android fixes for mods and saves (#297)

docs/launcher.md

@@ -5,19 +5,39 @@ that runs before `Game:load`. Besides ROM import (see the file's own header)
 it hosts a tabbed shell covering per-game save slots and a mod manager. This
 file documents the runtime model; the visual spec lives separately.
 
-## Android multi-ROM import
+## Android multi-ROM / mod / save import
 
-On Android, `love.system.pickFile()` opens the Storage Access Framework
-picker (`GameActivity.showRomFilePicker`); the chosen file is copied to
-`picked_rom.gb` in the app save directory. `RomImporter` then imports on
-refocus / Choose via `findPendingRom`: only a 1 MiB `.gb` whose SHA-1 maps
-to a version that is **not** yet ready counts as pending. A leftover
+On Android, `love.system.pickFile([kind])` opens the Storage Access Framework
+picker (`GameActivity.showFilePicker`); the chosen file is copied into the app
+save directory as:
+
+| `kind` | Destination |
+| --- | --- |
+| nil / `"rom"` | `picked_rom.gb` (open) |
+| `"mod"` | `picked_mod.zip` (open) |
+| `"sav"` / `"save"` | `picked_save.sav` (open) |
+
+Export uses a separate API: `love.system.createFile(suggestedName)` →
+`GameActivity.showCreateDocument` (`ACTION_CREATE_DOCUMENT`), which copies
+staged `pending_export.sav` to the user-chosen URI and writes `export_done.flag`
+for the launcher to acknowledge on refocus.
+
+`RomImporter` then imports on refocus / Choose:
+
+- **ROMs** via `findPendingRom`: only a 1 MiB `.gb` whose SHA-1 maps to a
+  version that is **not** yet ready counts as pending. A leftover
   `picked_rom.gb` from Red therefore cannot block Blue's Choose (issue #167).
-After a successful import the consumed save-dir `.gb` is removed.
+- **Mods** via `findPendingMod`: Prefer `picked_mod.zip`, or (on Choose) any
+  other `.zip` at the save-dir root (USB copy).
+- **Saves** via `findPendingSav`: Prefer `picked_save.sav`, or (on Choose) any
+  other `.sav` at the save-dir root.
+
+After a successful import the consumed save-dir file is removed.
 
 **Manual check (device/emulator):** import Red → switch to Blue → Choose →
 system file picker must appear (not a silent Red re-extract) → pick Blue →
-Blue becomes ready beside Red.
+Blue becomes ready beside Red. On the MODS tab, Import mod .zip must open the
+same system picker and install the chosen archive on return.
 
 ## Tab structure
 
@@ -78,6 +98,10 @@ The launcher-facing API:
 - `SaveData.createSlot(version)` -> new slot id, registered but with **no
   save file written**. An empty slot means the title screen offers NEW GAME
   only, which needs no further changes.
+- `SaveData.deleteSlot(version, slotId)` removes the slot's
+  main/`.bak`/`.tmp` files, drops it from the registry, and if it was active
+  points active at another remaining slot (or clears active when the list is
+  empty). The launcher's SAVE SLOT panel Delete control calls this.
 
 ## Launcher mod manager
 
@@ -114,6 +138,9 @@ before `Game:load`, so **it never loads a mod's entry chunk**; only
   temp first (mount only reaches save-dir-relative paths), the same way
   `RomImporter` handles a dropped ROM. A failed copy rolls its partial tree
   back, and every path unmounts and clears the staged temp file.
+- `LauncherMods.uninstall(id)` removes `mods/<id>/` and clears
+  `options.mods[id]` so a later reinstall starts from the loader's default
+  (enabled). The mods panel Delete control calls this and re-derives the list.
 
 ## Import / Export save
 
@@ -122,9 +149,10 @@ through `src/import/SaveFileIO.lua`, which sits on top of
 `src/save_convert/SaveConvert.lua` and the slot API in `SaveData`.
 
 - **Import save** is live once the game's ROM is imported (playable). It opens
-  a native `.sav` picker (`chooseSav`, the per-OS dialogs mirror `chooseZip`;
-  Android has no picker and shows a drop hint). `SaveFileIO.importToSlot`
-  reads the bytes (an absolute path, a dropped LOVE file, or raw bytes),
+  a native `.sav` picker (`chooseSav` on desktop; on Android,
+  `love.system.pickFile("sav")` → `picked_save.sav`, same SAF path as ROMs).
+  `SaveFileIO.importToSlot` reads the bytes (an absolute path, a save-dir
+  relative name, a dropped LOVE file, or raw bytes),
   guards the 32768-byte size, runs `SaveConvert.importSav` (which also rejects
   a bad main-data checksum), then registers a fresh slot (`SaveData.createSlot`),
   writes it (`SaveData.writeSlot`), and makes it active (`SaveData.setActiveSlot`).
@@ -136,9 +164,13 @@ through `src/import/SaveFileIO.lua`, which sits on top of
   slot, encodes it back with `SaveConvert.exportSav` (a slot never keeps
   `rawImport`, so this is a zero-filled template export, which is valid), and
   writes `exports/gen1recomp-<version>-<slotId>.sav` in the save directory
-  (`love.filesystem.createDirectory("exports")`). It returns the absolute path
-  (`love.filesystem.getSaveDirectory()`), which the notice line shows with a
-  desktop "Open folder" affordance (`love.system.openURL("file://" .. dir)`).
+  (`love.filesystem.createDirectory("exports")`). On desktop it returns the
+  absolute path (`love.filesystem.getSaveDirectory()`), which the notice line
+  shows with an "Open folder" affordance (`love.system.openURL("file://" .. dir)`).
+  On Android the bytes are also staged as `pending_export.sav` and
+  `love.system.createFile(suggestedName)` opens `ACTION_CREATE_DOCUMENT` so the
+  player can save to Downloads / Drive / etc.; on return `export_done.flag`
+  makes focus show "Save exported."
 - **Drag-drop.** `filedropped` routes a `.sav` to the import path for the
   currently active game tab; when a non-game tab (mods, or the locked yellow
   placeholder) is showing it defaults to red, the always-present first game

mobile/ANDROID.md

@@ -43,11 +43,11 @@ The embedded `game.love` deliberately excludes `data/generated/`,
 `assets/generated/`, and any ROM. It contains the first-boot Lua importer and
 `tools/rom_manifest.json`.
 
-ROM import on Android uses `love.system.pickFile()` →
-`GameActivity.showRomFilePicker` (Storage Access Framework), which copies the
-chosen file to `picked_rom.gb` under the app save directory. `RomImporter`
-imports pending (not-yet-ready) `.gb` files from that folder on Choose /
-refocus; see `docs/launcher.md` (Android multi-ROM import). The APK payload
+ROM / mod / save import on Android uses `love.system.pickFile([kind])` →
+`GameActivity.showFilePicker` (Storage Access Framework), which copies the
+chosen file under the app save directory as `picked_rom.gb`,
+`picked_mod.zip`, or `picked_save.sav`. `RomImporter` imports pending files
+from that folder on Choose / refocus; see `docs/launcher.md`. The APK payload
 itself remains data-free (no embedded ROM or generated cache).
 
