import fs from "node:fs/promises";
import path from "node:path";

const ROOT = process.cwd();

const ZONES = [
  { zoneId: "1", file: "특정어업수역Ⅰ.json", label: "Ⅰ", name: "수역I(동해)" },
  { zoneId: "2", file: "특정어업수역Ⅱ.json", label: "Ⅱ", name: "수역II(제주남방)" },
  { zoneId: "3", file: "특정어업수역Ⅲ.json", label: "Ⅲ", name: "수역III(서해남부)" },
  { zoneId: "4", file: "특정어업수역Ⅳ.json", label: "Ⅳ", name: "수역IV(서해중간)" },
];

// Inverse Web Mercator (EPSG:3857) -> WGS84 lon/lat
function mercatorToLonLat(x, y) {
  const R = 6378137;
  const lon = (x / R) * (180 / Math.PI);
  const lat = (2 * Math.atan(Math.exp(y / R)) - Math.PI / 2) * (180 / Math.PI);
  return [lon, lat];
}

function looksLikeLonLat(x, y) {
  return Math.abs(x) <= 180 && Math.abs(y) <= 90;
}

function convertPoint(pt) {
  if (!Array.isArray(pt) || pt.length < 2) return pt;
  const x = pt[0];
  const y = pt[1];
  if (typeof x !== "number" || typeof y !== "number") return pt;
  if (looksLikeLonLat(x, y)) return [x, y];
  return mercatorToLonLat(x, y);
}

function convertCoords(coords) {
  if (!Array.isArray(coords)) return coords;
  if (coords.length === 0) return coords;

  // Point: [x, y]
  if (typeof coords[0] === "number") return convertPoint(coords);

  // Nested arrays
  return coords.map(convertCoords);
}

async function main() {
  const rawDir = path.join(ROOT, "data", "raw", "zones");
  const outDir = path.join(ROOT, "apps", "web", "public", "data", "zones");
  await fs.mkdir(outDir, { recursive: true });

  const features = [];
  for (const z of ZONES) {
    const rawPath = path.join(rawDir, z.file);
    const txt = await fs.readFile(rawPath, "utf-8");
    const fc = JSON.parse(txt);
    if (!fc || fc.type !== "FeatureCollection" || !Array.isArray(fc.features)) {
      throw new Error(`Unexpected GeoJSON in ${rawPath}`);
    }

    for (const f of fc.features) {
      if (!f?.geometry?.coordinates) continue;
      const geometry = {
        ...f.geometry,
        coordinates: convertCoords(f.geometry.coordinates),
      };

      features.push({
        ...f,
        properties: {
          ...(f.properties || {}),
          zoneId: z.zoneId,
          zoneLabel: z.label,
          zoneName: z.name,
        },
        geometry,
      });
    }
  }

  const out = {
    type: "FeatureCollection",
    name: "zones.wgs84",
    features,
  };

  const outPath = path.join(outDir, "zones.wgs84.geojson");
  await fs.writeFile(outPath, JSON.stringify(out), "utf-8");
  // eslint-disable-next-line no-console
  console.log(`Wrote ${features.length} features -> ${path.relative(ROOT, outPath)}`);
}

main().catch((err) => {
  // eslint-disable-next-line no-console
  console.error(err);
  process.exit(1);
});