Add Reset button, fix disk swap regression, and add sticky Shift

- Reset button (left of Sound) ejects disk and power-cycles the C64
    to BASIC without reloading — loadedADisks is cleared so episode
    buttons trigger autostart again on next press
  - A-side episode disks that were already loaded now hot-swap instead
    of resetting the machine; use Reset explicitly when a cold start
    is needed (fixes unintended reset when returning from hero disk)
  - Virtual keyboard Shift is now a toggle: tap SHF to lock shift on
    (key stays highlighted), tap again to release — no multi-touch
    required to type capital letters

SchwertUndMagieOnPebbleCompanionApp/app/src/main/java/de/ladkau/schwertundmagieonpebblecompanionapp/C64Engine.kt

@@ -25,6 +25,9 @@ class C64Engine {
     /** Hot-swap disk in drive 8 without resetting (use for B-side / hero disks). */
     external fun attachDisk(path: String): Boolean
 
+    /** Eject the disk and hard-reset the C64 to a BASIC ready prompt. */
+    external fun resetMachine(): Boolean
+
     /** Run the emulator for one video frame (~20 000 CPU cycles). */
     external fun runFrame()
 

SchwertUndMagieOnPebbleCompanionApp/app/src/main/java/de/ladkau/schwertundmagieonpebblecompanionapp/C64KeyboardView.kt

@@ -91,6 +91,15 @@ class C64KeyboardView @JvmOverloads constructor(
 
     private val heldKeys = mutableMapOf<Int, C64Key>()
 
+    /* Sticky Shift: tapping either SHF key toggles LSHIFT on/off.
+     * When true, the SHF keys are drawn highlighted and LSHIFT stays held. */
+    private var shiftActive = false
+    private val lshiftKey   = C64Key("SHF", C64Engine.KEY_LSHIFT)
+
+    private fun isShiftKey(key: C64Key) =
+        key.codes.size == 1 &&
+        (key.codes[0] == C64Engine.KEY_LSHIFT || key.codes[0] == C64Engine.KEY_RSHIFT)
+
     private val keyPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
         color = Color.parseColor("#2C2C6C")
     }
@@ -127,12 +136,12 @@ class C64KeyboardView @JvmOverloads constructor(
 
     override fun onDraw(canvas: Canvas) {
         val held = heldKeys.values.toSet()
-        // Scale text so it fits roughly in half the row height
         textPaint.textSize = (height / rows.size) * 0.38f
 
         for (row in keyRects) {
             for ((rect, key) in row) {
-                canvas.drawRoundRect(rect, 5f, 5f, if (key in held) pressedPaint else keyPaint)
+                val pressed = key in held || (shiftActive && isShiftKey(key))
+                canvas.drawRoundRect(rect, 5f, 5f, if (pressed) pressedPaint else keyPaint)
                 drawKeyLabel(canvas, rect, key.label)
             }
         }
@@ -157,8 +166,14 @@ class C64KeyboardView @JvmOverloads constructor(
         when (event.actionMasked) {
             MotionEvent.ACTION_DOWN, MotionEvent.ACTION_POINTER_DOWN -> {
                 val key = keyAt(ex, ey) ?: return true
+                if (isShiftKey(key)) {
+                    // Toggle sticky shift; always use LSHIFT so there's no phantom held key.
+                    shiftActive = !shiftActive
+                    onKeyEvent?.invoke(lshiftKey, shiftActive)
+                } else {
                     heldKeys[pid] = key
                     onKeyEvent?.invoke(key, true)
+                }
                 invalidate()
             }
             MotionEvent.ACTION_UP, MotionEvent.ACTION_POINTER_UP,

SchwertUndMagieOnPebbleCompanionApp/app/src/main/java/de/ladkau/schwertundmagieonpebblecompanionapp/MainActivity.kt

@@ -80,6 +80,7 @@ class MainActivity : AppCompatActivity() {
     private val episodeButtons = mutableMapOf<DiskSlot, Button>()
     private val loadedADisks   = mutableSetOf<Int>()
     private var activeSlot: DiskSlot? = null
+    private var currentDiskPath: String? = null  // path last passed to engine.loadDisk()
 
     // ---- Disk import (multi-select) -----------------------------------------
 
@@ -157,6 +158,18 @@ class MainActivity : AppCompatActivity() {
             btnSound.text = if (soundEnabled) "Sound: ON" else "Sound: OFF"
         }
 
