apploader - enhance file selection process with improved debounce and metadata handling

Author: kidneyhex

install_from_files.js

@@ -3,6 +3,8 @@
  */
 function installFromFiles() {
   return new Promise(resolve => {
+    var MAX_WAIT_MS = 5000; // maximum time to wait for metadata.json
+    var RESCHEDULE_MS = 400; // retry interval while waiting
     // Ask user to select all files at once (multi-select)
     Espruino.Core.Utils.fileOpenDialog({
         id:"installappfiles",
@@ -14,7 +16,8 @@ function installFromFiles() {
       if (!installFromFiles.fileCollection) {
         installFromFiles.fileCollection = {
           files: [],
-          count: 0
+          count: 0,
+          firstTs: Date.now()
         };
       }
 
@@ -29,21 +32,38 @@ function installFromFiles() {
       // Use setTimeout to batch-process after all callbacks complete
       clearTimeout(installFromFiles.processTimeout);
       // Android may deliver multi-file selections with noticeable gaps.
-      // Use a longer debounce to ensure we collect all files before processing.
-      installFromFiles.processTimeout = setTimeout(function() {
-        var files = installFromFiles.fileCollection.files;
-        installFromFiles.fileCollection = null; // reset for next use
-
-        if (!files || files.length === 0) return resolve();
+      // Use a longer debounce and reschedule until metadata is present or max wait exceeded.
+      installFromFiles.processTimeout = setTimeout(function processSelection() {
+        var fc = installFromFiles.fileCollection;
+        var files = fc ? fc.files : null;
+        if (!files || files.length === 0) {
+          // nothing yet; keep waiting until max wait then resolve silently
+          if (fc && (Date.now() - fc.firstTs) < MAX_WAIT_MS) {
+            installFromFiles.processTimeout = setTimeout(processSelection, RESCHEDULE_MS);
+            return;
+          }
+          installFromFiles.fileCollection = null; // reset
+          return resolve();
+        }
 
         // Find metadata.json
         var metadataFile = files.find(f => f.name === 'metadata.json' || f.name.endsWith('/metadata.json'));
 
         if (!metadataFile) {
+          if (fc && (Date.now() - fc.firstTs) < MAX_WAIT_MS) {
+            // Keep waiting for the rest of the files
+            installFromFiles.processTimeout = setTimeout(processSelection, RESCHEDULE_MS);
+            return;
+          }
+          // Timed out waiting for metadata.json
+          installFromFiles.fileCollection = null; // reset
           showToast('No metadata.json found in selected files', 'error');
           return resolve();
         }
 
+        // We have metadata.json; stop collecting and proceed
+        installFromFiles.fileCollection = null; // reset for next use
+
         // Parse metadata.json
         var metadata;
         try {