
            if group_name != 'customer':
                groups[index] = (group_name, lambda partner: False, group_data)
        return groups

    def _notify_email_header_dict(self):
        headers = super(Channel, self)._notify_email_header_dict()
        headers['Precedence'] = 'list'
        # avoid out-of-office replies from MS Exchange
        # http://blogs.technet.com/b/exchange/archive/2006/10/06/3395024.aspx
        headers['X-Auto-Response-Suppress'] = 'OOF'
        if self.alias_domain and self.alias_name:
            headers['List-Id'] = '<%s.%s>' % (self.alias_name, self.alias_domain)
            headers['List-Post'] = '<mailto:%s@%s>' % (self.alias_name, self.alias_domain)
            # Avoid users thinking it was a personal message
            # X-Forge-To: will replace To: after SMTP envelope is determined by ir.mail.server
            list_to = '"%s" <%s@%s>' % (self.name, self.alias_name, self.alias_domain)
            headers['X-Forge-To'] = list_to
        return headers

    def _message_receive_bounce(self, email, partner):
        """ Override bounce management to unsubscribe bouncing addresses """
        for p in partner:
            if p.message_bounce >= self.MAX_BOUNCE_LIMIT:
                self._action_unfollow(p)
        return super(Channel, self)._message_receive_bounce(email, partner)

    def _notify_email_recipient_values(self, recipient_ids):
        # Excluded Blacklisted
        whitelist = self.env['res.partner'].sudo().browse(recipient_ids).filtered(lambda p: not p.is_blacklisted)
        # real mailing list: multiple recipients (hidden by X-Forge-To)
        if self.alias_domain and self.alias_name:
            return {
                'email_to': ','.join(formataddr((partner.name, partner.email_normalized)) for partner in whitelist if partner.email_normalized),
                'recipient_ids': [],
            }
        return super(Channel, self)._notify_email_recipient_values(whitelist.ids)

    def _extract_moderation_values(self, message_type, **kwargs):
        """ This method is used to compute moderation status before the creation
        of a message.  For this operation the message's author email address is required.
        This address is returned with status for other computations. """
        moderation_status = 'accepted'
        email = ''
        if self.moderation and message_type in ['email', 'comment']:
            author_id = kwargs.get('author_id')
            if author_id and isinstance(author_id, int):
                email = self.env['res.partner'].browse([author_id]).email
            elif author_id:
                email = author_id.email
            elif kwargs.get('email_from'):
                email = tools.email_split(kwargs['email_from'])[0]
            else:
                email = self.env.user.email
            if email in self.mapped('moderator_ids.email'):
                return moderation_status, email
            status = self.env['mail.moderation'].sudo().search([('email', '=', email), ('channel_id', 'in', self.ids)]).mapped('status')
            if status and status[0] == 'allow':
                moderation_status = 'accepted'
            elif status and status[0] == 'ban':
                moderation_status = 'rejected'
            else:
                moderation_status = 'pending_moderation'
        return moderation_status, email

    @api.returns('mail.message', lambda value: value.id)
    def message_post(self, *, message_type='notification', **kwargs):
        moderation_status, email = self._extract_moderation_values(message_type, **kwargs)
        if moderation_status == 'rejected':
            return self.env['mail.message']

        self.filtered(lambda channel: channel.is_chat).mapped('channel_last_seen_partner_ids').sudo().write({'is_pinned': True})

        message = super(Channel, self.with_context(mail_create_nosubscribe=True)).message_post(message_type=message_type, moderation_status=moderation_status, **kwargs)

