feat(dashcam): async import with polling status

- Import now returns immediately with {status: 'started'}
- Backend runs copy in a daemon thread, tracks job state in _import_job
- New GET /api/dash/import/status endpoint for polling
- UI polls every 3s, shows progress bar until done
- Page reload mid-import resumes polling automatically
- Prevents double-import with 'busy' guard

Co-authored-by: Copilot <[email protected]>

static/js/dash.js

@@ -17,10 +17,12 @@ const filesRefreshBtn = document.getElementById('dash-files-refresh-btn');
 const selectAllBtn = document.getElementById('dash-select-all-btn');
 const importSelectedBtn = document.getElementById('dash-import-selected-btn');
 const deleteAllBtn = document.getElementById('dash-delete-all-btn');
+
 let importInProgress = false;
 let importStartTime = null;
 let importTotal = 0;
 let importEtaInterval = null;
+let importPollInterval = null;
 
 function showImportProgress(msg, total) {
     importTotal = total || 0;
@@ -42,6 +44,8 @@ function showImportProgress(msg, total) {
 
 function showImportResult(msg) {
     clearInterval(importEtaInterval);
+    clearInterval(importPollInterval);
+    importPollInterval = null;
     importStatusBar.style.display = 'none';
     importResult.textContent = msg;
     importResultBar.style.display = 'block';
@@ -134,6 +138,7 @@ function renderDashcamFiles(summary) {
         actionsTd.className = 'dash-actions-td';
         const actionsDiv = document.createElement('div');
         actionsDiv.className = 'data-list-actions';
+
         const importButton = document.createElement('button');
         importButton.type = 'button';
         importButton.className = 'btn btn-sm btn-outline-primary btn-icon-mobile';
@@ -190,34 +195,62 @@ function deleteDashcamFile(path) {
     });
 }
 
-function describeImportResult(summary) {
-    let text = `Selected ${summary.found} video(s), copied ${summary.copied}, skipped ${summary.skipped} (already imported).`;
-    if (summary.errors && summary.errors.length) {
-        text += ` Errors: ${summary.errors.join('; ')}`;
+function describeImportResult(job) {
+    let text = `Copied ${job.copied}, skipped ${job.skipped} (already imported).`;
+    if (job.errors && job.errors.length) {
+        text += ` Errors: ${job.errors.join('; ')}`;
     }
     return text;
 }
 
-function importDashcamFiles(paths) {
-    showImportProgress(`Importing ${paths.length} video(s)…`, paths.length);
+function pollImportStatus() {
+    fetch('/api/dash/import/status')
+        .then(r => r.json())
+        .then(job => {
+            if (!job || job.status === 'none' || job.status === 'running') return;
+            clearInterval(importPollInterval);
+            importPollInterval = null;
+            setImportBusy(false);
+            if (job.status === 'ok') {
+                showImportResult(describeImportResult(job));
+                refreshDashcamFiles();
+            } else {
+                showImportResult(job.message || `Import failed: ${job.status}`);
+            }
+        })
+        .catch(() => {}); // ignore transient network errors while polling
+}
+
+function startImport(paths) {
+    const label = paths ? `Importing ${paths.length} video(s)…` : 'Importing all videos… this can take a while.';
+    showImportProgress(label, paths ? paths.length : 0);
     setImportBusy(true);
-    return fetchJson('/api/dash/import', {
+
+    const body = paths ? JSON.stringify({ paths }) : undefined;
+    fetch('/api/dash/import', {
         method: 'POST',
-        headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ paths }),
-    }).then(summary => {
-        showImportResult(describeImportResult(summary));
-        paths.forEach(path => {
-            const checkbox = Array.from(
-                fileListBody.querySelectorAll('[data-select-path]')
-            ).find(candidate => candidate.dataset.selectPath === path);
-            if (checkbox) checkbox.checked = false;
+        headers: body ? { 'Content-Type': 'application/json' } : {},
+        body,
+    })
+        .then(r => r.json())
+        .then(data => {
+            if (data.status === 'busy') {
+                showImportResult(data.message || 'Import already in progress.');
+                setImportBusy(false);
+                return;
+            }
+            if (data.status !== 'started') {
+                showImportResult(data.message || `Import error: ${data.status}`);
+                setImportBusy(false);
+                return;
+            }
+            clearInterval(importPollInterval);
+            importPollInterval = setInterval(pollImportStatus, 3000);
+        })
+        .catch(err => {
+            showImportResult(`Import request failed: ${err}`);
+            setImportBusy(false);
         });
-        return summary;
-    }).catch(err => {
-        showImportResult(`Selected import failed: ${err.message}`);
-        return null;
-    }).finally(() => setImportBusy(false));
 }
 
 function describeDevice(device) {
@@ -245,37 +278,13 @@ function scanForDashcam() {
         });
 }
 
-function importDashcam() {
-    showImportProgress('Importing all videos… this can take a while.', 0);
-    setImportBusy(true);
-
-    fetch('/api/dash/import', { method: 'POST' })
-        .then(response => response.json())
-        .then(summary => {
-            if (summary.status !== 'ok') {
-                showImportResult(summary.message || ('Import failed: ' + summary.status));
-                return;
-            }
-            let text = `Found ${summary.found} video(s), copied ${summary.copied}, skipped ${summary.skipped}.`;
-            if (summary.errors && summary.errors.length > 0) {
-                text += ` Errors: ${summary.errors.join('; ')}`;
-            }
-            showImportResult(text);
-            refreshDashcamFiles();
-        })
-        .catch(err => {
-            showImportResult('Error while importing: ' + err);
-        })
-        .finally(() => setImportBusy(false));
-}
-
 scanBtn.addEventListener('click', scanForDashcam);
-importBtn.addEventListener('click', importDashcam);
+importBtn.addEventListener('click', () => startImport(null));
 filesRefreshBtn.addEventListener('click', refreshDashcamFiles);
 fileListBody.addEventListener('click', event => {
     const importButton = event.target.closest('[data-import-path]');
     if (importButton) {
-        importDashcamFiles([importButton.dataset.importPath]);
+        startImport([importButton.dataset.importPath]);
         return;
     }
 
@@ -295,7 +304,7 @@ fileListBody.addEventListener('change', event => {
 importSelectedBtn.addEventListener('click', () => {
     const paths = selectedPaths();
     if (paths.length) {
-        importDashcamFiles(paths);
+        startImport(paths);
     }
 });
 selectAllBtn.addEventListener('click', () => {
@@ -322,6 +331,18 @@ deleteAllBtn.addEventListener('click', () => {
         });
 });
 
+// Check if an import is already running when page loads (e.g. after refresh mid-import)
+fetch('/api/dash/import/status')
+    .then(r => r.json())
+    .then(job => {
+        if (job && job.status === 'running') {
+            showImportProgress('Import in progress…', 0);
+            setImportBusy(true);
+            importPollInterval = setInterval(pollImportStatus, 3000);
+        }
+    })
+    .catch(() => {});
+
 // Auto-scan once when the page loads.
 scanForDashcam();
 refreshDashcamFiles();