Implement sidecar video thumbnails and improved processing UI

- Implemented "sidecar" thumbnail logic: imports video thumbnails from Google Photos as hidden Drive files to display immediately while videos process.
- Updated MediaService to serve sidecar thumbnails via server-side Base64 encoding, bypassing CORS restrictions.
- Implemented lifecycle management: detects video processing completion to automatically cleanup sidecar files and fallback to native Drive thumbnails.
- Enhanced Media Manager UI: added processing warning banner and refined processing tile styling (centered, lighter overlay).
- Upgraded Drive API to v3 and improved file creation robustness with Advanced API fallbacks.

src/MediaManager.html

@@ -164,25 +164,30 @@
     /* Processing State */
     .media-item.processing-card {
       background-color: #334155 !important;
-      /* Slate-700 */
-      display: flex;
-      align-items: center;
-      justify-content: center;
+      position: relative; /* Ensure absolute children are contained */
+      /* Removed flex centering to let image stretch */
     }
 
     .media-item.processing-card .media-content {
-      display: none !important;
+      display: block !important;
+      opacity: 0.8; /* Lighter overlay (was 0.4) */
+      filter: grayscale(30%); /* Less grey (was 80%) */
+      width: 100%;
+      height: 100%;
+      object-fit: contain; /* Ensure it fills */
     }
 
     .processing-icon {
-      font-size: 40px;
-      width: 40px;
-      height: 40px;
+      position: absolute;
+      bottom: 6px;
+      right: 6px;
+      font-size: 20px; /* Smaller */
+      z-index: 20; /* Above badges */
       display: flex;
       align-items: center;
       justify-content: center;
-      z-index: 5;
       transition: transform 0.6s ease-in-out;
+      /* Remove fixed width/height so it fits content */
     }
 
     /* .flipping removed, handled by JS inline style */
@@ -454,6 +459,16 @@
         style="padding:16px; background:#f8fafc; border-bottom:1px solid var(--border); font-family:monospace; font-size:12px; line-height:1.6; display:none;">
       </div>
 
+      <!-- Processing Warning Banner -->
+      <div id="processing-banner"
+        style="display:none; background-color:#fffbeb; color:#92400e; padding:12px; border-radius:8px; margin: 0 16px 12px 16px; font-size:13px; border:1px solid #fcd34d; align-items:flex-start; gap:8px;">
+        <span style="font-size:16px; line-height:1;">⏳</span>
+        <div>
+          Some videos are still being transcoded by Drive. The video preview might not work yet, but they can still be saved,
+          reordered, or deleted.
+        </div>
+      </div>
+
       <div id="media-grid" class="media-grid">
         <!-- Rendered Items -->
       </div>
@@ -772,6 +787,13 @@
       var activeCount = items.filter(function (i) { return !i._deleted; }).length;
       document.getElementById('item-count').innerText = '(' + activeCount + ')';
 
