fix: show progress modal for pre-extension-update backup

The pre-update backup ran synchronously in onExtensionBeforeUpdate with
no browser feedback — the page just hung until backup + update finished.

Now the system plugin injects JavaScript on com_installer and
com_joomlaupdate pages that intercepts the update button, shows a
Bootstrap modal with a progress bar, and runs the backup via the
stepped AJAX API (ajax.init + ajax.step). On completion it proceeds
with the original update. On failure it shows Skip & Cancel buttons.

The server-side handler remains as a fallback for CLI/API updates.
A session flag prevents double-running when JS already handled it.

Claude-Session: https://claude.ai/code/session_01MbEjBtsSjPuTWhqqrMS2wG

source/packages/com_mokosuitebackup/src/Controller/AjaxController.php

@@ -84,6 +84,24 @@ class AjaxController extends BaseController
 		$this->sendJson($result);
 	}
 
+	/**
+	 * Mark that the JS-driven pre-update backup has completed so the
+	 * server-side onExtensionBeforeUpdate handler skips its own run.
+	 * POST: task=ajax.markPreUpdateDone
+	 */
+	public function markPreUpdateDone(): void
+	{
+		if (!Session::checkToken('get') && !Session::checkToken('post')) {
+			$this->sendJson(['error' => true, 'message' => 'Invalid token'], 403);
+
+			return;
+		}
+
+		Factory::getSession()->set('mokosuitebackup.preupdate_js_done', true);
+
+		$this->sendJson(['success' => true]);
+	}
+
 	/**
 	 * Browse server directories for the folder picker field.
 	 * POST: task=ajax.browseDir&path=/some/path

source/packages/plg_system_mokosuitebackup/src/Extension/MokoSuiteBackup.php

@@ -28,6 +28,7 @@ final class MokoSuiteBackup extends CMSPlugin implements SubscriberInterface
 		return [
 			'onAfterInitialise'        => 'onAfterInitialise',
 			'onAfterRoute'             => 'onAfterRoute',
+			'onBeforeRender'           => 'onBeforeRender',
 			'onExtensionBeforeUpdate'  => 'onExtensionBeforeUpdate',
 			'onExtensionBeforeUninstall' => 'onExtensionBeforeUninstall',
 		];
@@ -347,10 +348,52 @@ final class MokoSuiteBackup extends CMSPlugin implements SubscriberInterface
 	}
 
 	/**
-	 * Run a backup before any extension is updated.
+	 * Inject JavaScript on installer/update pages to show a backup progress
+	 * modal before extension updates proceed.
+	 */
+	public function onBeforeRender(Event $event): void
+	{
+		$app = $this->getApplication();
+
+		if (!$app->isClient('administrator')) {
+			return;
+		}
+
+		$option = $app->input->getCmd('option', '');
+		$view   = $app->input->getCmd('view', '');
+
+		if ($option !== 'com_installer' && $option !== 'com_joomlaupdate') {
+			return;
+		}
+
+		$params = ComponentHelper::getParams('com_mokosuitebackup');
+
+		if (!(int) $params->get('backup_before_update', 0)) {
+			return;
+		}
+
+		$profileId = (int) $params->get('default_profile', 1);
+		$token     = \Joomla\CMS\Session\Session::getFormToken();
+
+		$js = $this->getPreUpdateBackupScript($profileId, $token);
+
+		$app->getDocument()->addScriptDeclaration($js);
+	}
+
+	/**
+	 * Run a backup before any extension is updated (server-side fallback
+	 * for CLI/API updates where JavaScript is not available).
 	 */
 	public function onExtensionBeforeUpdate(Event $event): void
 	{
+		$session = Factory::getSession();
+
+		if ($session->get('mokosuitebackup.preupdate_js_done', false)) {
+			$session->set('mokosuitebackup.preupdate_js_done', false);
+
+			return;
+		}
+
 		$this->runPreActionBackup('backup_before_update', 'Pre-update backup');
 	}
 
@@ -408,6 +451,161 @@ final class MokoSuiteBackup extends CMSPlugin implements SubscriberInterface
 		}
 	}
 
