first commit

backend/app/sender_validators.py

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+import re
+
+SENDER_ID_PATTERN = re.compile(r"^[A-Z0-9]{3,11}$")
+DLT_ENTITY_PATTERN = re.compile(r"^\d{12,25}$")
+
+
+def normalize_sender_id(value: str) -> str:
+    return value.strip().upper()
+
+
+def validate_sender_id(value: str) -> str:
+    sender_id = normalize_sender_id(value)
+    if not SENDER_ID_PATTERN.match(sender_id):
+        raise ValueError("Sender ID must be 3–11 uppercase letters or numbers")
+    return sender_id
+
+
+def validate_sender_type(value: str) -> str:
+    normalized = value.strip().lower()
+    if normalized not in {"promotional", "transactional"}:
+        raise ValueError("Type must be promotional or transactional")
+    return normalized
+
+
+def validate_purpose(value: str) -> str:
+    purpose = value.strip()
+    if len(purpose) < 10:
+        raise ValueError("Purpose must be at least 10 characters")
+    if len(purpose) > 500:
+        raise ValueError("Purpose must be 500 characters or fewer")
+    return purpose
+
+
+def validate_dlt_entity_id(value: str) -> str:
+    entity_id = value.strip()
+    if not DLT_ENTITY_PATTERN.match(entity_id):
+        raise ValueError("DLT Entity ID must be 12–25 digits")
+    return entity_id