Improved the way the date is shown

lib/ui/tiles/conversation_tile.dart

@@ -1,4 +1,5 @@
 import 'package:comunic/models/conversation.dart';
+import 'package:comunic/utils/date_utils.dart';
 import 'package:comunic/utils/intl_utils.dart';
 import 'package:flutter/material.dart';
 
@@ -36,7 +37,8 @@ class ConversationTile extends StatelessWidget {
       subtitle: Column(
         crossAxisAlignment: CrossAxisAlignment.stretch,
         children: <Widget>[
-          _buildSubInformation(Icons.access_time, "time"), //TODO : improve the way the time is shown
+          _buildSubInformation(
+              Icons.access_time, diffTimeFromNowToStr(conversation.lastActive)),
           _buildSubInformation(
             Icons.group,
             conversation.members.length == 1

lib/utils/date_utils.dart

@@ -0,0 +1,48 @@
+import 'package:comunic/utils/intl_utils.dart';
+
+/// Date utilities
+///
+/// @author Pierre HUBERT
+
+/// Get current timestamp
+int time() {
+  return (DateTime.now().millisecondsSinceEpoch / 1000).floor();
+}
+
+String diffTimeToStr(int amount) {
+  if (amount < 0) amount = 0;
+
+  // Seconds
+  if (amount < 60) return tr("%secs%s", args: {"secs": amount.toString()});
+
+  // Minutes
+  if (amount < 60 * 60)
+    return tr("%mins% min", args: {"mins": (amount / 60).floor().toString()});
+
+  // Hours
+  if (amount < 60 * 60 * 24)
+    return tr("%hours% h",
+        args: {"hours": (amount / (60 * 60)).floor().toString()});
+
+  // Days
+  if (amount < 60 * 60 * 24 * 30)
+    return tr("%days%d",
+        args: {"days": (amount / (60 * 60 * 24)).floor().toString()});
+
+  // Months
+  if (amount < 60 * 60 * 24 * 365) {
+    final months = (amount / (60 * 60 * 24 * 30)).floor();
+    return months == 1
+        ? tr("1 month")
+        : tr("%months% months", args: {"months": months.toString()});
+  }
+
+  // Years
+  final years = (amount / (60 * 60 * 24 * 365)).floor();
+  return years == 1 ? tr("1 year") : tr("%years% years",
+      args: {"years": years.toString()});
+}
+
+String diffTimeFromNowToStr(int date) {
+  return diffTimeToStr(time() - date);
+}