Add detail tooltips in server browser stability %

When hovering on stability percentages in the server browser, a tooltip
now shows the total downtime in the past 30 days, number of incidents,
their average length and the longest's duration.

src/backend/backend.py

@@ -7,7 +7,7 @@ import os
 import re
 import sys
 import time
-from datetime import datetime
+from datetime import datetime, timedelta
 from pathlib import Path
 from typing import Any, DefaultDict, Dict, List, Optional, Tuple, Union
 from urllib.parse import urlparse
@@ -492,8 +492,13 @@ class Backend:
                 )
 
 
-    def _get_homeserver_stability(self, logs: List[Dict[str, Any]]) -> float:
+    def _get_homeserver_stability(
+        self, logs: List[Dict[str, Any]],
+    ) -> Tuple[float, List[timedelta]]:
+        """Return server stability % and a list of downtime durations."""
+
         stability = 100.0
+        durations = []
 
         for period in logs:
             started_at     = datetime.fromtimestamp(period["datetime"])
@@ -503,13 +508,14 @@ class Backend:
                 continue
 
             lasted_minutes  = period["duration"] / 60
+            durations.append(timedelta(seconds=period["duration"]))
 
             stability -= (
                 (lasted_minutes * stability / 1000) /
                 max(1, time_since_now.days / 3)
             )
 
-        return stability
+        return (stability, durations)
 
 
     async def fetch_homeservers(self) -> None:
@@ -533,13 +539,16 @@ class Backend:
             if server["country"] == "USA":
                 server["country"] = "United States"
 
+            stability, durations = \
+                self._get_homeserver_stability(server["monitor"]["logs"])
+
             self.models["homeservers"][homeserver_url] = Homeserver(
                 id           = homeserver_url,
                 name         = server["name"],
                 site_url     = server["url"],
                 country      = server["country"],
-                stability =
-                    self._get_homeserver_stability(server["monitor"]["logs"]),
+                stability    = stability,
+                downtimes_ms = [d.total_seconds() * 1000 for d in durations],
             )
 
             coros.append(self._ping_homeserver(session, homeserver_url))

src/backend/models/items.py

@@ -49,6 +49,7 @@ class Homeserver(ModelItem):
     ping:           int         = -1
     status:         PingStatus  = PingStatus.Pinging
     stability:      float       = -1
+    downtimes_ms:   List[float] = field(default_factory=list)
 
     def __lt__(self, other: "Homeserver") -> bool:
         return (self.name.lower(), self.id) < (other.name.lower(), other.id)

src/gui/Pages/AddAccount/ServerDelegate.qml

@@ -79,6 +79,25 @@ HTile {
                 model.stability >= 95 ? theme.colors.positiveText :
                 model.stability >= 85 ? theme.colors.warningText :
                 theme.colors.errorText
+
+            HoverHandler { id: rightInfoHover }
+
+            HToolTip {
+                readonly property var times: JSON.parse(model.downtimes_ms)
+                readonly property real total: utils.sum(times)
+
+                visible: model.stability !== -1 && rightInfoHover.hovered
+                text:
+                    total === 0 ?
+                    qsTr("No downtimes in the last 30 days") :
+                    qsTr(
+                        "Last 30 days downtimes: %1, average: %2, " +
+                        "longest: %3, total: %4"
+                    ).arg(times.length)
+                     .arg(utils.formatRelativeTime(total / times.length))
+                     .arg(utils.formatRelativeTime(Math.max.apply(Math,times)))
+                     .arg(utils.formatRelativeTime(total))
+            }
         }
 
         HButton {