Implement Android installation wizard

android-project/app/build.gradle

@@ -9,6 +9,9 @@ else {
 
 android {
     compileSdkVersion 28
+    aaptOptions {
+        noCompress 'mpq'
+    }
     defaultConfig {
         if (buildAsApplication) {
             applicationId "org.diasurgical.devilutionx"

android-project/app/src/main/java/org/diasurgical/devilutionx/DevilutionXSDLActivity.java

@@ -1,13 +1,136 @@
-package org.diasurgical.devilutionx;
-
-import org.libsdl.app.SDLActivity;
-
-public class DevilutionXSDLActivity extends SDLActivity {
-	protected String[] getLibraries() {
-		return new String[]{
-				"SDL2",
-				"SDL2_ttf",
-				"devilutionx"
-		};
-	}
-}
+package org.diasurgical.devilutionx;
+
+import android.Manifest;
+import android.app.AlertDialog;
+import android.content.DialogInterface;
+import android.content.SharedPreferences;
+import android.content.pm.PackageManager;
+import android.os.Build;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.Looper;
+import android.preference.PreferenceManager;
+
+import org.libsdl.app.SDLActivity;
+
+import java.io.File;
+
+public class DevilutionXSDLActivity extends SDLActivity {
+	final String permission = Manifest.permission.READ_EXTERNAL_STORAGE;
+	private Handler permissionHandler;
+	private AlertDialog PermissionDialog;
+	private final String SharewareTitle = "Shareware version";
+	private SharedPreferences mPrefs;
+	final private String shouldShowInstallationGuidePref = "shouldShowInstallationGuide";
+
+	protected void onCreate(Bundle savedInstanceState) {
+		checkStoragePermission();
+
+		super.onCreate(savedInstanceState);
+	}
+
+	private boolean shouldShowInstallationGuide(boolean isDataAccessible) {
+		mPrefs = PreferenceManager.getDefaultSharedPreferences(this);
+		return mPrefs.getBoolean(shouldShowInstallationGuidePref, !isDataAccessible);
+	}
+
+	private void installationGuideShown() {
+		SharedPreferences.Editor editor = mPrefs.edit();
+		editor.putBoolean(shouldShowInstallationGuidePref, false);
+		editor.apply();
+	}
+
+	private void checkStoragePermission() {
+		if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.LOLLIPOP_MR1) {
+			checkStoragePermissionLollipop();
+			return;
+		}
+
+		if (PackageManager.PERMISSION_GRANTED != checkSelfPermission(permission)) {
+			requestPermissions(new String[]{permission}, 1);
+		}
+
+		boolean dataFileFound = hasDataFile();
+		boolean shouldShowInstallationGuide = shouldShowInstallationGuide(dataFileFound && PackageManager.PERMISSION_GRANTED == checkSelfPermission(permission));
+
+		if (!shouldShowInstallationGuide && !shouldShowRequestPermissionRationale(permission)) {
+			return;
+		}
+
+		String message = "To play the full version you must grant the application read access to " + System.getenv("EXTERNAL_STORAGE") + ".";
+		if (!dataFileFound) {
+			message = "To play the full version you must place DIABDAT.MPQ from the original game in " + System.getenv("EXTERNAL_STORAGE") + " and grant the application read access.\n\nIf you don't have the original game then you can buy Diablo from GOG.com.";
+			installationGuideShown();
+		}
+
+		permissionHandler = new Handler();
+
+		PermissionDialog = new AlertDialog.Builder(this)
+				.setTitle(SharewareTitle)
+				.setPositiveButton("OK", new DialogInterface.OnClickListener() {
+					public void onClick(DialogInterface dialog, int id) {
+						permissionHandler.post(new Runnable() {
+							@Override
+							public void run() {
+								throw new RuntimeException();
+							}
+						});
+					}
+				})
+				.setMessage(message)
+				.show();
+
+		if (dataFileFound) {
+			triggerPulse(); // Start full game as soon as we have file access
+		}
+
+		try {
+			Looper.loop();
+		} catch (RuntimeException ignored) {
+		}
+	}
+
+	private void checkStoragePermissionLollipop() {
+		boolean dataFileFound = hasDataFile();
+		boolean shouldShowInstallationGuide = shouldShowInstallationGuide(dataFileFound);
+		if (!shouldShowInstallationGuide) {
+			return;
+		}
+
+		String message = "To play the full version you must place DIABDAT.MPQ from the original game in " + System.getenv("EXTERNAL_STORAGE") + ".\n\nIf you don't have the original game then you can buy Diablo from GOG.com.";
+		new AlertDialog.Builder(this)
+				.setTitle(SharewareTitle)
+				.setPositiveButton("OK", null)
+				.setMessage(message)
+				.show();
+		installationGuideShown();
+	}
+
+	private void triggerPulse() {
+		permissionHandler.postDelayed(new Runnable() {
+			@Override
+			public void run() {
+				if (PackageManager.PERMISSION_GRANTED == checkSelfPermission(permission)) {
+					PermissionDialog.hide();
+					throw new RuntimeException();
+				}
+				triggerPulse();
+			}
+		}, 50);
+	}
+
+	private boolean hasDataFile() {
+		File fileLower = new File(System.getenv("EXTERNAL_STORAGE") + "/diabdat.mpq");
+		File fileUpper = new File(System.getenv("EXTERNAL_STORAGE") + "/DIABDAT.MPQ");
+
+		return fileUpper.exists() || fileLower.exists();
+	}
+
+	protected String[] getLibraries() {
+		return new String[]{
+				"SDL2",
+				"SDL2_ttf",
+				"devilutionx"
+		};
+	}
+}