+	/**
+	 * Build the inline JavaScript that intercepts extension update actions
+	 * and runs a stepped backup with a progress modal first.
+	 */
+	private function getPreUpdateBackupScript(int $profileId, string $token): string
+	{
+		$baseUrl = \Joomla\CMS\Uri\Uri::base() . 'index.php?option=com_mokosuitebackup&format=json&' . $token . '=1';
+
+		return <<<JS
+document.addEventListener('DOMContentLoaded', function() {
+    var msbOrigSubmit = Joomla.submitbutton;
+    var msbBackupRunning = false;
+    var msbPendingTask = null;
+
+    // Create modal
+    var msbModal = document.createElement('div');
+    msbModal.id = 'msbPreUpdateModal';
+    msbModal.className = 'modal fade';
+    msbModal.setAttribute('tabindex', '-1');
+    msbModal.setAttribute('data-bs-backdrop', 'static');
+    msbModal.setAttribute('data-bs-keyboard', 'false');
+    msbModal.innerHTML = '<div class="modal-dialog modal-dialog-centered"><div class="modal-content">'
+        + '<div class="modal-header"><h5 class="modal-title"><span class="icon-archive me-2"></span>Pre-Update Backup</h5></div>'
+        + '<div class="modal-body">'
+        + '<p id="msbStatusText">Creating a backup before updating...</p>'
+        + '<div class="progress" style="height:24px"><div id="msbProgressBar" class="progress-bar progress-bar-striped progress-bar-animated" style="width:0%">0%</div></div>'
+        + '<div id="msbLogArea" style="max-height:120px;overflow-y:auto;font-size:0.8rem;color:#64748b;margin-top:12px;font-family:monospace;white-space:pre-wrap"></div>'
+        + '</div>'
+        + '<div class="modal-footer" id="msbFooter" style="display:none">'
+        + '<button type="button" class="btn btn-secondary" id="msbSkipBtn">Skip & Update</button>'
+        + '<button type="button" class="btn btn-danger" id="msbCancelBtn">Cancel</button>'
+        + '</div>'
+        + '</div></div>';
+    document.body.appendChild(msbModal);
+
+    var bsModal = new bootstrap.Modal(msbModal);
+
+    function msbUpdateProgress(pct, msg) {
+        var bar = document.getElementById('msbProgressBar');
+        bar.style.width = pct + '%';
+        bar.textContent = pct + '%';
+        if (msg) document.getElementById('msbStatusText').textContent = msg;
+    }
+
+    function msbLog(msg) {
+        var log = document.getElementById('msbLogArea');
+        log.textContent += msg + '\\n';
+        log.scrollTop = log.scrollHeight;
+    }
+
+    function msbShowFooter() {
+        document.getElementById('msbFooter').style.display = '';
+    }
+
+    function msbFinish(success) {
+        msbBackupRunning = false;
+        if (success && msbPendingTask) {
+            msbUpdateProgress(100, 'Backup complete — proceeding with update...');
+            // Mark JS backup done so server-side handler skips
+            fetch('{$baseUrl}&task=ajax.markPreUpdateDone', {method:'POST', headers:{'X-Requested-With':'XMLHttpRequest'}});
+            setTimeout(function() {
+                bsModal.hide();
+                msbOrigSubmit.call(Joomla, msbPendingTask);
+                msbPendingTask = null;
+            }, 800);
+        }
+    }
+
+    function msbRunStep(sessionId) {
+        fetch('{$baseUrl}&task=ajax.step&session_id=' + encodeURIComponent(sessionId), {
+            method: 'POST',
+            headers: {'X-Requested-With': 'XMLHttpRequest'}
+        })
+        .then(function(r) { return r.json(); })
+        .then(function(data) {
+            if (data.error) {
+                msbUpdateProgress(data.progress || 0, 'Backup error: ' + data.message);
+                msbLog('ERROR: ' + data.message);
+                msbShowFooter();
+                return;
+            }
+            msbUpdateProgress(data.progress || 0, data.message || data.phase || 'Working...');
+            if (data.message) msbLog(data.message);
+            if (data.done) {
+                msbFinish(true);
+            } else {
+                msbRunStep(sessionId);
+            }
+        })
+        .catch(function(err) {
+            msbUpdateProgress(0, 'Backup request failed');
+            msbLog('Network error: ' + err.message);
+            msbShowFooter();
+        });
+    }
+
+    function msbStartBackup() {
+        msbBackupRunning = true;
+        msbUpdateProgress(0, 'Initializing backup...');
+        msbLog('Starting pre-update backup (profile {$profileId})...');
+
+        fetch('{$baseUrl}&task=ajax.init&profile_id={$profileId}&description=Pre-update+backup', {
+            method: 'POST',
+            headers: {'X-Requested-With': 'XMLHttpRequest'}
+        })
+        .then(function(r) { return r.json(); })
+        .then(function(data) {
+            if (data.error) {
+                msbUpdateProgress(0, 'Backup init failed: ' + data.message);
+                msbLog('INIT ERROR: ' + data.message);
+                msbShowFooter();
+                return;
+            }
+            msbLog('Backup initialized — ' + data.message);
+            msbUpdateProgress(data.progress || 5, data.message || 'Running...');
+            msbRunStep(data.session_id);
+        })
+        .catch(function(err) {
+            msbUpdateProgress(0, 'Could not start backup');
+            msbLog('Network error: ' + err.message);
+            msbShowFooter();
+        });
+    }
+
+    // Intercept Joomla toolbar submit
+    Joomla.submitbutton = function(task) {
+        if ((task === 'update.update' || task === 'update.install') && !msbBackupRunning) {
+            msbPendingTask = task;
+            bsModal.show();
+            msbStartBackup();
+            return;
+        }
+        msbOrigSubmit.call(Joomla, task);
+    };
+
+    // Skip button — proceed without backup
+    document.getElementById('msbSkipBtn').addEventListener('click', function() {
+        bsModal.hide();
+        msbBackupRunning = false;
+        if (msbPendingTask) {
+            msbOrigSubmit.call(Joomla, msbPendingTask);
+            msbPendingTask = null;
+        }
+    });
+
+    // Cancel button — abort everything
+    document.getElementById('msbCancelBtn').addEventListener('click', function() {
+        bsModal.hide();
+        msbBackupRunning = false;
+        msbPendingTask = null;
+    });
+});
+JS;
+	}
+
 	/**
 	 * Send a JSON response and terminate — used by web cron handler.
 	 */