from odoo import api, fields, models


class CommunitySchoolEnrollment(models.Model):
    _name = 'community.school.enrollment'
    _description = 'School Enrollment'
    _order = 'id desc'

    student_id = fields.Many2one('community.school.student', required=True, ondelete='cascade')
    class_id = fields.Many2one('community.school.class', required=True, ondelete='cascade')
    term_id = fields.Many2one(related='class_id.term_id', store=True)
    enrollment_date = fields.Date(default=fields.Date.context_today)
    state = fields.Selection(
        [
            ('waitlist', 'Waitlisted'),
            ('enrolled', 'Enrolled'),
            ('completed', 'Completed'),
            ('withdrawn', 'Withdrawn'),
        ],
        default='enrolled', required=True,
    )
    payment_state = fields.Selection(
        [('not_invoiced', 'Not Invoiced'), ('invoiced', 'Invoiced'), ('paid', 'Paid')],
        default='not_invoiced', required=True,
    )
    invoice_id = fields.Many2one('account.move', readonly=True, copy=False)
    attendance_ids = fields.One2many('community.school.attendance', 'enrollment_id')
    attendance_rate = fields.Float(compute='_compute_attendance_rate')

    is_at_risk = fields.Boolean(compute='_compute_is_at_risk')

    @api.depends('attendance_ids.state')
    def _compute_attendance_rate(self):
        for enrollment in self:
            records = enrollment.attendance_ids
            total = len(records)
            if not total:
                enrollment.attendance_rate = 0.0
                continue
            present = len(records.filtered(lambda a: a.state in ('present', 'late')))
            enrollment.attendance_rate = (present / total) * 100.0

    @api.depends('attendance_rate', 'attendance_ids')
    def _compute_is_at_risk(self):
        threshold = int(self.env['ir.config_parameter'].sudo().get_param(
            'community_school.at_risk_attendance_threshold', 70
        ))
        for enrollment in self:
            enrollment.is_at_risk = bool(enrollment.attendance_ids) and enrollment.attendance_rate < threshold

    def action_enroll_from_waitlist(self):
        for enrollment in self:
            if enrollment.state == 'waitlist' and enrollment.class_id.enrolled_count < enrollment.class_id.max_students:
                enrollment.state = 'enrolled'
        return True