        # Notifies the message author when his message is pending moderation if required on channel.
        # The fields "email_from" and "reply_to" are filled in automatically by method create in model mail.message.
        if self.moderation_notify and self.moderation_notify_msg and message_type in ['email','comment'] and moderation_status == 'pending_moderation':
            self.env['mail.mail'].sudo().create({
                'author_id': self.env.user.partner_id.id,
                'email_from': self.env.user.company_id.catchall_formatted or self.env.user.company_id.email_formatted,
                'body_html': self.moderation_notify_msg,
                'subject': 'Re: %s' % (kwargs.get('subject', '')),
                'email_to': email,
                'auto_delete': True,
                'state': 'outgoing'
            })
        return message

    def _message_post_after_hook(self, message, msg_vals):
        """
        Automatically set the message posted by the current user as seen for himself.
        """
        self._set_last_seen_message(message)
        return super()._message_post_after_hook(message=message, msg_vals=msg_vals)

    def _alias_get_error_message(self, message, message_dict, alias):
        if alias.alias_contact == 'followers' and self.ids:
            author = self.env['res.partner'].browse(message_dict.get('author_id', False))
            if not author or author not in self.channel_partner_ids:
                return _('restricted to channel members')
            return False
        return super(Channel, self)._alias_get_error_message(message, message_dict, alias)

    def init(self):
        self._cr.execute('SELECT indexname FROM pg_indexes WHERE indexname = %s', ('mail_channel_partner_seen_message_id_idx',))
        if not self._cr.fetchone():
            self._cr.execute('CREATE INDEX mail_channel_partner_seen_message_id_idx ON mail_channel_partner (channel_id,partner_id,seen_message_id)')

    # --------------------------------------------------
    # Moderation
    # --------------------------------------------------

    def send_guidelines(self):
        """ Send guidelines to all channel members. """
        if self.env.user in self.moderator_ids or self.env.user.has_group('base.group_system'):
            success = self._send_guidelines(self.channel_partner_ids)
            if not success:
                raise UserError(_('View "mail.mail_channel_send_guidelines" was not found. No email has been sent. Please contact an administrator to fix this issue.'))
        else:
            raise UserError(_("Only an administrator or a moderator can send guidelines to channel members!"))

    def _send_guidelines(self, partners):
        """ Send guidelines of a given channel. Returns False if template used for guidelines
        not found. Caller may have to handle this return value. """
        self.ensure_one()
        view = self.env.ref('mail.mail_channel_send_guidelines', raise_if_not_found=False)
        if not view:
            _logger.warning('View "mail.mail_channel_send_guidelines" was not found.')
            return False
        banned_emails = self.env['mail.moderation'].sudo().search([
            ('status', '=', 'ban'),
            ('channel_id', 'in', self.ids)
        ]).mapped('email')
        for partner in partners.filtered(lambda p: p.email and not (p.email in banned_emails)):
            company = partner.company_id or self.env.company
            create_values = {
                'email_from': company.catchall_formatted or company.email_formatted,
                'author_id': self.env.user.partner_id.id,
                'body_html': view._render({'channel': self, 'partner': partner}, engine='ir.qweb', minimal_qcontext=True),
                'subject': _("Guidelines of channel %s", self.name),
                'recipient_ids': [(4, partner.id)]
            }
            mail = self.env['mail.mail'].sudo().create(create_values)
        return True

    def _update_moderation_email(self, emails, status):
        """ This method adds emails into either white or black of the channel list of emails
            according to status. If an email in emails is already moderated, the method updates the email status.
            :param emails: list of email addresses to put in white or black list of channel.
            :param status: value is 'allow' or 'ban'. Emails are put in white list if 'allow', in black list if 'ban'.
        """
        self.ensure_one()
        splitted_emails = [tools.email_split(email)[0] for email in emails if tools.email_split(email)]
        moderated = self.env['mail.moderation'].sudo().search([
            ('email', 'in', splitted_emails),
            ('channel_id', 'in', self.ids)
        ])
        cmds = [(1, record.id, {'status': status}) for record in moderated]
        not_moderated = [email for email in splitted_emails if email not in moderated.mapped('email')]
        cmds += [(0, 0, {'email': email, 'status': status}) for email in not_moderated]
        return self.write({'moderation_ids': cmds})

    #------------------------------------------------------
    # Instant Messaging API
    #------------------------------------------------------
    # A channel header should be broadcasted:
    #   - when adding user to channel (only to the new added partners)
    #   - when folding/minimizing a channel (only to the user making the action)
    # A message should be broadcasted:
    #   - when a message is posted on a channel (to the channel, using _notify() method)

