import type { CostCentreGroup } from "@/app/(portal)/po/new/new-po-form";

type VesselLike = { id: string; name: string; code: string; siteId: string | null };
type SiteLike   = { id: string; name: string };

/**
 * Builds the grouped cost-centre list used by PO form dropdowns.
 * Each group = one site (as an optgroup), with the site itself as a selectable
 * option followed by its vessels.
 * Vessels with no site appear under an "Unassigned Vessels" group at the end.
 */
export function buildCostCentreGroups(
  vessels: VesselLike[],
  sites: SiteLike[]
): CostCentreGroup[] {
  const groups: CostCentreGroup[] = sites.map((s) => ({
    siteId: s.id,
    siteName: s.name,
    siteRef: `s:${s.id}`,
    vessels: vessels
      .filter((v) => v.siteId === s.id)
      .map((v) => ({ ref: `v:${v.id}`, label: `${v.code} — ${v.name}` })),
  }));

  const unassigned = vessels.filter((v) => !v.siteId);
  if (unassigned.length > 0) {
    groups.push({
      siteId: null,
      siteName: "Unassigned Vessels",
      siteRef: null,
      vessels: unassigned.map((v) => ({ ref: `v:${v.id}`, label: `${v.code} — ${v.name}` })),
    });
  }

  return groups;
}

/**
 * Builds grouped accounting codes for the SearchableSelect component.
 * Only returns leaf items (no children), grouped by sub-category.
 */
export function buildAccountGroups(
  leafAccounts: {
    id: string;
    code: string;
    name: string;
    parent: { name: string; code: string; parent: { name: string; code: string } | null } | null;
  }[]
) {
  const map = new Map<string, { id: string; code: string; name: string }[]>();
  for (const a of leafAccounts) {
    const subLabel = a.parent ? `${a.parent.code} — ${a.parent.name}` : "Uncategorised";
    const topLabel = a.parent?.parent ? `${a.parent.parent.name} › ` : "";
    const key = `${topLabel}${subLabel}`;
    if (!map.has(key)) map.set(key, []);
    map.get(key)!.push({ id: a.id, code: a.code, name: a.name });
  }
  return Array.from(map.entries()).map(([group, items]) => ({ group, items }));
}