from dateutil.relativedelta import relativedelta

from odoo import api, fields, models

MEMBER_ID_SEQUENCE_CODE = 'community.membership.member_id'
DEFAULT_MEMBER_ID_FORMAT = 'MEM-{year}-{seq}'


class ResPartner(models.Model):
    _inherit = 'res.partner'

    membership_member_id = fields.Char(
        string='Member ID', copy=False, index=True, readonly=True,
    )
    membership_tier_id = fields.Many2one('community.membership.tier', string='Membership Tier')
    membership_state = fields.Selection(
        [
            ('none', 'Not a Member'),
            ('invoiced', 'Invoiced'),
            ('active', 'Active'),
            ('renewal_due', 'Renewal Due'),
            ('expired', 'Expired'),
        ],
        default='none', copy=False, tracking=True,
    )
    membership_start = fields.Date(copy=False)
    membership_expiry = fields.Date(copy=False)
    family_head_id = fields.Many2one(
        'res.partner', string='Family Head',
        domain=[('membership_tier_id', '!=', False)],
        help="If this member belongs to a family membership, the primary member it is grouped under.",
    )
    is_volunteer = fields.Boolean(string='Volunteer')
    volunteer_hours = fields.Float(string='Volunteer Hours')

    def action_activate_membership(self):
        """Transition to 'active', generating a member ID and expiry if needed."""
        today = fields.Date.context_today(self)
        for partner in self:
            if not partner.membership_tier_id:
                continue
            vals = {'membership_state': 'active'}
            if not partner.membership_member_id:
                vals['membership_member_id'] = partner._generate_member_id()
            if not partner.membership_start:
                vals['membership_start'] = today
            duration_days = partner.membership_tier_id.duration_days()
            if duration_days:
                vals['membership_expiry'] = today + relativedelta(days=duration_days)
            partner.write(vals)
        return True

    def _generate_member_id(self):
        self.ensure_one()
        get_param = self.env['ir.config_parameter'].sudo().get_param
        member_id_format = get_param('community_membership.member_id_format', DEFAULT_MEMBER_ID_FORMAT)
        seq_number = self.env['ir.sequence'].next_by_code(MEMBER_ID_SEQUENCE_CODE) or '1'
        year = fields.Date.context_today(self).year
        return (
            member_id_format
            .replace('{year}', str(year))
            .replace('{seq}', seq_number)
        )