    # Anonymous method
    def _broadcast(self, partner_ids):
        """ Broadcast the current channel header to the given partner ids
            :param partner_ids : the partner to notify
        """
        notifications = self._channel_channel_notifications(partner_ids)
        self.env['bus.bus'].sendmany(notifications)

    def _channel_channel_notifications(self, partner_ids):
        """ Generate the bus notifications of current channel for the given partner ids
            :param partner_ids : the partner to send the current channel header
            :returns list of bus notifications (tuple (bus_channe, message_content))
        """
        notifications = []
        for partner in self.env['res.partner'].browse(partner_ids):
            user_id = partner.user_ids and partner.user_ids[0] or False
            if user_id:
                user_channels = self.with_user(user_id).with_context(
                    allowed_company_ids=user_id.company_ids.ids
                )
                for channel_info in user_channels.channel_info():
                    notifications.append([(self._cr.dbname, 'res.partner', partner.id), channel_info])
        return notifications

    def _notify_thread(self, message, msg_vals=False, **kwargs):
        # When posting a message on a mail channel, manage moderation and postpone notify users
        if not msg_vals or msg_vals.get('moderation_status') != 'pending_moderation':
            super(Channel, self)._notify_thread(message, msg_vals=msg_vals, **kwargs)
        else:
            message._notify_pending_by_chat()

    def _channel_message_notifications(self, message, message_format=False):
        """ Generate the bus notifications for the given message
            :param message : the mail.message to sent
            :returns list of bus notifications (tuple (bus_channe, message_content))
        """
        message_format = message_format or message.message_format()[0]
        notifications = []
        for channel in self:
            notifications.append([(self._cr.dbname, 'mail.channel', channel.id), dict(message_format)])
            # add uuid to allow anonymous to listen
            if channel.public == 'public':
                notifications.append([channel.uuid, dict(message_format)])
        return notifications

    @api.model
    def partner_info(self, all_partners, direct_partners):
        """
        Return the information needed by channel to display channel members
            :param all_partners: list of res.parner():
            :param direct_partners: list of res.parner():
            :returns: a list of {'id', 'name', 'email'} for each partner and adds {im_status} for direct_partners.
            :rtype : list(dict)
        """
        partner_infos = {partner['id']: partner for partner in all_partners.sudo().read(['id', 'name', 'email'])}
        # add im _status for direct_partners
        direct_partners_im_status = {partner['id']: partner for partner in direct_partners.sudo().read(['im_status'])}

        for i in direct_partners_im_status.keys():
            partner_infos[i].update(direct_partners_im_status[i])

        return partner_infos

    def channel_info(self, extra_info=False):
        """ Get the informations header for the current channels
            :returns a list of channels values
            :rtype : list(dict)
        """
        if not self:
            return []
        channel_infos = []
        # all relations partner_channel on those channels
        all_partner_channel = self.env['mail.channel.partner'].search([('channel_id', 'in', self.ids)])

        # all partner infos on those channels
        channel_dict = {channel.id: channel for channel in self}
        all_partners = all_partner_channel.mapped('partner_id')
        direct_channel_partners = all_partner_channel.filtered(lambda pc: channel_dict[pc.channel_id.id].channel_type == 'chat')
        direct_partners = direct_channel_partners.mapped('partner_id')
        partner_infos = self.partner_info(all_partners, direct_partners)

        # add last message preview (only used in mobile)
        addPreview = self._context.get('isMobile', False)
        if addPreview:
            channel_previews = {channel_preview['id']: channel_preview for channel_preview in self.channel_fetch_preview()}
        else:
            channel_last_message_ids = dict((r['id'], r['message_id']) for r in self._channel_last_message_ids())

        for channel in self:
            info = {
                'id': channel.id,
                'name': channel.name,
                'uuid': channel.uuid,
                'state': 'open',
                'is_minimized': False,
                'channel_type': channel.channel_type,
                'public': channel.public,
                'mass_mailing': channel.email_send,
                'moderation': channel.moderation,
                'is_moderator': self.env.uid in channel.moderator_ids.ids,
                'group_based_subscription': bool(channel.group_ids),
                'create_uid': channel.create_uid.id,
            }
            if extra_info:
                info['info'] = extra_info

