Add in-app file import and episode picker

Assets (ROMs and disk images) now live in getExternalFilesDir, making
  them accessible via USB file transfer and any file manager app without
  adb or root.

  - "Import ROMs" button walks through kernal/basic/chargen picks in
    sequence and restarts the emulator when done
  - "Import Disks" button opens a multi-select picker; files are saved
    as SCHWUM<N><P>.D64 (uppercased for consistent lookup)
  - 2×4 episode grid (1A–4B) lights up each button as its disk image
    becomes available; tapping loads that disk into drive 8

CLAUDE.md

@@ -101,17 +101,20 @@ The NDK must be installed: **Android Studio → SDK Manager → SDK Tools → ND
 
 After the first successful build, subsequent builds skip the VICE compilation step entirely (outputs are up-to-date).
 
-**C64 ROM files** must be pushed to the device separately (not redistributable).
+**C64 ROM files** must be copied to the device separately (not redistributable).
-VICE expects files named exactly `kernal`, `basic`, `chargen` (no extensions) in the
+VICE expects files named exactly `kernal`, `basic`, `chargen` (no extensions).
-app's private `filesDir`: `/data/data/de.ladkau.schwertundmagieonpebblecompanionapp/files/`
 
+**Via USB file transfer (recommended):** connect the phone, open it in Windows Explorer or
+Android File Transfer (Mac), and copy the files to:
+```
+Android/data/de.ladkau.schwertundmagieonpebblecompanionapp/files/
+```
+
+**Via adb (alternative):**
 ```bash
-adb push kernal  /data/local/tmp/kernal
+adb push kernal  /sdcard/Android/data/de.ladkau.schwertundmagieonpebblecompanionapp/files/kernal
-adb push basic   /data/local/tmp/basic
+adb push basic   /sdcard/Android/data/de.ladkau.schwertundmagieonpebblecompanionapp/files/basic
-adb push chargen /data/local/tmp/chargen
+adb push chargen /sdcard/Android/data/de.ladkau.schwertundmagieonpebblecompanionapp/files/chargen
-adb shell run-as de.ladkau.schwertundmagieonpebblecompanionapp cp /data/local/tmp/kernal  files/kernal
-adb shell run-as de.ladkau.schwertundmagieonpebblecompanionapp cp /data/local/tmp/basic   files/basic
-adb shell run-as de.ladkau.schwertundmagieonpebblecompanionapp cp /data/local/tmp/chargen files/chargen
 ```
 
 ### Key Kotlin/C files
@@ -127,8 +130,8 @@ adb shell run-as de.ladkau.schwertundmagieonpebblecompanionapp cp /data/local/tm
 
 ### Disk images
 
-The four original `.d64` disk images are in `versions/`. Load via:
+The four original `.d64` disk images are in `versions/`. Copy the relevant image to the
+same external files directory as the ROMs (via USB or adb), then load via:
 ```kotlin
-engine.loadDisk(filesDir.absolutePath + "/schwert_und_magie_1.d64")
+engine.loadDisk(getExternalFilesDir(null)!!.absolutePath + "/schwert_und_magie_1.d64")
 ```
-(Copy the relevant `.d64` to `filesDir` first via `adb push`.)

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

@@ -9,8 +9,10 @@ import java.nio.ByteBuffer
  * VICE source must be placed at app/src/main/jni/vice-src/ before building
  * (download from https://vice-emu.sourceforge.io/).
  *
- * ROM files (kernal, basic, chargen) must be copied to the app's filesDir
+ * ROM files (kernal, basic, chargen) and .d64 disk images must be copied to
- * before calling initEmulator().
+ * the app's external files directory before calling initEmulator().
+ * That directory is accessible via USB file transfer (no adb needed) at:
+ *   Android/data/de.ladkau.schwertundmagieonpebblecompanionapp/files/
  */
 class C64Engine {
 

