// Lists this repository's submissions and animates the exported HDF5 displacement fields of the disk as a 3D surface.
import * as THREE from "three";
import { OrbitControls } from "three/addons/controls/OrbitControls.js";
import h5wasm from "https://cdn.jsdelivr.net/npm/h5wasm@0.7/dist/esm/hdf5_hl.js";

const manifest = await (await fetch("manifest.json")).json();
const esc = (s) => String(s).replace(/[&<>"']/g, (c) => ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;" }[c]));

// ---------------------------------------------------------------- submissions table
const subsDiv = document.getElementById("submissions");
const fieldSolutions = [];
for (const [cid, ch] of Object.entries(manifest.challenges)) {
  const h3 = document.createElement("h3");
  h3.textContent = cid;
  subsDiv.appendChild(h3);
  for (const sub of ch.submissions) {
    const p = document.createElement("p");
    p.innerHTML = `<b>${esc(sub.submission_id)}</b> by ${esc(sub.submitter.name)}${sub.date ? " (" + esc(sub.date) + ")" : ""}. ${esc(sub.description || "")}` +
      (sub.code_url ? ` <a href="${esc(sub.code_url)}">code</a>` : "");
    subsDiv.appendChild(p);
    const rows = sub.solutions.map((s) => {
      if (s.fields && s.fields.available !== false) fieldSolutions.push({ label: `${sub.submission_id}/${s.solution_id}`, path: s.fields.path, challenge: cid });
      const fieldsLink = s.fields ? (s.fields.available === false ? ' <span class="muted">(fields stored in LFS, not published here)</span>' : ` <a href="${esc(s.fields.path)}">fields</a>`) : "";
      return `<tr><td>${esc(s.solution_id)}</td><td>${esc(s.method || "")}<br><span class="muted"><code>${esc(JSON.stringify(s.parameters || {}))}</code></span></td>` +
        `<td class="num">${s.timing_seconds ?? ""}</td><td class="muted">${esc((s.more_accurate_than || []).join(", "))}</td>` +
        `<td><div class="cplayer" data-src="${esc(s.output)}"></div><br><a href="${esc(s.output)}">wav</a>${fieldsLink}</td></tr>`;
    }).join("");
    const wrap = document.createElement("div");
    wrap.className = "wrap";
    wrap.innerHTML = `<table><tr><th>Solution</th><th>Method</th><th>Time (s)</th><th>Claimed more accurate than</th><th>Output</th></tr>${rows}</table>`;
    subsDiv.appendChild(wrap);
  }
}

const gains = manifest.playback_gain_db || {};
const firstGain = Object.values(gains).find((g) => typeof g === "number");
ChallengePlayer.controls(document.getElementById("playback"), { gainDb: typeof firstGain === "number" ? firstGain : 20, limiter: true });
ChallengePlayer.mount();

// ---------------------------------------------------------------- 3D viewer
const view = document.getElementById("view");
const status = document.getElementById("fieldStatus");
const select = document.getElementById("fieldSelect");
const playBtn = document.getElementById("playBtn");
const speed = document.getElementById("speed");
const speedLabel = document.getElementById("speedLabel");
const exag = document.getElementById("exag");
const exagLabel = document.getElementById("exagLabel");
const timeSlider = document.getElementById("timeSlider");
const derigid = document.getElementById("derigid");
const timeLabel = document.getElementById("timeLabel");

const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setPixelRatio(window.devicePixelRatio || 1);
view.appendChild(renderer.domElement);
const scene = new THREE.Scene();
const dark = matchMedia("(prefers-color-scheme: dark)").matches;
scene.background = new THREE.Color(dark ? 0x151515 : 0xffffff);
const camera = new THREE.PerspectiveCamera(40, 2, 0.01, 100);
camera.position.set(0.45, -0.6, 0.4);
camera.up.set(0, 0, 1);
const controls = new OrbitControls(camera, renderer.domElement);
controls.target.set(0, 0, 0);
scene.add(new THREE.AmbientLight(0xffffff, 0.6));
const dl = new THREE.DirectionalLight(0xffffff, 0.9);
dl.position.set(0.5, -0.8, 1.0);
scene.add(dl);

let field = null; // {x, y, t, u, nx, ny, nt, umax, emax, plane, vidx, verts, params}
let mesh = null;
let frame = 0;
let playing = false;
let lastTs = null;
let simTime = 0;

function resize() {
  const w = view.clientWidth, h = view.clientHeight;
  renderer.setSize(w, h, false);
  camera.aspect = w / h;
  camera.updateProjectionMatrix();
}
window.addEventListener("resize", () => { resize(); render(); });
resize();

