import {
  buildPaginatedResult,
  DEFAULT_PAGE_SIZE,
  err,
  ok,
  type PaginationInput,
  type ReadonlyDB,
} from "@tailor-platform/erp-kit/core";
import type { DB } from "../generated/kysely-tailordb";
import { InvalidQueryParamsError } from "../lib/errors.generated";

type CalculatedBlockOrderByField = "workDate";

export interface ListCalculatedBlocksByTimeEntryCodeInput extends PaginationInput<CalculatedBlockOrderByField> {
  timeEntryCodeKey: string;
  startDate?: Date;
  endDate?: Date;
}

/**
 * Function: listCalculatedBlocksByTimeEntryCode
 * Description: Lists CalculatedTimeBlocks matching a given timeEntryCodeKey
 * over a date range, paginated. This is the aggregation input for downstream
 * consumers such as payroll and Article-36 agreement threshold evaluation, which need every
 * block of a given category (e.g. overtime) across a period.
 */
export async function run(db: ReadonlyDB<DB>, input: ListCalculatedBlocksByTimeEntryCodeInput) {
  if (!input.timeEntryCodeKey) {
    return err(new InvalidQueryParamsError("timeEntryCodeKey is missing"));
  }

  if (input.startDate !== undefined && Number.isNaN(input.startDate.getTime())) {
    return err(new InvalidQueryParamsError(`startDate=${String(input.startDate)}`));
  }
  if (input.endDate !== undefined && Number.isNaN(input.endDate.getTime())) {
    return err(new InvalidQueryParamsError(`endDate=${String(input.endDate)}`));
  }
  if (
    input.startDate !== undefined &&
    input.endDate !== undefined &&
    input.endDate < input.startDate
  ) {
    return err(
      new InvalidQueryParamsError(
        `${input.startDate.toISOString()}..${input.endDate.toISOString()}`,
      ),
    );
  }

  const limit = input.limit ?? DEFAULT_PAGE_SIZE;
  const offset = input.offset ?? 0;
  const orderBy = input.orderBy ?? "id";
  const orderDirection = input.orderDirection ?? "asc";

  let query = db
    .selectFrom("CalculatedTimeBlock")
    .selectAll()
    .where("timeEntryCodeKey", "=", input.timeEntryCodeKey);

  if (input.startDate !== undefined) {
    query = query.where("workDate", ">=", input.startDate);
  }
  if (input.endDate !== undefined) {
    query = query.where("workDate", "<=", input.endDate);
  }

  const calculatedTimeBlocks = await query
    .orderBy(orderBy, orderDirection)
    .limit(limit + 1)
    .offset(offset)
    .execute();

  return ok(buildPaginatedResult(calculatedTimeBlocks, limit));
}