Added the ability to remove all watched videos from local playlists

Changes:
 - local_playlist_control.xml
   * A copy of playlist_control.xml
   * To hold the 'Remove Watched Videos' buttton

 - local_playlist_header.xml
   * Changed the include layout	to now include local_playlist_control.xml

 - strings.xml
   * added string 'remove_watched' with value 'Remove Watched'

 - LocalPlaylistFragment.java
   * Added the functionality to remove watched videos,
      to the 'Remove Watched Videos' button in local_playlist_control.xml.
      In the background via AsyncTask.
      This will also change the playlist's thumbnail, if the thumbnail video is removed.

Tested on:
 - Pixel

app/src/main/java/org/schabi/newpipe/local/playlist/LocalPlaylistFragment.java

@@ -2,6 +2,7 @@ package org.schabi.newpipe.local.playlist;
 
 import android.app.Activity;
 import android.content.Context;
+import android.os.AsyncTask;
 import android.os.Bundle;
 import android.os.Parcelable;
 import android.text.TextUtils;
@@ -24,11 +25,13 @@ import org.reactivestreams.Subscription;
 import org.schabi.newpipe.NewPipeDatabase;
 import org.schabi.newpipe.R;
 import org.schabi.newpipe.database.LocalItem;
+import org.schabi.newpipe.database.history.model.StreamHistoryEntry;
 import org.schabi.newpipe.database.playlist.PlaylistStreamEntry;
 import org.schabi.newpipe.extractor.stream.StreamInfoItem;
 import org.schabi.newpipe.extractor.stream.StreamType;
 import org.schabi.newpipe.info_list.InfoItemDialog;
 import org.schabi.newpipe.local.BaseLocalListFragment;
+import org.schabi.newpipe.local.history.HistoryRecordManager;
 import org.schabi.newpipe.player.playqueue.PlayQueue;
 import org.schabi.newpipe.player.playqueue.SinglePlayQueue;
 import org.schabi.newpipe.report.UserAction;
@@ -39,11 +42,13 @@ import org.schabi.newpipe.util.StreamDialogEntry;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import icepick.State;
+import io.reactivex.Flowable;
 import io.reactivex.android.schedulers.AndroidSchedulers;
 import io.reactivex.disposables.CompositeDisposable;
 import io.reactivex.disposables.Disposable;
@@ -71,6 +76,8 @@ public class LocalPlaylistFragment extends BaseLocalListFragment<List<PlaylistSt
     private View headerPlayAllButton;
     private View headerPopupButton;
     private View headerBackgroundButton;
+    private View headerRemoveWatchedButton;
+
     private ItemTouchHelper itemTouchHelper;
 
     private LocalPlaylistManager playlistManager;
@@ -142,10 +149,11 @@ public class LocalPlaylistFragment extends BaseLocalListFragment<List<PlaylistSt
 
         headerStreamCount = headerRootLayout.findViewById(R.id.playlist_stream_count);
 
-        playlistControl = headerRootLayout.findViewById(R.id.playlist_control);
+        playlistControl = headerRootLayout.findViewById(R.id.local_playlist_control);
         headerPlayAllButton = headerRootLayout.findViewById(R.id.playlist_ctrl_play_all_button);
         headerPopupButton = headerRootLayout.findViewById(R.id.playlist_ctrl_play_popup_button);
         headerBackgroundButton = headerRootLayout.findViewById(R.id.playlist_ctrl_play_bg_button);
+        headerRemoveWatchedButton = headerRootLayout.findViewById(R.id.playlist_ctrl_remove_watched_button);
 
         return headerRootLayout;
     }
@@ -260,6 +268,9 @@ public class LocalPlaylistFragment extends BaseLocalListFragment<List<PlaylistSt
         if (headerPopupButton != null) {
             headerPopupButton.setOnClickListener(null);
         }
+        if (headerRemoveWatchedButton != null) {
+            headerRemoveWatchedButton.setOnClickListener(null);
+        }
 