 ### SDK / NDK

mobile/android/gradle.properties

@@ -18,4 +18,4 @@ android.useAndroidX=true
 android.defaults.buildfeatures.buildconfig=true
 android.nonTransitiveRClass=true
 android.nonFinalResIds=true
-app.name=Pokemon Red
+app.name=gen1recomp

mobile/android/love/src/jni/love/src/common/android.cpp

@@ -183,13 +183,37 @@ void vibrate(double seconds)
 	env->DeleteLocalRef(activity);
 }
 
-bool showFilePicker()
+bool showFilePicker(const char *destFilename)
 {
+	if (destFilename == nullptr || destFilename[0] == '\0')
+		destFilename = "picked_rom.gb";
+
 	JNIEnv *env = (JNIEnv*) SDL_AndroidGetJNIEnv();
 	jclass activity = env->FindClass("org/love2d/android/GameActivity");
 
-	jmethodID method = env->GetStaticMethodID(activity, "showRomFilePicker", "()Z");
-	jboolean result = env->CallStaticBooleanMethod(activity, method);
+	jmethodID method = env->GetStaticMethodID(activity, "showFilePicker",
+		"(Ljava/lang/String;)Z");
+	jstring jname = env->NewStringUTF(destFilename);
+	jboolean result = env->CallStaticBooleanMethod(activity, method, jname);
+	env->DeleteLocalRef(jname);
+
+	env->DeleteLocalRef(activity);
+	return result;
+}
+
+bool showCreateDocument(const char *suggestedName)
+{
+	if (suggestedName == nullptr || suggestedName[0] == '\0')
+		suggestedName = "export.sav";
+
+	JNIEnv *env = (JNIEnv*) SDL_AndroidGetJNIEnv();
+	jclass activity = env->FindClass("org/love2d/android/GameActivity");
+
+	jmethodID method = env->GetStaticMethodID(activity, "showCreateDocument",
+		"(Ljava/lang/String;)Z");
+	jstring jname = env->NewStringUTF(suggestedName);
+	jboolean result = env->CallStaticBooleanMethod(activity, method, jname);
+	env->DeleteLocalRef(jname);
 
 	env->DeleteLocalRef(activity);
 	return result;

mobile/android/love/src/jni/love/src/common/android.h

@@ -63,9 +63,16 @@ void vibrate(double seconds);
  * Shows the system's "pick a document" UI (Storage Access Framework).
  * Returns true if the picker was launched; the picked file (if any) is
  * copied asynchronously by GameActivity.onActivityResult into the app's
- * external save directory, not returned here -- see src/import/RomImporter.lua.
+ * external save directory under destFilename (default picked_rom.gb), not
+ * returned here -- see src/import/RomImporter.lua.
  **/
-bool showFilePicker();
+bool showFilePicker(const char *destFilename = nullptr);
+
+/**
+ * Shows ACTION_CREATE_DOCUMENT so Lua can export a staged pending_export.sav
+ * to a user-chosen location. suggestedName is the dialog default filename.
+ **/
+bool showCreateDocument(const char *suggestedName = nullptr);
 
 /*
  * Helper functions for the filesystem module

mobile/android/love/src/jni/love/src/modules/system/System.cpp

@@ -22,6 +22,8 @@
 #include "common/config.h"
 #include "System.h"
 
+#include <cstring>
+
 #if defined(LOVE_MACOSX)
 #include <CoreServices/CoreServices.h>
 #elif defined(LOVE_IOS)
@@ -180,11 +182,32 @@ void System::vibrate(double seconds) const
 #endif
 }
 
-bool System::pickFile() const
+bool System::pickFile(const char *kind) const
 {
 #ifdef LOVE_ANDROID
-	return love::android::showFilePicker();
+	const char *dest = "picked_rom.gb";
+	if (kind != nullptr)
+	{
+		if (strcmp(kind, "mod") == 0)
+			dest = "picked_mod.zip";
+		else if (strcmp(kind, "sav") == 0 || strcmp(kind, "save") == 0)
+			dest = "picked_save.sav";
+		else if (strcmp(kind, "rom") == 0)
+			dest = "picked_rom.gb";
+	}
+	return love::android::showFilePicker(dest);
 #else
+	LOVE_UNUSED(kind);
+	return false;
+#endif
+}
+
+bool System::createFile(const char *suggestedName) const
+{
+#ifdef LOVE_ANDROID
+	return love::android::showCreateDocument(suggestedName);
+#else
+	LOVE_UNUSED(suggestedName);
 	return false;
 #endif
 }

mobile/android/love/src/jni/love/src/modules/system/System.h

@@ -111,9 +111,21 @@ public:
 	 * Android only for now; the result (if any) is not returned here -- see
 	 * love::android::showFilePicker and src/import/RomImporter.lua.
 	 *
+	 * @param kind Optional pick kind: nullptr/"rom" -> picked_rom.gb,
+	 *             "mod" -> picked_mod.zip, "sav"/"save" -> picked_save.sav.
 	 * @return Whether the picker was shown.
 	 **/
-	virtual bool pickFile() const;
+	virtual bool pickFile(const char *kind = nullptr) const;
+
+	/**
+	 * Shows the platform's native "create / save a file" UI (Android SAF
+	 * ACTION_CREATE_DOCUMENT). Copies staged pending_export.sav from the app
+	 * save directory to the user-chosen URI. See GameActivity.showCreateDocument.
+	 *
+	 * @param suggestedName Default filename shown in the dialog.
+	 * @return Whether the create dialog was shown.
+	 **/
+	virtual bool createFile(const char *suggestedName = nullptr) const;
 
 	/**
 	 * Gets if the user is playing music on background.

mobile/android/love/src/jni/love/src/modules/system/wrap_System.cpp

@@ -97,7 +97,15 @@ int w_vibrate(lua_State *L)
 
 int w_pickFile(lua_State *L)
 {
-	luax_pushboolean(L, instance()->pickFile());
+	const char *kind = luaL_optstring(L, 1, nullptr);
+	luax_pushboolean(L, instance()->pickFile(kind));
+	return 1;
+}
+
+int w_createFile(lua_State *L)
+{
+	const char *suggested = luaL_optstring(L, 1, nullptr);
+	luax_pushboolean(L, instance()->createFile(suggested));
 	return 1;
 }
 
@@ -117,6 +125,7 @@ static const luaL_Reg functions[] =
 	{ "openURL", w_openURL },
 	{ "vibrate", w_vibrate },
 	{ "pickFile", w_pickFile },
+	{ "createFile", w_createFile },
 	{ "hasBackgroundMusic", w_hasBackgroundMusic },
 	{ 0, 0 }
 };

mobile/android/love/src/main/java/org/love2d/android/GameActivity.java

@@ -22,12 +22,15 @@ package org.love2d.android;
 
 import org.libsdl.app.SDLActivity;
 
+import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.File;
+import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -61,13 +64,24 @@ public class GameActivity extends SDLActivity {
     protected final int[] recordAudioRequestDummy = new int[1];
     public static final int EXTERNAL_STORAGE_REQUEST_CODE = 2;
     public static final int RECORD_AUDIO_REQUEST_CODE = 3;
-    public static final int ROM_PICKER_REQUEST_CODE = 4;
-    // Mirrors conf.lua's t.identity ("pokemon-love2d"): where the picked ROM
+    public static final int FILE_PICKER_REQUEST_CODE = 4;
+    public static final int FILE_CREATE_REQUEST_CODE = 5;
+    /** @deprecated Prefer FILE_PICKER_REQUEST_CODE; kept for older call sites. */
+    public static final int ROM_PICKER_REQUEST_CODE = FILE_PICKER_REQUEST_CODE;
+    // Mirrors conf.lua's t.identity ("pokemon-love2d"): where the picked file
     // is dropped so RomImporter's existing folder scan finds it -- see
     // src/import/RomImporter.lua and Filesystem::setIdentity (sets Android's
     // save directory to getExternalFilesDir()/save/<identity>).
     private static final String ROM_SAVE_IDENTITY = "pokemon-love2d";
     private static final String PICKED_ROM_FILENAME = "picked_rom.gb";
+    private static final String PICKED_MOD_FILENAME = "picked_mod.zip";
+    private static final String PICKED_SAVE_FILENAME = "picked_save.sav";
+    private static final String PENDING_EXPORT_FILENAME = "pending_export.sav";
+    private static final String EXPORT_DONE_FILENAME = "export_done.flag";
+    // Destination basename for the in-flight SAF pick (set by showFilePicker).
+    private String pendingPickFilename = PICKED_ROM_FILENAME;
+    // Suggested download name for the in-flight SAF create (set by showCreateDocument).
+    private String pendingCreateSuggestedName = "export.sav";
     private static boolean immersiveActive = false;
     private static boolean needToCopyGameInArchive = false;
     private boolean storagePermissionUnnecessary = false;
@@ -341,59 +355,185 @@ public class GameActivity extends SDLActivity {
 
