Add validation for the feedback and model solution reveal rules

The validation rejected courses that used the reveal rule settings
since the validation code did not include those settings at all.

The SimpleDuration and AnyDate codes were moved so that the new
code may also refer to AnyDate.

access/course.py

@@ -30,12 +30,48 @@ def _get_datetime(value: Any) -> Optional[datetime]:
     return value
 
 
+class SimpleDuration(PydanticModel):
+    __root__: str
+
+    @root_validator
+    def simple_duration(cls, values: dict):
+        delta = values.get('__root__')
+        if not isinstance(delta, str):
+            raise ValueError("A duration must be a string")
+        if not delta:
+            raise ValueError("An empty string cannot be turned into a duration")
+
+        try:
+            int(delta[:-1])
+        except:
+            raise ValueError("Format: <integer>(y|m|d|h|w) e.g. 3d")
+
+        if delta[-1] in ("y", "m", "w", "d", "h"):
+            return values
+        else:
+            raise ValueError("Format: <integer>(y|m|d|h|w) e.g. 3d")
+
+AnyDuration = Union[timedelta, SimpleDuration]
+AnyDate = Union[datetime, date, str]
+# FIXME: str in AnyDate passes invalid dates and any strings.
+# str should be removed. However, removing it causes crashes with the Undefined type.
+
+
+Float0to1 = confloat(ge=0, le=1)
+
+
 class ConfigureOptions(PydanticModel):
     files: Dict[str,str] = {}
     # ellipsis (...) makes the field required in the case that a default url isn't specified
     url: str = settings.DEFAULT_GRADER_URL or ... # type: ignore
 
 
+class RevealRuleOptions(PydanticModel):
+    trigger: Literal["immediate", "manual", "time", "deadline", "deadline_all", "completion"]
+    time: NotRequired[AnyDate]
+    delay_minutes: NotRequired[NonNegativeInt]
+
+
 class ExerciseConfig(PydanticModel):
     data: Dict[str, dict]
     file: str
@@ -180,6 +216,8 @@ class Exercise(Item):
     max_group_size: NotRequired[NonNegativeInt]
     max_points: NotRequired[NonNegativeInt]
     points_to_pass: NotRequired[NonNegativeInt]
+    reveal_submission_feedback: NotRequired[RevealRuleOptions]
+    reveal_model_solutions: NotRequired[RevealRuleOptions]
     _config_obj: Optional[ExerciseConfig] = PrivateAttr(default=None)
 
     def config_file_info(self, course_dir: str, grader_config_dir: str) -> Optional[Tuple[str, str]]:
@@ -309,36 +347,6 @@ def validate_static_content(cls, paths: Localized[Path]):
 Chapter.update_forward_refs()
 
 
-class SimpleDuration(PydanticModel):
-    __root__: str
-
-    @root_validator
-    def simple_duration(cls, values: dict):
-        delta = values.get('__root__')
-        if not isinstance(delta, str):
-            raise ValueError("A duration must be a string")
-        if not delta:
-            raise ValueError("An empty string cannot be turned into a duration")
-
-        try:
-            int(delta[:-1])
-        except:
-            raise ValueError("Format: <integer>(y|m|d|h|w) e.g. 3d")
-
-        if delta[-1] in ("y", "m", "w", "d", "h"):
-            return values
-        else:
-            raise ValueError("Format: <integer>(y|m|d|h|w) e.g. 3d")
-
-AnyDuration = Union[timedelta, SimpleDuration]
-AnyDate = Union[datetime, date, str]
-# FIXME: str in AnyDate passes invalid dates and any strings.
-# str should be removed. However, removing it causes crashes with the Undefined type.
-
-
-Float0to1 = confloat(ge=0, le=1)
-
-
 class Module(Parent):
     name: Localized[str]
     key: str