/* 589-2 GL 바탕 따라가기 헬퍼 — `logic/B04_PreProcess_UI_MapGl_Frame.ts` 의 `glCameraOf` ·
 * `lonLatOfNormFn` · `preparedToGeoJson` · `ringsToPolygons` 를 stdin 입력으로 돌려 JSON 으로 냄.
 *   입력 { meta, lonlat: [[lon, lat]], views: [[w, h, scale, ox, oy, rotDeg]], norm: [[nx, ny]],
 *          layer, box, rings }
 *   views 마다 = 카메라 + 점마다 [캔버스 화면 px, MapLibre 식(세계 512 px · 돌림) 화면 px]
 */
const path = require("path");
const { makeLoader } = require("./helper_ts_stub_loader.cjs");

const ROOT = path.join(__dirname, "..", "..");
const { load } = makeLoader({ root: ROOT, ui: () => ({ themeColor: () => "" }) });
const render = load("B04_PreProcess", "B04_PreProcess_UI_MapRender.ts");
const prep = load("B04_PreProcess", "logic", "B04_PreProcess_UI_MapRender_Prepare.ts");
const frame = load("B04_PreProcess", "logic", "B04_PreProcess_UI_MapGl_Frame.ts");

const input = JSON.parse(require("fs").readFileSync(0, "utf-8"));
const { meta } = input;
const norm = render.createTmNormalizer(meta);

/** MapLibre 투영(웹 메르카토르 · 세계 512·2^z px · 돌림 = 화면 = R(−도) · 세계). */
function glScreen(camera, w, h, lon, lat) {
  const world = 512 * 2 ** camera.zoom;
  const X = (l) => ((l + 180) / 360) * world;
  const Y = (p) =>
    (0.5 - Math.log(Math.tan(Math.PI / 4 + (p * Math.PI) / 360)) / (2 * Math.PI)) * world;
  const dx = X(lon) - X(camera.center[0]);
  const dy = Y(lat) - Y(camera.center[1]);
  const a = (-camera.bearing * Math.PI) / 180;
  const gx = dx * Math.cos(a) - dy * Math.sin(a);
  const gy = dx * Math.sin(a) + dy * Math.cos(a);
  // 지도 칸 CSS 행렬(칸 가운데 축)
  const [ca, cb, cc, cd] = camera.css;
  return [w / 2 + ca * gx + cc * gy, h / 2 + cb * gx + cd * gy];
}

const out = {
  views: input.views.map(([w, h, scale, ox, oy, rotDeg]) => {
    const view = { width: w, height: h, scale, offsetX: ox, offsetY: oy };
    view.mapRect = render.computeMapRect(meta, w, h);
    const r = (rotDeg * Math.PI) / 180;
    const turn = ([x, y]) => [
      w / 2 + (x - w / 2) * Math.cos(r) - (y - h / 2) * Math.sin(r),
      h / 2 + (x - w / 2) * Math.sin(r) + (y - h / 2) * Math.cos(r),
    ];
    const toScreen = (nx, ny) => turn(render.normalizedToScreen(view, nx, ny));
    const camera = frame.glCameraOf(meta, norm, toScreen, w, h);
    const points = input.lonlat.map(([lon, lat]) => {
      const [nx, ny] = prep.normOfLonLat(norm, lon, lat);
      return [toScreen(nx, ny), glScreen(camera, w, h, lon, lat)];
    });
    // 화면 격자 → (되돌림) 정규화 → 경위도 → GL 화면 = 제자리여야
    const [ox0, oy0] = toScreen(0, 0);
    const [ox1, oy1] = toScreen(1, 0);
    const [ox2, oy2] = toScreen(0, 1);
    const ex = [ox1 - ox0, oy1 - oy0];
    const ey = [ox2 - ox0, oy2 - oy0];
    const det = ex[0] * ey[1] - ex[1] * ey[0];
    const toLonLat = frame.lonLatOfNormFn(norm);
    const screen = [];
    for (let i = 0; i <= 4; i += 1)
      for (let j = 0; j <= 4; j += 1) {
        const sx = (w * i) / 4;
        const sy = (h * j) / 4;
        const dx = sx - ox0;
        const dy = sy - oy0;
        const nx = (dx * ey[1] - dy * ey[0]) / det;
        const ny = (ex[0] * dy - ex[1] * dx) / det;
        const [lon, lat] = toLonLat(nx, ny);
        screen.push([[sx, sy], glScreen(camera, w, h, lon, lat)]);
      }
    return { camera, points, screen };
  }),
  back: (() => {
    const toLonLat = frame.lonLatOfNormFn(norm);
    return input.norm.map(([nx, ny]) => {
      const [lon, lat] = toLonLat(nx, ny);
      return [lon, lat, ...prep.normOfLonLat(norm, lon, lat)];
    });
  })(),
  geo: frame.preparedToGeoJson(input.layer, (nx, ny) => [nx, ny], input.box),
  geoAll: frame.preparedToGeoJson(input.layer, (nx, ny) => [nx, ny]),
  polygons: frame.ringsToPolygons(input.rings),
};
process.stdout.write(JSON.stringify(out));