feat: edit/delete authorities, blocked when referenced (#30)

crates/db/src/authority.rs

@@ -124,6 +124,115 @@ where
     }
 }
 
+/// Update an authority's `external_uri` and labels (full replace), recording an
+/// `updated` audit entry. Returns `false` if no such authority. `kind` is immutable.
+pub async fn update_authority(
+    conn: &mut sqlx::PgConnection,
+    actor: AuditActor,
+    id: AuthorityId,
+    external_uri: Option<&str>,
+    labels: &[LocalizedLabel],
+) -> Result<bool, sqlx::Error> {
+    let updated = sqlx::query("UPDATE authority SET external_uri = $2 WHERE id = $1")
+        .bind(id.to_uuid())
+        .bind(external_uri)
+        .execute(&mut *conn)
+        .await?
+        .rows_affected();
+
+    if updated == 0 {
+        return Ok(false);
+    }
+
+    sqlx::query("DELETE FROM authority_label WHERE authority_id = $1")
+        .bind(id.to_uuid())
+        .execute(&mut *conn)
+        .await?;
+
+    for label in labels {
+        sqlx::query("INSERT INTO authority_label (authority_id, lang, label) VALUES ($1, $2, $3)")
+            .bind(id.to_uuid())
+            .bind(&label.lang)
+            .bind(&label.label)
+            .execute(&mut *conn)
+            .await?;
+    }
+
+    audit::record(
+        &mut *conn,
+        &NewAuditEvent {
+            actor,
+            action: AuditAction::Updated,
+            entity_type: AUTHORITY_ENTITY_TYPE.to_owned(),
+            entity_id: id.to_uuid(),
+            changes: Vec::new(),
+        },
+    )
+    .await?;
+
+    Ok(true)
+}
+
+/// Count catalogue objects referencing `id` through an `authority`-typed field.
+pub async fn count_objects_referencing_authority<'e, E>(
+    executor: E,
+    id: AuthorityId,
+) -> Result<i64, sqlx::Error>
+where
+    E: sqlx::PgExecutor<'e>,
+{
+    sqlx::query_scalar(
+        "SELECT count(*) FROM object o WHERE EXISTS ( \
+           SELECT 1 FROM field_definition fd \
+           WHERE fd.data_type = 'authority' AND o.fields ->> fd.key = $1 )",
+    )
+    .bind(id.to_string())
+    .fetch_one(executor)
+    .await
+}
+
+/// Delete an authority (labels cascade) unless catalogue objects reference it,
+/// recording a `deleted` audit entry.
+pub async fn delete_authority(
+    conn: &mut sqlx::PgConnection,
+    actor: AuditActor,
+    id: AuthorityId,
+) -> Result<crate::DeleteOutcome, sqlx::Error> {
+    let exists = sqlx::query_scalar::<_, i32>("SELECT 1 FROM authority WHERE id = $1")
+        .bind(id.to_uuid())
+        .fetch_optional(&mut *conn)
+        .await?;
+
+    if exists.is_none() {
+        return Ok(crate::DeleteOutcome::NotFound);
+    }
+
+    let count = count_objects_referencing_authority(&mut *conn, id).await?;
+
+    if count > 0 {
+        return Ok(crate::DeleteOutcome::InUse { count });
+    }
+
+    sqlx::query("DELETE FROM authority WHERE id = $1")
+        .bind(id.to_uuid())
+        .execute(&mut *conn)
+        .await?;
+
+    audit::record(
+        &mut *conn,
+        &NewAuditEvent {
+            actor,
+            action: AuditAction::Deleted,
+            entity_type: AUTHORITY_ENTITY_TYPE.to_owned(),
+            entity_id: id.to_uuid(),
+            changes: Vec::new(),
+        },
+    )
+    .await?;
+
+    Ok(crate::DeleteOutcome::Deleted)
+}
+
 fn map_authority(row: sqlx::postgres::PgRow) -> Result<Authority, sqlx::Error> {
     let kind_str: String = row.try_get("kind")?;
     let kind = AuthorityKind::from_db(&kind_str)