            # add last message preview (only used in mobile)
            if addPreview:
                if channel in channel_previews:
                    info['last_message'] = channel_previews[channel]
                    info['last_message_id'] = channel_previews[channel]['last_message']['id']
                else:
                    info['last_message_id'] = False
            else:
                info['last_message_id'] = channel_last_message_ids.get(channel.id, False)
            # listeners of the channel
            channel_partners = all_partner_channel.filtered(lambda pc: channel.id == pc.channel_id.id)

            # find the channel partner state, if logged user
            if self.env.user and self.env.user.partner_id:
                # add needaction and unread counter, since the user is logged
                info['message_needaction_counter'] = channel.message_needaction_counter
                info['message_unread_counter'] = channel.message_unread_counter

                # add user session state, if available and if user is logged
                partner_channel = channel_partners.filtered(lambda pc: pc.partner_id.id == self.env.user.partner_id.id)
                if partner_channel:
                    partner_channel = partner_channel[0]
                    info['state'] = partner_channel.fold_state or 'open'
                    info['is_minimized'] = partner_channel.is_minimized
                    info['seen_message_id'] = partner_channel.seen_message_id.id
                    info['custom_channel_name'] = partner_channel.custom_channel_name
                    info['is_pinned'] = partner_channel.is_pinned

            # add members infos
            if channel.channel_type != 'channel':
                # avoid sending potentially a lot of members for big channels
                # exclude chat and other small channels from this optimization because they are
                # assumed to be smaller and it's important to know the member list for them
                partner_ids = channel_partners.mapped('partner_id').ids
                info['members'] = [partner_infos[partner] for partner in partner_ids]
            if channel.channel_type != 'channel':
                info['seen_partners_info'] = [{
                    'id': cp.id,
                    'partner_id': cp.partner_id.id,
                    'fetched_message_id': cp.fetched_message_id.id,
                    'seen_message_id': cp.seen_message_id.id,
                } for cp in channel_partners]

            channel_infos.append(info)
        return channel_infos

    def channel_fetch_message(self, last_id=False, limit=20):
        """ Return message values of the current channel.
            :param last_id : last message id to start the research
            :param limit : maximum number of messages to fetch
            :returns list of messages values
            :rtype : list(dict)
        """
        self.ensure_one()
        domain = [("channel_ids", "in", self.ids)]
        if last_id:
            domain.append(("id", "<", last_id))
        return self.env['mail.message'].message_fetch(domain=domain, limit=limit)

    # User methods
    @api.model
    def channel_get(self, partners_to, pin=True):
        """ Get the canonical private channel between some partners, create it if needed.
            To reuse an old channel (conversation), this one must be private, and contains
            only the given partners.
            :param partners_to : list of res.partner ids to add to the conversation
            :param pin : True if getting the channel should pin it for the current user
            :returns: channel_info of the created or existing channel
            :rtype: dict
        """
        if self.env.user.partner_id.id not in partners_to:
            partners_to.append(self.env.user.partner_id.id)
        # determine type according to the number of partner in the channel
        self.flush()
        self.env.cr.execute("""
            SELECT P.channel_id
            FROM mail_channel C, mail_channel_partner P
            WHERE P.channel_id = C.id
                AND C.public LIKE 'private'
                AND P.partner_id IN %s
                AND C.channel_type LIKE 'chat'
                AND NOT EXISTS (
                    SELECT *
                    FROM mail_channel_partner P2
                    WHERE P2.channel_id = C.id
                        AND P2.partner_id NOT IN %s
                )
            GROUP BY P.channel_id
            HAVING ARRAY_AGG(DISTINCT P.partner_id ORDER BY P.partner_id) = %s
            LIMIT 1
        """, (tuple(partners_to), tuple(partners_to), sorted(list(partners_to)),))
        result = self.env.cr.dictfetchall()
        if result:
            # get the existing channel between the given partners
            channel = self.browse(result[0].get('channel_id'))
            # pin up the channel for the current partner
            if pin:
                self.env['mail.channel.partner'].search([('partner_id', '=', self.env.user.partner_id.id), ('channel_id', '=', channel.id)]).write({'is_pinned': True})
            channel._broadcast(self.env.user.partner_id.ids)
        else:
            # create a new one
            channel = self.create({
                'channel_partner_ids': [(4, partner_id) for partner_id in partners_to],
                'public': 'private',
                'channel_type': 'chat',
                'email_send': False,
                'name': ', '.join(self.env['res.partner'].sudo().browse(partners_to).mapped('name')),
            })
            channel._broadcast(partners_to)
        return channel.channel_info()[0]

