From da8c27863cf8c6e633eb55686d4556f045fc35be Mon Sep 17 00:00:00 2001
From: Marius Andra <marius.andra@gmail.com>
Date: Fri, 15 Nov 2024 15:35:55 +0100
Subject: [PATCH] fix zones

---
 hogvm/__tests__/__snapshots__/date.js    | 31 ++++++++++++------------
 posthog/hogql/compiler/javascript_stl.py | 31 ++++++++++++------------
 2 files changed, 32 insertions(+), 30 deletions(-)

diff --git a/hogvm/__tests__/__snapshots__/date.js b/hogvm/__tests__/__snapshots__/date.js
index 66b2b87239e78..71af223af0e56 100644
--- a/hogvm/__tests__/__snapshots__/date.js
+++ b/hogvm/__tests__/__snapshots__/date.js
@@ -81,8 +81,8 @@ function __escapeIdentifier(identifier) {
 }
 function __isHogDateTime(obj) { return obj && obj.__hogDateTime__ === true }
 function __isHogDate(obj) { return obj && obj.__hogDate__ === true }
-function __DateTimeToString (dt) {
-        if (__isHogDateTime(dt)) {
+function __DateTimeToString(dt) {
+    if (__isHogDateTime(dt)) {
         const date = new Date(dt.dt * 1000);
         const timeZone = dt.zone || 'UTC';
         const milliseconds = Math.floor(dt.dt * 1000 % 1000);
@@ -101,25 +101,26 @@ function __DateTimeToString (dt) {
                 default: break;
             }
         }
+        const getOffset = (date, timeZone) => {
+            const tzDate = new Date(date.toLocaleString('en-US', { timeZone }));
+            const utcDate = new Date(date.toLocaleString('en-US', { timeZone: 'UTC' }));
+            const offset = (tzDate - utcDate) / 60000; // in minutes
+            const sign = offset >= 0 ? '+' : '-';
+            const absOffset = Math.abs(offset);
+            const hours = Math.floor(absOffset / 60);
+            const minutes = absOffset % 60;
+            return `${sign}${String(hours).padStart(2, '0')}:${String(minutes).padStart(2, '0')}`;
+        };
         let offset = 'Z';
         if (timeZone !== 'UTC') {
-            const tzOptions = { timeZone, timeZoneName: 'shortOffset' };
-            const tzFormatter = new Intl.DateTimeFormat('en-US', tzOptions);
-            const tzParts = tzFormatter.formatToParts(date);
-            const timeZoneNamePart = tzParts.find(part => part.type === 'timeZoneName');
-            if (timeZoneNamePart && timeZoneNamePart.value) {
-                const offsetString = timeZoneNamePart.value;
-                const match = offsetString.match(/GMT([+-]\d{2})(?::?(\d{2}))?/);
-                offset = match ? `${match[1][0]}${match[1].slice(1).padStart(2, '0')}:${(match[2] || '00').padStart(2, '0')}` : offsetString === 'GMT' ? '+00:00' : '';
-            }
+            offset = getOffset(date, timeZone);
         }
         let isoString = `${year}-${month}-${day}T${hour}:${minute}:${second}`;
-        if (milliseconds !== null) {
-            isoString += `.${milliseconds.toString().padStart(3, '0')}`;
-        }
+        isoString += `.${milliseconds.toString().padStart(3, '0')}`;
         isoString += offset;
         return isoString;
-    }}
+    }
+}
 
 let dt = fromUnixTimestamp(1234334543);
 print(dt);
diff --git a/posthog/hogql/compiler/javascript_stl.py b/posthog/hogql/compiler/javascript_stl.py
index dd5e9f6b02cb1..6fcbcb6f9de52 100644
--- a/posthog/hogql/compiler/javascript_stl.py
+++ b/posthog/hogql/compiler/javascript_stl.py
@@ -439,8 +439,8 @@
         ["__isHogDateTime", "__isHogDate", "__isHogError"],
     ],
     "__DateTimeToString": [
-        r"""function __DateTimeToString (dt) {
-        if (__isHogDateTime(dt)) {
+        r"""function __DateTimeToString(dt) {
+    if (__isHogDateTime(dt)) {
         const date = new Date(dt.dt * 1000);
         const timeZone = dt.zone || 'UTC';
         const milliseconds = Math.floor(dt.dt * 1000 % 1000);
@@ -459,25 +459,26 @@
                 default: break;
             }
         }
+        const getOffset = (date, timeZone) => {
+            const tzDate = new Date(date.toLocaleString('en-US', { timeZone }));
+            const utcDate = new Date(date.toLocaleString('en-US', { timeZone: 'UTC' }));
+            const offset = (tzDate - utcDate) / 60000; // in minutes
+            const sign = offset >= 0 ? '+' : '-';
+            const absOffset = Math.abs(offset);
+            const hours = Math.floor(absOffset / 60);
+            const minutes = absOffset % 60;
+            return `${sign}${String(hours).padStart(2, '0')}:${String(minutes).padStart(2, '0')}`;
+        };
         let offset = 'Z';
         if (timeZone !== 'UTC') {
-            const tzOptions = { timeZone, timeZoneName: 'shortOffset' };
-            const tzFormatter = new Intl.DateTimeFormat('en-US', tzOptions);
-            const tzParts = tzFormatter.formatToParts(date);
-            const timeZoneNamePart = tzParts.find(part => part.type === 'timeZoneName');
-            if (timeZoneNamePart && timeZoneNamePart.value) {
-                const offsetString = timeZoneNamePart.value;
-                const match = offsetString.match(/GMT([+-]\d{2})(?::?(\d{2}))?/);
-                offset = match ? `${match[1][0]}${match[1].slice(1).padStart(2, '0')}:${(match[2] || '00').padStart(2, '0')}` : offsetString === 'GMT' ? '+00:00' : '';
-            }
+            offset = getOffset(date, timeZone);
         }
         let isoString = `${year}-${month}-${day}T${hour}:${minute}:${second}`;
-        if (milliseconds !== null) {
-            isoString += `.${milliseconds.toString().padStart(3, '0')}`;
-        }
+        isoString += `.${milliseconds.toString().padStart(3, '0')}`;
         isoString += offset;
         return isoString;
-    }}
+    }
+}
     """,
         [],
     ],