Added emergency backup

app/src/main/java/eu/faircode/email/DB.java

@@ -226,6 +226,56 @@ public abstract class DB extends RoomDatabase {
 
             sInstance = migrate(acontext, getBuilder(acontext)).build();
 
+            sInstance.getQueryExecutor().execute(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        File dbfile = acontext.getDatabasePath(DB_NAME);
+                        if (dbfile.exists()) {
+                            Log.i("No emergency restore /dbfile");
+                            return;
+                        }
+
+                        File emergency = new File(acontext.getFilesDir(), "emergency.json");
+                        if (!emergency.exists()) {
+                            Log.i("No emergency restore /backup");
+                            return;
+                        }
+
+                        if (sInstance.account().getAccounts().size() > 0) {
+                            Log.i("No emergency restore /accounts");
+                            return;
+                        }
+
+                        Log.e("Emergency restore");
+
+                        String json = Helper.readText(emergency);
+                        JSONArray jaccounts = new JSONArray(json);
+                        for (int a = 0; a < jaccounts.length(); a++) {
+                            JSONObject jaccount = jaccounts.getJSONObject(a);
+                            EntityAccount account = EntityAccount.fromJSON(jaccount);
+                            account.id = sInstance.account().insertAccount(account);
+
+                            JSONArray jfolders = jaccount.getJSONArray("folders");
+                            for (int f = 0; f < jfolders.length(); f++) {
+                                EntityFolder folder = EntityFolder.fromJSON(jfolders.getJSONObject(f));
+                                folder.account = account.id;
+                                sInstance.folder().insertFolder(folder);
+                            }
+
+                            JSONArray jidentities = jaccount.getJSONArray("identities");
+                            for (int i = 0; i < jidentities.length(); i++) {
+                                EntityIdentity identity = EntityIdentity.fromJSON(jidentities.getJSONObject(i));
+                                identity.account = account.id;
+                                sInstance.identity().insertIdentity(identity);
+                            }
+                        }
+                    } catch (Throwable ex) {
+                        Log.e(ex);
+                    }
+                }
+            });
+
             try {
                 Log.i("Disabling view invalidation");
 

app/src/main/java/eu/faircode/email/WorkerCleanup.java

@@ -35,6 +35,9 @@ import androidx.work.WorkManager;
 import androidx.work.Worker;
 import androidx.work.WorkerParameters;
 
+import org.json.JSONArray;
+import org.json.JSONObject;
+
 import java.io.File;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -323,6 +326,34 @@ public class WorkerCleanup extends Worker {
                 EntityLog.log(context, "Analyze=" + (new Date().getTime() - analyze) + " ms");
             }
 
+            Log.i("Creating emergency backup");
+            try {
+                JSONArray jaccounts = new JSONArray();
+                List<EntityAccount> accounts = db.account().getAccounts();
+                for (EntityAccount account : accounts) {
+                    JSONObject jaccount = account.toJSON();
+
+                    JSONArray jfolders = new JSONArray();
+                    List<EntityFolder> folders = db.folder().getFolders(account.id, false, true);
+                    for (EntityFolder folder : folders)
+                        jfolders.put(folder.toJSON());
+                    jaccount.put("folders", jfolders);
+
+                    JSONArray jidentities = new JSONArray();
+                    List<EntityIdentity> identities = db.identity().getIdentities(account.id);
+                    for (EntityIdentity identity : identities)
+                        jidentities.put(identity.toJSON());
+                    jaccount.put("identities", jidentities);
+
+                    jaccounts.put(jaccount);
+                }
+
+                File emergency = new File(context.getFilesDir(), "emergency.json");
+                Helper.writeText(emergency, jaccounts.toString(2));
+            } catch (Throwable ex) {
+                Log.e(ex);
+            }
+
             if (manual) {
                 // https://www.sqlite.org/lang_vacuum.html
                 long size = context.getDatabasePath(db.getOpenHelper().getDatabaseName()).length();