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

@@ -1,13 +1,22 @@
 package de.ladkau.schwertundmagieonpebblecompanionapp
 
+import android.app.Activity
+import android.content.Intent
+import android.net.Uri
 import android.os.Bundle
 import android.os.Handler
 import android.os.Looper
+import android.provider.OpenableColumns
 import android.util.Log
+import android.widget.Button
 import android.widget.ScrollView
 import android.widget.TextView
+import android.widget.Toast
+import androidx.activity.result.ActivityResultLauncher
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.appcompat.app.AppCompatActivity
 import fi.iki.elonen.NanoHTTPD
+import java.io.File
 import java.text.SimpleDateFormat
 import java.util.Date
 import java.util.Locale
@@ -15,6 +24,10 @@ import java.util.Locale
 private const val PORT = 8888
 private const val TAG  = "SuM"
 
+private data class DiskSlot(val episode: Int, val part: Char, val btnId: Int) {
+    val fileName: String get() = "SCHWUM${episode}${part}.D64"
+}
+
 class MainActivity : AppCompatActivity() {
 
     private lateinit var tvStatus:  TextView
@@ -32,6 +45,66 @@ class MainActivity : AppCompatActivity() {
     private var emuThread: Thread? = null
     @Volatile private var emuRunning = false
 
+    // ---- disk slots ---------------------------------------------------------
+
+    private val diskSlots = listOf(
+        DiskSlot(1, 'A', R.id.btn_ep_1a), DiskSlot(1, 'B', R.id.btn_ep_1b),
+        DiskSlot(2, 'A', R.id.btn_ep_2a), DiskSlot(2, 'B', R.id.btn_ep_2b),
+        DiskSlot(3, 'A', R.id.btn_ep_3a), DiskSlot(3, 'B', R.id.btn_ep_3b),
+        DiskSlot(4, 'A', R.id.btn_ep_4a), DiskSlot(4, 'B', R.id.btn_ep_4b),
+    )
+    private val episodeButtons = mutableMapOf<DiskSlot, Button>()
+
+    // ---- ROM import (sequential: kernal → basic → chargen) -----------------
+
+    private val romNames = listOf("kernal", "basic", "chargen")
+    private var romImportIndex = 0
+
+    private val romPickerLauncher: ActivityResultLauncher<Intent> =
+        registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
+            if (result.resultCode == Activity.RESULT_OK) {
+                result.data?.data?.let { uri ->
+                    val target = romNames[romImportIndex]
+                    importFileToAssets(uri, target)
+                    appendLog("Imported: $target")
+                    romImportIndex++
+                    if (romImportIndex < romNames.size) {
+                        launchPicker(romPickerLauncher, "Select '${romNames[romImportIndex]}' ROM file")
+                    } else {
+                        romImportIndex = 0
+                        Toast.makeText(this, "ROMs imported — restarting emulator", Toast.LENGTH_SHORT).show()
+                        recreate()
+                    }
+                } ?: run { romImportIndex = 0 }
+            } else {
+                romImportIndex = 0
+            }
+        }
+
+    // ---- Disk import (multi-select) -----------------------------------------
+
+    private val diskPickerLauncher: ActivityResultLauncher<Intent> =
+        registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
+            if (result.resultCode == Activity.RESULT_OK) {
+                val uris = mutableListOf<Uri>()
+                result.data?.clipData?.let { clip ->
+                    for (i in 0 until clip.itemCount) uris.add(clip.getItemAt(i).uri)
+                } ?: result.data?.data?.let { uris.add(it) }
+
+                var count = 0
+                for (uri in uris) {
+                    val name = displayNameForUri(uri) ?: continue
+                    importFileToAssets(uri, name.uppercase())
+                    appendLog("Imported: $name")
+                    count++
+                }
+                if (count > 0) refreshDiskButtons()
+                appendLog("Imported $count disk image(s)")
+            }
+        }
+
+    // ---- lifecycle ----------------------------------------------------------
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
@@ -43,17 +116,35 @@ class MainActivity : AppCompatActivity() {
         display   = findViewById(R.id.c64_display)
         keyboard  = findViewById(R.id.c64_keyboard)
 
+        findViewById<Button>(R.id.btn_import_roms).setOnClickListener {
+            romImportIndex = 0
+            launchPicker(romPickerLauncher, "Select 'kernal' ROM file")
+        }
+        findViewById<Button>(R.id.btn_import_disks).setOnClickListener {
+            launchPicker(diskPickerLauncher, "Select SCHWUM disk images", multiSelect = true)
+        }
+
+        for (slot in diskSlots) {
+            val btn = findViewById<Button>(slot.btnId)
+            episodeButtons[slot] = btn
+            btn.setOnClickListener { loadDiskSlot(slot) }
+        }
+
         initEmulator()
+        refreshDiskButtons()
         startHttpServer()
         wireKeyboard()
     }
 
