Merge #8371: [Qt] Add out-of-sync modal info layer

08827df [Qt] modalinfolayer: removed unused comments, renamed signal, code style overhaul (Jonas Schnelli)
d8b062e [Qt] only update "amount of blocks left" when the header chain is in-sync (Jonas Schnelli)
e3245b4 [Qt] add out-of-sync modal info layer (Jonas Schnelli)
e47052f [Qt] ClientModel add method to get the height of the header chain (Jonas Schnelli)
a001f18 [Qt] Always pass the numBlocksChanged signal for headers tip changed (Jonas Schnelli)
bd44a04 [Qt] make Out-Of-Sync warning icon clickable (Jonas Schnelli)
0904c3c [Refactor] refactor function that forms human readable text out of a timeoffset (Jonas Schnelli)

src/qt/guiutil.cpp

@@ -955,4 +955,40 @@ QString formatTimeOffset(int64_t nTimeOffset)
   return QString(QObject::tr("%1 s")).arg(QString::number((int)nTimeOffset, 10));
 }
 
+QString formateNiceTimeOffset(qint64 secs)
+{
+    // Represent time from last generated block in human readable text
+    QString timeBehindText;
+    const int HOUR_IN_SECONDS = 60*60;
+    const int DAY_IN_SECONDS = 24*60*60;
+    const int WEEK_IN_SECONDS = 7*24*60*60;
+    const int YEAR_IN_SECONDS = 31556952; // Average length of year in Gregorian calendar
+    if(secs < 60)
+    {
+        timeBehindText = QObject::tr("%n seconds(s)","",secs);
+    }
+    else if(secs < 2*HOUR_IN_SECONDS)
+    {
+        timeBehindText = QObject::tr("%n minutes(s)","",secs/60);
+    }
+    else if(secs < 2*DAY_IN_SECONDS)
+    {
+        timeBehindText = QObject::tr("%n hour(s)","",secs/HOUR_IN_SECONDS);
+    }
+    else if(secs < 2*WEEK_IN_SECONDS)
+    {
+        timeBehindText = QObject::tr("%n day(s)","",secs/DAY_IN_SECONDS);
+    }
+    else if(secs < YEAR_IN_SECONDS)
+    {
+        timeBehindText = QObject::tr("%n week(s)","",secs/WEEK_IN_SECONDS);
+    }
+    else
+    {
+        qint64 years = secs / YEAR_IN_SECONDS;
+        qint64 remainder = secs % YEAR_IN_SECONDS;
+        timeBehindText = QObject::tr("%1 and %2").arg(QObject::tr("%n year(s)", "", years)).arg(QObject::tr("%n week(s)","", remainder/WEEK_IN_SECONDS));
+    }
+    return timeBehindText;
+}
 } // namespace GUIUtil