    @api.model
    def channel_get_and_minimize(self, partners_to):
        channel = self.channel_get(partners_to)
        if channel:
            self.channel_minimize(channel['uuid'])
        return channel

    @api.model
    def channel_fold(self, uuid, state=None):
        """ Update the fold_state of the given session. In order to syncronize web browser
            tabs, the change will be broadcast to himself (the current user channel).
            Note: the user need to be logged
            :param state : the new status of the session for the current user.
        """
        domain = [('partner_id', '=', self.env.user.partner_id.id), ('channel_id.uuid', '=', uuid)]
        for session_state in self.env['mail.channel.partner'].search(domain):
            if not state:
                state = session_state.fold_state
                if session_state.fold_state == 'open':
                    state = 'folded'
                else:
                    state = 'open'
            session_state.write({
                'fold_state': state,
                'is_minimized': bool(state != 'closed'),
            })
            self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), session_state.channel_id.channel_info()[0])

    @api.model
    def channel_minimize(self, uuid, minimized=True):
        values = {
            'fold_state': minimized and 'open' or 'closed',
            'is_minimized': minimized
        }
        domain = [('partner_id', '=', self.env.user.partner_id.id), ('channel_id.uuid', '=', uuid)]
        channel_partners = self.env['mail.channel.partner'].search(domain, limit=1)
        channel_partners.write(values)
        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), channel_partners.channel_id.channel_info()[0])

    @api.model
    def channel_pin(self, uuid, pinned=False):
        # add the person in the channel, and pin it (or unpin it)
        channel = self.search([('uuid', '=', uuid)])
        channel._execute_channel_pin(pinned)

    def _execute_channel_pin(self, pinned=False):
        """ Hook for website_livechat channel unpin and cleaning """
        self.ensure_one()
        channel_partners = self.env['mail.channel.partner'].search(
            [('partner_id', '=', self.env.user.partner_id.id), ('channel_id', '=', self.id)])
        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), self.channel_info('unsubscribe' if not pinned else False)[0])
        if channel_partners:
            channel_partners.write({'is_pinned': pinned})

    def channel_seen(self, last_message_id=None):
        """
        Mark channel as seen by updating seen message id of the current logged partner
        :param last_message_id: the id of the message to be marked as seen, last message of the
        thread by default. This param SHOULD be required, the default behaviour is DEPRECATED and
        kept only for compatibility reasons.
        """
        self.ensure_one()
        domain = [('channel_ids', 'in', self.ids)]
        if last_message_id:
            domain = expression.AND([domain, [('id', '<=', last_message_id)]])
        last_message = self.env['mail.message'].search(domain, order="id DESC", limit=1)
        if not last_message:
            return

        self._set_last_seen_message(last_message)

        data = {
            'info': 'channel_seen',
            'last_message_id': last_message.id,
            'partner_id': self.env.user.partner_id.id,
        }
        if self.channel_type == 'chat':
            self.env['bus.bus'].sendmany([[(self._cr.dbname, 'mail.channel', self.id), data]])
        else:
            data['channel_id'] = self.id
            self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), data)
        return last_message.id

    def _set_last_seen_message(self, last_message):
        """
        Set last seen message of `self` channels for the current user.
        :param last_message: the message to set as last seen message
        """
        channel_partner_domain = expression.AND([
            [('channel_id', 'in', self.ids)],
            [('partner_id', '=', self.env.user.partner_id.id)],
            expression.OR([
                [('seen_message_id', '=', False)],
                [('seen_message_id', '<', last_message.id)]
            ])
        ])
        channel_partner = self.env['mail.channel.partner'].search(channel_partner_domain)
        channel_partner.write({
            'fetched_message_id': last_message.id,
            'seen_message_id': last_message.id,
        })