-    // ---- emulator -------------------------------------------------------
+    // ---- emulator -----------------------------------------------------------
 
     private fun initEmulator() {
-        val romDir = filesDir.absolutePath
+        val assetDir = getExternalFilesDir(null) ?: filesDir
+        assetDir.mkdirs()
+        val romDir = assetDir.absolutePath
         val ok = engine.initEmulator(romDir)
-        tvStatus.text = if (ok) "Emulator ready" else "Emulator: no ROMs (stub mode)"
+        tvStatus.text = if (ok) "Emulator ready"
+                        else "Copy ROMs + .d64 to:\n$romDir"
         Log.d(TAG, "initEmulator=$ok romDir=$romDir")
 
         emuRunning = true
@@ -63,13 +154,12 @@ class MainActivity : AppCompatActivity() {
                 engine.runFrame()
                 display.updateFrame(engine)
                 val elapsed = System.currentTimeMillis() - t0
-                // Target ~50 fps (20 ms/frame)
                 if (elapsed < 20) Thread.sleep(20 - elapsed)
             }
         }.also { it.name = "emu-loop"; it.isDaemon = true; it.start() }
     }
 
-    // ---- virtual keyboard -----------------------------------------------
+    // ---- virtual keyboard ---------------------------------------------------
 
     private fun wireKeyboard() {
         keyboard.onKeyEvent = { key, pressed ->
@@ -81,7 +171,7 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
-    // ---- HTTP server (watch bridge) -------------------------------------
+    // ---- HTTP server (watch bridge) -----------------------------------------
 
     private fun startHttpServer() {
         server = CompanionServer(PORT, timeFormat,
@@ -101,7 +191,58 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
-    // ---- helpers --------------------------------------------------------
+    // ---- disk helpers -------------------------------------------------------
+
+    private fun diskFile(slot: DiskSlot): File? {
+        val assetDir = getExternalFilesDir(null) ?: filesDir
+        return assetDir.listFiles()?.firstOrNull { it.name.uppercase() == slot.fileName }
+    }
+
+    private fun refreshDiskButtons() {
+        for (slot in diskSlots) {
+            episodeButtons[slot]?.isEnabled = diskFile(slot) != null
+        }
+    }
+
+    private fun loadDiskSlot(slot: DiskSlot) {
+        val file = diskFile(slot) ?: run {
+            appendLog("Disk not found: ${slot.fileName}")
+            return
+        }
+        val ok = engine.loadDisk(file.absolutePath)
+        appendLog(if (ok) "Loaded: ${slot.fileName}" else "Load failed: ${slot.fileName}")
+    }
+
+    // ---- file import helpers ------------------------------------------------
+
+    private fun launchPicker(
+        launcher: ActivityResultLauncher<Intent>,
+        title: String,
+        multiSelect: Boolean = false
+    ) {
+        val intent = Intent(Intent.ACTION_OPEN_DOCUMENT).apply {
+            addCategory(Intent.CATEGORY_OPENABLE)
+            type = "*/*"
+            if (multiSelect) putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true)
+        }
+        launcher.launch(Intent.createChooser(intent, title))
+    }
+
+    private fun importFileToAssets(uri: Uri, fileName: String): File {
+        val assetDir = getExternalFilesDir(null) ?: filesDir
+        val dest = File(assetDir, fileName)
+        contentResolver.openInputStream(uri)?.use { input ->
+            dest.outputStream().use { output -> input.copyTo(output) }
+            Log.d(TAG, "Imported $uri → ${dest.absolutePath}")
+        } ?: appendLog("Could not open: $uri")
+        return dest
+    }
+
+    private fun displayNameForUri(uri: Uri): String? =
+        contentResolver.query(uri, arrayOf(OpenableColumns.DISPLAY_NAME), null, null, null)
+            ?.use { cursor -> if (cursor.moveToFirst()) cursor.getString(0) else null }
+
+    // ---- helpers ------------------------------------------------------------
 
     private fun appendLog(entry: String) {
         val ts = timeFormat.format(Date())

