import type { InternalQueryMethod } from "../types.js";
import { one } from "./one.js";
import { UnexpectedStateError } from "@slonik/errors";
import { generateUid } from "@slonik/utilities";

/**
 * Makes a query and expects exactly one result.
 * Returns value of the first column.
 * @throws NotFoundError If query returns no rows.
 * @throws DataIntegrityError If query returns multiple rows.
 */
export const oneFirst: InternalQueryMethod = async (
  log,
  connection,
  clientConfiguration,
  slonikSql,
  inheritedQueryId,
) => {
  const queryId = inheritedQueryId ?? generateUid();

  const row = await one(log, connection, clientConfiguration, slonikSql, queryId, {
    validationType: "ONE_COLUMN",
  });

  const keys = Object.keys(row);

  if (keys.length > 1) {
    log.error(
      {
        queryId,
      },
      "DataIntegrityError",
    );

    throw new UnexpectedStateError(
      "Expected query to return one result, but received multiple results.",
    );
  }

  return row[keys[0]];
};