make getMaxGraphDataLength/getMaxServerGraphDataLength methods static

lib/time.js

@@ -1,3 +1,5 @@
+const config = require('../config.json')
+
 class TimeTracker {
   constructor (app) {
     this._app = app
@@ -9,7 +11,7 @@ class TimeTracker {
 
     this._points.push(timestamp)
 
-    if (this._points.length > this._app.pingController.getMaxServerGraphDataLength()) {
+    if (this._points.length > TimeTracker.getMaxServerGraphDataLength()) {
       this._points.shift()
     }
 
@@ -19,6 +21,14 @@ class TimeTracker {
   getPoints () {
     return this._points
   }
+
+  static getMaxServerGraphDataLength () {
+    return Math.ceil(config.serverGraphDuration / config.rates.pingAll)
+  }
+
+  static getMaxGraphDataLength () {
+    return Math.ceil(config.graphDuration / config.rates.pingAll)
+  }
 }
 
 module.exports = TimeTracker