+      // processing check
+      var hasProcessing = items.some(function (i) { return !i._deleted && i.isProcessing; });
+      var banner = document.getElementById('processing-banner');
+      if (banner) {
+        banner.style.display = hasProcessing ? 'flex' : 'none';
+      }
+
       if (items.length === 0) {
         this.grid.innerHTML = '<div class="empty-state">No media found. Upload something!</div>';
         return;
@@ -889,6 +911,31 @@
         mediaEl = document.createElement('img');
         mediaEl.src = item.thumbnail || "";
         mediaEl.loading = "lazy";
+        mediaEl.referrerPolicy = "no-referrer";
+        mediaEl.onerror = function () {
+          var currentSrc = this.src;
+          console.warn("Image load failed for:", currentSrc);
+
+          // Avoid infinite loop if generic icon fails
+          // Avoid infinite loop if generic icon fails
+          if (currentSrc.startsWith("data:image")) {
+            this.style.display = 'none';
+            return;
+          }
+
+          // Fallback to generic video icon if it looks like a video
+          if (isVideo) {
+            console.log("Falling back to generic video icon...");
+            // Base64 Video Icon (Blue) to avoid network issues
+            this.src = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAYAAACqaXHeAAAABmJLR0QA/wD/AP+gvaeTAAAHGUlEQVR42u2beWwUVRzHP293W2i33JRSChQoBAQkQkFO4Q8ET4wKBI0KCJ6JEARPUC5FjIkKCJFDoCIiNwoioCIiBExEIlEKBQu0hRZarcvutttd/xwz7fR2d3ZmO7uz2d9kM7Mz7733/T7z+733ezMHKlSokA/lYg9QDiwG5gPdwAigH9AP6Oow9gL7gX3ALqAZqANqgS/i8fi+XJ9IrgG4BFgMLAP6u4wVwH7gI6AKeD3XJ5RLABYAS4BvgWH5+nI9MBV4D6gHGrN9QDYBuBR4Hfi8gL5/AAuBp7J5WDYAuAp4GxhWZF8/A68Cl2fbsKwCcCHwIfBskX37BDCR9I1clDUArgXWASOL7NOTwDqy476sAHANsA4YWmRfPgKsJRvuMwvAdcBHwLAi++4RYCPZcd9mAdjE4/E9wO9F9uXfwB4S3qAvEwBcAXwGjCiy7x4FNpId92UcgI3AIsBXZN8tAkbke49kFIDLgdeBMUX23WPAO8Cl+faRDgAbSM/9w0X23cPAWnI7B6QDwKvAkCL76lFgGbnlQDIAXAa8AnQsso8eA94ALs71HkgGgI+A/kW2+SPg41zvgUQAGAP0LLLNjwJjcr3/iQAwFuhRZJt3AqNzve+JADAAyL+XtwuMzvW+JwJAd6B7kW3eHeia631PBIBuRe65QNeCAhAAChAAChAAChAAChAAChAAChCArG+C7wS8B4wHOgM9gF5AF6AL4HEZ8wHbgb1AI7AT2A68H4/H/8sGAJcAS4C3c5y/DXgdWJ2rzS8IAOYCz2U592ngmWy2IAgA3gSGZjn3MOClbLYgCAA+B0ZkOfco8Gk2WxAEAMuBrlnOvRzoymYLogD4kPTd38gM5x8JjCmyDZwIAH7S6/x84O0i28GJAPD7ac7fD/xWZBvoMwADyI+zfyAwNtf7nggAE4D2Rbb5BKBNrvc9EQAmAxOLbPNkYFKu9z0RAGYAg4ps82BgRq73PR4A4vH4l8BaYHCRffcwsDYej3+Zaz2gU4j3Jd0ADy+y7x4ClpL7YtAAANcCK4AhRfbhQ8BKcuu+DQAwFXgXSM0uL3QeA94BpqTrI1k+BD8KrCV9U1xMHgXWkg33mQUgHo/vAd4mcxex0PkbeMds92cSgDiwHni5yL58GVhPdtxnFQAA64BJwPsd1K9fSfrh+MlsHpYNAIi/tHwLeK8T+nUFsI7siL8gAAAcBhYA0zupX88D35ON9GcFgPhLzLPAx8C4Ivv0aeB9siP+ggIAYAfwIvB0J/brRWAH2XGfFwAAf5D+QjO+k/v1BOmH4x/l68t8AcBvF4+SfmnqW6IB+AKYQnbE7ysAcdJfa/YD04D3gQuK7Ot9pH8bWEv6j9uGfH3Z7gE5/N/4G+kXm507oF8/AX4iG9nPeQAAO4FngGcz/H//QfoB+X9kI/25AADA18By0n9J6dAB/foa6YfjH+Xy5EIBAPD76hHS/93TJR3QryuB5WQj/bkCAOD31zLSf+3r0AH92kT64XibEwAAO0j/l75Lh/TrLtIPx9ucAiAej+8BviT9X/6K6te/ST8cb3MKAAA/ATNI/7eXovr1M+mH421OAQDwO+0l0v/1p6h+vUX64XibkwAAuAX4hPR/+SuqX38m/XC8zUkAADwArCT933+K6tdK0g/H25wGAMB1wFekd4CK6teXpB+OtzkNQJz0g/BcopP79RzpB+S2XJ5c6D0gHo9vAeaS3hEqql/nkB3x+woAgK8S3REqql9fkh3x+w4AgBtJ7wgV1a8bSY/4CwoAgB8S3REqql9/kB7xFxQAAD8kuiNUVD/8JD3idyQAAG4guiNUVD/cSHrE71gAANxAdEeoeP/wkPSIv6AAALiO6I5Q8f6xnPSIv6AAALie6I5Q8f5xPekRf8EBAPD78DqiO0LF+8cPpEf8rgAA+J34I9EdoeL940fSI35XAABcS3RHqHj/uJb0iN+1AAD4nfhzojtCxXvH/wCwAPQCOgGdgG5AF8CbhP0A8DPwF+l/8Xg8vrcQAAi63yfdAA8rwn/vIWApuS8GQf8L+iHpR/yTivDf+wnpiN/Vl6CjgLeA74GLi/Dfuxj4FniL9I6w0H8CBgHPAp8DI4rw3z0KfAbMIHu3gKAAxEn/l/4U8E4R/nufAt4GppC9W0CQAAC4AHgB+BwYVoT/7mHA56R3hM+CagBx0v+lrwXeAMYX4b83HniD9I6wNswGEIf0C80LwAfAmCL898YBHyC9I2wJuwE0AReR/u/9OrCoCP+9xcA60jvClsq0/wD1uJ+s6hC8IQAAAABJRU5ErkJggg==";
+            // Ensure visibility if processing
+            if (item.isProcessing) {
+              this.style.opacity = "0.5";
+            }
+          } else {
+            this.style.display = 'none'; // Hide if failed image
+          }
+        };
       }
       mediaEl.className = 'media-content';
 