     /**
      * Shows the system document picker (Storage Access Framework) so the
-     * player can pick their ROM from anywhere (Downloads, Drive, etc.)
-     * without needing to know where the app's external files folder is.
-     * Requires API 19+ (ACTION_OPEN_DOCUMENT); the picked file (if any)
+     * player can pick a ROM / mod / save from anywhere (Downloads, Drive,
+     * etc.) without needing to know where the app's external files folder
+     * is. Requires API 19+ (ACTION_OPEN_DOCUMENT); the picked file (if any)
      * arrives later in onActivityResult, not synchronously here.
+     *
+     * @param destFilename basename under the app save identity (e.g.
+     *                     picked_rom.gb, picked_mod.zip, picked_save.sav)
      */
     @Keep
-    public static boolean showRomFilePicker() {
+    public static boolean showFilePicker(String destFilename) {
         if (android.os.Build.VERSION.SDK_INT < 19) return false;
         GameActivity self = (GameActivity) mSingleton;
         if (self == null) return false;
+        if (destFilename == null || destFilename.length() == 0) {
+            destFilename = PICKED_ROM_FILENAME;
+        }
+        // Reject path separators so a hostile JNI caller cannot escape the
+        // save identity directory.
+        if (destFilename.indexOf('/') >= 0 || destFilename.indexOf('\\') >= 0) {
+            Log.d("GameActivity", "refusing unsafe picker dest: " + destFilename);
+            return false;
+        }
 
+        self.pendingPickFilename = destFilename;
         Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
         intent.addCategory(Intent.CATEGORY_OPENABLE);
         intent.setType("*/*");
         try {
-            self.startActivityForResult(intent, ROM_PICKER_REQUEST_CODE);
+            self.startActivityForResult(intent, FILE_PICKER_REQUEST_CODE);
             return true;
         } catch (Exception e) {
-            Log.d("GameActivity", "could not open ROM file picker: " + e.getMessage());
+            Log.d("GameActivity", "could not open file picker: " + e.getMessage());
             return false;
         }
     }
 
+    /** ROM convenience wrapper; prefer showFilePicker with an explicit name. */
+    @Keep
+    public static boolean showRomFilePicker() {
+        return showFilePicker(PICKED_ROM_FILENAME);
+    }
+
+    /** Mod .zip convenience wrapper used by love.system.pickFile("mod"). */
+    @Keep
+    public static boolean showModFilePicker() {
+        return showFilePicker(PICKED_MOD_FILENAME);
+    }
+
+    /** Battery .sav convenience wrapper used by love.system.pickFile("sav"). */
+    @Keep
+    public static boolean showSaveFilePicker() {
+        return showFilePicker(PICKED_SAVE_FILENAME);
+    }
+
+    /**
+     * Shows ACTION_CREATE_DOCUMENT so the player can save a staged export
+     * (pending_export.sav in the app save identity) to Downloads / Drive /
+     * etc. Suggested name is the dialog's default filename.
+     */
+    @Keep
+    public static boolean showCreateDocument(String suggestedName) {
+        if (android.os.Build.VERSION.SDK_INT < 19) return false;
+        GameActivity self = (GameActivity) mSingleton;
+        if (self == null) return false;
+        if (suggestedName == null || suggestedName.length() == 0) {
+            suggestedName = "export.sav";
+        }
+        if (suggestedName.indexOf('/') >= 0 || suggestedName.indexOf('\\') >= 0) {
+            Log.d("GameActivity", "refusing unsafe create name: " + suggestedName);
+            return false;
+        }
+        File source = new File(
+            new File(self.getExternalFilesDir(null), "save"),
+            ROM_SAVE_IDENTITY + "/" + PENDING_EXPORT_FILENAME);
+        if (!source.isFile()) {
+            Log.d("GameActivity", "no pending export at " + source);
+            return false;
+        }
+
+        self.pendingCreateSuggestedName = suggestedName;
+        Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
+        intent.addCategory(Intent.CATEGORY_OPENABLE);
+        intent.setType("application/octet-stream");
+        intent.putExtra(Intent.EXTRA_TITLE, suggestedName);
+        try {
+            self.startActivityForResult(intent, FILE_CREATE_REQUEST_CODE);
+            return true;
+        } catch (Exception e) {
+            Log.d("GameActivity", "could not open create-document picker: " + e.getMessage());
+            return false;
+        }
+    }
+
+    private File saveIdentityDir() {
+        return new File(new File(getExternalFilesDir(null), "save"), ROM_SAVE_IDENTITY);
+    }
+
+    private boolean copyFileToUri(File source, Uri destUri) {
+        InputStream in = null;
+        OutputStream out = null;
+        try {
+            in = new BufferedInputStream(new FileInputStream(source));
+            out = getContentResolver().openOutputStream(destUri);
+            if (out == null) return false;
+            byte[] buf = new byte[8192];
+            int n;
+            while ((n = in.read(buf)) != -1) {
+                out.write(buf, 0, n);
+            }
+            out.flush();
+            return true;
+        } catch (IOException e) {
+            Log.d("GameActivity", "copy to URI failed: " + e.getMessage());
+            return false;
+        } finally {
+            try { if (in != null) in.close(); } catch (IOException ignored) {}
+            try { if (out != null) out.close(); } catch (IOException ignored) {}
+        }
+    }
+
     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
         super.onActivityResult(requestCode, resultCode, data);
-        if (requestCode != ROM_PICKER_REQUEST_CODE) return;
+        if (requestCode == FILE_CREATE_REQUEST_CODE) {
             if (resultCode != RESULT_OK || data == null || data.getData() == null) {
-            Log.d("GameActivity", "ROM picker returned no file (cancelled?)");
+                Log.d("GameActivity", "create-document cancelled");
+                return;
+            }
+            File source = new File(saveIdentityDir(), PENDING_EXPORT_FILENAME);
+            if (!source.isFile()) {
+                Log.d("GameActivity", "pending export missing at result time");
+                return;
+            }
+            Uri uri = data.getData();
+            if (copyFileToUri(source, uri)) {
+                // Signal Lua on next focus that the SAF export finished.
+                File flag = new File(saveIdentityDir(), EXPORT_DONE_FILENAME);
+                try {
+                    FileOutputStream fos = new FileOutputStream(flag, false);
+                    fos.write("ok".getBytes());
+                    fos.close();
+                } catch (IOException e) {
+                    Log.d("GameActivity", "could not write export_done flag: " + e.getMessage());
+                }
+                // Keep pending_export.sav so a retry still works; Lua may remove it.
+            } else {
+                Log.d("GameActivity", "could not write export to " + uri);
+            }
+            return;
+        }
+        if (requestCode != FILE_PICKER_REQUEST_CODE) return;
+        if (resultCode != RESULT_OK || data == null || data.getData() == null) {
+            Log.d("GameActivity", "file picker returned no file (cancelled?)");
             return;
         }
 
