from odoo import api, fields, models
from odoo.exceptions import ValidationError
from datetime import timedelta


class TeamRoster(models.Model):
    _name = 'team.roster'
    _description = 'Team Roster'
    _inherit = ['mail.thread', 'mail.activity.mixin']

    name = fields.Char(
        required=True
    )

    start_date = fields.Date(
        required=True
    )

    end_date = fields.Date(
        required=True
    )

    state = fields.Selection([
        ('draft', 'Draft'),
        ('generated', 'Generated'),
        ('approved', 'Approved')
    ], default='draft')

    line_ids = fields.One2many(
        'team.roster.line',
        'roster_id'
    )



    def action_generate_roster(self):

        shifts = self.env[
            'resource.calendar'
        ].search([])

        employees = self.env[
            'hr.employee'
        ].search([
            ('active', '=', True)
        ])

        if not shifts:
            return

        self.line_ids.unlink()

        shift_count = len(shifts)

        current_date = self.start_date

        counter = 0

        while current_date <= self.end_date:

            for emp in employees:

                self.env[
                    'team.roster.line'
                ].create({

                    'roster_id': self.id,

                    'employee_id': emp.id,

                    'shift_id':
                        shifts[
                            counter %
                            shift_count
                        ].id,

                    'roster_date':
                        current_date

                })

                counter += 1

            current_date += timedelta(days=1)

        self.state = 'generated'




class TeamRosterLine(models.Model):
    _name = 'team.roster.line'
    _description = 'Team Roster Line'

    roster_id = fields.Many2one(
        'team.roster'
    )

    employee_id = fields.Many2one(
        'hr.employee',
        required=True
    )

    shift_id = fields.Many2one(
        'resource.calendar',
        required=True,
        string="Shift"
    )

    roster_date = fields.Date(
        required=True
    )

    department_id = fields.Many2one(
        related='employee_id.department_id',
        store=True
    )

    @api.constrains(
        'employee_id',
        'roster_date'
    )
    def _check_duplicate(self):

        for rec in self:

            duplicate = self.search([
                ('employee_id', '=', rec.employee_id.id),
                ('roster_date', '=', rec.roster_date),
                ('id', '!=', rec.id)
            ])

            if duplicate:

                raise ValidationError(
                    "Employee already has a shift assigned."
                )