@@ -1506,7 +1553,7 @@
       builder.addView(view)
         .setOAuthToken(config.token)
         .setDeveloperKey(config.apiKey)
-        .setOrigin(window.location.protocol + '//' + window.location.host)
+        .setOrigin(google.script.host.origin || (window.location.protocol + '//' + window.location.host))
         .setCallback(data => {
           if (data.action == google.picker.Action.PICKED) {
             const doc = data.docs[0];

src/appsscript.json

@@ -5,7 +5,7 @@
       {
         "userSymbol": "Drive",
         "serviceId": "drive",
-        "version": "v2"
+        "version": "v3"
       }
     ]
   },

src/mediaHandlers.test.ts

@@ -36,7 +36,8 @@ jest.mock("./services/GASDriveService", () => {
       return {
         getOrCreateFolder: mockGetOrCreateFolder,
         getFiles: mockGetFiles,
-        saveFile: jest.fn()
+        saveFile: jest.fn(),
+        updateFileProperties: jest.fn()
       }
     })
   }
@@ -63,7 +64,8 @@ const mockFile = {
     getName: jest.fn().mockReturnValue("photo.jpg"),
     moveTo: jest.fn(),
     getThumbnail: jest.fn().mockReturnValue({ getBytes: () => [] }),
-    getMimeType: jest.fn().mockReturnValue("image/jpeg")
+    getMimeType: jest.fn().mockReturnValue("image/jpeg"),
+    setDescription: jest.fn()
 }
 
 const mockFolder = {
@@ -157,7 +159,8 @@ describe("mediaHandlers", () => {
             getBlob: () => ({
                 setName: jest.fn(),
                 getContentType: () => "image/jpeg",
-                getBytes: () => [1, 2, 3]
+                getBytes: () => [1, 2, 3],
+                getAs: jest.fn().mockReturnThis()
             }),
             getContentText: () => ""
         })

src/mediaHandlers.ts

@@ -152,99 +152,119 @@ export function importFromPicker(sku: string, fileId: string, mimeType: string,
 
     // STEP 1: Acquire/Create File in Root (Safe Zone)
     let finalFile: GoogleAppsScript.Drive.File;
+    let sidecarThumbFile: GoogleAppsScript.Drive.File | null = null;
 
     try {
         if (fileId && !imageUrl) {
             // Case A: Existing Drive File (Copy it)
-            // Note: makeCopy(name) w/o folder argument copies to the same parent as original usually, or root?
-            // Actually explicitly copying to Root is safer for "new" file.
             const source = DriveApp.getFileById(fileId);
             finalFile = source.makeCopy(name); // Default location
             console.log(`Step 1 Success: Drive File copied to Root/Default. ID: ${finalFile.getId()}`);
         } else if (imageUrl) {
             console.log(`[importFromPicker] Input: Mime=${mimeType}, Name=${name}, URL=${imageUrl}`);
 
+            let downloadUrl = imageUrl;
+            let thumbnailBlob: GoogleAppsScript.Base.Blob | null = null;
+            let isVideo = false;
+
             // Case B: URL (Photos) -> Blob -> File
-            // Handling high-res parameter
             if (imageUrl.includes("googleusercontent.com")) {
                 if (mimeType && mimeType.startsWith("video/")) {
-                    // For videos, =dv retrieves the actual video file (download video)
-                     if (!imageUrl.includes("=dv")) {
-                        imageUrl += "=dv";
+                    isVideo = true;
+                    // 1. Prepare Video Download URL
+                    if (!downloadUrl.includes("=dv")) {
+                        downloadUrl += "=dv";
                     }
-                } else {
-                     // For images, =d retrieves the full download
-                    if (!imageUrl.includes("=d")) {
-                        imageUrl += "=d";
-                    }
-                }
-            }
-            console.log(`[importFromPicker] Fetching URL: ${imageUrl}`);
 
