1 files changed, 20 insertions, 1 deletions
diff --git a/routes/getSchedule.js b/routes/getSchedule.js
index ed9f1a9..f6c3cb6 100644
--- a/routes/getSchedule.js
+++ b/routes/getSchedule.js
@@ -6,10 +6,25 @@ const iconv = require('iconv-lite')
 const getUserIndex = require('../lib/getUserIndex')
 const getURLOfUser = require('../lib/getURLOfUser')
 
+// copied from http://www.meetingpointmco.nl/Roosters-AL/doc/dagroosters/untisscripts.js,
+// were using the same code as they do to be sure that we always get the same
+// week number.
+function getWeekNumber (target) {
+  const dayNr = (target.getDay() + 6) % 7
+  target.setDate(target.getDate() - dayNr + 3)
+  const firstThursday = target.valueOf()
+  target.setMonth(0, 1)
+  if (target.getDay() !== 4) {
+    target.setMonth(0, 1 + ((4 - target.getDay()) + 7) % 7)
+  }
+
+  return 1 + Math.ceil((firstThursday - target) / 604800000)
+}
+
 router.get('/:type/:value', function (req, res, next) {
   getUserIndex().then(users => {
     const { type, value } = req.params
-    const { week } = req.query
+    let { week } = req.query
     const user =
       users.filter(user => user.type === type && user.value === value)[0]
 
@@ -17,6 +32,10 @@ router.get('/:type/:value', function (req, res, next) {
       next(new Error(`${type}${value} is not in the user index.`))
     }
 
+    if (!week) {
+      week = getWeekNumber(new Date())
+    }
+
     const { index } = user
 
     const url = getURLOfUser(type, index, week)