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


class EducationDepartment(models.Model):
    _name = 'education.department'
    _description = 'Department'
    _order = 'name'

    name = fields.Char(required=True, string='Department Name')
    code = fields.Char(string='Department Code', required=True, index=True)
    campus_id = fields.Many2one(
        'education.campus',
        string='Campus',
        required=True,
        ondelete='restrict',
        index=True,
    )
    company_id = fields.Many2one(
        'res.company',
        related='campus_id.company_id',
        store=True,
        readonly=True,
        index=True,
    )
    head_teacher_id = fields.Many2one('res.partner', string='Head Teacher')
    active = fields.Boolean(default=True)
    program_ids = fields.One2many('education.program', 'department_id', string='Programs')

    _sql_constraints = [
        ('uniq_department_code_company', 'unique(code, company_id)', 'Department code must be unique per company.'),
    ]

    @api.constrains('code')
    def _check_code_format(self):
        for rec in self:
            if rec.code and not rec.code.strip():
                raise ValidationError('Department code cannot be blank.')

    @api.constrains('name', 'company_id')
    def _check_name_unique(self):
        for rec in self:
            similar = self.search([
                ('company_id', '=', rec.company_id.id),
                ('name', '=ilike', rec.name),
                ('campus_id', '=', rec.campus_id.id),
                ('id', '!=', rec.id),
            ])
            if similar:
                raise ValidationError('Department name must be unique within a campus.')