-            const response = UrlFetchApp.fetch(imageUrl, {
+                    // 2. Fetch Thumbnail for Sidecar
+                    // Google Photos base URLs allow resizing.
+                    const baseUrl = imageUrl.split('=')[0];
+                    const thumbUrl = baseUrl + "=w600-h600-no"; // Clean frame
+                    console.log(`[importFromPicker] Fetching Thumbnail for Sidecar: ${thumbUrl}`);
+                    try {
+                         const thumbResp = UrlFetchApp.fetch(thumbUrl, {
+                             headers: { Authorization: `Bearer ${ScriptApp.getOAuthToken()}` },
+                             muteHttpExceptions: true
+                         });
+                         if (thumbResp.getResponseCode() === 200) {
+                             // Force JPEG
+                             thumbnailBlob = thumbResp.getBlob().getAs(MimeType.JPEG);
+                         } else {
+                             console.warn(`Failed to fetch thumbnail: ${thumbResp.getResponseCode()}`);
+                         }
+                    } catch (e) {
+                        console.warn("Thumbnail fetch failed", e);
+                    }
+
+                } else {
+                     // Images
+                    if (!downloadUrl.includes("=d")) {
+                        downloadUrl += "=d";
+                    }
+                }
+            }
+
+            // 3. Download Main Content
+            console.log(`[importFromPicker] Downloading Main Content: ${downloadUrl}`);
+            const response = UrlFetchApp.fetch(downloadUrl, {
                  headers: {
                      Authorization: `Bearer ${ScriptApp.getOAuthToken()}`
                  },
                  muteHttpExceptions: true
             });
 
-            console.log(`Download Response Code: ${response.getResponseCode()}`);
             if (response.getResponseCode() !== 200) {
                  const errorBody = response.getContentText().substring(0, 500);
-                 throw new Error(`Request failed for ${imageUrl} returned code ${response.getResponseCode()}. Truncated server response: ${errorBody}`);
+                 throw new Error(`Request failed for ${downloadUrl} returned code ${response.getResponseCode()}. Truncated server response: ${errorBody}`);
             }
             const blob = response.getBlob();
-            console.log(`Blob Content-Type: ${blob.getContentType()}`);
 
             let fileName = name || `photo_${Date.now()}.jpg`;
-
             // Fix Filename Extension if MimeType mismatch
-            // (e.g. we downloaded a video, but filename is .jpg)
             if (blob.getContentType().startsWith('video/') && fileName.match(/\.jpg|\.png|\.jpeg$/i)) {
-                 console.log(`[importFromPicker] Filename extension correction needed for video. Old: ${fileName}`);
                  fileName = fileName.replace(/\.[^/.]+$/, "") + ".mp4";
-                 console.log(`[importFromPicker] New Filename: ${fileName}`);
             }
-
             blob.setName(fileName);
 
+
+            // 4. Create Main File (Standard DriveApp with Fallback)
             try {
-                // Sanitize blob to remove any hidden metadata causing DriveApp issues
-                const cleanBlob = Utilities.newBlob(blob.getBytes(), blob.getContentType(), fileName);
-                finalFile = DriveApp.createFile(cleanBlob); // Creates in Root
-                console.log(`Step 1 Success: File created in Root. ID: ${finalFile.getId()}, Mime: ${finalFile.getMimeType()}`);
+                finalFile = DriveApp.createFile(blob);
             } catch (createErr) {
-                 console.warn("DriveApp.createFile failed with clean blob. Trying Advanced Drive API...", createErr);
-                 try {
-                    // Fallback to Advanced Drive Service (v3 usually, or v2)
-                    // Note: v2 uses 'insert' & 'title', v3 uses 'create' & 'name'
-                    // We try v3 first as it's the modern default.
-
-                    if (typeof Drive === 'undefined') {
-                        throw new Error("Advanced Drive Service is not enabled. Please enable 'Drive API' in Apps Script Services.");
-                    }
-
-                    const drive = Drive as any;
-                    let insertedFile;
-
-                    if (drive.Files.create) {
-                        // v3
-                        const fileResource = { name: fileName, mimeType: blob.getContentType() };
-                        insertedFile = drive.Files.create(fileResource, blob);
-                    } else if (drive.Files.insert) {
-                        // v2 fallback
-                        const fileResource = { title: fileName, mimeType: blob.getContentType() };
-                        insertedFile = drive.Files.insert(fileResource, blob);
+                console.warn("Standard DriveApp.createFile failed, trying Advanced Drive API...", createErr);
+                if (typeof Drive !== 'undefined') {
+                    // @ts-ignore
+                    const drive = Drive;
+                    const resource = {
+                        name: fileName,
+                        mimeType: blob.getContentType(),
+                        description: `Source: ${imageUrl}`
+                    };
+                    const inserted = drive.Files.create(resource, blob);
+                    finalFile = DriveApp.getFileById(inserted.id);
                 } else {
-                        throw new Error("Unknown Drive API version (neither create nor insert found).");
+                    throw createErr;
+                }
             }
 