function buildMesh() {
  if (mesh) { scene.remove(mesh); mesh.geometry.dispose(); mesh.material.dispose(); }
  const { x, y, nx, ny, vidx, verts, params } = field;
  // vertices: the grid points inside the disk; triangles: cells whose four corners are all inside
  const pos = new Float32Array(verts.length * 3);
  for (let k = 0; k < verts.length; k++) {
    const [i, j] = verts[k];
    pos[3 * k] = x[i]; pos[3 * k + 1] = y[j]; pos[3 * k + 2] = 0;
  }
  const idx = [];
  for (let j = 0; j < ny - 1; j++) for (let i = 0; i < nx - 1; i++) {
    const a = vidx[j * nx + i], b = vidx[j * nx + i + 1], c = vidx[(j + 1) * nx + i], d = vidx[(j + 1) * nx + i + 1];
    if (a < 0 || b < 0 || c < 0 || d < 0) continue;
    idx.push(a, b, d, a, d, c);
  }
  const geo = new THREE.BufferGeometry();
  geo.setAttribute("position", new THREE.BufferAttribute(pos, 3));
  geo.setAttribute("color", new THREE.BufferAttribute(new Float32Array(verts.length * 3), 3));
  geo.setIndex(idx);
  const mat = new THREE.MeshStandardMaterial({ vertexColors: true, side: THREE.DoubleSide, metalness: 0.1, roughness: 0.7 });
  mesh = new THREE.Mesh(geo, mat);
  scene.add(mesh);
  // the rim at rest, for reference
  const R = params.disk_radius || Math.max(...x);
  const circ = [];
  for (let k = 0; k <= 128; k++) circ.push(new THREE.Vector3(R * Math.cos(2 * Math.PI * k / 128), R * Math.sin(2 * Math.PI * k / 128), 0));
  mesh.add(new THREE.Line(new THREE.BufferGeometry().setFromPoints(circ), new THREE.LineBasicMaterial({ color: dark ? 0x555555 : 0xbbbbbb })));
  // strike marker
  if (typeof params.strike_x === "number") {
    const marker = new THREE.Mesh(new THREE.SphereGeometry(0.004, 12, 12), new THREE.MeshBasicMaterial({ color: 0xd04040 }));
    marker.position.set(params.strike_x, params.strike_y, 0.004);
    mesh.add(marker);
  }
}

function updateSurface() {
  if (!field || !mesh) return;
  const { u, nx, ny, x, y, plane, verts } = field;
  const rigidOff = derigid.checked;
  const umax = rigidOff ? field.emax : field.umax;
  const pos = mesh.geometry.attributes.position;
  const col = mesh.geometry.attributes.color;
  const scale = umax > 0 ? (0.03 * Math.pow(10, parseFloat(exag.value)) / umax) * 0.1 : 0; // exaggerated height
  const base = frame * nx * ny;
  const c0 = plane[3 * frame], gx = plane[3 * frame + 1], gy = plane[3 * frame + 2];
  for (let k = 0; k < verts.length; k++) {
    const [i, j] = verts[k];
    let v = u[base + j * nx + i];
    if (rigidOff) v -= c0 + gx * x[i] + gy * y[j];
    pos.setZ(k, v * scale);
    const s = umax > 0 ? Math.max(-1, Math.min(1, v / umax)) : 0;
    col.setXYZ(k, s > 0 ? 1 : 1 + s * 0.8, 1 - Math.abs(s) * 0.7, s < 0 ? 1 : 1 - s * 0.8);
  }
  pos.needsUpdate = true;
  col.needsUpdate = true;
  mesh.geometry.computeVertexNormals();
  timeSlider.value = String(frame);
  timeLabel.textContent = `${(field.t[frame] * 1e3).toFixed(0)} ms`;
}

function render() { renderer.render(scene, camera); }
controls.addEventListener("change", render);

function solve3(A, b) {
  // Gaussian elimination for the 3 x 3 normal equations of the plane fit
  const M = A.map((row, i) => [...row, b[i]]);
  for (let c = 0; c < 3; c++) {
    let p = c;
    for (let r = c + 1; r < 3; r++) if (Math.abs(M[r][c]) > Math.abs(M[p][c])) p = r;
    [M[c], M[p]] = [M[p], M[c]];
    if (Math.abs(M[c][c]) < 1e-300) return [0, 0, 0];
    for (let r = 0; r < 3; r++) if (r !== c) {
      const f = M[r][c] / M[c][c];
      for (let k = c; k < 4; k++) M[r][k] -= f * M[c][k];
    }
  }
  return [M[0][3] / M[0][0], M[1][3] / M[1][1], M[2][3] / M[2][2]];
}

