From 72c7cba9dcc23ccb3a8d3ec7011d4eddd5c9e6f9 Mon Sep 17 00:00:00 2001
From: Joschua Becker <jb@scolasti.co>
Date: Thu, 25 Apr 2024 17:07:45 +0200
Subject: [PATCH] fixed: ms-ics-fix

---
 src/ms-ics-fix/README.md | 18 ++++++++----------
 src/ms-ics-fix/index.js  | 15 +++------------
 2 files changed, 11 insertions(+), 22 deletions(-)

diff --git a/src/ms-ics-fix/README.md b/src/ms-ics-fix/README.md
index d07e742..889b4d5 100644
--- a/src/ms-ics-fix/README.md
+++ b/src/ms-ics-fix/README.md
@@ -30,13 +30,14 @@ Key problem here is, that they are exporting ICS files, which are not RFC compli
 
 ```yml
 # ...
-TZID:UTC                 # Server indicates its using UTC
+TZID:UTC                          # Server indicates its using UTC
+# ...
+TZID:Central Europe Standard Time # Suddenly it indicates the correct timezone
 # ...
 BEGIN:VEVENT
 # ...
-DTSTAMP:20240425T132325Z # Server using a local timezone
-# ...                      and not using the UTC-OFFSET value
-# ...                      as it should to indicate the timezone
+DTSTAMP:20240101T130000Z          # Server using UTC, tho it said it uses CEST
+# ...
 END:VEVENT
 # ...
 ```
@@ -58,18 +59,17 @@ To fix this, this tool will work like an ICS proxy, which will fix the timezone
 |-----------------------------|---------|---------------|---------------------------------------------------------|
 | `ICS_ON_DEMAND`             | boolean | `false`       | Whether to enable the on demand mode.                   |
 | `ICS_{counter}_URL`         | string  | `null`        | The URL of the ICS file to serve.                       |
-| `ICS_{counter}_TZID`        | string  | `null`        | The timezone of the ICS file.                           |
 | `ICS_{counter}_PATH`        | string? | `null`        | The path to serve the ICS file.                         |
 
 ## On Demand Mode
 
-If `ICS_ON_DEMAND` is set to `true`, you can make a GET request to `/` with the query parameter `url` and `tzid`.
+If `ICS_ON_DEMAND` is set to `true`, you can make a GET request to `/` with the query parameter `url`.
 
 ```http
-/?url=https%3A%2F%2Fexample.com%2Fcalendar.ics&tzid=Europe%2FBerlin
+/?url=https%3A%2F%2Fexample.com%2Fcalendar.ics
 ```
 
-This will return the ICS file from `https://example.com/calendar.ics` with the timezone `Europe/Berlin`.
+This will return the ICS file from `https://example.com/calendar.ics`.
 
 **Don't forget to URL encode the query parameters.**
 
@@ -84,10 +84,8 @@ services:
       - "3000:3000"
     environment:
       ICS_0_URL: "https://example.com/calendar1.ics"
-      ICS_0_TZID: "Europe/Berlin"
       ICS_0_PATH: "your-new-filename-which-will-be-served.ics"
       ICS_1_URL: "https://example.com/calendar2.ics"
-      ICS_1_TZID: "Europe/Berlin"
       # ...
 ```
 
diff --git a/src/ms-ics-fix/index.js b/src/ms-ics-fix/index.js
index 898e333..af02742 100644
--- a/src/ms-ics-fix/index.js
+++ b/src/ms-ics-fix/index.js
@@ -13,7 +13,6 @@ let counter = 0
 while (process.env[`ICS_${counter}_URL`]) {
   config.ics.push({
     url: process.env[`ICS_${counter}_URL`],
-    tz: process.env[`ICS_${counter}_TZID`],
     path: process.env[`ICS_${counter}_PATH`],
   })
   counter++
@@ -24,7 +23,7 @@ config.ics = (() => {
   const n = []
   const s = new Set()
   for (const ics of config.ics) {
-    if (!ics.url || !ics.tz) continue // Skip invalid ICS
+    if (!ics.url) continue // Skip invalid ICS
     if (s.has(ics.path)) ics.path = null // Reset path if duplicated
     let c = -1
     if (!ics.path) do { // Generate path if not provided
@@ -38,17 +37,9 @@ config.ics = (() => {
 })();
 
 // The little magic, microsoft is too lazy to implement...
-async function doIcsFix(url, tz) {
+async function doIcsFix(url) {
   const ics = await fetch(url).then(res => res.text())
-  return ics.replace(/^TZID:.*$/gm, `TZID:UTC`).split('\n').map(line => {
-    // Translate DTSTART and DTEND from the specified timezone to UTC
-    if (!line.startsWith('DTSTART') && !line.startsWith('DTEND')) return line
-    const date = line.split(':')[1]
-    const dt = new Date(date)
-    const dtUTC = new Date(dt.toLocaleString('en-US', { timeZone: tz }))
-    return `${line.split(':')[0]}:${dtUTC.toISOString().replace(/[-:]/g, '').replace(/\.\d+/, '')}`
-    return line
-  }).join('\n')
+  return ics.replace(/^TZID:.*$/gm, `TZID:UTC`)
 }
 
 app.get('*', (req, res) => {