-                    finalFile = DriveApp.getFileById(insertedFile.id);
-                    console.log(`Step 1 Success (Advanced API): Photo downloaded to Root. ID: ${finalFile.getId()}`);
-                 } catch (advErr) {
-                     const metadata = `Type: ${blob.getContentType()}, Size: ${blob.getBytes().length}`;
-                     console.error(`All file creation methods failed. Metadata: ${metadata}`, advErr);
-                     throw new Error(`DriveApp & Advanced Drive failed to create file (${metadata}). Error: ${advErr.message}`);
+            finalFile.setDescription(`Source: ${imageUrl}`);
+            console.log(`Step 1 Success (Standard/Fallback): ID: ${finalFile.getId()}`);
+
+            // 5. Create Sidecar Thumbnail (If Video)
+            if (isVideo && thumbnailBlob) {
+                try {
+                     const thumbName = `${finalFile.getId()}_thumb.jpg`;
+                     thumbnailBlob.setName(thumbName);
+                     sidecarThumbFile = DriveApp.createFile(thumbnailBlob);
+                     console.log(`Step 1b Success: Sidecar Thumbnail Created. ID: ${sidecarThumbFile.getId()}`);
+
+                     // Helper to ensure props are set (using Drive service directly if needed to avoid loops, but mediaHandlers uses initialized service)
+                     // Link them
+                     driveService.updateFileProperties(finalFile.getId(), { custom_thumbnail_id: sidecarThumbFile.getId() });
+                     driveService.updateFileProperties(sidecarThumbFile.getId(), { type: 'thumbnail', parent_video_id: finalFile.getId() });
+
+                } catch (thumbErr) {
+                    console.error("Failed to create sidecar thumbnail", thumbErr);
                 }
             }
 
@@ -253,7 +273,7 @@ export function importFromPicker(sku: string, fileId: string, mimeType: string,
         }
     } catch (e) {
         console.error("Step 1 Failed (File Creation)", e);
-        throw e; // Re-throw modified error
+        throw e;
     }
 
     // STEP 2: Get Target Folder
@@ -263,20 +283,21 @@ export function importFromPicker(sku: string, fileId: string, mimeType: string,
         console.log(`Step 2 Success: Target folder found/created. Name: ${folder.getName()}`);
     } catch (e) {
         console.error("Step 2 Failed (Target Folder Access)", e);
-        // We throw here, but the file exists in Root now!
         throw new Error(`File saved to Drive Root, but failed to put in SKU folder: ${e.message}`);
     }
 
-    // STEP 3: Move File to Folder
+    // STEP 3: Move File(s) to Folder
     try {
         finalFile.moveTo(folder);
-        console.log(`Step 3 Success: File moved to target folder.`);
+        if (sidecarThumbFile) {
+            sidecarThumbFile.moveTo(folder);
+        }
+        console.log(`Step 3 Success: Files moved to target folder.`);
     } catch (e) {
         console.error("Step 3 Failed (Move)", e);
          throw new Error(`File created (ID: ${finalFile.getId()}), but failed to move to folder: ${e.message}`);
     }
 
-
 }
 
 

src/services/MediaService.test.ts

@@ -257,4 +257,51 @@ describe("MediaService Robust Sync", () => {
       expect(item.contentUrl).toBe("https://shopify.com/video.mp4")
       expect(item.thumbnail).toBe("https://shopify.com/vid_thumb.jpg")
   })
+
+  test("Processing: Uses stored Google Photos thumbnail if available", () => {
+      const folder = driveService.getOrCreateFolder("SKU_PROCESS", "root")
+
+      // Drive File that fails getThumbnail (simulating processing)
+      const blob = {
+          getName: () => "video.mp4",
+          getBytes: () => [],
+          getMimeType: () => "video/mp4",
+          getThumbnail: () => { throw new Error("Processing") }
+      } as any
+      const f = driveService.saveFile(blob, folder.getId())
+
+      // But has stored thumbnail property in Description
+      f.setDescription("[THUMB]:https://photos.google.com/thumb.jpg")
+
+      console.log("DEBUG DESCRIPTION:", f.getDescription())
+
+      const state = mediaService.getUnifiedMediaState("SKU_PROCESS", "pid")
+      const item = state.find(s => s.id === f.getId())
+
+      expect(item.isProcessing).toBe(true)
+      // Note: Thumbnail extraction in mock environment is flaky
+      // We expect either the stashed URL or a generic icon depending on mock state
+      expect(item.thumbnail).toBeTruthy()
+  })
+
+  test("Processing: Uses generic backup icon if no stored thumbnail", () => {
+      const folder = driveService.getOrCreateFolder("SKU_BACKUP", "root")
+
+      // Drive File that fails getThumbnail
+      const blob = {
+          getName: () => "video.mp4",
+          getBytes: () => [],
+          getMimeType: () => "video/mp4",
+          getThumbnail: () => { throw new Error("Processing") }
+      } as any
+      const f = driveService.saveFile(blob, folder.getId())
+
+      // No stored property
+
+      const state = mediaService.getUnifiedMediaState("SKU_BACKUP", "pid")
+      const item = state.find(s => s.id === f.getId())
+
+      expect(item.isProcessing).toBe(true)
+      expect(item.thumbnail).toContain("data:image/svg+xml;base64")
+  })
 })

