From ef2580feba1432ed00bfaa5c91ab68e9c279186f Mon Sep 17 00:00:00 2001
From: RunasSudo <runassudo@yingtongli.me>
Date: Mon, 21 Apr 2025 23:18:40 +1000
Subject: [PATCH] Implement write for DateTime

---
 csla_binary/binary_writer.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/csla_binary/binary_writer.py b/csla_binary/binary_writer.py
index daeee28..beefe74 100644
--- a/csla_binary/binary_writer.py
+++ b/csla_binary/binary_writer.py
@@ -14,6 +14,7 @@
 #   You should have received a copy of the GNU Affero General Public License
 #   along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+from datetime import datetime
 from decimal import Decimal
 import io
 import struct
@@ -85,6 +86,10 @@ class CslaBinaryWriter:
 		# BinaryWriter.WriteInt32
 		self.stream.write(struct.pack('<i', value))
 	
+	def write_int64(self, value):
+		# BinaryWriter.WriteInt64
+		self.stream.write(struct.pack('<q', value))
+	
 	def write_string(self, value):
 		# BinaryWriter.WriteString - "The string is prefixed with the length, encoded as an integer seven bits at a time."
 		encoded_string = value.encode('utf-8')
@@ -106,6 +111,9 @@ class CslaBinaryWriter:
 		if isinstance(value, Decimal):
 			return self.write_object_decimal(value)
 		
+		if isinstance(value, datetime):
+			return self.write_object_datetime(value)
+		
 		if isinstance(value, str):
 			return self.write_object_string(value)
 		
@@ -124,6 +132,15 @@ class CslaBinaryWriter:
 		self.write_int32(len(value))
 		self.stream.write(value)
 	
+	def write_object_datetime(self, value):
+		# CslaBinaryWriter.Write(DateTime)
+		timestamp_unix = value.timestamp()
+		timestamp = timestamp_unix * 10000000  # Convert seconds to ticks (10^9 / 100)
+		timestamp += 621355968000000000  # Add unix epoch in .NET ticks - https://gist.github.com/kristopherjohnson/397d0f74213a0087f1a1
+		timestamp = int(timestamp)  # Number of 100-nanosecond intervals that have elapsed since January 1, 0001 at 00:00:00.000
+		self.stream.write(bytes([CslaKnownTypes.DateTime.value]))
+		self.write_int64(timestamp)
+	
 	def write_object_decimal(self, value):
 		# CslaBinaryWriter.Write(Decimal)
 		self.stream.write(bytes([CslaKnownTypes.Decimal.value]))