import { err, ok, type CommandContext } from "@tailor-platform/erp-kit/core";
import type { Transaction } from "../generated/kysely-tailordb";
import { KeyImmutableError, TimeEntryCodeNotFoundError } from "../lib/errors.generated";

export type UpdateTimeEntryCodeInput = {
  id: string;
} & {
  displayName?: string;
  category?: string;
  payMapKey?: string;
};

/**
 * Function: updateTimeEntryCode
 * Description: Corrects a TimeEntryCode's displayName, category, or
 * payMapKey. The key itself is immutable — it is never accepted as part of
 * this command's input — so a genuinely new time type must be created as a
 * new code, not a rename of an existing one.
 */
export async function run(db: Transaction, input: UpdateTimeEntryCodeInput, _ctx: CommandContext) {
  const timeEntryCode = await db
    .selectFrom("TimeEntryCode")
    .selectAll()
    .where("id", "=", input.id)
    .forUpdate()
    .executeTakeFirst();
  if (!timeEntryCode) {
    return err(new TimeEntryCodeNotFoundError(input.id));
  }

  // `key` is a natural/lookup key, not a mutable field — it is intentionally
  // absent from UpdateTimeEntryCodeInput. Guard against a caller bypassing
  // the type and attempting to change it directly.
  if ("key" in input) {
    return err(new KeyImmutableError(timeEntryCode.key));
  }

  const updates: {
    displayName?: string;
    category?: string;
    payMapKey?: string;
  } = {};
  if (input.displayName !== undefined) updates.displayName = input.displayName;
  if (input.category !== undefined) updates.category = input.category;
  if (input.payMapKey !== undefined) updates.payMapKey = input.payMapKey;

  const updated = await db
    .updateTable("TimeEntryCode")
    .set(updates)
    .where("id", "=", input.id)
    .returningAll()
    .executeTakeFirstOrThrow();

  return ok({ timeEntryCode: updated });
}