    def channel_fetched(self):
        """ Broadcast the channel_fetched notification to channel members
            :param channel_ids : list of channel id that has been fetched by current user
        """
        for channel in self:
            if not channel.channel_message_ids.ids:
                return
            if channel.channel_type != 'chat':
                return
            last_message_id = channel.channel_message_ids.ids[0] # zero is the index of the last message
            channel_partner = self.env['mail.channel.partner'].search([('channel_id', '=', channel.id), ('partner_id', '=', self.env.user.partner_id.id)], limit=1)
            if channel_partner.fetched_message_id.id == last_message_id:
                # last message fetched by user is already up-to-date
                return
            channel_partner.write({
                'fetched_message_id': last_message_id,
            })
            data = {
                'id': channel_partner.id,
                'info': 'channel_fetched',
                'last_message_id': last_message_id,
                'partner_id': self.env.user.partner_id.id,
            }
            self.env['bus.bus'].sendmany([[(self._cr.dbname, 'mail.channel', channel.id), data]])

    def channel_invite(self, partner_ids):
        """ Add the given partner_ids to the current channels and broadcast the channel header to them.
            :param partner_ids : list of partner id to add
        """
        partners = self.env['res.partner'].browse(partner_ids)
        # add the partner
        for channel in self:
            partners_to_add = partners - channel.channel_partner_ids
            channel.write({'channel_last_seen_partner_ids': [(0, 0, {'partner_id': partner_id}) for partner_id in partners_to_add.ids]})
            for partner in partners_to_add:
                if partner.id != self.env.user.partner_id.id:
                    notification = _('<div class="o_mail_notification">%(author)s invited %(new_partner)s to <a href="#" class="o_channel_redirect" data-oe-id="%(channel_id)s">#%(channel_name)s</a></div>') % {
                        'author': self.env.user.display_name,
                        'new_partner': partner.display_name,
                        'channel_id': channel.id,
                        'channel_name': channel.name,
                    }
                else:
                    notification = _('<div class="o_mail_notification">joined <a href="#" class="o_channel_redirect" data-oe-id="%s">#%s</a></div>') % (channel.id, channel.name,)
                self.message_post(body=notification, message_type="notification", subtype_xmlid="mail.mt_comment", author_id=partner.id, notify_by_email=False)

        # broadcast the channel header to the added partner
        self._broadcast(partner_ids)

    def _can_invite(self, partner_id):
        """Return True if the current user can invite the partner to the channel."""
        self.ensure_one()
        sudo_self = self.sudo()
        if sudo_self.public == 'public':
            return True
        if sudo_self.public == 'private':
            return self.is_member

        # get the user related to the invited partner
        partner = self.env['res.partner'].browse(partner_id).exists()
        invited_user_id = partner.user_ids[:1]
        if invited_user_id:
            return (self.env.user | invited_user_id) <= sudo_self.group_public_id.users
        return False

    @api.model
    def channel_set_custom_name(self, channel_id, name=False):
        domain = [('partner_id', '=', self.env.user.partner_id.id), ('channel_id.id', '=', channel_id)]
        channel_partners = self.env['mail.channel.partner'].search(domain, limit=1)
        channel_partners.write({
            'custom_channel_name': name,
        })

    def notify_typing(self, is_typing):
        """ Broadcast the typing notification to channel members
            :param is_typing: (boolean) tells whether the current user is typing or not
        """
        notifications = []
        for channel in self:
            data = {
                'info': 'typing_status',
                'is_typing': is_typing,
                'partner_id': self.env.user.partner_id.id,
                'partner_name': self.env.user.partner_id.name,
            }
            notifications.append([(self._cr.dbname, 'mail.channel', channel.id), data]) # notify backend users
            notifications.append([channel.uuid, data]) # notify frontend users
        self.env['bus.bus'].sendmany(notifications)