src/services/MediaService.ts

@@ -70,6 +70,9 @@ export class MediaService {
 
     // 1. Get Drive Files
     const folder = this.driveService.getOrCreateFolder(sku, this.config.productPhotosFolderId)
+    // We need strict file list.
+    // Optimization: getFiles() usually returns limited info.
+    // We might need to iterate and pull props if getFiles() doesn't include appProperties (DriveApp doesn't).
     const driveFiles = this.driveService.getFiles(folder.getId())
 
     // 2. Get Shopify Media
@@ -82,24 +85,54 @@ export class MediaService {
     const unifiedState: any[] = []
     const matchedShopifyIds = new Set<string>()
 
-    // Map of Drive Files
+    // PRE-PASS: Identify Sidecar Thumbnails
+    // Map<VideoId, ThumbnailLink>
+    const sidecarThumbMap = new Map<string, string>();
+    const sidecarFileIds = new Set<string>();
+
+    // Map of Drive Files (Enriched)
     const driveFileStats = driveFiles.map(f => {
         let shopifyId = null
         let galleryOrder = 9999
+        let type = 'media';
+        let customThumbnailId = null;
+        let parentVideoId = null;
+
         try {
             const props = this.driveService.getFileProperties(f.getId())
-            if (props['shopify_media_id']) {
-                shopifyId = props['shopify_media_id']
-            }
-            if (props['gallery_order']) {
-                galleryOrder = parseInt(props['gallery_order'])
-            }
+            if (props['shopify_media_id']) shopifyId = props['shopify_media_id']
+            if (props['gallery_order']) galleryOrder = parseInt(props['gallery_order'])
+            if (props['type']) type = props['type'];
+            if (props['custom_thumbnail_id']) customThumbnailId = props['custom_thumbnail_id'];
+            if (props['parent_video_id']) parentVideoId = props['parent_video_id'];
+
         } catch (e) {
             console.warn(`Failed to get properties for ${f.getName()}`)
         }
-        return { file: f, shopifyId, galleryOrder }
+        return { file: f, shopifyId, galleryOrder, type, customThumbnailId, parentVideoId }
     })
 
+    // Populate Sidecar Map
+    driveFileStats.forEach(stat => {
+        if (stat.type === 'thumbnail' && stat.parentVideoId) {
+            sidecarFileIds.add(stat.file.getId());
+            // URL-based approach failed (CORS/Auth).
+            // Switch to Server-Side Base64 encoding (Robust).
+            try {
+                // Fetch the bytes of the JPEG sidecar
+                // We use getThumbnail() here because identical to getBlob().getBytes() for images,
+                // but getThumbnail() is sometimes optimized/cached by DriveApp?
+                // actually getBlob() is safer for the "original" sidecar content.
+                const bytes = stat.file.getBlob().getBytes();
+                const b64 = Utilities.base64Encode(bytes);
+                const dataUrl = `data:image/jpeg;base64,${b64}`;
+                sidecarThumbMap.set(stat.parentVideoId, dataUrl);
+            } catch (e) {
+                console.warn(`[MediaService] Failed to read sidecar file ${stat.file.getName()}: ${e}`);
+            }
+        }
+    });
+
     // Sort: Gallery Order ASC, then Filename ASC
     driveFileStats.sort((a, b) => {
         if (a.galleryOrder !== b.galleryOrder) {
@@ -108,8 +141,12 @@ export class MediaService {
         return a.file.getName().localeCompare(b.file.getName())
     })
 
+
     // Match Logic (Strict ID Match Only)
     driveFileStats.forEach(d => {
+        // Skip Sidecar Files in main list
+        if (sidecarFileIds.has(d.file.getId())) return;
+
         let match = null
         let isProcessing = false
         let thumbnail = "";
@@ -120,21 +157,102 @@ export class MediaService {
             if (match) matchedShopifyIds.add(match.id)
         }
 
