From e84383373ab75da912201382c8340364872f7af8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Richard=20Kub=C3=AD=C4=8Dek?= <rici.kubicek@gmail.com>
Date: Thu, 16 Jan 2025 13:02:53 +0100
Subject: [PATCH] data_types: Date - a new data type

---
 utils/__init__.py   |  0
 utils/data_types.py | 62 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 utils/__init__.py
 create mode 100644 utils/data_types.py

diff --git a/utils/__init__.py b/utils/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/utils/data_types.py b/utils/data_types.py
new file mode 100644
index 0000000..af65e71
--- /dev/null
+++ b/utils/data_types.py
@@ -0,0 +1,62 @@
+from datetime import datetime
+from typing import Optional
+
+import json
+
+
+class Date:
+    def __init__(self, date_str: Optional[str] = None):
+        """
+        Creates a Date instance that supports typing and validation for the format YYYY-MM-DD.
+
+        :param date_str: Date in the format YYYY-MM-DD or None.
+        """
+        self.date: Optional[datetime] = None
+        if date_str:
+            self.date = self._validate_date(date_str)
+
+    @staticmethod
+    def _validate_date(date_str: str) -> datetime:
+        """
+        Validates that the date is in the format YYYY-MM-DD.
+
+        :param date_str: Date as a string.
+        :return: Validated date as a datetime instance.
+        """
+        try:
+            return datetime.strptime(date_str, "%Y-%m-%d")
+        except ValueError:
+            raise ValueError(f"Date must be in format YYYY-MM-DD, got: {date_str}")
+
+    def __str__(self) -> str:
+        """
+        Returns the date as a string in the format YYYY-MM-DD, or 'None' if not set.
+        """
+        return self.date.strftime("%Y-%m-%d") if self.date else "None"
+
+    def is_set(self) -> bool:
+        """
+        Returns True if the date is set, otherwise False.
+        """
+        return self.date is not None
+
+    def to_dict(self) -> Optional[str]:
+        """
+        Converts the Date object to a serializable format.
+        :return: The date as a string in YYYY-MM-DD format, or None if not set.
+        """
+        return self.date.strftime("%Y-%m-%d") if self.date else None
+
+    def to_json(self) -> Optional[str]:
+        """
+        Converts the Date object to a JSON serializable format.
+        :return: The date as a string in YYYY-MM-DD format, or None if not set.
+        """
+        return self.to_dict()
+
+
+class DateEncoder(json.JSONEncoder):
+    def default(self, o):
+        if isinstance(o, Date):
+            return o.to_json()
+        return super().default(o)