from odoo import fields, models, api


class Elective(models.Model):
    _name = 'yuthon.school.elective'
    _description = '选修课'

    name = fields.Char(
        string='选修课名称',
        required=True,
        help='如：Odoo 工作流开发、OWL 前端框架入门',
    )
    description = fields.Text(
        string='课程简介',
    )
    teacher_id = fields.Many2one(
        'yuthon.school.teacher',
        string='授课教师',
    )
    student_ids = fields.Many2many(
        'yuthon.school.student',
        'yuthon_elective_student_rel',
        'elective_id',
        'student_id',
        string='选课学生',
        help='选择选修该课程的学生（Many2many 关系演示）',
    )
    student_count = fields.Integer(
        string='选课人数',
        compute='_compute_student_count',
        store=True,
    )
    active = fields.Boolean(
        string='启用',
        default=True,
    )

    @api.depends('student_ids')
    def _compute_student_count(self):
        for record in self:
            record.student_count = len(record.student_ids)