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

import ast

from odoo import api, fields, models, tools, _
from odoo.exceptions import UserError


class IrFilters(models.Model):
    _name = 'ir.filters'
    _description = 'Filters'
    _order = 'model_id, name, id desc'

    name = fields.Char(string='Filter Name', translate=True, required=True)
    user_id = fields.Many2one('res.users', string='User', ondelete='cascade',
                              help="The user this filter is private to. When left empty the filter is public "
                                   "and available to all users.")
    domain = fields.Text(default='[]', required=True)
    context = fields.Text(default='{}', required=True)
    sort = fields.Text(default='[]', required=True)
    model_id = fields.Selection(selection='_list_all_models', string='Model', required=True)
    is_default = fields.Boolean(string='Default Filter')
    action_id = fields.Many2one('ir.actions.actions', string='Action', ondelete='cascade',
                                help="The menu action this filter applies to. "
                                     "When left empty the filter applies to all menus "
                                     "for this model.")
    active = fields.Boolean(default=True)

    @api.model
    def _list_all_models(self):
        self._cr.execute("SELECT model, name FROM ir_model ORDER BY name")
        return self._cr.fetchall()

    @api.multi
    def copy(self, default=None):
        self.ensure_one()
        default = dict(default or {}, name=_('%s (copy)') % self.name)
        return super(IrFilters, self).copy(default)

    @api.multi
    def _get_eval_domain(self):
        self.ensure_one()
        return ast.literal_eval(self.domain)

    @api.model
    def _get_action_domain(self, action_id=None):
        """Return a domain component for matching filters that are visible in the
           same context (menu/view) as the given action."""
        if action_id:
            # filters specific to this menu + global ones
            return [('action_id', 'in', [action_id, False])]
        # only global ones
        return [('action_id', '=', False)]

    @api.model
    def get_filters(self, model, action_id=None):
        """Obtain the list of filters available for the user on the given model.

        :param action_id: optional ID of action to restrict filters to this action
            plus global filters. If missing only global filters are returned.
            The action does not have to correspond to the model, it may only be
            a contextual action.
        :return: list of :meth:`~osv.read`-like dicts containing the
            ``name``, ``is_default``, ``domain``, ``user_id`` (m2o tuple),
            ``action_id`` (m2o tuple) and ``context`` of the matching ``ir.filters``.
        """
        # available filters: private filters (user_id=uid) and public filters (uid=NULL),
        # and filters for the action (action_id=action_id) or global (action_id=NULL)
        action_domain = self._get_action_domain(action_id)
        filters = self.search(action_domain + [('model_id', '=', model), ('user_id', 'in', [self._uid, False])])
        user_context = self.env.user.context_get()
        return filters.with_context(user_context).read(['name', 'is_default', 'domain', 'context', 'user_id', 'sort'])

    @api.model
    def _check_global_default(self, vals, matching_filters):
        """ _check_global_default(dict, list(dict), dict) -> None

        Checks if there is a global default for the model_id requested.

        If there is, and the default is different than the record being written
        (-> we're not updating the current global default), raise an error
        to avoid users unknowingly overwriting existing global defaults (they
        have to explicitly remove the current default before setting a new one)

        This method should only be called if ``vals`` is trying to set
        ``is_default``

        :raises odoo.exceptions.UserError: if there is an existing default and
                                            we're not updating it
        """
        domain = self._get_action_domain(vals.get('action_id'))
        defaults = self.search(domain + [
            ('model_id', '=', vals['model_id']),
            ('user_id', '=', False),
            ('is_default', '=', True),
        ])

        if not defaults:
            return
        if matching_filters and (matching_filters[0]['id'] == defaults.id):
            return

        raise UserError(_("There is already a shared filter set as default for %(model)s, delete or change it before setting a new default") % {'model': vals.get('model_id')})

    @api.model
    @api.returns('self', lambda value: value.id)
    def create_or_replace(self, vals):
        action_id = vals.get('action_id')
        current_filters = self.get_filters(vals['model_id'], action_id)
        matching_filters = [f for f in current_filters
                            if f['name'].lower() == vals['name'].lower()
                            # next line looks for matching user_ids (specific or global), i.e.
                            # f.user_id is False and vals.user_id is False or missing,
                            # or f.user_id.id == vals.user_id
                            if (f['user_id'] and f['user_id'][0]) == vals.get('user_id')]

        if vals.get('is_default'):
            if vals.get('user_id'):
                # Setting new default: any other default that belongs to the user
                # should be turned off
                domain = self._get_action_domain(action_id)
                defaults = self.search(domain + [
                    ('model_id', '=', vals['model_id']),
                    ('user_id', '=', vals['user_id']),
                    ('is_default', '=', True),
                ])
                if defaults:
                    defaults.write({'is_default': False})
            else:
                self._check_global_default(vals, matching_filters)

        # When a filter exists for the same (name, model, user) triple, we simply
        # replace its definition (considering action_id irrelevant here)
        if matching_filters:
            matching_filter = self.browse(matching_filters[0]['id'])
            matching_filter.write(vals)
            return matching_filter

        return self.create(vals)

    _sql_constraints = [
        # Partial constraint, complemented by unique index (see below). Still
        # useful to keep because it provides a proper error message when a
        # violation occurs, as it shares the same prefix as the unique index.
        ('name_model_uid_unique', 'unique (name, model_id, user_id, action_id)', 'Filter names must be unique'),
    ]

    @api.model_cr_context
    def _auto_init(self):
        result = super(IrFilters, self)._auto_init()
        # Use unique index to implement unique constraint on the lowercase name (not possible using a constraint)
        tools.create_unique_index(self._cr, 'ir_filters_name_model_uid_unique_action_index',
            self._table, ['lower(name)', 'model_id', 'COALESCE(user_id,-1)', 'COALESCE(action_id,-1)'])
        return result
