# 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 __future__ import division

import datetime

from sql import Literal
from sql.aggregate import Sum

from trytond.model import ModelView, ModelSQL, fields, Unique
from trytond.pyson import Not, Bool, Eval
from trytond.transaction import Transaction
from trytond.pool import Pool
from trytond.tools import reduce_ids, grouped_slice
from trytond import backend

__all__ = ['Work', 'WorkContext']


class Work(ModelSQL, ModelView):
    'Work'
    __name__ = 'timesheet.work'
    name = fields.Char('Name',
        states={
            'invisible': Bool(Eval('origin')),
            'required': ~Eval('origin'),
            },
        depends=['origin'])
    origin = fields.Reference('Origin', selection='get_origin',
        states={
            'invisible': Bool(Eval('name')),
            'required': ~Eval('name'),
            },
        depends=['name'])
    active = fields.Boolean('Active')
    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')
    timesheet_end_date = fields.Date('Timesheet End')
    company = fields.Many2One('company.company', 'Company', required=True,
        select=True)
    timesheet_lines = fields.One2Many('timesheet.line', 'work',
        'Timesheet Lines',
        depends=['active'],
        states={
            'readonly': Not(Bool(Eval('active'))),
            })
    # 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(Work, cls).__setup__()
        t = cls.__table__()
        cls._sql_constraints += [
            ('origin_unique', Unique(t, t.origin, t.company),
                'The origin must be unique per company.'),
            ]
        cls._error_messages.update({
                'mismatch_company': ('The company of the work "%(work)s" '
                    'is different then the origin\'s company'),
                })

    @classmethod
    def __register__(cls, module_name):
        TableHandler = backend.get('TableHandler')
        table_h = TableHandler(cls, module_name)
        table = cls.__table__()
        cursor = Transaction().connection.cursor()

        super(Work, cls).__register__(module_name)

        # Migration from 4.0: remove required on name
        table_h.not_null_action('name', 'remove')

        # Migration from 4.0: remove parent, left and right
        if table_h.column_exist('parent'):
            id2name = {}
            id2parent = {}
            cursor.execute(*table.select(
                    table.id, table.parent, table.name))
            for id_, parent, name in cursor:
                id2name[id_] = name
                id2parent[id_] = parent

            for id_, name in id2name.iteritems():
                parent = id2parent[id_]
                while parent:
                    name = '%s\\%s' % (id2name[parent], name)
                    parent = id2parent[parent]
                cursor.execute(*table.update(
                        [table.name], [name],
                        where=table.id == id_))
            table_h.drop_column('parent')
        table_h.drop_column('left')
        table_h.drop_column('right')

        # Migration from 4.0: remove timesheet_available
        if table_h.column_exist('timesheet_available'):
            cursor.execute(*table.delete(
                    where=table.timesheet_available == False))
            table_h.drop_column('timesheet_available')

    @staticmethod
    def default_active():
        return True

    @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')
        models = cls._get_origin()
        models = Model.search([
                ('model', 'in', models),
                ])
        return [('', '')] + [(m.model, m.name) 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.fetchall():
                # 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 self.origin:
            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 = {}
        default = default.copy()
        if 'timesheet_lines' not in default:
            default['timesheet_lines'] = None
        return super(Work, cls).copy(works, default=default)

    @classmethod
    def validate(cls, works):
        super(Work, cls).validate(works)
        for work in works:
            if work.origin and not work._validate_company():
                cls.raise_user_error('mismatch_company', {
                        'work': work.rec_name,
                        })

    def _validate_company(self):
        return True

    @classmethod
    def search_global(cls, text):
        for record, rec_name, icon in super(Work, cls).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):
    'Work Context'
    __name__ = 'timesheet.work.context'
    from_date = fields.Date('From Date')
    to_date = fields.Date('To Date')