    #------------------------------------------------------
    # Instant Messaging View Specific (Slack Client Action)
    #------------------------------------------------------
    @api.model
    def channel_fetch_slot(self):
        """ Return the channels of the user grouped by 'slot' (channel, direct_message or private_group), and
            the mapping between partner_id/channel_id for direct_message channels.
            :returns dict : the grouped channels and the mapping
        """
        values = {}
        my_partner_id = self.env.user.partner_id.id
        pinned_channels = self.env['mail.channel.partner'].search([('partner_id', '=', my_partner_id), ('is_pinned', '=', True)]).mapped('channel_id')

        # get the group/public channels
        values['channel_channel'] = self.search([('channel_type', '=', 'channel'), ('public', 'in', ['public', 'groups']), ('channel_partner_ids', 'in', [my_partner_id])]).channel_info()

        # get the pinned 'direct message' channel
        direct_message_channels = self.search([('channel_type', '=', 'chat'), ('id', 'in', pinned_channels.ids)])
        values['channel_direct_message'] = direct_message_channels.channel_info()

        # get the private group
        values['channel_private_group'] = self.search([('channel_type', '=', 'channel'), ('public', '=', 'private'), ('channel_partner_ids', 'in', [my_partner_id])]).channel_info()
        return values

    @api.model
    def channel_search_to_join(self, name=None, domain=None):
        """ Return the channel info of the channel the current partner can join
            :param name : the name of the researched channels
            :param domain : the base domain of the research
            :returns dict : channel dict
        """
        if not domain:
            domain = []
        domain = expression.AND([
            [('channel_type', '=', 'channel')],
            [('channel_partner_ids', 'not in', [self.env.user.partner_id.id])],
            [('public', '!=', 'private')],
            domain
        ])
        if name:
            domain = expression.AND([domain, [('name', 'ilike', '%'+name+'%')]])
        return self.search(domain).read(['name', 'public', 'uuid', 'channel_type'])

    def channel_join_and_get_info(self):
        self.ensure_one()
        added = self.action_follow()
        if added and self.channel_type == 'channel' and not self.email_send:
            notification = _('<div class="o_mail_notification">joined <a href="#" class="o_channel_redirect" data-oe-id="%s">#%s</a></div>') % (self.id, self.name,)
            self.message_post(body=notification, message_type="notification", subtype_xmlid="mail.mt_comment")

        if added and self.moderation_guidelines:
            self._send_guidelines(self.env.user.partner_id)

        channel_info = self.channel_info('join')[0]
        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), channel_info)
        return channel_info

    @api.model
    def channel_create(self, name, privacy='public'):
        """ Create a channel and add the current partner, broadcast it (to make the user directly
            listen to it when polling)
            :param name : the name of the channel to create
            :param privacy : privacy of the channel. Should be 'public' or 'private'.
            :return dict : channel header
        """
        # create the channel
        new_channel = self.create({
            'name': name,
            'public': privacy,
            'email_send': False,
        })
        notification = _('<div class="o_mail_notification">created <a href="#" class="o_channel_redirect" data-oe-id="%s">#%s</a></div>') % (new_channel.id, new_channel.name,)
        new_channel.message_post(body=notification, message_type="notification", subtype_xmlid="mail.mt_comment")
        channel_info = new_channel.channel_info('creation')[0]
        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', self.env.user.partner_id.id), channel_info)
        return channel_info

    @api.model
    def get_mention_suggestions(self, search, limit=8):
        """ Return 'limit'-first channels' id, name and public fields such that the name matches a
            'search' string. Exclude channels of type chat (DM), and private channels the current
            user isn't registered to. """
        domain = expression.AND([
                        [('name', 'ilike', search)],
                        [('channel_type', '=', 'channel')],
                        expression.OR([
                            [('public', '!=', 'private')],
                            [('channel_partner_ids', 'in', [self.env.user.partner_id.id])]
                        ])
                    ])
        return self.search_read(domain, ['id', 'name', 'public'], limit=limit)

