From e3fb76fae006b0736a8673e4e0bf18b35cd0dada Mon Sep 17 00:00:00 2001
From: Trevor Cox <trevor.cox@appazur.com>
Date: Mon, 4 Jul 2022 10:02:27 -0700
Subject: [PATCH] Add datetime_rule_variable/DateTimeType.

---
 business_rules/fields.py    |  1 +
 business_rules/operators.py | 41 ++++++++++++++++++++++++++++++++++++-
 business_rules/variables.py |  6 +++++-
 3 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/business_rules/fields.py b/business_rules/fields.py
index a1c64240..087e2879 100644
--- a/business_rules/fields.py
+++ b/business_rules/fields.py
@@ -3,3 +3,4 @@
 FIELD_NO_INPUT = 'none'
 FIELD_SELECT = 'select'
 FIELD_SELECT_MULTIPLE = 'select_multiple'
+FIELD_DATETIME = 'datetime'
diff --git a/business_rules/operators.py b/business_rules/operators.py
index d43e5b1f..2af60bd9 100644
--- a/business_rules/operators.py
+++ b/business_rules/operators.py
@@ -1,10 +1,12 @@
 import inspect
 import re
+from datetime import datetime
 from functools import wraps
 from six import string_types, integer_types
 
 from .fields import (FIELD_TEXT, FIELD_NUMERIC, FIELD_NO_INPUT,
-                     FIELD_SELECT, FIELD_SELECT_MULTIPLE)
+                     FIELD_SELECT, FIELD_SELECT_MULTIPLE,
+                     FIELD_DATETIME)
 from .utils import fn_name_to_pretty_label, float_to_decimal
 from decimal import Decimal, Inexact, Context
 
@@ -235,3 +237,40 @@ def shares_exactly_one_element_with(self, other_value):
     @type_operator(FIELD_SELECT_MULTIPLE)
     def shares_no_elements_with(self, other_value):
         return not self.shares_at_least_one_element_with(other_value)
+
+
+@export_type
+class DateTimeType(BaseType):
+    # This implementation handles only naive datetimes, as provided by
+    # HTML5 datetime-local inputs. For another approach, see:
+    #  business_rules in https://github.com/TencentBlueKing/bk-itsm/
+
+    name = "datetime"
+    # HTML5 datetime-local text format:
+    DATETIME_FORMAT = "%Y-%m-%dT%H:%M"
+
+    def _assert_valid_value_and_cast(self, value):
+        """
+        Parse string into datetime.datetime instance.
+        """
+        if isinstance(value, datetime):
+            return value
+
+        try:
+            return datetime.strptime(value, self.DATETIME_FORMAT)
+        except (ValueError, TypeError):
+            raise AssertionError("{0} is not a valid date/time.".format(value))
+
+    @type_operator(FIELD_DATETIME, label="Equal To")
+    def equal_to(self, other_datetime):
+        return self.value == other_datetime
+
+    @type_operator(FIELD_DATETIME, label="After")
+    def after_than_or_equal_to(self, other_datetime):
+        print(f'after_than_or_equal_to {self.value} {other_datetime}')
+        return self.value >= other_datetime
+
+    @type_operator(FIELD_DATETIME, label="Before")
+    def before_than_or_equal_to(self, other_datetime):
+        print(f'before_than_or_equal_to {self.value} {other_datetime}')
+        return self.value <= other_datetime
diff --git a/business_rules/variables.py b/business_rules/variables.py
index b7863f60..0b4fe064 100644
--- a/business_rules/variables.py
+++ b/business_rules/variables.py
@@ -6,7 +6,8 @@
                         StringType,
                         BooleanType,
                         SelectType,
-                        SelectMultipleType)
+                        SelectMultipleType,
+                        DateTimeType)
 
 class BaseVariables(object):
     """ Classes that hold a collection of variables to use with the rules
@@ -59,3 +60,6 @@ def select_rule_variable(label=None, options=None):
 
 def select_multiple_rule_variable(label=None, options=None):
     return rule_variable(SelectMultipleType, label=label, options=options)
+
+def datetime_rule_variable(label=None):
+    return _rule_variable_wrapper(DateTimeType, label)