feat(demo): enhance directory demo to persist across page reloads

- Append visit history to session-log.txt instead of overwriting
- Create unique timestamped test files on each visit
- Show previous visit count when revisiting the same folder
- List all files (no longer truncated at 5)

Author: cs-util

docs/implementation-progress.md

@@ -1,5 +1,11 @@
 # Implementation Progress
 
+## 2026-01-27: Enhanced Directory Demo
+- Updated "Open Directory" demo to support persistence across page reloads.
+- Creates a `session-log.txt` that appends visit history (visit count, timestamp, files found).
+- Creates a unique timestamped `test-<timestamp>.txt` file on each visit.
+- On subsequent visits, reads existing log and increments visit counter.
+
 ## 2026-01-27: README Update
 - Refactored `README.md` to be more open-source friendly.
 - Added "Features", "Interactive Demo", and "Getting Started" sections.

index.html

@@ -135,23 +135,51 @@ <h1>Android File System Demo</h1>
 
                 log(`📂 Directory selected: ${dirHandle.name}`);
 
-                // List contents
-                let count = 0;
+                // List contents and count files
+                const entries = [];
                 log("--- Listing Files ---");
                 for await (const entry of dirHandle.values()) {
+                    entries.push(entry);
                     log(` - ${entry.kind}: ${entry.name}`);
-                    count++;
-                    if(count > 5) { log("... (more files hidden)"); break; }
+                }
+                if (entries.length === 0) {
+                    log("  (empty folder)");
                 }
 
-                // Write a test file into this directory
-                log("📝 Creating 'test-log.txt' in this folder...");
-                const newFileHandle = await dirHandle.getFileHandle('test-log.txt', { create: true });
-                const writable = await newFileHandle.createWritable();
-                await writable.write("This file was created by the web app inside your folder!");
-                await writable.close();
+                // Check if session-log.txt exists and read its content
+                let existingLog = "";
+                let visitCount = 1;
+                try {
+                    const existingHandle = await dirHandle.getFileHandle('session-log.txt', { create: false });
+                    const file = await existingHandle.getFile();
+                    existingLog = await file.text();
+                    // Count previous visits
+                    const matches = existingLog.match(/Visit #\d+/g);
+                    visitCount = matches ? matches.length + 1 : 1;
+                    log(`📖 Found existing session-log.txt (${visitCount - 1} previous visits)`);
+                } catch {
+                    log("📝 No previous session-log.txt found, creating fresh log...");
+                }
 
-                log("✅ 'test-log.txt' created successfully inside folder.");
+                // Write/append to session log
+                const timestamp = new Date().toISOString();
+                const newEntry = `\n--- Visit #${visitCount} ---\nTimestamp: ${timestamp}\nFiles found: ${entries.length}\n`;
+                
+                const logHandle = await dirHandle.getFileHandle('session-log.txt', { create: true });
+                const logWritable = await logHandle.createWritable();
+                await logWritable.write(existingLog + newEntry);
+                await logWritable.close();
+                log(`✅ Updated session-log.txt (Visit #${visitCount})`);
+
+                // Create a unique timestamped file on each visit
+                const uniqueFileName = `test-${Date.now()}.txt`;
+                const uniqueHandle = await dirHandle.getFileHandle(uniqueFileName, { create: true });
+                const uniqueWritable = await uniqueHandle.createWritable();
+                await uniqueWritable.write(`Created during visit #${visitCount} at ${timestamp}`);
+                await uniqueWritable.close();
+                log(`✅ Created '${uniqueFileName}'`);
+
+                log(`\n🎉 Demo complete! Reload page and select same folder to see persistence.`);
 
             } catch (err) {
                 if (err.name === 'AbortError') log("User cancelled folder picker.");