         Uri uri = data.getData();
-        File destDir = new File(new File(getExternalFilesDir(null), "save"), ROM_SAVE_IDENTITY);
+        File destDir = saveIdentityDir();
         if (!destDir.exists() && !destDir.mkdirs()) {
             Log.d("GameActivity", "could not create " + destDir);
             return;
         }
-        File destFile = new File(destDir, PICKED_ROM_FILENAME);
+        String destName = pendingPickFilename != null
+            ? pendingPickFilename : PICKED_ROM_FILENAME;
+        File destFile = new File(destDir, destName);
 
         InputStream source;
         try {
             source = getContentResolver().openInputStream(uri);
         } catch (FileNotFoundException e) {
-            Log.d("GameActivity", "could not open picked ROM: " + e.getMessage());
+            Log.d("GameActivity", "could not open picked file: " + e.getMessage());
             return;
         }
         if (source == null) {
-            Log.d("GameActivity", "ContentResolver returned no stream for picked ROM");
+            Log.d("GameActivity", "ContentResolver returned no stream for picked file");
             return;
         }
         if (!copyAssetFile(source, destFile.getPath())) {
-            Log.d("GameActivity", "could not copy picked ROM to " + destFile);
+            Log.d("GameActivity", "could not copy picked file to " + destFile);
         }
     }
 

src/core/SaveData.lua

@@ -552,6 +552,44 @@ function SaveData.writeSlot(version, slotId, saveTable)
   return true
 end
 
+-- Delete a registered slot: remove its main/.bak/.tmp files, drop it from the
+-- options registry, and if it was active point active at another remaining
+-- slot (or clear active when the list is empty).  Returns true, or false +
+-- an error string when the id is unknown / not registered.
+function SaveData.deleteSlot(version, slotId)
+  version = version or GameVersion.get()
+  if not knownVersion(version) then return false, "unknown version" end
+  if type(slotId) ~= "string" or slotId == "" then
+    return false, "missing slot id"
+  end
+  local fs = persistFs(nil)
+  ensureVersionSlots(version, fs)
+  local opts = SaveData.loadOptions(fs)
+  opts.saveSlots = opts.saveSlots or {}
+  local reg = opts.saveSlots[version]
+  if not reg or not reg.list then return false, "slot not registered" end
+  local found, idx = false, nil
+  for i, id in ipairs(reg.list) do
+    if id == slotId then found = true; idx = i; break end
+  end
+  if not found then return false, "slot not registered" end
+
+  local main, bak, tmp = slotNames(version, slotId)
+  remove(fs, main)
+  remove(fs, bak)
+  remove(fs, tmp)
+
+  table.remove(reg.list, idx)
+  if reg.active == slotId then
+    reg.active = reg.list[1]  -- may be nil when the list is now empty
+  end
+  opts.saveSlots[version] = reg
+  SaveData.saveOptions(opts, fs)
+  slotsChecked[version] = true
+  activeSlotCache[version] = reg.active or false
+  return true
+end
+
 -- Test seam: drop the process-global slot cache so a suite can exercise
 -- migration/resolution against a freshly injected filesystem.  Unused by
 -- the game, which resolves each version exactly once per boot.

src/import/RomImporter.lua

@@ -290,6 +290,39 @@ local function findPendingRom(ready)
   return nil
 end
 
+-- Android SAF writes mod picks to picked_mod.zip; USB copies may use any
+-- .zip basename at the save-dir root.  preferAny=true also accepts those USB
+-- copies (Choose / Import); focus only consumes the SAF basename so a random
+-- leftover archive is never auto-installed on every refocus.
+local function findPendingMod(preferAny)
+  local preferred = "picked_mod.zip"
+  if love.filesystem.getInfo(preferred, "file") then
+    return preferred
+  end
+  if not preferAny then return nil end
+  for _, name in ipairs(love.filesystem.getDirectoryItems("")) do
+    if name:lower():match("%.zip$") and love.filesystem.getInfo(name, "file") then
+      return name
+    end
+  end
+  return nil
+end
+
+-- Same pattern as findPendingMod for battery saves (picked_save.sav / *.sav).
+local function findPendingSav(preferAny)
+  local preferred = "picked_save.sav"
+  if love.filesystem.getInfo(preferred, "file") then
+    return preferred
+  end
+  if not preferAny then return nil end
+  for _, name in ipairs(love.filesystem.getDirectoryItems("")) do
+    if name:lower():match("%.sav$") and love.filesystem.getInfo(name, "file") then
+      return name
+    end
+  end
+  return nil
+end
+
 local function chooseRom(promptName)
   promptName = promptName or "Pokemon"
   local prompt = "Choose your " .. promptName .. " ROM"
@@ -320,8 +353,8 @@ local function chooseRom(promptName)
 end
 
 -- Open a native picker for a mod .zip (mirrors chooseRom's per-OS dialogs).
--- Returns the chosen absolute path or nil.  Android has no picker; the mods
--- panel steers that case to the drag-drop hint instead.
+-- Returns the chosen absolute path or nil.  Android uses love.system.pickFile
+-- ("mod") instead -- see RomImporter:chooseMod.
 local function chooseZip()
   local prompt = "Choose a mod .zip"
   local platform = love.system.getOS()
@@ -351,8 +384,8 @@ local function chooseZip()
 end
 
 -- Open a native picker for a raw .sav battery save (mirrors chooseZip's per-OS
--- dialogs).  Returns the chosen absolute path or nil.  Android has no picker;
--- the SAVE FILES card steers that case to the drag-drop hint instead.
+-- dialogs).  Returns the chosen absolute path or nil.  Android uses
+-- love.system.pickFile("sav") instead -- see RomImporter:chooseSaveImport.
 local function chooseSav()
   local prompt = "Choose a .sav save file"
   local platform = love.system.getOS()
@@ -429,10 +462,16 @@ function RomImporter.new(onComplete, opts)
     -- affordance (desktop love.system.openURL).
     saveNotice = {},
     -- MODS panel state (pass 3): mods is the cached LauncherMods.list() array
-    -- (refreshed lazily on first draw and after any toggle/install); modScroll
-    -- is the list scroll offset (px, clamped in draw); modNotice is the last
-    -- install result { ok, text } shown as a line above the list.
+    -- (refreshed lazily on first draw and after any toggle/install/delete);
+    -- modScroll is the list scroll offset (px, clamped in draw); modNotice is
+    -- the last install/delete result { ok, text } shown as a line above the list.
     mods = nil, modScroll = 0, modNotice = nil,
+    -- Android SAF: which game tab should receive the next picked_save.sav when
+    -- focus consumes it (set by chooseSaveImport before opening the picker).
+    androidPendingVersion = nil,
+    -- Android SAF create-document: which game's SAVE FILES card should show
+    -- "Save exported." when export_done.flag appears on focus.
+    androidPendingExportVersion = nil,
   }, RomImporter)
 
