(function () {
    const form = document.getElementById('form-edit-zbiorka') || document.getElementById('form-add-zbiorka') || document.querySelector('form');

    const map = [
        ['uzyj_konta', 'numer_konta'],
        ['uzyj_blik', 'numer_telefonu_blik']
    ];

    const warnBox = document.getElementById('kanalyWarning');

    function showWarn(show) {
        if (!warnBox) return;
        warnBox.classList.toggle('d-none', !show);
    }

    function getEl(id) { return document.getElementById(id); }

    function toggleField(chkId, inputId) {
        const chk = getEl(chkId);
        const inp = getEl(inputId);
        if (!inp || !chk) return;
        const on = chk.checked;
        inp.disabled = !on;
        if (on) inp.setAttribute('required', '');
        else inp.removeAttribute('required');
    }

    function atLeastOneOn() {
        return map.some(([c]) => getEl(c)?.checked);
    }

    function blinkInvalid(el) {
        if (!el) return;
        el.classList.add('is-invalid');
        setTimeout(() => el.classList.remove('is-invalid'), 400);
    }

    function preventUncheckLast(e) {
        const target = e.target;
        if (target.checked) return;
        const after = map.map(([c]) => c === target.id ? false : !!getEl(c)?.checked);
        if (!after.some(Boolean)) {
            e.preventDefault();
            target.checked = true;
            showWarn(true);
            blinkInvalid(target);
        } else {
            showWarn(false);
        }
    }

    function onToggle(chkId, inputId) {
        toggleField(chkId, inputId);
        showWarn(!atLeastOneOn());
    }

    map.forEach(([chkId, inputId]) => {
        const chk = getEl(chkId);
        if (!chk) return;
        chk.addEventListener('click', preventUncheckLast);
        chk.addEventListener('change', () => onToggle(chkId, inputId));
        toggleField(chkId, inputId);
    });
    showWarn(!atLeastOneOn());

    if (form) {
        form.addEventListener('submit', function (e) {
            if (!atLeastOneOn()) {
                e.preventDefault();
                showWarn(true);
                blinkInvalid(getEl('uzyj_konta') || getEl('uzyj_blik'));
                (getEl('uzyj_konta') || getEl('uzyj_blik'))?.focus();
                return;
            }

            for (const [chkId, inputId] of map) {
                const chk = getEl(chkId), inp = getEl(inputId);
                if (chk?.checked && inp && !inp.value.trim()) {
                    e.preventDefault();
                    showWarn(true);
                    blinkInvalid(inp);
                    inp.focus();
                    return;
                }
            }
        });
    }
})();