    @api.model
    def channel_fetch_listeners(self, uuid):
        """ Return the id, name and email of partners listening to the given channel """
        self._cr.execute("""
            SELECT P.id, P.name, P.email
            FROM mail_channel_partner CP
                INNER JOIN res_partner P ON CP.partner_id = P.id
                INNER JOIN mail_channel C ON CP.channel_id = C.id
            WHERE C.uuid = %s""", (uuid,))
        return self._cr.dictfetchall()

    def channel_fetch_preview(self):
        """ Return the last message of the given channels """
        if not self:
            return []
        channels_last_message_ids = self._channel_last_message_ids()
        channels_preview = dict((r['message_id'], r) for r in channels_last_message_ids)
        last_messages = self.env['mail.message'].browse(channels_preview).message_format()
        for message in last_messages:
            channel = channels_preview[message['id']]
            del(channel['message_id'])
            channel['last_message'] = message
        return list(channels_preview.values())

    def _channel_last_message_ids(self):
        """ Return the last message of the given channels."""
        if not self:
            return []
        self.flush()
        self.env.cr.execute("""
            SELECT mail_channel_id AS id, MAX(mail_message_id) AS message_id
            FROM mail_message_mail_channel_rel
            WHERE mail_channel_id IN %s
            GROUP BY mail_channel_id
            """, (tuple(self.ids),))
        return self.env.cr.dictfetchall()

    #------------------------------------------------------
    # Commands
    #------------------------------------------------------
    @api.model
    @ormcache()
    def get_mention_commands(self):
        """ Returns the allowed commands in channels """
        commands = []
        for n in dir(self):
            match = re.search('^_define_command_(.+?)$', n)
            if match:
                command = getattr(self, n)()
                command['name'] = match.group(1)
                commands.append(command)
        return commands

    def execute_command(self, command='', **kwargs):
        """ Executes a given command """
        self.ensure_one()
        command_callback = getattr(self, '_execute_command_' + command, False)
        if command_callback:
            command_callback(**kwargs)

    def _send_transient_message(self, partner_to, content):
        """ Notifies partner_to that a message (not stored in DB) has been
            written in this channel """
        self.env['bus.bus'].sendone((self._cr.dbname, 'res.partner', partner_to.id), {
            'body': "<span class='o_mail_notification'>" + content + "</span>",
            'channel_ids': [self.id],
            'info': 'transient_message',
        })

    def _define_command_help(self):
        return {'help': _("Show a helper message")}

    def _execute_command_help(self, **kwargs):
        partner = self.env.user.partner_id
        if self.channel_type == 'channel':
            msg = _("You are in channel <b>#%s</b>.", self.name)
            if self.public == 'private':
                msg += _(" This channel is private. People must be invited to join it.")
        else:
            all_channel_partners = self.env['mail.channel.partner'].with_context(active_test=False)
            channel_partners = all_channel_partners.search([('partner_id', '!=', partner.id), ('channel_id', '=', self.id)])
            msg = _("You are in a private conversation with <b>@%s</b>.") % (channel_partners[0].partner_id.name if channel_partners else _('Anonymous'))
        msg += _("""<br><br>
            Type <b>@username</b> to mention someone, and grab his attention.<br>
            Type <b>#channel</b> to mention a channel.<br>
            Type <b>/command</b> to execute a command.<br>
            Type <b>:shortcut</b> to insert a canned response in your message.<br>""")

        self._send_transient_message(partner, msg)

    def _define_command_leave(self):
        return {'help': _("Leave this channel")}

    def _execute_command_leave(self, **kwargs):
        if self.channel_type == 'channel':
            self.action_unfollow()
        else:
            self.channel_pin(self.uuid, False)

    def _define_command_who(self):
        return {
            'channel_types': ['channel', 'chat'],
            'help': _("List users in the current channel")
        }

    def _execute_command_who(self, **kwargs):
        partner = self.env.user.partner_id
        members = [
            '<a href="#" data-oe-id='+str(p.id)+' data-oe-model="res.partner">@'+p.name+'</a>'
            for p in self.channel_partner_ids[:30] if p != partner
        ]
        if len(members) == 0:
            msg = _("You are alone in this channel.")
        else:
            dots = "..." if len(members) != len(self.channel_partner_ids) - 1 else ""
            msg = _("Users in this channel: %(members)s %(dots)s and you.", members=", ".join(members), dots=dots)

        self._send_transient_message(partner, msg)