   for _, version in ipairs(GameVersion.ORDER) do
@@ -491,10 +530,40 @@ end
 -- The system picker runs as a separate top activity, so LOVE's own
 -- love.focus/love.visible pause while it's up (see main.lua) -- once the
 -- player returns here with a file picked, GameActivity has already copied
--- it into the save directory, so a pending-ROM rescan on refocus picks it
--- up without the player needing to tap the button again.
+-- it into the save directory, so a pending-file rescan on refocus picks it
+-- up without the player needing to tap the button again.  Mod and save SAF
+-- drops (picked_mod.zip / picked_save.sav) are consumed first so a leftover
+-- ROM pick cannot steal the focus path when both games are already ready.
 function RomImporter:focus(f)
   if not (f and self.android and self.workState ~= "working") then return end
+  -- SAF create-document finished: GameActivity wrote export_done.flag.
+  if love.filesystem.getInfo("export_done.flag", "file") then
+    love.filesystem.remove("export_done.flag")
+    love.filesystem.remove("pending_export.sav")
+    local version = self.androidPendingExportVersion or self:_savedropTarget()
+    self.androidPendingExportVersion = nil
+    self.saveNotice[version] = { ok = true, text = "Save exported." }
+    if self.tab == "mods" or self.tab == "yellow" then self.tab = version end
+    return
+  end
+  local modName = findPendingMod(false)
+  if modName then
+    self:_installMod(modName)
+    if self.modNotice and self.modNotice.ok then
+      love.filesystem.remove(modName)
+    end
+    return
+  end
+  local savName = findPendingSav(false)
+  if savName then
+    local version = self.androidPendingVersion or self:_savedropTarget()
+    self.androidPendingVersion = nil
+    self:_importSave(version, savName)
+    if self.saveNotice[version] and self.saveNotice[version].ok then
+      love.filesystem.remove(savName)
+    end
+    return
+  end
   if self.ready.red and self.ready.blue then return end
   local name, data = findPendingRom(self.ready)
   if name then self:startData(data, name) end
@@ -672,13 +741,38 @@ function RomImporter:_installMod(source)
   self.tab = "mods"
 end
 
--- "Import mod .zip" button: open a native picker (desktop) and install the
--- pick.  Android has no picker, so it points the player at the drop path.
+-- Remove an installed mod from the save-dir mods/ tree and refresh the panel.
+function RomImporter:_deleteMod(id)
+  if self.workState == "working" then return end
+  local LauncherMods = require("src.mods.LauncherMods")
+  local ok, res = LauncherMods.uninstall(id)
+  if ok then
+    self:_refreshMods()
+    self.modNotice = { ok = true, text = "Deleted " .. tostring(id) }
+  else
+    self.modNotice = { ok = false, text = tostring(res) }
+  end
+end
+
+-- "Import mod .zip" button: open a native picker and install the pick.
+-- Android mirrors ROM import: scan for a pending .zip in the save dir (USB
+-- or a fresh SAF drop), else love.system.pickFile("mod") -> picked_mod.zip
+-- which focus/Choose consumes on return.
 function RomImporter:chooseMod()
   if self.workState == "working" then return end
   if self.android then
-    self.modNotice =
-      { ok = false, text = "Drop a mod .zip onto the window to install it." }
+    local name = findPendingMod(true)
+    if name then
+      self:_installMod(name)
+      if self.modNotice and self.modNotice.ok then
+        love.filesystem.remove(name)
+      end
+      return
+    end
+    if not love.system.pickFile("mod") then
+      self.modNotice = { ok = false,
+        text = "Could not open the file picker. Copy a mod .zip via USB." }
+    end
     return
   end
   local path = chooseZip()
@@ -722,13 +816,26 @@ function RomImporter:_importSave(version, source)
   end
 end
 
--- "Import save" button: open a native .sav picker (desktop) and import the pick.
--- Android has no picker, so it points the player at the drop path.
+-- "Import save" button: open a native .sav picker and import the pick.
+-- Android mirrors ROM / mod import via love.system.pickFile("sav").
 function RomImporter:chooseSaveImport(version)
   if self.workState == "working" then return end
   if self.android then
-    self.saveNotice[version] =
-      { ok = false, text = "Drop a .sav onto the window to import it." }
+    local name = findPendingSav(true)
+    if name then
+      self.androidPendingVersion = version
+      self:_importSave(version, name)
+      if self.saveNotice[version] and self.saveNotice[version].ok then
+        love.filesystem.remove(name)
+      end
+      return
+    end
+    self.androidPendingVersion = version
+    if not love.system.pickFile("sav") then
+      self.androidPendingVersion = nil
+      self.saveNotice[version] = { ok = false,
+        text = "Could not open the file picker. Copy a .sav via USB." }
+    end
     return
   end
   local path = chooseSav()
@@ -736,16 +843,58 @@ function RomImporter:chooseSaveImport(version)
 end
 
 -- "Export save" button: write the active slot back out to a raw .sav in the save
--- directory's exports/ folder and show the path (with an open-folder affordance)
--- on the SAVE FILES card.
+-- directory's exports/ folder.  On desktop, show the path with an open-folder
+-- affordance.  On Android, stage pending_export.sav and open the system
+-- create-document picker (love.system.createFile) so the player can save to
+-- Downloads / Drive / etc. -- the app-private exports/ path is not useful there.
 function RomImporter:exportSave(version)
   if self.workState == "working" then return end
   local ok, res = require("src.import.SaveFileIO").exportActiveSlot(version)
-  if ok then
+  if not ok then
+    self.saveNotice[version] = { ok = false, text = tostring(res) }
+    return
+  end
+  if self.android then
+    local rel = res:match("exports[/\\][^/\\]+$")
+    local data = rel and love.filesystem.read(rel)
+    if not data then
+      self.saveNotice[version] = { ok = false,
+        text = "Exported, but could not stage the file for the picker." }
+      return
+    end
+    local suggested = rel:match("[^/\\]+$") or "export.sav"
+    local wrote, writeErr = love.filesystem.write("pending_export.sav", data)
+    if not wrote then
+      self.saveNotice[version] = { ok = false,
+        text = "Could not stage the export: " .. tostring(writeErr) }
+      return
+    end
+    self.androidPendingExportVersion = version
+    if love.system.createFile and love.system.createFile(suggested) then
+      self.saveNotice[version] = { ok = true,
+        text = "Pick where to save " .. suggested .. "..." }
+    else
+      self.androidPendingExportVersion = nil
+      self.saveNotice[version] = { ok = true,
+        text = "Exported inside the app folder (picker unavailable)." }
+    end
+    return
+  end
   local dir = res:match("^(.*)[/\\][^/\\]+$")
   self.saveNotice[version] = { ok = true, text = "Exported to " .. res, dir = dir }
+end
+
+-- Delete a save slot from the registry and disk, then refresh the panel.  If the
+-- deleted slot was active, SaveData.deleteSlot points active at another slot.
+function RomImporter:_deleteSlot(version, id)
+  if self.workState == "working" then return end
+  local SaveData = require("src.core.SaveData")
+  local ok, err = SaveData.deleteSlot(version, id)
+  if ok then
+    self:_refreshSlots(version)
+    self.saveNotice[version] = { ok = true, text = "Deleted " .. tostring(id) .. "." }
   else
-    self.saveNotice[version] = { ok = false, text = tostring(res) }
+    self.saveNotice[version] = { ok = false, text = tostring(err) }
   end
 end
 
