import { eq } from "drizzle-orm";
import type { AppDatabase } from "../database-context.js";
import { circuitListEquipmentIdentifiers } from "../schema/circuit-list-equipment-identifiers.js";

export function normalizeEquipmentIdentifier(value: string): string {
  return value.trim().toLowerCase();
}

/**
 * The DB-level normalized unique index uses SQLite's built-in lower(),
 * which only folds ASCII a-z and leaves German characters (Ä/Ö/Ü/ß/…)
 * untouched, so it alone would let e.g. "Ä1" and "ä1" coexist. This check
 * normalizes with JS's Unicode-aware toLowerCase() against every
 * identifier already registered for the circuit list (circuits and
 * distribution-board components share one BMK namespace via
 * circuit_list_equipment_identifiers), catching what the DB index cannot.
 */
export function assertEquipmentIdentifierAvailable(
  database: AppDatabase,
  circuitListId: string,
  equipmentIdentifier: string,
  excludeOwnerId?: string
): void {
  const candidate = normalizeEquipmentIdentifier(equipmentIdentifier);
  const existing = database
    .select({
      ownerId: circuitListEquipmentIdentifiers.ownerId,
      equipmentIdentifier: circuitListEquipmentIdentifiers.equipmentIdentifier,
    })
    .from(circuitListEquipmentIdentifiers)
    .where(eq(circuitListEquipmentIdentifiers.circuitListId, circuitListId))
    .all();
  const duplicate = existing.some(
    (row) =>
      row.ownerId !== excludeOwnerId &&
      normalizeEquipmentIdentifier(row.equipmentIdentifier) === candidate
  );
  if (duplicate) {
    throw new Error("Duplicate equipmentIdentifier in circuit list.");
  }
}