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

import datetime

from sql import Literal
from sql.aggregate import Sum

from trytond.i18n import gettext
from trytond.model import ModelSQL, ModelStorage, ModelView, Unique, fields
from trytond.pool import Pool
from trytond.pyson import Bool, Eval, If
from trytond.tools import grouped_slice, reduce_ids
from trytond.transaction import Transaction

from .exceptions import CompanyValidationError


class Work(ModelSQL, ModelView):
    __name__ = 'timesheet.work'
    name = fields.Char('Name',
        states={
            'invisible': Bool(Eval('origin')),
            'required': ~Eval('origin'),
            },
        help="The main identifier of the work.")
    origin = fields.Reference('Origin', selection='get_origin',
        states={
            'invisible': Bool(Eval('name')),
            'required': ~Eval('name'),
            },
        help="Use to relate the time spent to other records.")
    duration = fields.Function(fields.TimeDelta('Timesheet Duration',
            'company_work_time', help="Total time spent on this work."),
        'get_duration')
    timesheet_start_date = fields.Date('Timesheet Start',
        domain=[
            If(Eval('timesheet_start_date') & Eval('timesheet_end_date'),
                ('timesheet_start_date', '<=', Eval('timesheet_end_date')),
                ()),
            ],
        help="Restrict adding lines before the date.")
    timesheet_end_date = fields.Date('Timesheet End',
        domain=[
            If(Eval('timesheet_start_date') & Eval('timesheet_end_date'),
                ('timesheet_end_date', '>=', Eval('timesheet_start_date')),
                ()),
            ],
        help="Restrict adding lines after the date.")
    company = fields.Many2One(
        'company.company', "Company", required=True,
        help="Make the work belong to the company.")
    timesheet_lines = fields.One2Many('timesheet.line', 'work',
        'Timesheet Lines',
        help="Spend time on this work.")
    # Self referring field to use for aggregation in graph view
    work = fields.Function(fields.Many2One('timesheet.work', 'Work'),
        'get_work')

    @classmethod
    def __setup__(cls):
        super().__setup__()
        t = cls.__table__()
        cls._sql_constraints += [
            ('origin_unique', Unique(t, t.origin, t.company),
                'timesheet.msg_work_origin_unique_company'),
            ]

    @staticmethod
    def default_company():
        return Transaction().context.get('company')

    @classmethod
    def _get_origin(cls):
        'Return list of Model names for origin Reference'
        return []

    @classmethod
    def get_origin(cls):
        Model = Pool().get('ir.model')
        get_name = Model.get_name
        models = cls._get_origin()
        return [('', '')] + [(m, get_name(m)) for m in models]

    @classmethod
    def get_duration(cls, works, name):
        pool = Pool()
        Line = pool.get('timesheet.line')
        transaction = Transaction()
        cursor = transaction.connection.cursor()
        context = transaction.context

        table_w = cls.__table__()
        line = Line.__table__()
        ids = [w.id for w in works]
        durations = dict.fromkeys(ids, None)
        where = Literal(True)
        if context.get('from_date'):
            where &= line.date >= context['from_date']
        if context.get('to_date'):
            where &= line.date <= context['to_date']
        if context.get('employees'):
            where &= line.employee.in_(context['employees'])

        query_table = table_w.join(line, 'LEFT',
            condition=line.work == table_w.id)

        for sub_ids in grouped_slice(ids):
            red_sql = reduce_ids(table_w.id, sub_ids)
            cursor.execute(*query_table.select(table_w.id, Sum(line.duration),
                    where=red_sql & where,
                    group_by=table_w.id))
            for work_id, duration in cursor:
                # SQLite uses float for SUM
                if duration and not isinstance(duration, datetime.timedelta):
                    duration = datetime.timedelta(seconds=duration)
                durations[work_id] = duration
        return durations

    def get_work(self, name):
        return self.id

    def get_rec_name(self, name):
        if isinstance(self.origin, ModelStorage):
            return self.origin.rec_name
        else:
            return self.name

    @classmethod
    def search_rec_name(cls, name, clause):
        if clause[1].startswith('!') or clause[1].startswith('not '):
            bool_op = 'AND'
        else:
            bool_op = 'OR'
        return [bool_op,
            ('name',) + tuple(clause[1:]),
            ] + [
                ('origin.rec_name',) + tuple(clause[1:]) + (origin,)
                for origin in cls._get_origin()]

    @classmethod
    def copy(cls, works, default=None):
        if default is None:
            default = {}
        else:
            default = default.copy()
        default.setdefault('timesheet_lines', None)
        return super().copy(works, default=default)

    @classmethod
    def validate(cls, works):
        super().validate(works)
        for work in works:
            if work.origin and not work._validate_company():
                raise CompanyValidationError(
                    gettext('timesheet.msg_work_company_different_origin',
                        work=work.rec_name))

    def _validate_company(self):
        return True

    @classmethod
    def search_global(cls, text):
        for record, rec_name, icon in super().search_global(text):
            icon = icon or 'tryton-clock'
            yield record, rec_name, icon

    @property
    def hours(self):
        if not self.duration:
            return 0
        return self.duration.total_seconds() / 60 / 60


class WorkContext(ModelView):
    __name__ = 'timesheet.work.context'
    from_date = fields.Date('From Date',
        help="Do not take into account lines before the date.")
    to_date = fields.Date('To Date',
        help="Do not take into account lines after the date.")