Revert "Spam filter experiment"

This reverts commit 5922d30104.

app/build.gradle

@@ -389,7 +389,4 @@ dependencies {
     // http://www.freeutils.net/source/jcharset/
     // https://mvnrepository.com/artifact/net.freeutils/jcharset
     implementation "net.freeutils:jcharset:$jcharset_version"
-
-    // https://github.com/ptnplanet/Java-Naive-Bayes-Classifier
-    implementation "com.github.ptnplanet:Java-Naive-Bayes-Classifier:1.0.7"
 }

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

@@ -1419,7 +1419,6 @@ class Core {
                 parts.isPlainOnly(),
                 HtmlHelper.getPreview(body),
                 parts.getWarnings(message.warning));
-        JunkFilter.classify(context, body, folder.type);
 
         if (body != null)
             EntityLog.log(context, "Operation body size=" + body.length());
@@ -2074,7 +2073,6 @@ class Core {
                                 parts.isPlainOnly(),
                                 HtmlHelper.getPreview(body),
                                 parts.getWarnings(message.warning));
-                        JunkFilter.classify(context, body, folder.type);
 
                         for (EntityAttachment attachment : parts.getAttachments())
                             parts.downloadAttachment(context, attachment);
@@ -2869,8 +2867,6 @@ class Core {
                             parts.isPlainOnly(),
                             HtmlHelper.getPreview(body),
                             parts.getWarnings(message.warning));
-                    JunkFilter.classify(context, body, folder.type);
-
                     if (stats != null && body != null)
                         stats.content += body.length();
                     Log.i(folder.name + " inline downloaded message id=" + message.id +
@@ -3265,8 +3261,6 @@ class Core {
                             parts.isPlainOnly(),
                             HtmlHelper.getPreview(body),
                             parts.getWarnings(message.warning));
-                    JunkFilter.classify(context, body, folder.type);
-
                     if (stats != null && body != null)
                         stats.content += body.length();
                     Log.i(folder.name + " downloaded message id=" + message.id +

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

@@ -1,76 +0,0 @@
-package eu.faircode.email;
-
-import android.content.Context;
-
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
-import java.util.Arrays;
-import java.util.List;
-import java.util.concurrent.ExecutorService;
-
-import de.daslaboratorium.machinelearning.classifier.Classification;
-import de.daslaboratorium.machinelearning.classifier.Classifier;
-import de.daslaboratorium.machinelearning.classifier.bayes.BayesClassifier;
-
-public class JunkFilter {
-    private static final Classifier<String, String> bayes = new BayesClassifier<>();
-
-    private static final ExecutorService executor =
-            Helper.getBackgroundExecutor(1, "junk");
-
-    static void classify(Context context, String html, String folderType) {
-        if (EntityFolder.isOutgoing(folderType) ||
-                EntityFolder.ARCHIVE.equals(folderType))
-            return;
-
-        final boolean junk = EntityFolder.JUNK.equals(folderType);
-
-        executor.submit(new Runnable() {
-            @Override
-            public void run() {
-                try {
-                    String text = HtmlHelper.getText(context, html);
-                    List<String> words = Arrays.asList(text.split("[^\\p{L}\\p{N}'`]+"));
-
-                    Classification<String, String> classification = bayes.classify(words);
-                    Log.i("MMM folder=" + folderType + " category=" + (classification == null ? null : classification.getCategory()));
-
-                    bayes.learn(junk ? "junk" : "ham", words);
-                } catch (Throwable ex) {
-                    Log.e(ex);
-                }
-            }
-        });
-    }
-
-    static void save(Context context) {
-        final File file = new File(context.getFilesDir(), "junk.filter");
-
-        executor.submit(new Runnable() {
-            @Override
-            public void run() {
-                try (FileOutputStream fos = new FileOutputStream(file)) {
-                } catch (Throwable ex) {
-                    Log.e(ex);
-                }
-            }
-        });
-    }
-
-    static void load(Context context) {
-        final File file = new File(context.getFilesDir(), "junk.filter");
-
-        executor.submit(new Runnable() {
-            @Override
-            public void run() {
-                if (!file.exists())
-                    return;
-                try (FileInputStream fis = new FileInputStream(file)) {
-                } catch (Throwable ex) {
-                    Log.e(ex);
-                }
-            }
-        });
-    }
-}

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

@@ -617,8 +617,6 @@ public class ServiceSynchronize extends ServiceBase implements SharedPreferences
         });
 
         prefs.registerOnSharedPreferenceChangeListener(this);
-
-        JunkFilter.load(this);
     }
 
     @Override
@@ -688,8 +686,6 @@ public class ServiceSynchronize extends ServiceBase implements SharedPreferences
         NotificationManager nm = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
         nm.cancel(Helper.NOTIFICATION_SYNCHRONIZE);
 
-        JunkFilter.save(this);
-
         super.onDestroy();
     }