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

@@ -30,12 +30,98 @@
             android:textSize="12sp" />
     </LinearLayout>
 
+    <!-- Import buttons -->
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:layout_marginTop="4dp">
+
+        <Button
+            android:id="@+id/btn_import_roms"
+            android:layout_width="0dp"
+            android:layout_height="36dp"
+            android:layout_weight="1"
+            android:layout_marginEnd="2dp"
+            android:text="Import ROMs"
+            android:textSize="11sp"
+            style="?attr/materialButtonOutlinedStyle" />
+
+        <Button
+            android:id="@+id/btn_import_disks"
+            android:layout_width="0dp"
+            android:layout_height="36dp"
+            android:layout_weight="1"
+            android:layout_marginStart="2dp"
+            android:text="Import Disks"
+            android:textSize="11sp"
+            style="?attr/materialButtonOutlinedStyle" />
+
+    </LinearLayout>
+
+    <!-- Episode selector — row A (parts 1A–4A), row B (parts 1B–4B) -->
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="4dp"
+        android:text="Load episode:"
+        android:textColor="#888888"
+        android:textSize="11sp" />
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal">
+
+        <Button android:id="@+id/btn_ep_1a" style="?attr/materialButtonOutlinedStyle"
+            android:layout_width="0dp" android:layout_height="36dp" android:layout_weight="1"
+            android:layout_marginEnd="1dp" android:text="1A" android:textSize="11sp"
+            android:enabled="false" />
+        <Button android:id="@+id/btn_ep_2a" style="?attr/materialButtonOutlinedStyle"
+            android:layout_width="0dp" android:layout_height="36dp" android:layout_weight="1"
+            android:layout_marginStart="1dp" android:layout_marginEnd="1dp" android:text="2A" android:textSize="11sp"
+            android:enabled="false" />
+        <Button android:id="@+id/btn_ep_3a" style="?attr/materialButtonOutlinedStyle"
+            android:layout_width="0dp" android:layout_height="36dp" android:layout_weight="1"
+            android:layout_marginStart="1dp" android:layout_marginEnd="1dp" android:text="3A" android:textSize="11sp"
+            android:enabled="false" />
+        <Button android:id="@+id/btn_ep_4a" style="?attr/materialButtonOutlinedStyle"
+            android:layout_width="0dp" android:layout_height="36dp" android:layout_weight="1"
+            android:layout_marginStart="1dp" android:text="4A" android:textSize="11sp"
+            android:enabled="false" />
+    </LinearLayout>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:layout_marginTop="2dp">
+
+        <Button android:id="@+id/btn_ep_1b" style="?attr/materialButtonOutlinedStyle"
+            android:layout_width="0dp" android:layout_height="36dp" android:layout_weight="1"
+            android:layout_marginEnd="1dp" android:text="1B" android:textSize="11sp"
+            android:enabled="false" />
+        <Button android:id="@+id/btn_ep_2b" style="?attr/materialButtonOutlinedStyle"
+            android:layout_width="0dp" android:layout_height="36dp" android:layout_weight="1"
+            android:layout_marginStart="1dp" android:layout_marginEnd="1dp" android:text="2B" android:textSize="11sp"
+            android:enabled="false" />
+        <Button android:id="@+id/btn_ep_3b" style="?attr/materialButtonOutlinedStyle"
+            android:layout_width="0dp" android:layout_height="36dp" android:layout_weight="1"
+            android:layout_marginStart="1dp" android:layout_marginEnd="1dp" android:text="3B" android:textSize="11sp"
+            android:enabled="false" />
+        <Button android:id="@+id/btn_ep_4b" style="?attr/materialButtonOutlinedStyle"
+            android:layout_width="0dp" android:layout_height="36dp" android:layout_weight="1"
+            android:layout_marginStart="1dp" android:text="4B" android:textSize="11sp"
+            android:enabled="false" />
+    </LinearLayout>
+
     <!-- C64 display (320×200, scales to fill width, capped at 40 % of screen height) -->
     <de.ladkau.schwertundmagieonpebblecompanionapp.C64DisplayView
         android:id="@+id/c64_display"
         android:layout_width="match_parent"
         android:layout_height="0dp"
         android:layout_weight="3"
+        android:layout_marginTop="4dp"
         android:background="#000044" />
 
     <!-- Virtual keyboard -->