(function () {
    function parsePayload(element) {
        var raw = element.getAttribute('data-scs') || '{}';
        try {
            return JSON.parse(raw);
        } catch (error) {
            return null;
        }
    }

    function setBusy(button, busy) {
        button.disabled = !!busy;
        button.setAttribute('data-loading', busy ? '1' : '0');
    }

    document.addEventListener('click', function (event) {
        var button = event.target.closest('.scs-checkout-button');
        if (!button) {
            return;
        }

        event.preventDefault();
        if (button.getAttribute('data-loading') === '1') {
            return;
        }

        var payload = parsePayload(button);
        if (!payload || !payload.nonce) {
            alert((window.scs_ajax && scs_ajax.error_text) || 'Unable to start payment.');
            return;
        }

        setBusy(button, true);

        var formData = new FormData();
        formData.append('action', 'scs_create_session');
        formData.append('nonce', payload.nonce);
        formData.append('payload', JSON.stringify(payload));

        var ajaxUrl = (window.scs_ajax && scs_ajax.ajax_url) || '';

        fetch(ajaxUrl, {
            method: 'POST',
            credentials: 'same-origin',
            body: formData
        })
            .then(function (response) {
                return response.json();
            })
            .then(function (data) {
                if (data && data.success && data.data && data.data.url) {
                    window.location.href = data.data.url;
                    return;
                }

                var message = (data && data.data && data.data.message)
                    ? data.data.message
                    : ((window.scs_ajax && scs_ajax.error_text) || 'Unable to start payment.');

                alert(message);
            })
            .catch(function () {
                alert((window.scs_ajax && scs_ajax.error_text) || 'Unable to start payment.');
            })
            .finally(function () {
                setBusy(button, false);
            });
    });
})();