feat: rename + delete vocabularies, blocked when in use (#30)

crates/db/src/vocab.rs

@@ -293,6 +293,88 @@ pub async fn delete_term(
     Ok(crate::DeleteOutcome::Deleted)
 }
 
+/// Rename a vocabulary's key, recording an `updated` audit entry. Returns `false` if no
+/// such vocabulary. A unique-key collision surfaces as the underlying sqlx error (23505).
+pub async fn rename_vocabulary(
+    conn: &mut sqlx::PgConnection,
+    actor: AuditActor,
+    id: VocabularyId,
+    key: &str,
+) -> Result<bool, sqlx::Error> {
+    let updated = sqlx::query("UPDATE vocabulary SET key = $2 WHERE id = $1")
+        .bind(id.to_uuid())
+        .bind(key)
+        .execute(&mut *conn)
+        .await?
+        .rows_affected();
+
+    if updated == 0 {
+        return Ok(false);
+    }
+
+    audit::record(
+        &mut *conn,
+        &NewAuditEvent {
+            actor,
+            action: AuditAction::Updated,
+            entity_type: VOCABULARY_ENTITY_TYPE.to_owned(),
+            entity_id: id.to_uuid(),
+            changes: Vec::new(),
+        },
+    )
+    .await?;
+
+    Ok(true)
+}
+
+/// Delete a vocabulary unless it still has terms or is bound by a field definition
+/// (both would otherwise hit the FK `RESTRICT`). Records a `deleted` audit entry.
+pub async fn delete_vocabulary(
+    conn: &mut sqlx::PgConnection,
+    actor: AuditActor,
+    id: VocabularyId,
+) -> Result<crate::DeleteOutcome, sqlx::Error> {
+    let exists = sqlx::query_scalar::<_, i32>("SELECT 1 FROM vocabulary WHERE id = $1")
+        .bind(id.to_uuid())
+        .fetch_optional(&mut *conn)
+        .await?;
+
+    if exists.is_none() {
+        return Ok(crate::DeleteOutcome::NotFound);
+    }
+
+    let count: i64 = sqlx::query_scalar(
+        "SELECT (SELECT count(*) FROM term WHERE vocabulary_id = $1) \
+              + (SELECT count(*) FROM field_definition WHERE vocabulary_id = $1)",
+    )
+    .bind(id.to_uuid())
+    .fetch_one(&mut *conn)
+    .await?;
+
+    if count > 0 {
+        return Ok(crate::DeleteOutcome::InUse { count });
+    }
+
+    sqlx::query("DELETE FROM vocabulary WHERE id = $1")
+        .bind(id.to_uuid())
+        .execute(&mut *conn)
+        .await?;
+
+    audit::record(
+        &mut *conn,
+        &NewAuditEvent {
+            actor,
+            action: AuditAction::Deleted,
+            entity_type: VOCABULARY_ENTITY_TYPE.to_owned(),
+            entity_id: id.to_uuid(),
+            changes: Vec::new(),
+        },
+    )
+    .await?;
+
+    Ok(crate::DeleteOutcome::Deleted)
+}
+
 fn map_vocabulary(row: sqlx::postgres::PgRow) -> Result<Vocabulary, sqlx::Error> {
     Ok(Vocabulary {
         id: VocabularyId::from_uuid(row.try_get("id")?),