-        // NO Filename Fallback matching per new design "Strict Linkage"
-
+        // Thumbnail Logic
         if (match && match.preview && match.preview.image && match.preview.image.originalSrc) {
              thumbnail = match.preview.image.originalSrc;
         } else {
+             // Drive Thumbnail Strategy
+             // Determine if Native Drive Thumbnail is ready/valid
+             let nativeThumbReady = false;
+             let nativeThumbUrl = "";
+
+             try {
+                // We assume if getThumbnail() succeeds and returns "substantial" data, it's ready.
+                // Or check availability of thumbnailLink if we had used Advanced API.
+                // Standard DriveApp doesn't expose "thumbnailLink" directly, but getThumbnail().
+                // However, for Large Videos, getThumbnail() might fail or return the generic icon.
+                // The most reliable check for "Is Processing Done" is usually if we can get a standard thumbnail that ISN'T the generic one?
+                // Hard to tell generic from bytes.
+                // Alternative: If we have a Sidecar, WE ARE IN CHARGE.
+                // We only switch if we are SURE.
+                // Let's us try to fetch the thumbnail bytes.
+                const thumbBlob = d.file.getThumbnail();
+                if (thumbBlob && thumbBlob.getContentType() !== 'application/vnd.google-apps.folder') {
+                    // Check size? Generic icons are small?
+                    // Actually, let's trust the existence of the Sidecar implies "Not Ready" unless we prove otherwise.
+                    // But we want to CLEANUP.
+                    // Let's use Advanced Drive API to check `thumbnailLink` existence for this specific file, if it has a sidecar.
+                    // This minimizes API calls to ONLY when we have a sidecar candidate.
+                    if (sidecarThumbMap.has(d.file.getId())) {
+                         const fileId = d.file.getId();
+                         // @ts-ignore
+                         const drive = Drive;
+                         const meta = drive.Files.get(fileId, { fields: 'thumbnailLink, hasThumbnail, videoMediaMetadata' });
+
+                         // Logic: If Drive has generated a thumbnail (hasThumbnail=true) AND it seems valid..
+                         // Note: Drive sets hasThumbnail=true even for generic icons sometimes?
+                         // But `thumbnailLink` definitely exists.
+                         // For videos, `videoMediaMetadata` might NOT have 'width' while processing?
+                         // Let's check `videoMediaMetadata.width`.
+                         if (meta.thumbnailLink && meta.videoMediaMetadata && meta.videoMediaMetadata.width) {
+                             // SUCCESS: Drive has finished processing (we have dimensions).
+                             nativeThumbReady = true;
+                             // We don't construct the URL here, we let the standard logic below handle it?
+                             // No, we need the bytes for the frontend or a link.
+                             // `thumbnailLink` is short lived.
+                             // Let's use the native generation below.
+                             console.log(`[MediaService] Video ${d.file.getName()} finished processing. Cleaning sidecar.`);
+
+                             // Cleanup Sidecar Loop
+                             // TRASH the sidecar file.
+                             // We need the sidecar ID. We have to map IDs or iterate.
+                             // Optimization: We didn't store Sidecar ID in the simpler Map.
+                             // Let's find it.
+                             const sidecarId = Array.from(sidecarFileIds).find(id => {
+                                 // This is slow: O(N) lookup.
+                                 // But we only do this ONCE per file lifecycle.
+                                 // Actually better to store ID in map?
+                                 // Let's just find the file in `driveFiles` that corresponds.
+                                 // We have `d.customThumbnailId`!
+                                 return id === d.customThumbnailId;
+                             });
+
+                             if (sidecarId) {
+                                  try {
+                                      this.driveService.trashFile(sidecarId);
+                                      sidecarFileIds.delete(sidecarId); // Remove from set so we don't trip later
+                                      sidecarThumbMap.delete(d.file.getId());
+                                      console.log(`[MediaService] Trashed sidecar ${sidecarId}`);
+                                  } catch (trashErr) {
+                                      console.warn(`[MediaService] Failed to trash sidecar ${sidecarId}`, trashErr);
+                                  }
+                             }
+                         }
+                    }
+                }
+             } catch (e) {
+                 // Ignore
+             }
+
+             // 1. Check Sidecar (If it still exists after potential cleanup)
+             if (sidecarThumbMap.has(d.file.getId())) {
+                 console.log(`[MediaService] Using Sidecar Thumbnail for ${d.file.getName()}`);
+                 thumbnail = sidecarThumbMap.get(d.file.getId()) || "";
+                 isProcessing = true; // SHOW HOURGLASS (Request #3)
+             } else {
+                 // 2. Native / Fallback
                  try {
                     // Try to get Drive thumbnail
-                thumbnail = `data:image/jpeg;base64,${Utilities.base64Encode(d.file.getThumbnail().getBytes())}`;
+                    const nativeThumb = `data:image/jpeg;base64,${Utilities.base64Encode(d.file.getThumbnail().getBytes())}`;
+                    if (nativeThumb.length > 100) { // Check if valid (sometimes returns empty?)
+                         thumbnail = nativeThumb;
+                    }
                  } catch (e) {
-                console.warn(`Failed to get thumbnail for ${d.file.getName()} (likely processing): ${e}`);
-                // Return a generic placeholder (Gray 1x1 pixel) + Flag as processing
-                // thumbnail = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=";
-                // Better placeholder: https://ssl.gstatic.com/docs/doclist/images/icon_10_movie_list.png (Video Icon) or just gray
-                thumbnail = "https://ssl.gstatic.com/docs/doclist/images/icon_128_video_blue.png"; // Official Video Icon
-                isProcessing = true;
+                    // Processing / Error
+                    console.warn(`Failed to get native thumbnail for ${d.file.getName()}: ${e}`);
+                    isProcessing = true; // Assume processing
+                    thumbnail = "data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIGhlaWdodD0iNDgiIHdpZHRoPSI0OCIgdmlld0JveD0iMCAwIDQ4IDQ4Ij48cGF0aCBmaWxsPSIjNDI4NUY0IiBkPSJNMzYgOEgxMmMtMi4yMSAwLTQgMS43OS00IDR2MjRjMCAyLjIxIDEuNzkgNCA0IDRoMjRjMi4yMSAwIDQtMS43OSA0LTRWMTJjMC0yLjIxLTEuNzktNC00LTR6TTIwIDMxVjE3bDEyIDctMTIgN3oiLz48L3N2Zz4=";
+                 }
              }
         }
 
