refactor: simplify Campaign editor validation

src/govoplan_campaign/backend/campaign/mail_profile_boundary.py

@@ -29,6 +29,47 @@ class CampaignMailProfileBoundaryError(ValueError):
     """
 
 
+def _validated_opt_ins(value: Any) -> dict[str, bool]:
+    if not isinstance(value, dict) or any(
+        key not in CAMPAIGN_OPT_IN_KEYS for key in value
+    ):
+        raise CampaignMailProfileBoundaryError(
+            "Campaign editor opt_ins contains unsupported fields"
+        )
+    if any(not isinstance(item, bool) for item in value.values()):
+        raise CampaignMailProfileBoundaryError(
+            "Campaign editor opt_ins values must be booleans"
+        )
+    return copy.deepcopy(value)
+
+
+def _is_valid_field_override(key: Any, value: Any) -> bool:
+    return (
+        isinstance(key, str)
+        and bool(key.strip())
+        and len(key) <= 256
+        and isinstance(value, bool)
+    )
+
+
+def _validated_field_overrides(value: Any) -> dict[str, bool]:
+    if not isinstance(value, dict) or len(value) > 10_000:
+        raise CampaignMailProfileBoundaryError(
+            "Campaign editor field_overrides must be a bounded object"
+        )
+    if any(not _is_valid_field_override(key, item) for key, item in value.items()):
+        raise CampaignMailProfileBoundaryError(
+            "Campaign editor field_overrides must map short field names to booleans"
+        )
+    return copy.deepcopy(value)
+
+
+def _validated_required_string(value: Any, *, max_length: int, error: str) -> str:
+    if not isinstance(value, str) or not value.strip() or len(value) > max_length:
+        raise CampaignMailProfileBoundaryError(error)
+    return value.strip()
+
+
 def validate_campaign_editor_state(
     value: dict[str, Any] | None,
     *,
@@ -55,32 +96,17 @@ def validate_campaign_editor_state(
 
     result: dict[str, Any] = {}
     if "created_from" in value:
-        created_from = value["created_from"]
-        if not isinstance(created_from, str) or not created_from.strip() or len(created_from) > 128:
-            raise CampaignMailProfileBoundaryError("Campaign editor created_from must be a short string")
-        result["created_from"] = created_from.strip()
+        result["created_from"] = _validated_required_string(
+            value["created_from"],
+            max_length=128,
+            error="Campaign editor created_from must be a short string",
+        )
     if "opt_ins" in value:
-        opt_ins = value["opt_ins"]
-        if not isinstance(opt_ins, dict) or any(key not in CAMPAIGN_OPT_IN_KEYS for key in opt_ins):
-            raise CampaignMailProfileBoundaryError("Campaign editor opt_ins contains unsupported fields")
-        if any(not isinstance(item, bool) for item in opt_ins.values()):
-            raise CampaignMailProfileBoundaryError("Campaign editor opt_ins values must be booleans")
-        result["opt_ins"] = copy.deepcopy(opt_ins)
+        result["opt_ins"] = _validated_opt_ins(value["opt_ins"])
     if "field_overrides" in value:
-        overrides = value["field_overrides"]
-        if not isinstance(overrides, dict) or len(overrides) > 10_000:
-            raise CampaignMailProfileBoundaryError("Campaign editor field_overrides must be a bounded object")
-        if any(
-            not isinstance(key, str)
-            or not key.strip()
-            or len(key) > 256
-            or not isinstance(item, bool)
-            for key, item in overrides.items()
-        ):
-            raise CampaignMailProfileBoundaryError(
-                "Campaign editor field_overrides must map short field names to booleans"
-            )
-        result["field_overrides"] = copy.deepcopy(overrides)
+        result["field_overrides"] = _validated_field_overrides(
+            value["field_overrides"]
+        )
     if "review_send" in value:
         result["review_send"] = _validated_server_review_state(value["review_send"])
     return result
@@ -122,34 +148,62 @@ def campaign_editor_state_for_edit(value: Any) -> dict[str, Any]:
     return state
 
 
+def _is_valid_reviewed_message_key(value: Any) -> bool:
+    return isinstance(value, str) and bool(value.strip()) and len(value) <= 512
+
+
+def _validated_reviewed_message_keys(value: Any) -> list[str]:
+    if not isinstance(value, list) or len(value) > 100_000:
+        raise CampaignMailProfileBoundaryError(
+            "Campaign reviewed message keys are invalid"
+        )
+    if any(not _is_valid_reviewed_message_key(key) for key in value):
+        raise CampaignMailProfileBoundaryError(
+            "Campaign reviewed message keys are invalid"
+        )
+    return list(dict.fromkeys(key.strip() for key in value))
+
+
+def _validated_review_actor(value: Any) -> str | None:
+    if value is not None and (not isinstance(value, str) or len(value) > 256):
+        raise CampaignMailProfileBoundaryError("Campaign review actor is invalid")
+    return value
+
+
 def _validated_server_review_state(value: Any) -> dict[str, Any]:
-    if not isinstance(value, dict) or any(key not in CAMPAIGN_REVIEW_STATE_KEYS for key in value):
-        raise CampaignMailProfileBoundaryError("Campaign review editor state is invalid")
+    if not isinstance(value, dict) or any(
+        key not in CAMPAIGN_REVIEW_STATE_KEYS for key in value
+    ):
+        raise CampaignMailProfileBoundaryError(
+            "Campaign review editor state is invalid"
+        )
     build_token = value.get("build_token")
     inspected = value.get("inspection_complete")
     keys = value.get("reviewed_message_keys", [])
     updated_at = value.get("updated_at")
     updated_by = value.get("updated_by_user_id")
-    if not isinstance(build_token, str) or not build_token.strip() or len(build_token) > 256:
-        raise CampaignMailProfileBoundaryError("Campaign review build token is invalid")
+    validated_build_token = _validated_required_string(
+        build_token,
+        max_length=256,
+        error="Campaign review build token is invalid",
+    )
     if not isinstance(inspected, bool):
-        raise CampaignMailProfileBoundaryError("Campaign review completion state is invalid")
-    if (
-        not isinstance(keys, list)
-        or len(keys) > 100_000
-        or any(not isinstance(key, str) or not key.strip() or len(key) > 512 for key in keys)
-    ):
-        raise CampaignMailProfileBoundaryError("Campaign reviewed message keys are invalid")
-    if not isinstance(updated_at, str) or not updated_at.strip() or len(updated_at) > 128:
-        raise CampaignMailProfileBoundaryError("Campaign review timestamp is invalid")
-    if updated_by is not None and (not isinstance(updated_by, str) or len(updated_by) > 256):
-        raise CampaignMailProfileBoundaryError("Campaign review actor is invalid")
+        raise CampaignMailProfileBoundaryError(
+            "Campaign review completion state is invalid"
+        )
+    validated_keys = _validated_reviewed_message_keys(keys)
+    validated_updated_at = _validated_required_string(
+        updated_at,
+        max_length=128,
+        error="Campaign review timestamp is invalid",
+    )
+    validated_updated_by = _validated_review_actor(updated_by)
     return {
-        "build_token": build_token.strip(),
+        "build_token": validated_build_token,
         "inspection_complete": inspected,
-        "reviewed_message_keys": list(dict.fromkeys(key.strip() for key in keys)),
-        "updated_at": updated_at.strip(),
-        "updated_by_user_id": updated_by,
+        "reviewed_message_keys": validated_keys,
+        "updated_at": validated_updated_at,
+        "updated_by_user_id": validated_updated_by,
     }