From d0c9a7e482a87e3613ea0599d98352e021bb442b Mon Sep 17 00:00:00 2001
From: Stefan Ostermann <stefan@ostermail.de>
Date: Sun, 5 Oct 2025 18:10:50 +0200
Subject: [PATCH] [ai] random mode

---
 USER_MANUAL.md |  1 +
 src/main.cpp   | 38 +++++++++++++++++++++++++++++++++++---
 src/main.h     | 10 ++++++----
 web/index.html |  1 +
 4 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/USER_MANUAL.md b/USER_MANUAL.md
index 6379127..c980ba6 100644
--- a/USER_MANUAL.md
+++ b/USER_MANUAL.md
@@ -133,6 +133,7 @@ Option A: Map through the web app (recommended)
 5) Choose Mode:
    - Single (s): Play just the selected song/file once.
    - Folder (f): Play all files in the selected folder once, then stop.
+   - Random (r): Play all files in the selected folder in random order once, then stop.
    - Continuous (c): Loop through the selected folder continuously.
 6) Click “Update Mapping”.
 
diff --git a/src/main.cpp b/src/main.cpp
index 3b8e845..109cdb6 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -14,6 +14,9 @@
 #include <SD.h>
 #include <MFRC522.h> //RFID Reader
 #include <map>
+#if defined(ESP32)
+#include <esp_system.h>
+#endif
 
 // define pins for RFID
 #define CS_RFID 32 // SIC, tried 4 and 32 but only this worked!
@@ -127,6 +130,7 @@ uint16_t voltage_threshold_counter = 0;
 
 size_t free_heap = 0;
 
+// webrequest_blockings is a simple watchdog counter that tracks how long at least one HTTP request has been “active” (not yet disconnected) according to the AsyncWebServer.
 int webrequest_blockings = 0;
 
 void activateSD()
@@ -534,8 +538,8 @@ void playSongByRFID(String id)
     targetIsFolder = true;
   }
 
-  // If the mapping targets a folder (or explicitly 'f' mode), activate folder tracking
-  if (targetIsFolder || entry.mode == 'f')
+  // If the mapping targets a folder (or explicitly 'f' or 'r' mode), activate folder tracking
+  if (targetIsFolder || entry.mode == 'f' || entry.mode == 'r')
   {
     folderModeActive = true;
     folderRootNode = currentNode;
@@ -543,6 +547,19 @@ void playSongByRFID(String id)
     folderFlatList.clear();
     folderRootNode->buildFlatMP3List(folderFlatList);
 
+    // If random-folder mode requested, shuffle the flat list once
+    if (entry.mode == 'r' && folderFlatList.size() > 1)
+    {
+      // Fisher-Yates shuffle using Arduino random()
+      for (int i = (int)folderFlatList.size() - 1; i > 0; --i)
+      {
+        int j = (int)random((long)(i + 1)); // 0..i
+        auto tmp = folderFlatList[i];
+        folderFlatList[i] = folderFlatList[j];
+        folderFlatList[j] = tmp;
+      }
+    }
+
     // Find index of current playing file within the folder list
     for (size_t i = 0; i < folderFlatList.size(); i++)
     {
@@ -554,6 +571,14 @@ void playSongByRFID(String id)
         break;
       }
     }
+    // If random mode, make sure the current file is at the start so next advance is random
+    if (entry.mode == 'r' && folderFlatIndex > 0 && folderFlatIndex < (int)folderFlatList.size())
+    {
+      auto tmp = folderFlatList[0];
+      folderFlatList[0] = folderFlatList[folderFlatIndex];
+      folderFlatList[folderFlatIndex] = tmp;
+      folderFlatIndex = 0;
+    }
 
     // Compute root path for safety checks (path up to last '/')
     int lastSlash = mp3File.lastIndexOf('/');
@@ -1337,6 +1362,13 @@ void setup()
   activateSD();
   Serial.println("SD initialization done.");
 
+  // Seed RNG for shuffle mode
+#if defined(ESP32)
+  randomSeed(esp_random());
+#else
+  randomSeed((uint32_t)micros());
+#endif
+
   // Load configuration from SD card
   Serial.println("Loading configuration...");
   loadConfig();
@@ -1503,7 +1535,7 @@ const String getSysDir(const String filename)
 
 void loop()
 {
-  if (webreq_cnt > 0 && webrequest_blockings > 5000) {
+  if (webreq_cnt > 0 && webrequest_blockings > 10000) {
     Serial.println("excessive webrequest blocking!");
     webreq_cnt = 0;
     webrequest_blockings = 0;
diff --git a/src/main.h b/src/main.h
index 54051cf..0ea461e 100644
--- a/src/main.h
+++ b/src/main.h
@@ -84,10 +84,12 @@ boolean prepareSleepMode = false;
 
 class DirectoryNode;
 
-// Mapping entry that stores target (file or folder) and playback mode:
-// 's' = single (default) - play only the selected song (or single file in folder)
-// 'f' = folder  - play files inside the selected folder, then stop
-// 'c' = continuous - continuously play (like previous continuousMode)
+/* Mapping entry that stores target (file or folder) and playback mode:
+ * 's' = single (default) - play only the selected song (or single file in folder)
+ * 'f' = folder  - play files inside the selected folder, then stop
+ * 'r' = random-folder - play files inside the selected folder in random order, then stop
+ * 'c' = continuous - continuously play (like previous continuousMode)
+ */
 struct MappingEntry {
   String target;
   char mode;
diff --git a/web/index.html b/web/index.html
index 1e07812..68bc744 100644
--- a/web/index.html
+++ b/web/index.html
@@ -120,6 +120,7 @@
               <select id="mode" name="mode">
                 <option value="s">Single (play selected song / file)</option>
                 <option value="f">Folder (play selected folder, then stop)</option>
+                <option value="r">Random (randomize order in folder, then stop)</option>
                 <option value="c">Continuous (continuous playback / loop folder)</option>
               </select>
             </div>