import * as THREE from "three";
import { OrbitControls } from "three/addons/controls/OrbitControls.js";
import { HEXAGRAMS, TRIGRAMS } from "./hexagrams.js";
import { DETAILS } from "./details.js";

/* ============================================================
   State
   ============================================================ */
let scene, camera, renderer, controls, raycaster, pointer;
let group;                    // holds every hexagram card
const cards = [];             // { mesh, hex, angle, targetScale }
let hovered = null;
let selected = null;
let matchSet = null;          // Set of hexagram numbers matching search, or null
let hintTimer;

const els = {
  container: document.getElementById("scene-container"),
  loader: document.getElementById("loader"),
  panel: document.getElementById("panel"),
  panelContent: document.getElementById("panel-content"),
  panelClose: document.getElementById("panel-close"),
  modal: document.getElementById("modal"),
  modalContent: document.getElementById("modal-content"),
  modalClose: document.getElementById("modal-close"),
  langToggle: document.getElementById("lang-toggle"),
  pickOne: document.getElementById("pick-one"),
  search: document.getElementById("search"),
  hint: document.getElementById("hint")
};

let targetRotY = null;   // when set, the ring eases toward this Y rotation

/* ============================================================
   Card texture — draw a hexagram onto a canvas
   ============================================================ */
function drawCard(hex, highlight = false) {
  const W = 260, H = 348;
  const c = document.createElement("canvas");
  c.width = W; c.height = H;
  const ctx = c.getContext("2d");

  // rounded card background
  roundRect(ctx, 8, 8, W - 16, H - 16, 20);
  ctx.fillStyle = "rgba(10,12,26,0.92)";
  ctx.fill();
  ctx.lineWidth = highlight ? 5 : 3;
  ctx.strokeStyle = highlight ? "#f7e2a6" : "rgba(233,196,106,0.55)";
  ctx.stroke();

  // King Wen number
  ctx.fillStyle = "#e9c46a";
  ctx.textAlign = "center";
  ctx.font = "600 30px 'Noto Serif SC', serif";
  ctx.fillText(String(hex.n).padStart(2, "0"), W / 2, 48);

  // six lines, bottom (index 0) at the bottom
  const step = 25, thick = 13, baseBottom = 198;
  const cx = W / 2, fullHalf = 78, gap = 15;
  for (let i = 0; i < 6; i++) {
    const y = baseBottom - i * step;
    ctx.fillStyle = "#f4d58d";
    const isYang = hex.lines[i] === "1";
    if (isYang) {
      bar(ctx, cx - fullHalf, y - thick / 2, fullHalf * 2, thick);
    } else {
      const segW = fullHalf - gap / 2;
      bar(ctx, cx - fullHalf, y - thick / 2, segW, thick);
      bar(ctx, cx + gap / 2, y - thick / 2, segW, thick);
    }
  }

  // Chinese name
  ctx.fillStyle = "#f4d58d";
  ctx.font = "600 46px 'Noto Serif SC', serif";
  ctx.fillText(hex.cn, W / 2, 270);

  // pinyin
  ctx.fillStyle = "#b9b3a3";
  ctx.font = "italic 20px 'Noto Serif SC', serif";
  ctx.fillText(hex.py, W / 2, 302);

  return c;
}

function roundRect(ctx, x, y, w, h, r) {
  ctx.beginPath();
  ctx.moveTo(x + r, y);
  ctx.arcTo(x + w, y, x + w, y + h, r);
  ctx.arcTo(x + w, y + h, x, y + h, r);
  ctx.arcTo(x, y + h, x, y, r);
  ctx.arcTo(x, y, x + w, y, r);
  ctx.closePath();
}
function bar(ctx, x, y, w, h) {
  roundRect(ctx, x, y, w, h, h / 2);
  ctx.fill();
}

/* ============================================================
   Build the 3D scene
   ============================================================ */
function init() {
  scene = new THREE.Scene();

  camera = new THREE.PerspectiveCamera(
    52, window.innerWidth / window.innerHeight, 0.1, 200
  );
  camera.position.set(0, 3, 17);

  renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true });
  renderer.setSize(window.innerWidth, window.innerHeight);
  renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
  renderer.outputColorSpace = THREE.SRGBColorSpace;
  els.container.appendChild(renderer.domElement);

  controls = new OrbitControls(camera, renderer.domElement);
  controls.enableDamping = true;
  controls.dampingFactor = 0.08;
  controls.enablePan = false;
  controls.minDistance = 8;
  controls.maxDistance = 30;
  controls.autoRotate = true;
  controls.autoRotateSpeed = 0.55;
  controls.target.set(0, 0, 0);
  controls.minPolarAngle = Math.PI * 0.18;
  controls.maxPolarAngle = Math.PI * 0.82;

