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


class EducationLibraryReservation(models.Model):
    _name = 'education.library.reservation'
    _description = 'Library Reservation'
    _rec_name = 'name'
    _order = 'reservation_date desc, priority desc'

    name = fields.Char(string='Reference', required=True, copy=False, readonly=True, default=lambda self: _('New'))
    member_id = fields.Many2one('education.library.member', string='Member', required=True)
    book_id = fields.Many2one('education.library.book', string='Book', required=True)
    
    reservation_date = fields.Date(string='Reservation Date', default=fields.Date.context_today, required=True)
    expiry_date = fields.Date(string='Expiry Date')
    fulfilled_date = fields.Date(string='Fulfilled Date')
    
    state = fields.Selection([
        ('draft', 'Draft'),
        ('active', 'Active'),
        ('fulfilled', 'Fulfilled'),
        ('cancelled', 'Cancelled'),
        ('expired', 'Expired')
    ], string='Status', default='draft', required=True)
    
    priority = fields.Integer(string='Priority', default=10)

    @api.model_create_multi
    def create(self, vals_list):
        for vals in vals_list:
            if vals.get('name', _('New')) == _('New'):
                vals['name'] = self.env['ir.sequence'].next_by_code('education.library.reservation') or _('New')
        return super().create(vals_list)

    @api.constrains('member_id', 'book_id', 'state')
    def _check_duplicate_reservation(self):
        for record in self:
            if record.state == 'active':
                duplicates = self.search([
                    ('member_id', '=', record.member_id.id),
                    ('book_id', '=', record.book_id.id),
                    ('state', '=', 'active'),
                    ('id', '!=', record.id)
                ])
                if duplicates:
                    raise ValidationError(_('A member cannot have multiple active reservations for the same book.'))

    def action_activate(self):
        for record in self:
            if not record.member_id.active:
                raise ValidationError(_('Active member required to make a reservation.'))
            record.state = 'active'
            
            # Set expiry date if not set and configured
            if not record.expiry_date:
                max_days = int(self.env['ir.config_parameter'].sudo().get_param('education_library.max_reservation_days', 2))
                record.expiry_date = record.reservation_date + fields.Date.context_today().replace(day=record.reservation_date.day) # Simplified for time Delta, will fix properly with datetime.timedelta
                from datetime import timedelta
                record.expiry_date = record.reservation_date + timedelta(days=max_days)

    def action_fulfill(self):
        for record in self:
            record.write({
                'state': 'fulfilled',
                'fulfilled_date': fields.Date.today()
            })

    def action_cancel(self):
        self.write({'state': 'cancelled'})

    @api.model
    def _cron_expire_reservations(self):
        expired = self.search([
            ('state', '=', 'active'),
            ('expiry_date', '<', fields.Date.today())
        ])
        expired.write({'state': 'expired'})