from odoo import api, models, _


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

    @api.model
    def _get_available_qr_methods(self):
        rslt = super()._get_available_qr_methods()
        # Nižšia sequence ako natívny EPC/SCT QR (sequence 20 v
        # account_qr_code_sepa) - SPAYD sa uprednostní, keď je eligible.
        rslt.append(('spayd', _("SPAYD (Czech QR Platba)"), 6))
        return rslt

    def _get_error_messages_for_qr(self, qr_method, debtor_partner, currency):
        if qr_method == 'spayd':
            if currency.name not in ('CZK', 'EUR'):
                return _("SPAYD podporuje len menu CZK alebo EUR.")
            if not self._spayd_to_iban():
                return _("Bankový účet nemá platné číslo účtu ani IBAN pre SPAYD.")
            if debtor_partner and debtor_partner.country_id and debtor_partner.country_id.code != 'CZ':
                return _("SPAYD je určený pre zákazníkov z Českej republiky.")
            return None
        return super()._get_error_messages_for_qr(qr_method, debtor_partner, currency)

    def _check_for_qr_code_errors(self, qr_method, amount, currency, debtor_partner, free_communication, structured_communication):
        if qr_method == 'spayd':
            return None
        return super()._check_for_qr_code_errors(qr_method, amount, currency, debtor_partner, free_communication, structured_communication)

    def _get_qr_code_generation_params(self, qr_method, amount, currency, debtor_partner, free_communication, structured_communication):
        if qr_method == 'spayd':
            iban = self._spayd_to_iban()
            vs_source = structured_communication or free_communication or ''
            vs = ''.join(filter(str.isdigit, vs_source))[-10:]
            spayd = f"SPD*1.0*ACC:{iban}*AM:{amount:.2f}*CC:{currency.name}*X-VS:{vs}"
            return {
                'barcode_type': 'QR',
                'quiet': 0,
                'width': 128,
                'height': 128,
                'humanreadable': 0,
                'value': spayd,
            }
        return super()._get_qr_code_generation_params(qr_method, amount, currency, debtor_partner, free_communication, structured_communication)

    def _spayd_to_iban(self):
        """Vráti IBAN pre tento bankový účet, vhodný pre SPAYD QR (ACC pole).

        Podporuje český lokálny formát ('123-456/0800' alebo '456/0800') aj
        priamo zadaný IBAN (akejkoľvek krajiny).
        """
        self.ensure_one()
        acc_number = self.acc_number
        if not acc_number:
            return ''

        clean_acc = acc_number.replace(' ', '').upper()

        # Už IBAN (ľubovoľná krajina): 2 písmená + 2-číslicový kontrolný súčet.
        if len(clean_acc) >= 4 and clean_acc[:2].isalpha() and clean_acc[2:4].isdigit():
            return clean_acc

        try:
            parts = clean_acc.split('/')
            if len(parts) != 2:
                return clean_acc  # nie je český formát ani IBAN - vrátime pôvodné

            bank_code = parts[1].zfill(4)
            account_parts = parts[0].split('-')
            if len(account_parts) == 2:
                prefix = account_parts[0].zfill(6)
                main = account_parts[1].zfill(10)
            else:
                prefix = '000000'
                main = account_parts[0].zfill(10)

            # ISO 7064 mod 97-10: BBAN + krajina ako čísla (C=12, Z=35) + '00'.
            check_string = f"{bank_code}{prefix}{main}123500"
            checksum = 98 - (int(check_string) % 97)
            return f"CZ{str(checksum).zfill(2)}{bank_code}{prefix}{main}"
        except (ValueError, IndexError):
            return clean_acc