# -*- coding: utf-8 -*-


from datetime import timedelta
from odoo import models, fields, api, exceptions, _


class Course(models.Model):
    _name = 'openacademy.course'
    _description = "OpenAcademy Courses"

    name = fields.Char(string="Title", required=True)
    description = fields.Text()

    responsible_id = fields.Many2one('res.users', string='Responsible', ondelete='set null', index=True)
    session_ids = fields.One2many('openacademy.session', 'course_id', string="Sessions")

    _sql_constraints = [
        ('name_description_check',
         'CHECK(name != description)',
         "The title of the course should not be the description"),

        ('name_unique',
         'UNIQUE(name)',
         "The course title must be unique"),
    ]


class Session(models.Model):
    _name = 'openacademy.session'
    _description = "OpenAcademy Sessions"

    name = fields.Char(required=True)
    start_date = fields.Date(default=fields.Date.today())
    duration = fields.Float(digits=(6, 2), help="Duration in days")
    seats = fields.Integer(string="Number of seats")

    instructor_id = fields.Many2one('res.partner', string='Instructor')
    course_id = fields.Many2one('openacademy.course', string='Course', ondelete='cascade', required=True)
    attendee_ids = fields.Many2many('res.partner', string="Attendees")
    active = fields.Boolean(default=True)

    taken_seats = fields.Float(string="Taken seats", compute='_taken_seats')

    end_date = fields.Date(string="End Date", store=True,
                           compute='_get_end_date', inverse='_set_end_date')

    attendees_count = fields.Integer(
        string="Attendees count", compute='_get_attendees_count', store=True)

    color = fields.Integer()

    @api.depends('seats', 'attendee_ids')
    def _taken_seats(self):
        for r in self:
            if not r.seats:
                r.taken_seats = 0.0
            else:
                r.taken_seats = 100.0 * len(r.attendee_ids) / r.seats

    @api.onchange('seats', 'attendee_ids')
    def _verify_valid_seats(self):
        if self.seats < 0:
            return {
                'warning': {
                    'title': _("Incorrect 'seats' value"),
                    'message': _("The number of available seats may not be negative"),
                },
            }
        if self.seats < len(self.attendee_ids):
            return {
                'warning': {
                    'title': "Too many attendees",
                    'message': "Increase seats or remove excess attendees",
                },
            }

    @api.depends('start_date', 'duration')
    def _get_end_date(self):
        for r in self:
            if not (r.start_date and r.duration):
                r.end_date = r.start_date
                continue

            # Add duration to start_date, but: Monday + 5 days = Saturday, so
            # subtract one second to get on Friday instead
            duration = timedelta(days=r.duration, seconds=-1)
            r.end_date = r.start_date + duration

    def _set_end_date(self):
        for r in self:
            if not (r.start_date and r.end_date):
                continue

            # Compute the difference between dates, but: Friday - Monday = 4 days,
            # so add one day to get 5 days instead
            r.duration = (r.end_date - r.start_date).days + 1

    @api.depends('attendee_ids')
    def _get_attendees_count(self):
        for r in self:
            r.attendees_count = len(r.attendee_ids)

    @api.constrains('instructor_id', 'attendee_ids')
    def _check_instructor_not_in_attendees(self):
        for r in self:
            if r.instructor_id and r.instructor_id in r.attendee_ids:
                raise exceptions.ValidationError("A session's instructor can't be an attendee")