         if (databaseSubscription != null) {
             databaseSubscription.cancel();
@@ -358,6 +369,13 @@ public class LocalPlaylistFragment extends BaseLocalListFragment<List<PlaylistSt
                 NavigationHelper.playOnPopupPlayer(activity, getPlayQueue(), false));
         headerBackgroundButton.setOnClickListener(view ->
                 NavigationHelper.playOnBackgroundPlayer(activity, getPlayQueue(), false));
+        headerRemoveWatchedButton.setOnClickListener(
+                view -> {
+                    //Solution, Scorched Earth, Copy non duplicates, clear playlist, then copy back over
+                    //Other options didn't work as intended, or crashed. Like deleteItem(playlist_item) crashes when called in this function.
+                    new RemoveWatchedStreams().execute();
+                }
+        );
 
         headerPopupButton.setOnLongClickListener(view -> {
             NavigationHelper.enqueueOnPopupPlayer(activity, getPlayQueue(), true);
@@ -684,5 +702,74 @@ public class LocalPlaylistFragment extends BaseLocalListFragment<List<PlaylistSt
         }
         return new SinglePlayQueue(streamInfoItems, index);
     }
+
+    private class RemoveWatchedStreams extends AsyncTask<String, Long, Long> {
+        List<PlaylistStreamEntry> localItems = new ArrayList<>();
+        Long RemovedItemCount = 0l;
+        boolean thumbNailVideoRemoved = false;
+
+        @Override
+        protected void onPreExecute() {
+            super.onPreExecute();
+            showLoading();
+            localItems.clear();
+        }
+
+        @Override
+        protected Long doInBackground(String... urls) {
+
+            HistoryRecordManager recordManager = new HistoryRecordManager(getContext());
+            Iterator<StreamHistoryEntry> it_history;
+            StreamHistoryEntry history_item;
+
+            Flowable<List<PlaylistStreamEntry>> playlist = playlistManager.getPlaylistStreams(playlistId);
+            Iterator<PlaylistStreamEntry> it_playlist = playlist.blockingFirst().iterator();
+            PlaylistStreamEntry playlist_item = null;
+
+            boolean isNonDuplicate;
+
+            while (it_playlist.hasNext()) {
+                playlist_item = it_playlist.next();
+
+                it_history = recordManager.getStreamHistory().blockingFirst().iterator();
+
+                isNonDuplicate = true;
+                while (it_history.hasNext()) {
+                    history_item = it_history.next();
+                    if (history_item.streamId == playlist_item.streamId) {
+                        isNonDuplicate = false;
+                        break;
+                    }
+                }
+                if (isNonDuplicate) {
+                    localItems.add(playlist_item);
+                }
+                else
+                {
+                    RemovedItemCount++;
+                    if(playlistManager.getPlaylistThumbnail(playlistId).equals(playlist_item.thumbnailUrl))
+                    {
+                        thumbNailVideoRemoved = true;
+                    }
+                }
+            }
+            return this.RemovedItemCount;
+        }
+
+        @Override
+        protected void onPostExecute(Long result) {
+            itemListAdapter.clearStreamItemList();
+            itemListAdapter.addItems(localItems);
+            localItems.clear();
+
+            if (thumbNailVideoRemoved)
+                updateThumbnailUrl();
+
+            setVideoCount(itemListAdapter.getItemsList().size());
+
+            saveChanges();
+            hideLoading();
+        }
+    }
 }
 

