// vents.js — hydrothermal vents as map markers (pure): clusters on a lat/lon grid sized to ≈ px screen pixels
import { R_KM } from './geo.js';

const FLOW = ['weak flow', 'steady flow', 'strong flow'];

export const zoomBucket = kmPerPx => Math.floor(Math.log(kmPerPx) / Math.log(1.5));

export function clusterVents(vents, kmPerPx, px = 40) {
  const deg = Math.max(1e-6, (kmPerPx * px * 180) / (Math.PI * R_KM));
  const cells = new Map();
  for (const v of vents) {
    const key = `${Math.floor(v.lat / deg)}:${Math.floor(v.lon / deg)}`;
    const c = cells.get(key);
    if (c) {
      c.lat += v.lat;
      c.lon += v.lon;
      c.n++;
    } else cells.set(key, { lat: v.lat, lon: v.lon, n: 1, v });
  }
  return [...cells.values()].map(c => (c.n === 1 ? c : { lat: c.lat / c.n, lon: c.lon / c.n, n: c.n, v: null }));
}

export function ventText(v, types, minerals) {
  return `${types[v.type] ?? 'vent'} · ${Math.round(v.temp_c)} °C · ${minerals[v.mineral] ?? '?'} · ${FLOW[v.flow] ?? ''}`;
}