// NASA FIRMS layer (Wave 6.1) — raw VIIRS S-NPP satellite fire detections,
// worldwide, last 24 h. This is the sensor-level truth EONET curates from:
// every thermal anomaly the satellite saw, colored/sized by fire radiative
// power. CSV comes via proxy/firms (key injected server-side, 1 h cache).

export default function create(ctx) {
  const { viewer, Cesium, ui } = ctx;
  const pts = viewer.scene.primitives.add(new Cesium.PointPrimitiveCollection());
  pts.show = false;

  let enabled = false;
  let loaded = false;
  let timer = null;
  const REFRESH_MS = 1800000; // 30 min; server caches 1 h anyway

  const DIM = Cesium.Color.fromCssColorString('#b3572c').withAlpha(0.8);
  const MID = Cesium.Color.fromCssColorString('#ff7a2f').withAlpha(0.9);
  const HOT = Cesium.Color.fromCssColorString('#ffd24a');
  const OUTLINE = Cesium.Color.BLACK;

  ui.addLayer('firms', 'Fire hotspots (NASA FIRMS)', false, (on) => {
    enabled = on;
    pts.show = on;
    if (on && !loaded) refresh();
    if (on && !timer) timer = setInterval(refresh, REFRESH_MS);
    if (!on && timer) { clearInterval(timer); timer = null; }
    if (!on) { ui.hidePickOverlay(); ui.setStatus('firms', '', 'ok'); }
    else if (loaded) ui.setStatus('firms', statusText(), 'ok');
  }, 'Earth & hazards');

  function statusText() { return `${pts.length} detections · 24h · VIIRS`; }

  async function refresh() {
    if (!loaded) ui.setStatus('firms', 'fetching detections…', 'warn');
    let res;
    try {
      res = await fetch('proxy/firms');
    } catch {
      ui.setStatus('firms', 'network error', 'err'); return;
    }
    if (res.status === 503) { ui.setStatus('firms', 'no key — add firmscredentials.json', 'err'); return; }
    if (!res.ok) { ui.setStatus('firms', `HTTP ${res.status}`, 'warn'); return; }
    const text = await res.text();
    const lines = text.trim().split('\n');
    const head = (lines.shift() || '').split(',');
    const col = (n) => head.indexOf(n);
    const iLat = col('latitude'), iLon = col('longitude'), iFrp = col('frp');
    const iBright = col('bright_ti4'), iDate = col('acq_date'), iTime = col('acq_time');
    const iSat = col('satellite'), iDn = col('daynight'), iConf = col('confidence');
    if (iLat < 0 || iLon < 0) { ui.setStatus('firms', 'unexpected CSV shape', 'err'); return; }
    pts.removeAll();
    for (const line of lines) {
      const c = line.split(',');
      const lat = +c[iLat], lon = +c[iLon], frp = +c[iFrp] || 0;
      if (!isFinite(lat) || !isFinite(lon)) continue;
      pts.add({
        position: Cesium.Cartesian3.fromDegrees(lon, lat),
        pixelSize: frp > 50 ? 6 : frp > 5 ? 4 : 3,
        color: frp > 50 ? HOT : frp > 5 ? MID : DIM,
        outlineColor: OUTLINE,
        outlineWidth: 1,
        disableDepthTestDistance: 50000,
        id: {
          layer: 'firms', frp,
          bright: +c[iBright] || null, date: c[iDate], time: c[iTime],
          sat: c[iSat], dn: c[iDn], conf: c[iConf],
        },
      });
    }
    loaded = true;
    if (enabled) ui.setStatus('firms', statusText(), 'ok');
  }

  function handlePick(picked) {
    if (!enabled || picked?.id?.layer !== 'firms') return false;
    const d = picked.id;
    const hhmm = String(d.time || '').padStart(4, '0');
    ui.showPickOverlay('🛰 VIIRS fire detection', [
      ['FRP', d.frp ? `${d.frp.toFixed(1)} MW` : '—'],
      ['Brightness', d.bright ? `${d.bright.toFixed(0)} K` : '—'],
      ['Seen', `${d.date || '—'} ${hhmm.slice(0, 2)}:${hhmm.slice(2)} UTC`],
      ['Satellite', `${d.sat === 'N' ? 'Suomi NPP' : d.sat || '—'} · ${d.dn === 'D' ? 'day' : 'night'}`],
      ['Confidence', { l: 'low', n: 'nominal', h: 'high' }[d.conf] || d.conf || '—'],
    ]);
    return true;
  }
  function clearPick() { ui.hidePickOverlay(); }

  return { id: 'firms', handlePick, clearPick };
}