async function loadField(entry) {
  const path = entry.path;
  status.textContent = `Loading ${path} (this may take a while, the file is large)…`;
  playing = false;
  playBtn.textContent = "Play";
  try {
    const { FS } = await h5wasm.ready;
    const resp = await fetch(path);
    const buf = new Uint8Array(await resp.arrayBuffer());
    if (buf.length < 200 && new TextDecoder().decode(buf).startsWith("version https://git-lfs")) {
      status.textContent = `${path} is a git LFS pointer; the object was not published with this site.`;
      return;
    }
    const name = "current.h5";
    try { FS.unlink(name); } catch (_) {}
    FS.writeFile(name, buf);
    const file = new h5wasm.File(name, "r");
    const x = Float64Array.from(file.get("x").value);
    const y = Float64Array.from(file.get("y").value);
    const t = Float64Array.from(file.get("t").value);
    const u = Float32Array.from(file.get("u").value);
    file.close();
    const nx = x.length, ny = y.length, nt = t.length;
    // grid points inside the disk are those with finite values in the first frame
    const vidx = new Int32Array(nx * ny).fill(-1);
    const verts = [];
    for (let j = 0; j < ny; j++) for (let i = 0; i < nx; i++) {
      if (Number.isFinite(u[j * nx + i])) { vidx[j * nx + i] = verts.length; verts.push([i, j]); }
    }
    // best-fit plane per frame over the inside points (rigid translation and rotations of the free disk)
    let s1 = 0, sx = 0, sy = 0, sxx = 0, sxy = 0, syy = 0;
    for (const [i, j] of verts) { s1 += 1; sx += x[i]; sy += y[j]; sxx += x[i] * x[i]; sxy += x[i] * y[j]; syy += y[j] * y[j]; }
    const A = [[s1, sx, sy], [sx, sxx, sxy], [sy, sxy, syy]];
    const plane = new Float64Array(nt * 3);
    let umax = 0, emax = 0;
    for (let k = 0; k < nt; k++) {
      const base = k * nx * ny;
      let b0 = 0, bx = 0, by = 0;
      for (const [i, j] of verts) { const v = u[base + j * nx + i]; b0 += v; bx += v * x[i]; by += v * y[j]; }
      const [c0, gx, gy] = solve3(A, [b0, bx, by]);
      plane[3 * k] = c0; plane[3 * k + 1] = gx; plane[3 * k + 2] = gy;
      for (const [i, j] of verts) {
        const v = u[base + j * nx + i];
        const e = v - c0 - gx * x[i] - gy * y[j];
        if (Math.abs(v) > umax) umax = Math.abs(v);
        if (Math.abs(e) > emax) emax = Math.abs(e);
      }
    }
    const params = (manifest.parameters || {})[entry.challenge] || {};
    field = { x, y, t, u, nx, ny, nt, umax, emax, plane, vidx, verts, params };
    timeSlider.max = String(field.nt - 1);
    frame = 0;
    simTime = 0;
    buildMesh();
    updateSurface();
    render();
    status.textContent = `${path}: ${verts.length} grid points inside the disk × ${field.nt} frames, max |u| = ${(umax * 1e3).toFixed(2)} mm including rigid motion, ${(emax * 1e3).toFixed(3)} mm elastic`;
  } catch (e) {
    status.textContent = `Could not load ${path}: ${e}`;
  }
}

function tick(ts) {
  if (!playing || !field) return;
  if (lastTs !== null) {
    const factor = Math.pow(10, parseFloat(speed.value));
    simTime += ((ts - lastTs) / 1000) * factor;
    const tEnd = field.t[field.nt - 1];
    if (simTime > tEnd) simTime = 0;
    const dt = field.t[1] - field.t[0];
    frame = Math.min(field.nt - 1, Math.round(simTime / dt));
    updateSurface();
    render();
  }
  lastTs = ts;
  requestAnimationFrame(tick);
}

playBtn.addEventListener("click", () => {
  playing = !playing;
  playBtn.textContent = playing ? "Pause" : "Play";
  lastTs = null;
  if (playing) requestAnimationFrame(tick);
});
timeSlider.addEventListener("input", () => {
  if (!field) return;
  frame = parseInt(timeSlider.value, 10);
  simTime = field.t[frame];
  updateSurface();
  render();
});
const updSpeed = () => { speedLabel.textContent = `${Math.pow(10, parseFloat(speed.value)).toPrecision(2)} × real time`; };
const updExag = () => { exagLabel.textContent = `×${Math.pow(10, parseFloat(exag.value)).toPrecision(2)}`; updateSurface(); render(); };
speed.addEventListener("input", updSpeed);
exag.addEventListener("input", updExag);
derigid.addEventListener("change", () => { updateSurface(); render(); });
updSpeed();
exagLabel.textContent = `×${Math.pow(10, parseFloat(exag.value)).toPrecision(2)}`;
select.addEventListener("change", () => loadField(fieldSolutions[parseInt(select.value, 10)]));

fieldSolutions.forEach((f, k) => {
  const o = document.createElement("option");
  o.value = String(k);
  o.textContent = f.label;
  select.appendChild(o);
});
render();
if (fieldSolutions.length) loadField(fieldSolutions[0]);
else status.textContent = "No solution in this repository exports a displacement field that is published with this site.";