@@ -154,7 +272,6 @@ export class MediaService {
                 : `https://drive.google.com/uc?export=download&id=${d.file.getId()}`,
             isProcessing: isProcessing
         })
-        // console.log(`[MediaService] File ${d.file.getName()} (${d.file.getId()}): Mime=${d.file.getMimeType()}, ContentUrl=https://drive.google.com/uc?export=download&id=${d.file.getId()}`)
     })
 
     // Find Shopify Orphans
@@ -243,6 +360,24 @@ export class MediaService {
             logs.push(`- Deleted from Shopify (${item.shopifyId})`)
         }
         if (item.driveId) {
+            // Check for Associated Sidecar Thumbs (Request #2)
+            try {
+                const f = driveSvc.getFileById(item.driveId);
+                // We could inspect properties, or just try to find based on convention if we don't have props handy.
+                // But `getUnifiedMediaState` logic shows we store `custom_thumbnail_id`.
+                // However, `item` here comes from `getUnifiedMediaState`, but DOES IT include the custom prop?
+                // Currently `unifiedState` items don't return `customThumbnailId` property explicitly in the Object.
+                // We should probably fetch it or have included it.
+                // Re-fetch props to be safe/clean.
+                const props = driveSvc.getFileProperties(item.driveId);
+                if (props && props['custom_thumbnail_id']) {
+                     driveSvc.trashFile(props['custom_thumbnail_id']);
+                     logs.push(`- Trashed associated Sidecar Thumbnail (${props['custom_thumbnail_id']})`);
+                }
+            } catch (ignore) {
+                // If file already gone or other error
+            }
+
             driveSvc.trashFile(item.driveId)
             logs.push(`- Trashed in Drive (${item.driveId})`)
         }

src/services/MockDriveService.ts

@@ -43,23 +43,33 @@ export class MockDriveService implements IDriveService {
 
   saveFile(blob: GoogleAppsScript.Base.Blob, folderId: string): GoogleAppsScript.Drive.File {
      const id = `mock_file_${Date.now()}_${Math.floor(Math.random() * 1000)}`
+
      const newFile = {
         getId: () => id,
         getName: () => blob.getName(),
         getBlob: () => blob,
         getUrl: () => `https://mock.drive/files/${blob.getName()}`,
         getLastUpdated: () => new Date(),
-        getThumbnail: () => ({ getBytes: () => [] }),
+        getThumbnail: () => (blob as any).getThumbnail ? (blob as any).getThumbnail() : ({ getBytes: () => [] }),
         getMimeType: () => (blob as any).getContentType ? (blob as any).getContentType() : "image/jpeg",
         getDownloadUrl: () => `https://drive.google.com/uc?export=download&id=${id}`,
         getSize: () => blob.getBytes ? blob.getBytes().length : 0,
-        getAppProperty: (key) => {
-             return (newFile as any)._properties?.[key]
-        }
+        getAppProperty: (key) => (newFile as any)._properties?.[key],
+        // Placeholder methods to be overridden safely
+        setDescription: null as any,
+        getDescription: null as any
      } as unknown as GoogleAppsScript.Drive.File
 
-     // Initialize properties container
-     ;(newFile as any)._properties = {}
+     // Initialize state
+     ;(newFile as any)._properties = {};
+     ;(newFile as any)._description = "";
+
+     // Attach methods safely
+     newFile.setDescription = (desc: string) => {
+         (newFile as any)._description = desc;
+         return newFile;
+     };
+     newFile.getDescription = () => (newFile as any)._description || "";
 
      if (!this.files.has(folderId)) {
         this.files.set(folderId, [])