# This file is part of Tryton.  The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.
from textwrap import TextWrapper

from sql import Null
from sql.conditionals import Case

from ..model import ModelView, ModelSQL, ModelStorage, fields
from ..pool import Pool
from ..transaction import Transaction
from ..tools import grouped_slice, reduce_ids
from ..pyson import Eval
from .resource import ResourceMixin

__all__ = ['Note', 'NoteRead']


class Note(ResourceMixin, ModelSQL, ModelView):
    "Note"
    __name__ = 'ir.note'
    message = fields.Text('Message', states={
            'readonly': Eval('id', 0) > 0,
            })
    message_wrapped = fields.Function(fields.Text('Message'),
        'on_change_with_message_wrapped')
    unread = fields.Function(fields.Boolean('Unread'), 'get_unread',
        searcher='search_unread', setter='set_unread')

    @staticmethod
    def default_unread():
        return False

    @classmethod
    def get_wrapper(cls):
        return TextWrapper(width=79)

    @fields.depends('message')
    def on_change_with_message_wrapped(self, name=None):
        wrapper = self.get_wrapper()
        return '\n'.join(map(wrapper.fill, self.message.splitlines()))

    @classmethod
    def get_unread(cls, ids, name):
        pool = Pool()
        Read = pool.get('ir.note.read')
        cursor = Transaction().connection.cursor()
        user_id = Transaction().user
        table = cls.__table__()
        read = Read.__table__()

        unread = {}
        for sub_ids in grouped_slice(ids):
            where = reduce_ids(table.id, sub_ids)
            query = table.join(read, 'LEFT',
                condition=(table.id == read.note)
                & (read.user == user_id)
                ).select(table.id,
                    Case((read.user != Null, False), else_=True),
                    where=where)
            cursor.execute(*query)
            unread.update(cursor.fetchall())
        return unread

    @classmethod
    def search_unread(cls, name, clause):
        pool = Pool()
        Read = pool.get('ir.note.read')
        user_id = Transaction().user
        table = cls.__table__()
        read = Read.__table__()

        _, operator, value = clause
        assert operator in ['=', '!=']
        Operator = fields.SQL_OPERATORS[operator]

        where = Operator(Case((read.user != Null, False), else_=True), value)
        query = table.join(read, 'LEFT',
            condition=(table.id == read.note)
            & (read.user == user_id)
            ).select(table.id, where=where)
        return [('id', 'in', query)]

    @classmethod
    def set_unread(cls, notes, name, value):
        pool = Pool()
        Read = pool.get('ir.note.read')
        user_id = Transaction().user
        if not value:
            Read.create([{'note': n.id, 'user': user_id} for n in notes])
        else:
            reads = []
            for sub_notes in grouped_slice(notes):
                reads += Read.search([
                        ('note', 'in', [n.id for n in sub_notes]),
                        ('user', '=', user_id),
                        ])
            Read.delete(reads)

    @classmethod
    def write(cls, notes, values, *args):
        # Avoid changing write meta data if only unread is set
        if args or values.keys() != ['unread']:
            super(Note, cls).write(notes, values, *args)
        else:
            # Check access write and clean cache
            ModelStorage.write(notes, values)
            cls.set_unread(notes, 'unread', values['unread'])


class NoteRead(ModelSQL):
    "Note Read"
    __name__ = 'ir.note.read'
    note = fields.Many2One('ir.note', 'Note', required=True,
        ondelete='CASCADE')
    user = fields.Many2One('res.user', 'User', required=True,
        ondelete='CASCADE')