From 84cb1e0e0f2150d1c3239939cfd2c8193977bfd0 Mon Sep 17 00:00:00 2001
From: ChoiHwaa <107089378+ChoiHwaa@users.noreply.github.com>
Date: Tue, 14 Jun 2022 01:52:47 +0100
Subject: [PATCH] Fix for serialize datetime

---
 telethon/tl/tlobject.py | 42 ++++++++++++++++-------------------------
 1 file changed, 16 insertions(+), 26 deletions(-)

diff --git a/telethon/tl/tlobject.py b/telethon/tl/tlobject.py
index 4b94e00f..25f8ab5a 100644
--- a/telethon/tl/tlobject.py
+++ b/telethon/tl/tlobject.py
@@ -4,23 +4,11 @@ import struct
 from datetime import datetime, date, timedelta, timezone
 import time
 
-_EPOCH_NAIVE = datetime(*time.gmtime(0)[:6])
-_EPOCH_NAIVE_LOCAL = datetime(*time.localtime(0)[:6])
-_EPOCH = _EPOCH_NAIVE.replace(tzinfo=timezone.utc)
-
-
-def _datetime_to_timestamp(dt):
-    # If no timezone is specified, it is assumed to be in utc zone
-    if dt.tzinfo is None:
-        dt = dt.replace(tzinfo=timezone.utc)
-    # We use .total_seconds() method instead of simply dt.timestamp(), 
-    # because on Windows the latter raises OSError on datetimes ~< datetime(1970,1,1)
-    secs = int((dt - _EPOCH).total_seconds())
-    # Make sure it's a valid signed 32 bit integer, as used by Telegram.
-    # This does make very large dates wrap around, but it's the best we
-    # can do with Telegram's limitations.
-    return struct.unpack('i', struct.pack('I', secs & 0xffffffff))[0]
-
+def _getNativeTimeZone():
+    offset = time.timezone
+    if time.localtime().tm_isdst:
+        offset += 1
+    return timezone(timedelta(hours=offset))
 
 def _json_default(value):
     if isinstance(value, bytes):
@@ -142,15 +130,17 @@ class TLObject:
         if not dt and not isinstance(dt, timedelta):
             return b'\0\0\0\0'
 
-        if isinstance(dt, datetime):
-            dt = _datetime_to_timestamp(dt)
-        elif isinstance(dt, date):
-            dt = _datetime_to_timestamp(datetime(dt.year, dt.month, dt.day))
-        elif isinstance(dt, float):
-            dt = int(dt)
-        elif isinstance(dt, timedelta):
-            # Timezones are tricky. datetime.utcnow() + ... timestamp() works
-            dt = _datetime_to_timestamp(datetime.utcnow() + dt)
+        try:
+            if isinstance(dt, datetime):
+                dt = int(dt.timestamp())
+            elif isinstance(dt, date):
+                dt = int(datetime(dt.year, dt.month, dt.day).timestamp())
+            elif isinstance(dt, float):
+                dt = int(dt)
+            elif isinstance(dt, timedelta):
+                dt = int(datetime.fromtimestamp(dt.total_seconds()).timestamp())
+        except OSError:
+            dt = 0
 
         if isinstance(dt, int):
             return struct.pack('<i', dt)