WIP checkpoint: Trust & Safety: Moderation data model + Alembic migration

backend/alembic/versions/0003_moderation.py

@@ -18,16 +18,40 @@ branch_labels: Union[str, Sequence[str], None] = None
 depends_on: Union[str, Sequence[str], None] = None
 
 
+def _create_enum_if_not_exists(enum_name: str, values: list[str]) -> None:
+    """Create a PostgreSQL ENUM type if it does not already exist."""
+    bind = op.get_bind()
+    # Check if the type already exists in pg_type
+    result = bind.execute(
+        sa.text(
+            "SELECT 1 FROM pg_type WHERE typname = :name"
+        ).bindparams(name=enum_name)
+    ).fetchone()
+    if result is None:
+        values_str = ", ".join(f"'{v}'" for v in values)
+        op.execute(f"CREATE TYPE {enum_name} AS ENUM ({values_str})")
+
+
 def upgrade() -> None:
     """Add role, banned_until, suspended_until to users table
     and create reports, moderation_actions, appeals tables."""
 
+    # --- Create ENUM types if they don't exist ---
+    _create_enum_if_not_exists("user_role", ["user", "moderator", "admin"])
+    _create_enum_if_not_exists("report_target_type", ["user", "world", "asset", "chat_message"])
+    _create_enum_if_not_exists("report_reason_category", [
+        "harassment", "hate_speech", "sexual_content",
+        "violence", "spam", "self_harm", "other"
+    ])
+    _create_enum_if_not_exists("report_status", ["open", "in_review", "resolved", "dismissed"])
+    _create_enum_if_not_exists("report_resolution", ["warn", "suspend", "ban", "restrict", "remove"])
+    _create_enum_if_not_exists("moderation_target_type", ["user", "world", "asset", "chat_message"])
+    _create_enum_if_not_exists("moderation_action_type", ["warn", "suspend", "ban", "restrict", "remove", "restore"])
+    _create_enum_if_not_exists("appeal_status", ["pending", "approved", "rejected"])
+
     # --- Extend users table ---
 
-    # Add role column as ENUM
-    op.execute(
-        "CREATE TYPE user_role AS ENUM ('user', 'moderator', 'admin')"
-    )
+    # Add role column
     op.add_column(
         "users",
         sa.Column(
@@ -176,9 +200,8 @@ def downgrade() -> None:
     op.drop_column("users", "banned_until")
     op.drop_column("users", "role")
 
-    # Drop the user_role enum type
+    # Drop the enum types
     op.execute("DROP TYPE IF EXISTS user_role")
-    # Drop other enum types created
     op.execute("DROP TYPE IF EXISTS report_target_type")
     op.execute("DROP TYPE IF EXISTS report_reason_category")
     op.execute("DROP TYPE IF EXISTS report_status")