@@ -1427,9 +1576,17 @@ function RomImporter:mousepressed(x, y, button)
     end
     return
   end
-  -- SAVE SLOT rows.  On desktop a press only ARMS a click: _updateSlotDrag
-  -- commits it on release when the pointer did not move (a moved pointer scrolls
-  -- instead).  Android has no reliable pointer polling, so it selects on press.
+  -- SAVE SLOT rows / Delete.  Delete is checked first so a tap on the Delete
+  -- label never also selects the row.  On desktop a press only ARMS a click:
+  -- _updateSlotDrag commits it on release when the pointer did not move (a
+  -- moved pointer scrolls instead).  Android has no reliable pointer polling,
+  -- so it selects on press.  Delete fires immediately (small fixed target).
+  for _, r in ipairs(self.slotDeleteRects or {}) do
+    if inside(r, x, y) then
+      self:_deleteSlot(self.panelVersion, r.id)
+      return
+    end
+  end
   for _, r in ipairs(self.slotRects or {}) do
     if inside(r, x, y) then
       if self.android then
@@ -1445,12 +1602,18 @@ function RomImporter:mousepressed(x, y, button)
     self:_newSlot(self.panelVersion); return
   end
   -- Mods panel: the import button dispatches on press (fixed header, no scroll
-  -- conflict); a toggle switch, which lives in the scrollable list, only ARMS a
-  -- press so _updateSlotDrag can tell a click from a drag-scroll (Android, with
-  -- no pointer polling, toggles on press).
+  -- conflict); Delete fires immediately; a toggle switch, which lives in the
+  -- scrollable list, only ARMS a press so _updateSlotDrag can tell a click from
+  -- a drag-scroll (Android, with no pointer polling, toggles on press).
   if inside(self.modImportRect, x, y) then
     self:chooseMod(); return
   end
+  for _, r in ipairs(self.modDeleteRects or {}) do
+    if inside(r, x, y) then
+      self:_deleteMod(r.id)
+      return
+    end
+  end
   for _, r in ipairs(self.modRects or {}) do
     if inside(r, x, y) then
       if self.android then
@@ -1759,7 +1922,8 @@ function RomImporter:_drawGamePanel(version, x, y, w, h)
   elseif locked then
     sfHintText, sfHintCol = "Not available yet.", PAL.warning
   elseif self.android then
-    sfHintText, sfHintCol = "Import a .sav, or drop one on the window.", PAL.warning
+    sfHintText, sfHintCol =
+      "Import or export a .sav with the system file picker.", PAL.warning
   else
     sfHintText, sfHintCol =
       "Import a .sav to a new slot, or export the active slot.", PAL.warning
@@ -1999,6 +2163,8 @@ function RomImporter:_drawSaveSlotPanel(version, x, y, w, h)
     love.graphics.printf("No saves yet - start a new game or import one.",
       rx + 12 * s, listTop + listH / 2 - self.hintFont:getHeight() / 2,
       rw - 24 * s, "center")
+    self.slotRects = {}
+    self.slotDeleteRects = {}
   elseif listH > 0 then
     local nameH = self.slotNameFont:getHeight()
     local metaH = self.labelFont:getHeight()
@@ -2017,6 +2183,7 @@ function RomImporter:_drawSaveSlotPanel(version, x, y, w, h)
     self.slotScroll[version] = scroll
 
     self.slotRects = {}
+    self.slotDeleteRects = {}
     love.graphics.setScissor(math.floor(rx), math.floor(listTop),
       math.ceil(rw), math.ceil(listH))
     for i, slot in ipairs(slots) do
@@ -2029,6 +2196,20 @@ function RomImporter:_drawSaveSlotPanel(version, x, y, w, h)
         col(selected and PAL.green or PAL.cardBorder, selected and 0.9 or 0.22)
         love.graphics.rectangle("line", rx, ry, rw, rowH, rr, rr)
 
+        -- Delete label (bottom-right); reserve its width so name/meta don't overlap
+        love.graphics.setFont(self.hintFont)
+        local delText = "Delete"
+        local delW = self.hintFont:getWidth(delText)
+        local delH = self.hintFont:getHeight()
+        local delX = rx + rw - 12 * s - delW
+        local delY = ry + rowH - rowPadV - delH
+        local drect = { x = delX - 6 * s, y = delY - 4 * s,
+          width = delW + 12 * s, height = delH + 8 * s, id = slot.id }
+        local dhot = self:_hover(drect)
+        col(dhot and PAL.red or PAL.warning)
+        love.graphics.print(delText, delX, delY)
+        local rightReserve = delW + 18 * s
+
         -- LOADED pill (top-right of the active row), then reserve its width
         local pillW = 0
         if selected then
@@ -2048,7 +2229,7 @@ function RomImporter:_drawSaveSlotPanel(version, x, y, w, h)
         love.graphics.setFont(self.slotNameFont)
         col(PAL.white)
         local name = slot.name or "NEW GAME"
-        printB(ellipsize(self.slotNameFont, name, rw - 24 * s - pillW),
+        printB(ellipsize(self.slotNameFont, name, rw - 24 * s - math.max(pillW, rightReserve)),
           rx + 12 * s, ry + rowPadV)
 
         local metaTxt
@@ -2061,7 +2242,7 @@ function RomImporter:_drawSaveSlotPanel(version, x, y, w, h)
         end
         love.graphics.setFont(self.labelFont)
         col(PAL.warning)
-        love.graphics.print(ellipsize(self.labelFont, metaTxt, rw - 24 * s),
+        love.graphics.print(ellipsize(self.labelFont, metaTxt, rw - 24 * s - rightReserve),
           rx + 12 * s, ry + rowPadV + nameH + 4 * s)
 
         -- clip the hit rect to the visible list band so a partly-scrolled row
@@ -2072,6 +2253,12 @@ function RomImporter:_drawSaveSlotPanel(version, x, y, w, h)
           self.slotRects[#self.slotRects + 1] =
             { x = rx, y = vy, width = rw, height = vy2 - vy, id = slot.id }
         end
+        local dvy = math.max(drect.y, listTop)
+        local dvy2 = math.min(drect.y + drect.height, listBottom)
+        if dvy2 > dvy then
+          self.slotDeleteRects[#self.slotDeleteRects + 1] =
+            { x = drect.x, y = dvy, width = drect.width, height = dvy2 - dvy, id = slot.id }
+        end
       end
     end
     love.graphics.setScissor()
@@ -2165,14 +2352,14 @@ function RomImporter:_drawModsPanel(x, y, w, h)
 
   local top = y + headerH + 14 * s
 
-  -- notice line: the last install result, else the drag-drop hint
+  -- notice line: the last install/delete result, else the platform hint
   love.graphics.setFont(self.hintFont)
   if self.modNotice then
     col(self.modNotice.ok and PAL.green or PAL.red)
     love.graphics.printf(self.modNotice.text, x, top, w, "left")
   else
     col(PAL.warning)
-    love.graphics.printf(self.android and "Copy a mod .zip via USB."
+    love.graphics.printf(self.android and "Or copy a mod .zip via USB."
       or "Or drop a mod .zip onto the window.", x, top, w, "left")
   end
   top = top + self.hintFont:getHeight() + 12 * s
@@ -2187,20 +2374,25 @@ function RomImporter:_drawModsPanel(x, y, w, h)
     dashedRoundRect(x, top, w, boxH, 14 * s, 7 * s, 5 * s)
     love.graphics.setFont(self.hintFont)
     col(PAL.warning)
-    love.graphics.printf("No mods installed - drop a mod .zip here to add one.",
+    local emptyHint = self.android
+      and "No mods installed - tap Import mod .zip to add one."
+      or "No mods installed - drop a mod .zip here to add one."
+    love.graphics.printf(emptyHint,
       x + 16 * s, top + boxH / 2 - self.hintFont:getHeight() / 2, w - 32 * s, "center")
     self.modRects = {}
+    self.modDeleteRects = {}
     self._modMax = 0
     return
   end
 
