// Aggregate-agnostic row helpers shared by the modules' repositories.

export function pick<T extends object, K extends keyof T>(row: T, keys: readonly K[]): Pick<T, K> {
  const picked = {} as Pick<T, K>;
  for (const key of keys) {
    picked[key] = row[key];
  }
  return picked;
}

/** Runtime rows carry app-extension columns the schema types do not know. */
export function extractCustomFields(row: object, knownColumns: readonly string[]) {
  const known = new Set(knownColumns);
  const customFields: Record<string, unknown> = {};
  for (const [key, value] of Object.entries(row)) {
    if (!known.has(key)) {
      customFields[key] = value;
    }
  }
  return customFields;
}

function isSameColumnValue(a: unknown, b: unknown) {
  if (a instanceof Date || b instanceof Date) {
    return a instanceof Date && b instanceof Date && a.getTime() === b.getTime();
  }
  return a === b;
}

export function changedColumns(before: Record<string, unknown>, after: Record<string, unknown>) {
  const changes: Record<string, unknown> = {};
  for (const [column, value] of Object.entries(after)) {
    if (!isSameColumnValue(before[column], value)) {
      changes[column] = value;
    }
  }
  return changes;
}