  raycaster = new THREE.Raycaster();
  pointer = new THREE.Vector2();

  addStars();
  addGlow();
  buildCards();

  window.addEventListener("resize", onResize);
  renderer.domElement.addEventListener("pointermove", onPointerMove);
  renderer.domElement.addEventListener("pointerdown", onPointerDown);

  animate();
}

/* Cylinder wall: 4 rings of 16 hexagrams */
function buildCards() {
  group = new THREE.Group();
  scene.add(group);

  const R = 6.6;
  const perRing = 16;
  const rows = 4;
  const rowGap = 2.72;
  const yTop = ((rows - 1) * rowGap) / 2;

  HEXAGRAMS.forEach((hex, i) => {
    const row = Math.floor(i / perRing);
    const col = i % perRing;
    const angle = (col / perRing) * Math.PI * 2;
    const x = Math.sin(angle) * R;
    const z = Math.cos(angle) * R;
    const y = yTop - row * rowGap;

    const tex = new THREE.CanvasTexture(drawCard(hex));
    tex.colorSpace = THREE.SRGBColorSpace;
    tex.anisotropy = renderer.capabilities.getMaxAnisotropy();

    const mat = new THREE.MeshBasicMaterial({
      map: tex,
      transparent: true,
      color: 0xd7d1bf,
      side: THREE.DoubleSide
    });
    const geo = new THREE.PlaneGeometry(1.72, 2.3);
    const mesh = new THREE.Mesh(geo, mat);
    mesh.position.set(x, y, z);
    mesh.lookAt(x * 2, y, z * 2); // face outward, away from center

    const entry = { mesh, hex, angle, targetScale: 1, baseTex: tex, hiTex: null };
    mesh.userData = entry;
    cards.push(entry);
    group.add(mesh);
  });
}

function addStars() {
  const count = 1400;
  const positions = new Float32Array(count * 3);
  for (let i = 0; i < count; i++) {
    const r = 40 + Math.random() * 55;
    const th = Math.random() * Math.PI * 2;
    const ph = Math.acos(2 * Math.random() - 1);
    positions[i * 3] = r * Math.sin(ph) * Math.cos(th);
    positions[i * 3 + 1] = r * Math.cos(ph);
    positions[i * 3 + 2] = r * Math.sin(ph) * Math.sin(th);
  }
  const geo = new THREE.BufferGeometry();
  geo.setAttribute("position", new THREE.BufferAttribute(positions, 3));
  const mat = new THREE.PointsMaterial({
    color: 0xe9c46a, size: 0.35, transparent: true, opacity: 0.55, sizeAttenuation: true
  });
  scene.add(new THREE.Points(geo, mat));
}

/* soft glowing core in the centre of the ring */
function addGlow() {
  const canvas = document.createElement("canvas");
  canvas.width = canvas.height = 256;
  const ctx = canvas.getContext("2d");
  const g = ctx.createRadialGradient(128, 128, 0, 128, 128, 128);
  g.addColorStop(0, "rgba(244,213,141,0.55)");
  g.addColorStop(0.4, "rgba(233,196,106,0.18)");
  g.addColorStop(1, "rgba(233,196,106,0)");
  ctx.fillStyle = g;
  ctx.fillRect(0, 0, 256, 256);
  const tex = new THREE.CanvasTexture(canvas);
  tex.colorSpace = THREE.SRGBColorSpace;
  const sprite = new THREE.Sprite(new THREE.SpriteMaterial({
    map: tex, transparent: true, depthWrite: false, blending: THREE.AdditiveBlending
  }));
  sprite.scale.set(9, 9, 1);
  scene.add(sprite);
}

/* ============================================================
   Interaction
   ============================================================ */
function setPointer(e) {
  pointer.x = (e.clientX / window.innerWidth) * 2 - 1;
  pointer.y = -(e.clientY / window.innerHeight) * 2 + 1;
}

function pick() {
  raycaster.setFromCamera(pointer, camera);
  const hits = raycaster.intersectObjects(group.children, false);
  return hits.length ? hits[0].object.userData : null;
}

function onPointerMove(e) {
  setPointer(e);
  const entry = pick();
  if (entry !== hovered) {
    hovered = entry;
    renderer.domElement.style.cursor = entry ? "pointer" : "grab";
    refreshStates();
  }
}

let downPos = null;
function onPointerDown(e) {
  downPos = { x: e.clientX, y: e.clientY };
  const startEntry = pick();
  const up = (ev) => {
    window.removeEventListener("pointerup", up);
    if (!downPos) return;
    const moved = Math.hypot(ev.clientX - downPos.x, ev.clientY - downPos.y);
    downPos = null;
    if (moved < 6 && startEntry) selectHex(startEntry);
  };
  window.addEventListener("pointerup", up);
}

function selectHex(entry) {
  selected = entry;
  controls.autoRotate = false;
  hideHint();
  openPanel(entry.hex);
  refreshStates();
}