-  -- card metrics (design: rounded 14, padding 14x16; toggle 56x28)
+  -- card metrics (design: rounded 14, padding 14x16; toggle 56x28; Delete under)
   local padH, padV = 16 * s, 14 * s
   local cardGap, cardR = 10 * s, 14 * s
   local tw, th = 52 * s, 28 * s
   local innerW = w - 2 * padH
   local chipH = self.hintFont:getHeight() + 8 * s
-  local clusterH = chipH + 6 * s + th   -- status chip stacked over the toggle
+  local delH = self.hintFont:getHeight()
+  local clusterH = chipH + 6 * s + th + 6 * s + delH
 
   love.graphics.setFont(self.stateFont)
   local nameH = self.stateFont:getHeight()
@@ -2210,7 +2402,8 @@ function RomImporter:_drawModsPanel(x, y, w, h)
   for i, m in ipairs(mods) do
     local chipText = modStatusChip(m.status)
     local chipW = self.hintFont:getWidth(chipText) + 20 * s
-    local clusterW = math.max(chipW, tw)
+    local delW = self.hintFont:getWidth("Delete")
+    local clusterW = math.max(chipW, tw, delW)
     local leftW = math.max(40 * s, innerW - clusterW - 14 * s)
     local descH = 0
     if m.description ~= "" then
@@ -2221,7 +2414,7 @@ function RomImporter:_drawModsPanel(x, y, w, h)
     local contentH = padV * 2 + nameH + (descH > 0 and (6 * s + descH) or 0)
     local cardH = math.max(contentH, padV * 2 + clusterH)
     layout[i] = { h = cardH, leftW = leftW, clusterW = clusterW,
-      chipText = chipText, chipW = chipW }
+      chipText = chipText, chipW = chipW, delW = delW }
     total = total + cardH
   end
   total = total + (#mods - 1) * cardGap
@@ -2231,6 +2424,7 @@ function RomImporter:_drawModsPanel(x, y, w, h)
   local scroll = clamp(self.modScroll or 0, 0, maxScroll)
   self.modScroll = scroll
   self.modRects = {}
+  self.modDeleteRects = {}
 
   love.graphics.setScissor(math.floor(x), math.floor(top),
     math.ceil(w), math.ceil(listH))
@@ -2269,7 +2463,7 @@ function RomImporter:_drawModsPanel(x, y, w, h)
         love.graphics.printf(m.description, nx, ny + nameH + 6 * s, L.leftW, "left")
       end
 
-      -- right cluster: status chip stacked over the toggle, vertically centred
+      -- right cluster: status chip, toggle, Delete — vertically centred
       local clusterX = x + w - padH - L.clusterW
       local clusterY = cy + (cardH - clusterH) / 2
       local _, chipColor = modStatusChip(m.status)
@@ -2303,14 +2497,29 @@ function RomImporter:_drawModsPanel(x, y, w, h)
       col(PAL.white)
       love.graphics.circle("fill", kcx, ty + th / 2, kd / 2)
 
-      -- hit rect clipped to the visible list band (a partly-scrolled toggle is
-      -- only clickable where it actually shows)
+      -- Delete under the toggle
+      local delX = clusterX + (L.clusterW - L.delW) / 2
+      local delY = ty + th + 6 * s
+      local drect = { x = delX - 6 * s, y = delY - 2 * s,
+        width = L.delW + 12 * s, height = delH + 4 * s, id = m.id }
+      local dhot = self:_hover(drect)
+      love.graphics.setFont(self.hintFont)
+      col(dhot and PAL.red or PAL.warning)
+      love.graphics.print("Delete", delX, delY)
+
+      -- hit rects clipped to the visible list band
       local vy = math.max(trect.y, top)
       local vy2 = math.min(trect.y + trect.height, top + listH)
       if vy2 > vy then
         self.modRects[#self.modRects + 1] =
           { x = trect.x, y = vy, width = trect.width, height = vy2 - vy, id = m.id }
       end
+      local dvy = math.max(drect.y, top)
+      local dvy2 = math.min(drect.y + drect.height, top + listH)
+      if dvy2 > dvy then
+        self.modDeleteRects[#self.modDeleteRects + 1] =
+          { x = drect.x, y = dvy, width = drect.width, height = dvy2 - dvy, id = m.id }
+      end
     end
     cy = cy + cardH + cardGap
   end

src/import/SaveFileIO.lua

@@ -47,12 +47,20 @@ local function readSource(source)
     return source
   end
   local f, openErr = io.open(source, "rb")
-  if not f then return nil, "could not read the save file: " .. tostring(openErr) end
+  if f then
     local data = f:read("*a")
     f:close()
     if type(data) ~= "string" then return nil, "the save file was empty" end
     return data
   end
+  -- Android SAF drops (picked_save.sav) and USB copies land in the LOVE save
+  -- directory; io.open cannot see them, so fall back to love.filesystem.
+  if love and love.filesystem and love.filesystem.read then
+    local data = love.filesystem.read(source)
+    if type(data) == "string" then return data end
+  end
+  return nil, "could not read the save file: " .. tostring(openErr)
+end
 
 -- importToSlot(source, version) -> ok, slotIdOrErr
 -- source: an absolute path, a LOVE DroppedFile, or raw 32768 bytes.  On success

src/mods/LauncherMods.lua

@@ -3,11 +3,12 @@
 -- manifests only.  The full loader (src/mods/Loader.lua) still owns the real
 -- load at boot; this reads the same options.mods enable-state the loader
 -- writes, derives per-mod status with the pure ManagerState.resolveToggle,
--- and installs a dropped/chosen .zip into the save-dir "mods/<id>/" tree.
+-- installs a dropped/chosen .zip into the save-dir "mods/<id>/" tree, and
+-- uninstalls a mod by removing that tree + clearing options.mods[id].
 --
 -- Split in two: the pure derivation (deriveList, locateRoot) has no love and
--- no filesystem, so the engine tier can table-drive it; the discovery and
--- install paths reach for love.filesystem and SaveData.
+-- no filesystem, so the engine tier can table-drive it; the discovery,
+-- install, and uninstall paths reach for love.filesystem and SaveData.
 
 local Manifest = require("src.mods.Manifest")
 local ManagerState = require("src.mods.ManagerState")
@@ -332,4 +333,34 @@ function LauncherMods.installZip(source)
   return true, manifest.id
 end
 
+-- uninstall(id) -> true  |  nil, errString
+-- Removes mods/<id>/ from the save directory and clears options.mods[id] so the
+-- loader and in-game manager no longer see it.  Rejects unknown / missing ids.
+-- Does not touch other mods' enable state.
+function LauncherMods.uninstall(id)
+  if type(id) ~= "string" or id == "" then
+    return nil, "missing mod id"
+  end
+  if id:find("[/\\]") or id == "." or id == ".." then
+    return nil, "invalid mod id"
+  end
+  if not (love and love.filesystem) then
+    return nil, "mod uninstall needs LOVE"
+  end
+  local fs = love.filesystem
+  local dest = "mods/" .. id
+  if not fs.getInfo(dest) then
+    return nil, "mod '" .. id .. "' is not installed"
+  end
+  removeTree(dest)
+  -- Drop the enable flag so a reinstall of the same id starts from the
+  -- loader's default (enabled) rather than a stale false.
+  local options = SaveData.loadOptions()
+  if options.mods and options.mods[id] ~= nil then
+    options.mods[id] = nil
+    SaveData.saveOptions(options)
+  end
+  return true
+end
+
 return LauncherMods

tests/engine/launcher_mods_tests.lua

@@ -190,4 +190,22 @@ do
   check(err ~= nil, "the no-root case carries a reason")
 end
 
