(function () {
    var overlay = null;
    var loadingMessage = null;
    var dialog = null;
    var dialogTitle = null;
    var dialogBody = null;
    var dialogIcon = null;

    function cacheElements() {
        overlay = document.getElementById('ui-loading-overlay');
        loadingMessage = document.getElementById('ui-loading-message');
        dialog = document.getElementById('ui-dialog');
        dialogTitle = document.getElementById('ui-dialog-title');
        dialogBody = document.getElementById('ui-dialog-body');
        dialogIcon = document.getElementById('ui-dialog-icon');
    }

    function showLoading(message) {
        if (!overlay) {
            return;
        }

        if (loadingMessage) {
            loadingMessage.textContent = message || 'Processing...';
        }

        overlay.hidden = false;
        overlay.setAttribute('aria-hidden', 'false');
        document.body.classList.add('ui-is-loading');
    }

    function hideLoading() {
        if (!overlay) {
            return;
        }

        overlay.hidden = true;
        overlay.setAttribute('aria-hidden', 'true');
        document.body.classList.remove('ui-is-loading');

        document.querySelectorAll('.ui-btn.is-loading').forEach(function (btn) {
            btn.classList.remove('is-loading');
            btn.disabled = false;
        });
    }

    function showDialog(type, message, title) {
        if (!dialog || !dialogBody) {
            return;
        }

        var isError = type === 'error';
        var isSuccess = type === 'success';

        if (dialogTitle) {
            dialogTitle.textContent = title || (isError ? 'Gagal' : isSuccess ? 'Berhasil' : 'Informasi');
        }

        dialogBody.textContent = message || '';

        if (dialogIcon) {
            dialogIcon.className = 'ui-dialog__icon';
            dialogIcon.classList.add(isError ? 'is-error' : isSuccess ? 'is-success' : 'is-info');
            dialogIcon.textContent = isError ? '!' : isSuccess ? '✓' : 'i';
        }

        dialog.hidden = false;
        dialog.setAttribute('aria-hidden', 'false');

        var closeBtn = dialog.querySelector('[data-ui-dialog-close].ui-dialog__btn');
        if (closeBtn) {
            closeBtn.focus();
        }
    }

    function hideDialog() {
        if (!dialog) {
            return;
        }

        dialog.hidden = true;
        dialog.setAttribute('aria-hidden', 'true');
    }

    function markButtonLoading(button) {
        if (!button || button.disabled) {
            return;
        }

        button.classList.add('ui-btn', 'is-loading');
        button.disabled = true;
    }

    function shouldSkipForm(form) {
        if (form.dataset.uiNoLoading !== undefined) {
            return true;
        }

        var method = (form.getAttribute('method') || 'get').toLowerCase();
        return method === 'get';
    }

    function resolveLoadingMessage(form, submitter) {
        if (submitter && submitter.dataset.loadingMessage) {
            return submitter.dataset.loadingMessage;
        }

        if (form.dataset.loadingMessage) {
            return form.dataset.loadingMessage;
        }

        return 'Memproses permintaan...';
    }

    function bindForms(root) {
        var scope = root || document;

        scope.querySelectorAll('form').forEach(function (form) {
            if (shouldSkipForm(form) || form.dataset.uiFormBound === '1') {
                return;
            }

            form.dataset.uiFormBound = '1';
            form.addEventListener('submit', function (event) {
                var submitter = event.submitter || form.querySelector('[type="submit"]');
                showLoading(resolveLoadingMessage(form, submitter));

                if (submitter) {
                    markButtonLoading(submitter);
                }
            });
        });
    }

    function bindDialog() {
        if (!dialog) {
            return;
        }

        dialog.querySelectorAll('[data-ui-dialog-close]').forEach(function (el) {
            el.addEventListener('click', hideDialog);
        });

        document.addEventListener('keydown', function (event) {
            if (event.key === 'Escape' && dialog && !dialog.hidden) {
                hideDialog();
            }
        });
    }

    function consumeFlashPayload(root) {
        var scope = root || document;
        var node = scope.querySelector ? scope.querySelector('#ui-flash-payload') : document.getElementById('ui-flash-payload');
        if (!node) {
            return;
        }

        try {
            var payload = JSON.parse(node.textContent || '{}');
            if (payload.message) {
                showDialog(payload.type || 'info', payload.message);
            }
            node.remove();
        } catch (e) {
            console.warn('[UI] Invalid flash payload', e);
        }
    }

    function onFrameLoad(frame) {
        hideLoading();
        bindForms(frame);
        consumeFlashPayload(frame);
    }

    window.UiFeedback = {
        showLoading: showLoading,
        hideLoading: hideLoading,
        showDialog: showDialog,
        hideDialog: hideDialog,
        onFrameLoad: onFrameLoad,
    };

    document.addEventListener('DOMContentLoaded', function () {
        cacheElements();
        bindForms();
        bindDialog();
        hideLoading();
        consumeFlashPayload();
    });

    window.addEventListener('pageshow', function () {
        hideLoading();
    });
})();