combine multiple post info in DataStore.Info instead of returning first

Previously, only the first one was returned for site-wide requests,
and now all returned information will be correctly aggregated,
and the PostInfo.URL and PostInfo.ReadOnly parameters will be dropped.

backend/app/store/comment.go

@@ -45,9 +45,9 @@ type Edit struct {
 
 // PostInfo holds summary for given post url
 type PostInfo struct {
-	URL      string    `json:"url"`
+	URL      string    `json:"url,omitempty"` // can be attached to site-wide comments but won't be set then
 	Count    int       `json:"count"`
-	ReadOnly bool      `json:"read_only,omitempty" bson:"read_only,omitempty"`
+	ReadOnly bool      `json:"read_only,omitempty" bson:"read_only,omitempty"` // can be attached to site-wide comments but won't be set then
 	FirstTS  time.Time `json:"first_time,omitempty" bson:"first_time,omitempty"`
 	LastTS   time.Time `json:"last_time,omitempty" bson:"last_time,omitempty"`
 }
@@ -98,6 +98,7 @@ func (c *Comment) SetDeleted(mode DeleteMode) {
 	c.Text = ""
 	c.Orig = ""
 	c.Score = 0
+	c.Controversy = 0
 	c.Votes = map[string]bool{}
 	c.VotedIPs = make(map[string]VotedIPInfo)
 	c.Edit = nil

backend/app/store/service/service.go

@@ -754,7 +754,23 @@ func (s *DataStore) Info(locator store.Locator, readonlyAge int) (store.PostInfo
 	if len(res) == 0 {
 		return store.PostInfo{}, fmt.Errorf("post %+v not found", locator)
 	}
-	return res[0], nil
+	// URL request
+	if locator.URL != "" {
+		return res[0], nil
+	}
+	// site-wide request which returned multiple store.PostInfo, so that URL and ReadOnly flags don't make sense
+	var info store.PostInfo
+	for _, i := range res {
+		info.Count += i.Count
+		if info.FirstTS.IsZero() || i.FirstTS.Before(info.FirstTS) {
+			info.FirstTS = i.FirstTS
+		}
+		if info.LastTS.IsZero() || i.LastTS.After(info.LastTS) {
+			info.LastTS = i.LastTS
+		}
+	}
+	return info, nil
+
 }
 
 // Delete comment by id