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


class DanceBatch(models.Model):
    _name = "dance.batch"
    _description = "Dance Batch"
    _order = "start_date desc, name"

    name = fields.Char(required=True)
    dance_style = fields.Selection(
        [
            ("bharatanatyam", "Bharatanatyam"),
            ("kathak", "Kathak"),
            ("hiphop", "Hip-Hop"),
            ("contemporary", "Contemporary"),
            ("zumba", "Zumba"),
        ],
        string="Dance Style",
        required=True,
    )
    level = fields.Selection(
        [
            ("beginner", "Beginner"),
            ("intermediate", "Intermediate"),
            ("advanced", "Advanced"),
        ],
        required=True,
    )
    instructor_id = fields.Many2one("hr.employee", string="Instructor", required=True)
    room = fields.Char()
    capacity = fields.Integer(default=20)
    active_enrollment_count = fields.Integer(
        string="Current Strength",
        compute="_compute_enrollment_counts",
        store=True,
    )
    enrollment_count = fields.Integer(compute="_compute_enrollment_counts", store=True)
    available_seats = fields.Integer(compute="_compute_enrollment_counts", store=True)
    is_almost_full = fields.Boolean(compute="_compute_capacity_warning")
    capacity_warning = fields.Char(compute="_compute_capacity_warning")

    start_date = fields.Date(required=True)
    end_date = fields.Date()
    start_time = fields.Float(string="Start Time")
    end_time = fields.Float(string="End Time")
    schedule_days = fields.Char(
        string="Schedule Days",
        help="Example: Sat or Mon/Wed",
    )

    status = fields.Selection(
        [
            ("upcoming", "Upcoming"),
            ("active", "Active"),
            ("completed", "Completed"),
            ("cancelled", "Cancelled"),
        ],
        default="upcoming",
        required=True,
    )

    enrollment_ids = fields.One2many(
        "dance.enrollment",
        "batch_id",
        string="Enrollments",
    )

    @api.depends("enrollment_ids.status", "capacity")
    def _compute_enrollment_counts(self):
        for batch in self:
            active_enrollments = batch.enrollment_ids.filtered(
                lambda enrollment: enrollment.status == "active"
            )
            batch.active_enrollment_count = len(active_enrollments)
            batch.enrollment_count = len(batch.enrollment_ids)
            batch.available_seats = max(batch.capacity - len(active_enrollments), 0)

    @api.depends("active_enrollment_count", "capacity", "available_seats")
    def _compute_capacity_warning(self):
        for batch in self:
            batch.is_almost_full = bool(
                batch.capacity
                and batch.active_enrollment_count < batch.capacity
                and batch.available_seats <= 2
            )
            if batch.is_almost_full:
                batch.capacity_warning = "Batch almost full (%s/%s)" % (
                    batch.active_enrollment_count,
                    batch.capacity,
                )
            elif batch.capacity and batch.active_enrollment_count >= batch.capacity:
                batch.capacity_warning = "Batch is full (%s/%s)" % (
                    batch.active_enrollment_count,
                    batch.capacity,
                )
            else:
                batch.capacity_warning = False

    @api.constrains("capacity")
    def _check_capacity(self):
        for batch in self:
            if batch.capacity < 0:
                raise ValidationError("Capacity cannot be negative.")
            if batch.capacity and batch.active_enrollment_count > batch.capacity:
                raise ValidationError("Capacity cannot be less than current strength.")

    @api.constrains("start_date", "end_date")
    def _check_dates(self):
        for batch in self:
            if batch.end_date and batch.start_date and batch.end_date < batch.start_date:
                raise ValidationError("End date cannot be before start date.")

    @api.constrains("start_time", "end_time")
    def _check_times(self):
        for batch in self:
            if batch.end_time and batch.start_time and batch.end_time <= batch.start_time:
                raise ValidationError("End time must be after start time.")

    def action_view_enrollments(self):
        self.ensure_one()
        return {
            "name": "Enrollments",
            "type": "ir.actions.act_window",
            "res_model": "dance.enrollment",
            "view_mode": "tree,form",
            "domain": [("batch_id", "=", self.id)],
            "context": {"default_batch_id": self.id},
        }