app/src/main/res/layout/local_playlist_control.xml

@@ -0,0 +1,115 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<LinearLayout
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/local_playlist_control"
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:visibility="invisible"
+    tools:visibility="visible">
+
+    <LinearLayout
+        android:id="@+id/playlist_ctrl_play_bg_button"
+        android:layout_width="match_parent"
+        android:layout_height="@dimen/playlist_ctrl_height"
+        android:layout_weight="1"
+        android:gravity="center"
+        android:clickable="true"
+        android:focusable="true"
+        android:background="?attr/selectableItemBackground">
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:gravity="center_vertical"
+            android:text="@string/controls_background_title"
+            android:textSize="@dimen/channel_rss_title_size"
+            android:textColor="?attr/colorAccent"
+            android:drawablePadding="4dp"
+            android:drawableLeft="?attr/audio"
+            android:drawableStart="?attr/audio"/>
+    </LinearLayout>
+
+    <View android:id="@+id/anchorLeft"
+        android:layout_width="1dp"
+        android:layout_height="match_parent"
+        android:clickable="false"
+        android:layout_marginBottom="@dimen/playlist_ctrl_seperator_margin"
+        android:layout_marginTop="@dimen/playlist_ctrl_seperator_margin"
+        android:background="?attr/colorAccent"/>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center"
+        android:clickable="true"
+        android:focusable="true"
+        android:background="?attr/selectableItemBackground"
+        android:id="@+id/playlist_ctrl_play_all_button">
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:gravity="center_vertical"
+            android:text="@string/play_all"
+            android:textSize="@dimen/channel_rss_title_size"
+            android:textColor="?attr/colorAccent"/>
+    </LinearLayout>
+
+    <View android:id="@+id/anchorMiddle"
+        android:layout_width="1dp"
+        android:layout_height="match_parent"
+        android:clickable="false"
+        android:layout_marginBottom="@dimen/playlist_ctrl_seperator_margin"
+        android:layout_marginTop="@dimen/playlist_ctrl_seperator_margin"
+        android:background="?attr/colorAccent"/>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:gravity="center"
+        android:clickable="true"
+        android:focusable="true"
+        android:background="?attr/selectableItemBackground"
+        android:id="@+id/playlist_ctrl_play_popup_button">
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:gravity="center_vertical"
+            android:text="@string/controls_popup_title"
+            android:textSize="@dimen/channel_rss_title_size"
+            android:textColor="?attr/colorAccent"
+            android:drawablePadding="4dp"
+            android:drawableLeft="?attr/popup"
+            android:drawableStart="?attr/popup"/>
+    </LinearLayout>
+
+    <View android:id="@+id/anchorRight"
+        android:layout_width="1dp"
+        android:layout_height="match_parent"
+        android:clickable="false"
+        android:layout_marginBottom="@dimen/playlist_ctrl_seperator_margin"
+        android:layout_marginTop="@dimen/playlist_ctrl_seperator_margin"
+        android:background="?attr/colorAccent"/>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_weight="1.2"
+        android:gravity="center"
+        android:clickable="true"
+        android:focusable="true"
+        android:background="?attr/selectableItemBackground"
+        android:id="@+id/playlist_ctrl_remove_watched_button">
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:paddingLeft="15px"
+            android:gravity="center_vertical"
+            android:text="@string/remove_watched"
+            android:textColor="?attr/colorAccent"
+            android:textSize="@dimen/channel_rss_title_size" />
+    </LinearLayout>
+</LinearLayout>

app/src/main/res/layout/local_playlist_header.xml

@@ -50,7 +50,7 @@
         android:layout_height="wrap_content"
         android:layout_below="@id/playlist_stream_count">
 
-        <include layout="@layout/playlist_control"/>
+        <include layout="@layout/local_playlist_control" />
     </LinearLayout>
 
 </RelativeLayout>

app/src/main/res/values/strings.xml

@@ -637,4 +637,6 @@
     <string name="feed_use_dedicated_fetch_method_enable_button">Enable fast mode</string>
     <string name="feed_use_dedicated_fetch_method_disable_button">Disable fast mode</string>
     <string name="feed_use_dedicated_fetch_method_help_text">Do you think feed loading is too slow? If so, try enabling fast loading (you can change it in settings or by pressing the button below).\n\nNewPipe offers two feed loading strategies:\n• Fetching the whole subscription channel, which is slow but complete.\n• Using a dedicated service endpoint, which is fast but usually not complete.\n\nThe difference between the two is that the fast one usually lacks some information, like the item\'s duration or type (can\'t distinguish between live videos and normal ones) and it may return less items.\n\nYouTube is an example of a service that offers this fast method with its RSS feed.\n\nSo the choice boils down to what you prefer: speed or precise information.</string>
-</resources>
+
+    <string name="remove_watched">Remove Watched</string>
+</resources>