import { fold } from './text';
import type { Place } from './types';

export interface Labels {
  byLabel: Map<string, Place>;
  labelOf: Map<string, string>;
  list: string[];
}

/** Unique human-readable label per place, usable as a datalist value. */
export function buildLabels(places: Place[]): Labels {
  const byLabel = new Map<string, Place>();
  const labelOf = new Map<string, string>();
  for (const p of places) {
    if (!p.name) continue;
    const addr = [p.tags['addr:street'], p.tags['addr:housenumber']].filter(Boolean).join(' ');
    let label = addr ? `${p.name} — ${addr}` : p.name;
    if (byLabel.has(label)) label = `${label} (${p.id})`;
    byLabel.set(label, p);
    labelOf.set(p.id, label);
  }
  return { byLabel, labelOf, list: [...byLabel.keys()] };
}

/** Exact label, else unique folded match on name prefix. */
export function resolveLabel(labels: Labels, text: string): Place | null {
  const exact = labels.byLabel.get(text.trim());
  if (exact) return exact;
  const q = fold(text.trim());
  if (!q) return null;
  const hits = [...labels.byLabel.entries()].filter(([l]) => fold(l).startsWith(q));
  return hits.length === 1 ? hits[0]![1] : null;
}