from odoo import api, fields, models


class McAttendance(models.Model):
    _name = "mc.attendance"
    _inherit = ["mail.thread"]
    _description = "Attendance"
    _order = "date desc, student_id"
    _rec_name = "display_name"

    student_id = fields.Many2one("mc.student", string="Student", required=True, ondelete="restrict")
    batch_id = fields.Many2one("mc.batch", string="Batch", required=True, ondelete="restrict")
    date = fields.Date(string="Date", required=True, default=fields.Date.context_today)
    session = fields.Char(
        string="Session", required=True, default="Daily",
        help='e.g. "Daily" for a single roll call, or "Period 2" for period-wise attendance.',
    )
    subject_id = fields.Many2one("mc.subject", string="Subject", ondelete="restrict")
    state = fields.Selection(
        [
            ("present", "Present"),
            ("absent", "Absent"),
            ("late", "Late"),
            ("on_leave", "On Leave"),
        ],
        string="Status", required=True, default="present", tracking=True,
    )
    marked_by = fields.Many2one(
        "res.users", string="Marked By", default=lambda self: self.env.user, readonly=True,
    )

    _student_date_session_uniq = models.Constraint(
        "unique(student_id, date, session)",
        "Attendance for this student on this date and session has already been recorded.",
    )

    @api.depends("student_id.name", "date", "session")
    def _compute_display_name(self):
        for attendance in self:
            attendance.display_name = "%s - %s (%s)" % (
                attendance.student_id.name or "?", attendance.date, attendance.session,
            )