+-- ------- uninstall: rejects bad ids without needing a real mods tree
+
+do
+  local ok, err = LauncherMods.uninstall("")
+  eq(ok, nil, "empty id is rejected")
+  check(tostring(err):find("missing", 1, true) ~= nil, "empty-id reason")
+
+  ok, err = LauncherMods.uninstall("../escape")
+  eq(ok, nil, "path-like ids are rejected")
+  check(tostring(err):find("invalid", 1, true) ~= nil, "path-id reason")
+
+  ok, err = LauncherMods.uninstall("ghost")
+  -- Without a mods/ghost tree (and with the love stub's getInfo), uninstall
+  -- either needs LOVE or reports not installed -- never silently succeeds.
+  eq(ok, nil, "a missing mod does not uninstall")
+  check(err ~= nil, "missing-mod uninstall carries a reason")
+end
+
 T.finish("launcher_mods")

tests/engine/save_slots.lua

@@ -165,6 +165,41 @@ do
   T.eq(SaveData.createSlot("red"), "slot3", "ids increment past the highest")
 end
 
+-- ---------------------------------------------- deleteSlot
+
+do
+  local files = fresh()
+  local a = SaveData.createSlot("red")
+  local b = SaveData.createSlot("red")
+  SaveData.setActiveSlot("red", b)
+  local save = SaveData.newGame()
+  save.player.name = "KEEP"
+  T.check(SaveData.writeSlot("red", a, save), "seed slot1 with a save")
+  save.player.name = "GONE"
+  T.check(SaveData.writeSlot("red", b, save), "seed slot2 with a save")
+
+  local ok, err = SaveData.deleteSlot("red", b)
+  T.check(ok, "deleteSlot removes the active slot: " .. tostring(err))
+  T.eq(files["saves/red/slot2.lua"], nil, "slot2's file is gone")
+  T.check(files["saves/red/slot1.lua"] ~= nil, "the other slot's file stays")
+  local opts = SaveSerializer.decode(files["options.lua"])
+  T.eq(opts.saveSlots.red.active, a, "active falls back to the remaining slot")
+  T.eq(#opts.saveSlots.red.list, 1, "the deleted id is dropped from the list")
+  T.eq(opts.saveSlots.red.list[1], a, "only slot1 remains registered")
+
+  ok = SaveData.deleteSlot("red", a)
+  T.check(ok, "deleting the last slot succeeds")
+  opts = SaveSerializer.decode(files["options.lua"])
+  T.eq(#opts.saveSlots.red.list, 0, "the registry list is empty")
+  T.eq(opts.saveSlots.red.active, nil, "active clears when no slots remain")
+  T.eq(#SaveData.listSlots("red"), 0, "listSlots reports an empty install")
+
+  local bad, badErr = SaveData.deleteSlot("red", "slot99")
+  T.check(not bad, "deleting an unknown slot fails")
+  T.check(tostring(badErr):find("not registered", 1, true) ~= nil,
+    "unknown-slot error is user-presentable")
+end
+
 -- ---------------------------------------------- saveNames follows the slot
 
 do

tests/rom_importer_android_mod_pick_test.lua

@@ -0,0 +1,104 @@
+-- Android mod / save Import must open the SAF picker (love.system.pickFile
+-- with kind) and consume picked_mod.zip / picked_save.sav on focus, mirroring
+-- the ROM flow.  Self-contained: `luajit tests/rom_importer_android_mod_pick_test.lua`.
+package.path = "./?.lua;./?/init.lua;" .. package.path
+if not _G.love then _G.love = require("tests.love_stub") end
+
+local S = require("tests.harness").suite("rom importer android mod/save pick")
+local eq = S.eq
+local check = S.check
+
+local RomImporter = require("src.import.RomImporter")
+
+love.system = love.system or {}
+local saved = {
+  getOS = love.system.getOS,
+  pickFile = love.system.pickFile,
+}
+
+local pickCalls = {}
+love.system.getOS = function() return "Android" end
+love.system.pickFile = function(kind)
+  pickCalls[#pickCalls + 1] = kind or "rom"
+  return true
+end
+
+local function freshImporter(ready)
+  return setmetatable({
+    android = true,
+    workState = nil,
+    tab = "mods",
+    ready = {
+      red = ready.red and true or false,
+      blue = ready.blue and true or false,
+    },
+    saveNotice = {},
+    modNotice = nil,
+    androidPendingVersion = nil,
+    _installMod = function(self, source)
+      self._installed = source
+      self.modNotice = { ok = true, text = "Installed test" }
+    end,
+    _importSave = function(self, version, source)
+      self._imported = { version = version, source = source }
+      self.saveNotice[version] = { ok = true, text = "Imported" }
+    end,
+    _savedropTarget = RomImporter._savedropTarget,
+    _refreshMods = function() end,
+    _refreshSlots = function() end,
+  }, RomImporter)
+end
+
+-- Choose mod with nothing pending opens the mod picker.
+pickCalls = {}
+local ri = freshImporter({ red = true, blue = true })
+ri:chooseMod()
+eq(#pickCalls, 1, "chooseMod opens the picker when no pending zip exists")
+eq(pickCalls[1], "mod", "chooseMod asks pickFile for a mod")
+
+-- Pending USB zip installs without opening the picker.
+love.filesystem.write("usb_mod.zip", "PK\0fake")
+pickCalls = {}
+ri = freshImporter({ red = true, blue = true })
+ri:chooseMod()
+eq(#pickCalls, 0, "chooseMod installs a pending zip without opening the picker")
+eq(ri._installed, "usb_mod.zip", "chooseMod consumed the USB zip")
+check(love.filesystem.getInfo("usb_mod.zip") == nil,
+  "successful install removes the pending zip")
+
+-- Focus consumes picked_mod.zip even when both ROMs are already ready.
+love.filesystem.write("picked_mod.zip", "PK\0saf")
+ri = freshImporter({ red = true, blue = true })
+ri:focus(true)
+eq(ri._installed, "picked_mod.zip", "focus installs the SAF mod drop")
+check(love.filesystem.getInfo("picked_mod.zip") == nil,
+  "successful focus install removes picked_mod.zip")
+
+-- Choose save opens the sav picker when nothing is pending.
+pickCalls = {}
+ri = freshImporter({ red = true, blue = true })
+ri.tab = "blue"
+ri:chooseSaveImport("blue")
+eq(#pickCalls, 1, "chooseSaveImport opens the picker when no pending sav exists")
+eq(pickCalls[1], "sav", "chooseSaveImport asks pickFile for a sav")
+eq(ri.androidPendingVersion, "blue", "pending version is remembered for focus")
+
+-- Focus consumes picked_save.sav into the remembered version.
+love.filesystem.write("picked_save.sav", string.rep("S", 32))
+ri = freshImporter({ red = true, blue = true })
+ri.androidPendingVersion = "blue"
+ri:focus(true)
+check(ri._imported ~= nil, "focus imports the SAF save drop")
+eq(ri._imported.version, "blue", "focus imports into the pending version")
+eq(ri._imported.source, "picked_save.sav", "focus reads the SAF save filename")
+check(love.filesystem.getInfo("picked_save.sav") == nil,
+  "successful focus import removes picked_save.sav")
+
+love.system.getOS = saved.getOS
+love.system.pickFile = saved.pickFile
+-- leftover cleanup if a failed assertion left files behind
+love.filesystem.remove("usb_mod.zip")
+love.filesystem.remove("picked_mod.zip")
+love.filesystem.remove("picked_save.sav")
+
+S.finish()

tests/run_tests.lua

@@ -3115,6 +3115,8 @@ runSuites({ "tests/rom_importer_cursor_test.lua" })
 -- ---------------------------------------------- Android second ROM pick (#167)
 runSuites({ "tests/rom_importer_android_pick_test.lua" })
 
+-- ---------------------------------------------- Android mod / save SAF pick
+runSuites({ "tests/rom_importer_android_mod_pick_test.lua" })
 -- ---------------------------------------------- parity workstream tests
 -- Each tests/parity_*.lua is a self-contained file (own bootstrap + check,
 -- error()s if any assertion fails).  Globbed, so dropping a new parity