ChangeScreen2: Respect comment visibility strategy

Bug: Issue 2456
Change-Id: I71f9ae2664a8f8c7f4eb8e019696764982781f58

gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen2.java

@@ -747,7 +747,7 @@ public class ChangeScreen2 extends Screen {
     related.set(info, revision);
     reviewers.set(info);
     quickApprove.set(info, revision);
-    history.set(commentLinkProcessor, changeId, info);
+    history.set(commentLinkProcessor, changeId, info, expandAll, collapseAll);
 
     if (Gerrit.isSignedIn()) {
       initEditMessageAction(info, revision);

gerrit-gwtui/src/main/java/com/google/gerrit/client/change/History.java

@@ -14,6 +14,10 @@
 
 package com.google.gerrit.client.change;
 
+import static com.google.gerrit.reviewdb.client.AccountGeneralPreferences.CommentVisibilityStrategy.COLLAPSE_ALL;
+import static com.google.gerrit.reviewdb.client.AccountGeneralPreferences.CommentVisibilityStrategy.EXPAND_ALL;
+
+import com.google.gerrit.client.Gerrit;
 import com.google.gerrit.client.account.AccountInfo;
 import com.google.gerrit.client.changes.ChangeApi;
 import com.google.gerrit.client.changes.ChangeInfo;
@@ -22,10 +26,12 @@ import com.google.gerrit.client.changes.CommentInfo;
 import com.google.gerrit.client.rpc.NativeMap;
 import com.google.gerrit.client.rpc.Natives;
 import com.google.gerrit.client.ui.CommentLinkProcessor;
+import com.google.gerrit.reviewdb.client.AccountGeneralPreferences.CommentVisibilityStrategy;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gwt.core.client.JsArray;
 import com.google.gwt.user.client.rpc.AsyncCallback;
+import com.google.gwt.user.client.ui.Button;
 import com.google.gwt.user.client.ui.FlowPanel;
 import com.google.gwt.user.client.ui.Widget;
 
@@ -39,6 +45,10 @@ import java.util.Map;
 import java.util.Set;
 
 class History extends FlowPanel {
+  // This basically means 7 days in milliseconds and could be rewritten as
+  // TimeUnit.DAYS.toMillis(7)
+  // in plain Java, but unfortunately it isn't available in GWT
+  private final static long AGE = 7 * 24 * 60 * 60 * 1000L;
   private CommentLinkProcessor clp;
   private Change.Id changeId;
 
@@ -46,7 +56,8 @@ class History extends FlowPanel {
   private final Map<AuthorRevision, List<CommentInfo>> byAuthor =
       new HashMap<AuthorRevision, List<CommentInfo>>();
 
-  void set(CommentLinkProcessor clp, Change.Id id, ChangeInfo info) {
+  void set(CommentLinkProcessor clp, Change.Id id, ChangeInfo info,
+      Button expandAll, Button collapseAll) {
     this.clp = clp;
     this.changeId = id;
 
@@ -60,6 +71,7 @@ class History extends FlowPanel {
         add(ui);
       }
     }
+    initCommentVisibilityStrategy(expandAll, collapseAll);
   }
 
   CommentLinkProcessor getCommentLinkProcessor() {
@@ -149,6 +161,51 @@ class History extends FlowPanel {
     return match;
   }
 
+  private void initCommentVisibilityStrategy(Button expandAll, Button collapseAll) {
+    CommentVisibilityStrategy commentVisibilityStrategy =
+        CommentVisibilityStrategy.EXPAND_RECENT;
+    if (Gerrit.isSignedIn()) {
+      commentVisibilityStrategy = Gerrit.getUserAccount()
+          .getGeneralPreferences().getCommentVisibilityStrategy();
+    }
+
+    Timestamp aged = new Timestamp(System.currentTimeMillis() - AGE);
+
+    int n = getWidgetCount();
+    for (int i = 0; i < n; i++) {
+      Message msg = (Message) getWidget(i);
+
+      boolean isRecent = (i == n - 1)
+          ? true
+          : msg.getMessageInfo().date().after(aged);
+
+      boolean isOpen = false;
+      switch (commentVisibilityStrategy) {
+        case COLLAPSE_ALL:
+          break;
+        case EXPAND_ALL:
+          isOpen = true;
+          break;
+        case EXPAND_MOST_RECENT:
+          isOpen = i == n - 1;
+          break;
+        case EXPAND_RECENT:
+        default:
+          isOpen = isRecent;
+          break;
+      }
+      msg.setOpen(isOpen);
+    }
+
+    if (commentVisibilityStrategy == COLLAPSE_ALL) {
+      expandAll.setVisible(true);
+      collapseAll.setVisible(false);
+    } else if (commentVisibilityStrategy == EXPAND_ALL) {
+      expandAll.setVisible(false);
+      collapseAll.setVisible(true);
+    }
+  }
+
   private static final class AuthorRevision {
     final int author;
     final int revision;