Use MODE for favoriteSlot in HistoryInfo

app/src/main/java/com/hippo/ehviewer/EhDB.java

@@ -328,15 +328,16 @@ public class EhDB {
 
     public static synchronized void putHistoryInfo(GalleryInfo galleryInfo) {
         HistoryDao dao = db.historyDao();
-        HistoryInfo info = dao.load(galleryInfo.gid);
-        if (null != info) {
-            // Update time
-            info.time = System.currentTimeMillis();
+        HistoryInfo info;
+        if (galleryInfo instanceof HistoryInfo) {
+            info = (HistoryInfo) galleryInfo;
+        } else {
+            info = new HistoryInfo(galleryInfo);
+        }
+        info.time = System.currentTimeMillis();
+        if (null != dao.load(info.gid)) {
             dao.update(info);
         } else {
-            // New history
-            info = new HistoryInfo(galleryInfo);
-            info.time = System.currentTimeMillis();
             dao.insert(info);
         }
     }

app/src/main/java/com/hippo/ehviewer/dao/HistoryInfo.java

@@ -20,8 +20,10 @@ public class HistoryInfo extends GalleryInfo {
             return new HistoryInfo[size];
         }
     };
+
+    // Use MODE for favoriteSlot
     @ColumnInfo(name = "MODE")
-    public int mode;
+    private int mode;
     @ColumnInfo(name = "TIME")
     public long time;
 
@@ -43,10 +45,11 @@ public class HistoryInfo extends GalleryInfo {
         this.rating = galleryInfo.rating;
         this.simpleTags = galleryInfo.simpleTags;
         this.simpleLanguage = galleryInfo.simpleLanguage;
+        this.favoriteSlot = galleryInfo.favoriteSlot;
     }
 
     public HistoryInfo(int mode, long time) {
-        this.mode = mode;
+        this.favoriteSlot = mode - 2;
         this.time = time;
     }
 
@@ -131,11 +134,11 @@ public class HistoryInfo extends GalleryInfo {
     }
 
     public int getMode() {
-        return mode;
+        return favoriteSlot + 2;
     }
 
     public void setMode(int mode) {
-        this.mode = mode;
+        this.favoriteSlot = mode - 2;
     }
 
     public long getTime() {

app/src/main/java/com/hippo/ehviewer/dao/LocalFavoriteInfo.java

@@ -44,6 +44,7 @@ public class LocalFavoriteInfo extends GalleryInfo {
     }
 
     public LocalFavoriteInfo() {
+        this.favoriteSlot = -1;
     }
 
     public long getGid() {