import { ok, err, type CommandContext } from "@tailor-platform/erp-kit/core";
import type { Transaction } from "../generated/kysely-tailordb";
import {
  DuplicateCodeError,
  MissingRequiredFieldError,
  InvalidUomError,
} from "../lib/errors.generated";
import type { PrimitivesQueries } from "../module";

export interface CreateProductInput {
  code: string;
  name: string;
  description?: string;
  unitId: string;
}

/**
 * Function: createProduct
 *
 * Creates a new product in DRAFT status with a unique code.
 */
export async function run<CF extends Record<string, unknown>>(
  db: Transaction,
  input: CreateProductInput & CF,
  ctx: CommandContext,
  primitivesQueries: Pick<PrimitivesQueries, "getUnit">,
) {
  const { code, name, description, unitId, ...customFields } = input;

  // Validate required fields
  if (!code?.trim()) {
    return err(new MissingRequiredFieldError("code"));
  }
  if (!name?.trim()) {
    return err(new MissingRequiredFieldError("name"));
  }

  // Check code uniqueness
  const existingCode = await db
    .selectFrom("Product")
    .select("id")
    .where("code", "=", code)
    .forUpdate()
    .executeTakeFirst();
  if (existingCode) {
    return err(new DuplicateCodeError(code));
  }

  // Validate UoM
  const unitResult = await primitivesQueries.getUnit(db, { id: unitId }, ctx);
  if (!unitResult.ok) return err(new InvalidUomError(unitId));
  if (unitResult.value.unit?.status !== "ACTIVE") {
    return err(new InvalidUomError(unitId));
  }

  // Create product
  const product = await db
    .insertInto("Product")
    .values({
      ...(customFields as Record<string, unknown>),
      code,
      name,
      description: description ?? null,
      unitId,
      status: "DRAFT",
    })
    .returningAll()
    .executeTakeFirstOrThrow();

  return ok({ product });
}