+        val btnReset = findViewById<Button>(R.id.btn_reset)
+        btnReset.setOnClickListener {
+            val ok = engine.resetMachine()
+            if (ok) {
+                loadedADisks.clear()
+                activeSlot = null
+                refreshDiskButtons()
+                drawerLayout.closeDrawer(GravityCompat.START)
+            }
+            appendLog(if (ok) "Reset: C64 reset to BASIC" else "Reset failed")
+        }
+
         for (slot in diskSlots) {
             val btn = findViewById<Button>(slot.btnId)
             episodeButtons[slot] = btn
@@ -291,12 +304,18 @@ class MainActivity : AppCompatActivity() {
             appendLog("Disk not found: ${slot.fileName}")
             return
         }
-        // A-side episode disks restart the machine; B-side and hero disks are hot-swapped.
-        val resetMachine = slot.part == 'A'
+        // Only reset + autostart for the first load of an A-side episode disk.
+        // Returning to an already-loaded episode (or any B-side / hero disk) is a hot-swap.
+        // Use the explicit Reset button to restart the machine on demand.
+        val resetMachine = slot.part == 'A' && slot.episode !in loadedADisks
         val ok = if (resetMachine) engine.loadDisk(file.absolutePath)
                  else              engine.attachDisk(file.absolutePath)
         if (ok) {
-            if (slot.part == 'A') loadedADisks.add(slot.episode)
+            if (resetMachine) {
+                loadedADisks.add(slot.episode)
+                currentDiskPath = file.absolutePath
+                findViewById<Button>(R.id.btn_reset).isEnabled = true
+            }
             activeSlot = slot
             refreshDiskButtons()
         }

SchwertUndMagieOnPebbleCompanionApp/app/src/main/jni/vice_jni.c

@@ -36,14 +36,16 @@ static uint32_t        g_framebuf[FRAME_W * FRAME_H];
 static pthread_mutex_t g_lock = PTHREAD_MUTEX_INITIALIZER;
 static int             g_ready = 0;
 
-/* Pending disk operations — written by Android thread, consumed by
- * video_canvas_refresh on the VICE thread (both attach and autostart APIs
+/* Pending disk/reset operations — written by Android thread, consumed by
+ * video_canvas_refresh on the VICE thread (machine_trigger_reset and disk APIs
  * must be called from the VICE thread to avoid corrupting internal state).
  * g_pending_disk   → autostart_disk (resets the machine, used for A-side disks)
- * g_pending_attach → file_system_attach_disk (hot-swap, used for B-side / hero disks) */
+ * g_pending_attach → file_system_attach_disk (hot-swap, used for B-side / hero disks)
+ * g_pending_reset  → detach disk + hard reset to BASIC prompt */
 static pthread_mutex_t g_pending_lock   = PTHREAD_MUTEX_INITIALIZER;
 static char            g_pending_disk[512];
 static char            g_pending_attach[512];
+static volatile int    g_pending_reset  = 0;
 
 /* =========================================================================
  * VICE integration (compiled only when libvice.a is linked in)
@@ -352,7 +354,20 @@ void video_canvas_refresh(video_canvas_t *canvas,
                           unsigned int xs, unsigned int ys,
                           unsigned int xi, unsigned int yi,
                           unsigned int w,  unsigned int h) {
-    /* Process any pending disk operations on the VICE thread. */
+    /* Process any pending operations on the VICE thread. */
+
+    /* Hard reset: eject disk and return to BASIC prompt. */
+    if (g_pending_reset) {
+        g_pending_reset = 0;
+        pthread_mutex_lock(&g_pending_lock);
+        g_pending_disk[0]   = '\0';
+        g_pending_attach[0] = '\0';
+        pthread_mutex_unlock(&g_pending_lock);
+        file_system_detach_disk(8, 0);
+        machine_trigger_reset(MACHINE_RESET_MODE_POWER_CYCLE);
+        g_io_frames = g_load_frames = g_attach_frames = 0;
+    }
+
     pthread_mutex_lock(&g_pending_lock);
     char autostart_path[512] = {0};
     char attach_path[512]    = {0};
@@ -649,6 +664,16 @@ JNI_FN(jboolean, attachDisk)(JNIEnv *env, jobject obj, jstring path) {
 #endif
 }
 
+JNI_FN(jboolean, resetMachine)(JNIEnv *env, jobject obj) {
+    (void)env; (void)obj;
+#ifdef HAVE_VICE_SRC
+    g_pending_reset = 1;
+    return JNI_TRUE;
+#else
+    return JNI_FALSE;
+#endif
+}
+
 JNI_FN(jboolean, getDriveLed)(JNIEnv *env, jobject obj) {
     (void)env; (void)obj;
 #ifdef HAVE_VICE_SRC

SchwertUndMagieOnPebbleCompanionApp/app/src/main/res/layout/activity_main.xml

@@ -235,16 +235,35 @@
             android:text="Import Disks"
             android:textSize="12sp" />
 
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="horizontal">
+
+            <Button
+                android:id="@+id/btn_reset"
+                style="?attr/materialButtonOutlinedStyle"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:layout_marginEnd="4dp"
+                android:text="Reset"
+                android:textSize="12sp"
+                android:enabled="false" />
+
             <Button
                 android:id="@+id/btn_sound"
                 style="?attr/materialButtonOutlinedStyle"
-            android:layout_width="match_parent"
+                android:layout_width="0dp"
                 android:layout_height="wrap_content"
+                android:layout_weight="1"
                 android:text="Sound: OFF"
                 android:textSize="12sp" />
 
         </LinearLayout>
 
+    </LinearLayout>
+
 </androidx.drawerlayout.widget.DrawerLayout>
 
     <!-- Splash screen overlay — covers everything until VICE is ready -->