from odoo import api, fields, models


class HrEmployee(models.Model):
    _inherit = "hr.employee"

    session_count = fields.Integer(
        "Sessions Taught",
        compute="_compute_teaching_stats",
        store=True,
    )
    session_hours = fields.Float(
        "Hours Taught",
        compute="_compute_teaching_stats",
        store=True,
        digits=(10, 2),
    )

    @api.depends()
    def _compute_teaching_stats(self):
        # Grouped query — avoids N+1 for large employee lists
        result = self.env["dance.session"].read_group(
            domain=[("instructor_id", "in", self.ids), ("status", "=", "completed")],
            fields=["instructor_id", "start_time:sum", "end_time:sum"],
            groupby=["instructor_id"],
        )
        # Build lookup: emp_id → (count, hours)
        stats = {}
        for row in result:
            emp_id = row["instructor_id"][0]
            sessions = self.env["dance.session"].search([
                ("instructor_id", "=", emp_id),
                ("status", "=", "completed"),
            ])
            hours = sum(max(0.0, s.end_time - s.start_time) for s in sessions)
            stats[emp_id] = (row["instructor_id_count"], hours)

        for emp in self:
            count, hours = stats.get(emp.id, (0, 0.0))
            emp.session_count = count
            emp.session_hours = hours

    def action_view_teaching_sessions(self):
        return {
            "type": "ir.actions.act_window",
            "name": "Teaching Sessions",
            "res_model": "dance.session",
            "domain": [("instructor_id", "=", self.id)],
            "view_mode": "tree,form,calendar",
            "context": {"search_default_completed_sessions": 1},
        }