From 193cc58443f1a55e049a6f04de27c27d158a75d0 Mon Sep 17 00:00:00 2001
From: Y <theYinYeti@yalis.fr>
Date: Tue, 1 Oct 2019 20:34:53 +0200
Subject: [PATCH] newer RFC 5545 spec (https://icalendar.org/validator.html)

---
 README.adoc     |  6 ++++--
 epsiEDTtoICS.sh | 49 ++++++++++++++++++++++++++++++++-----------------
 2 files changed, 36 insertions(+), 19 deletions(-)

diff --git a/README.adoc b/README.adoc
index 92e9ff2..efc15c1 100644
--- a/README.adoc
+++ b/README.adoc
@@ -47,8 +47,10 @@ into entries like that:
 
 ```
 BEGIN:VEVENT
-DTSTART:20191001T130000+0200
-DTEND:20191001T150000+0200
+UID:20191001T110000Z/epsi2ics/YOUR.LOGIN@HOSTNAME
+DTSTAMP:20191001T184200Z
+DTSTART:20191001T110000Z
+DTEND:20191001T130000Z
 SUMMARY:HTLM5 / CSS3
 LOCATION:N202(HEP Nantes)
 DESCRIPTION:🗣 teacher name 👥 class-group name
diff --git a/epsiEDTtoICS.sh b/epsiEDTtoICS.sh
index e7b3fe5..76ca085 100755
--- a/epsiEDTtoICS.sh
+++ b/epsiEDTtoICS.sh
@@ -3,6 +3,9 @@
 # Copyright © 2019 Y. Gablin, under the GPL-3.0-or-later license.
 # Full licensing information in the LICENSE file, or gnu.org/licences/gpl-3.0.txt if the file is missing.
 #
+# This script only works when executed in the timezone of the calendar, and only if this timezone offset
+# is low enough to keep all events in the day they belong to in the web calendar (usually −6h ≤ TZ ≤ +8h).
+#
 # from EPSI “edtmobilityeng” to ICS, for the current school year
 # $1: EPSI Login (firstname.lastname)
 # $2: output file (else standard output)
@@ -12,6 +15,7 @@ if [ -n "$2" -a -d "$(dirname "$2")" -a -w "$(dirname "$2")" ]; then
 fi
 
 (
+  dtstamp=$(date -u +%Y%m%dT%H%M%SZ)
   currentYear=$(date +%Y)
   splitDay=$(date +%j -d "${currentYear}-08-01" | sed 's/^0*//') # XXXX-08-01 ∈ [1 … 366]
   dayOfYear=$(date +%j | sed 's/^0*//')                          #  this day  ∈ [1 … 366]
@@ -27,7 +31,7 @@ fi
   cat <<-ENDOFTEXT
 BEGIN:VCALENDAR
 VERSION:2.0
-PRODID:yalis.fr/epsi2ical v1.0/FR
+PRODID:yalis.fr/epsi2ical v1.1
 ENDOFTEXT
 
   while [ $offset -lt $offsetMax ]; do
@@ -41,23 +45,32 @@ ENDOFTEXT
     | tr '\r\n' ' ' \
     | sed -r 's/[[:blank:]]+/ /g' \
     | grep -oE '<DIV [^>]*class="Case" [^>]*style="[^"]*left *:[^"]*"|DIV [^>]*style="[^"]*left *:[^"]*" [^>]*class="Case"|<td [^>]*class="TC(ase|Prof|hdeb|Salle)"([^<]|<[^/]|</[^t]|</t[^d])*</td>' \
-    | awk -vmon=$mon -vtue=$tue -vwed=$wed -vthu=$thu -vfri=$fri -F$'\t' '
+    | awk -vmon=$mon -vtue=$tue -vwed=$wed -vthu=$thu -vfri=$fri -vid="epsi2ics/${1}@${HOSTNAME}" -vdtstamp=$dtstamp -F$'\t' '
       function out() {
-        if (ase!="") printf( \
-          "BEGIN:VEVENT\nDTSTART:%s%s%s\nDTEND:%s%s%s\nSUMMARY:%s\nLOCATION:%s\nDESCRIPTION:🗣 %s 👥 %s\nEND:VEVENT\n", \
-          day, from, zone, \
-          day, to, zone, \
-          ase, \
-          where, \
-          prof, who)
+        if (from!="" && to!="" && ase!="") printf( \
+          "BEGIN:VEVENT\nUID:%s/%s\nDTSTAMP:%s\nDTSTART:%s\nDTEND:%s\nSUMMARY:%s\nLOCATION:%s\nDESCRIPTION:🗣 %s 👥 %s\nEND:VEVENT\n", \
+                           from, id,        dtstamp,    from,     to,         ase,         where,             prof, who)
+        from=""
+        to=""
         ase=""
+        where=""
         prof=""
         who=""
         day=""
-        zone=""
-        from=""
-        to=""
-        where=""
+        zoneH=0
+        zoneM=0
+      }
+      function toZtime(localH, localM) {
+        localM-=zoneM
+        if (localM<0) {
+          localM+=60
+          localH-=1
+        } else if (localM>59) {
+          localM-=60
+          localH+=1
+        }
+        localH-=zoneH
+        return sprintf("%s%02d%02d00Z", day, localH, localM)
       }
       /class="Case"/ {
         out()
@@ -68,7 +81,8 @@ ENDOFTEXT
         else if (pc < 170) tmpd=thu
         else               tmpd=fri
         day=substr(tmpd, 1, 9)
-        zone=substr(tmpd, 10)
+        zoneH=substr(tmpd, 10, 3)+0
+        zoneM=(substr(tmpd, 10, 1) substr(tmpd, 13, 2))+0
       }
       /class="TCase"/ {
         ase=gensub(".*</div>(.*)</.*", "\\1", 1)
@@ -79,9 +93,9 @@ ENDOFTEXT
         who=tmp[2]
       }
       /class="TChdeb"/ {
-        split(gensub(".*> *([^ ]{2}):?([^ ]{2}) *- *([^ ]{2}):?([^ ]{2}) *</.*", "\\1\\2\t\\3\\4", 1), tmp)
-        from=tmp[1] "00"
-        to=tmp[2] "00"
+        split(gensub(".*> *0?([0-9]+):0?([0-9]+) *- *0?([0-9]+):0?([0-9]+) *</.*", "\\1\t\\2\t\\3\t\\4", 1), tmp)
+        from=toZtime(tmp[1], tmp[2])
+        to=toZtime(tmp[3], tmp[4])
       }
       /class="TCSalle"/ {
         where=gensub(".*>(Salle:)?(.*)</.*", "\\2", 1)
@@ -96,4 +110,5 @@ ENDOFTEXT
 END:VCALENDAR
 ENDOFTEXT
 ) \
+| env LANG=fr_FR@euro sed -r 's/(.{73})(.)/\1\n \2/g' \
 | sed 's/$/\r/'