import type { Destination, TripItem } from "@/lib/types";
import { loadTrip, saveTrip } from "@/lib/tripStorage";

export function destToTripItem(d: Destination, months = 1): TripItem {
  return {
    slug: d.slug,
    name: d.name,
    country: d.country,
    emoji: d.emoji,
    cost: d.cost,
    months,
    note: "",
  };
}

/** Merge destinations into local trip. Skips cities already present. */
export function mergeDestinationsIntoTrip(
  dests: Destination[],
  months = 1
): { trip: TripItem[]; added: number; skipped: number } {
  const trip = loadTrip<TripItem>();
  const existing = new Set(trip.map((t) => t.slug));
  let added = 0;
  let skipped = 0;
  for (const d of dests) {
    if (existing.has(d.slug)) {
      skipped += 1;
      continue;
    }
    trip.push(destToTripItem(d, months));
    existing.add(d.slug);
    added += 1;
  }
  if (added > 0) saveTrip(trip);
  return { trip, added, skipped };
}