/* apply scale/color based on hover, selection and search */
function refreshStates() {
  cards.forEach((c) => {
    const isMatch = !matchSet || matchSet.has(c.hex.n);
    let scale = 1, color = 0xd7d1bf;

    if (!isMatch) {
      scale = 0.9; color = 0x2f3040;
    } else {
      if (c === selected) { scale = 1.22; color = 0xffffff; }
      else if (c === hovered) { scale = 1.14; color = 0xffffff; }
      else if (matchSet) { scale = 1.05; color = 0xffffff; }
    }
    c.targetScale = scale;
    c.mesh.material.color.setHex(color);
    c.mesh.material.opacity = isMatch ? 1 : 0.35;
  });
}

/* ============================================================
   Detail panel (bilingual — both languages rendered, CSS toggles)
   ============================================================ */
function trigramCells(hex) {
  const lower = TRIGRAMS[hex.lines.slice(0, 3)];
  const upper = TRIGRAMS[hex.lines.slice(3, 6)];
  const cell = (t, roleCn, roleEn) => `
    <div class="tg">
      <div class="tg-role"><span class="cn-only">${roleCn}</span><span class="en-only">${roleEn}</span></div>
      <div class="tg-name">${t.cn} · ${t.nature}</div>
      <div class="tg-en">${t.en}</div>
    </div>`;
  return `<div class="hx-trigrams">
      ${cell(upper, "上卦", "Upper")}
      ${cell(lower, "下卦", "Lower")}
    </div>`;
}

function glyphHtml(hex) {
  let rows = "";
  for (let i = 0; i < 6; i++) {
    const yang = hex.lines[i] === "1";
    rows += yang
      ? `<div class="hx-line yang"><span class="hx-seg"></span></div>`
      : `<div class="hx-line yin"><span class="hx-seg"></span><span class="hx-seg"></span></div>`;
  }
  return `<div class="hx-glyph">${rows}</div>`;
}

function openPanel(hex) {
  els.panelContent.innerHTML = `
    <div class="hx-head">
      <div class="hx-number">${String(hex.n).padStart(2, "0")}
        <small><span class="cn-only">第${hex.n}卦</span><span class="en-only">HEXAGRAM</span></small>
      </div>
      <div class="hx-names">
        <div class="hx-cn">${hex.cn}</div>
        <div class="hx-py">${hex.py}</div>
        <div class="hx-en">${hex.en}</div>
      </div>
    </div>
    ${glyphHtml(hex)}
    ${trigramCells(hex)}
    <button class="details-btn" id="details-btn">Details · 詳解</button>
    <div class="hx-desc">
      <div class="lang-block">
        <h4>卦辭釋義 · 中文</h4>
        <p lang="zh">${hex.dc}</p>
      </div>
      <div class="lang-block">
        <h4>Interpretation · English</h4>
        <p lang="en">${hex.de}</p>
      </div>
    </div>
  `;
  els.panel.classList.remove("hidden");
  els.panel.setAttribute("aria-hidden", "false");

  const btn = document.getElementById("details-btn");
  if (btn) btn.addEventListener("click", () => openDetails(hex));
}

/* ============================================================
   Details modal — classical Judgment, Image and guidance
   ============================================================ */
function openDetails(hex) {
  const d = DETAILS[hex.n];
  if (!d) return;
  els.modalContent.innerHTML = `
    <div class="md-head">
      <div class="md-num">${String(hex.n).padStart(2, "0")}</div>
      <div>
        <div class="md-cn">${hex.cn}</div>
        <div class="md-py">${hex.py}</div>
        <div class="md-en">${hex.en}</div>
      </div>
    </div>

    <div class="md-section">
      <h3>卦辭 · The Judgment</h3>
      <p class="md-classic" lang="zh">${d.gua}</p>
      <p class="md-trans" lang="en">${d.guaEn}</p>
    </div>

    <div class="md-section">
      <h3>大象傳 · The Image</h3>
      <p class="md-classic" lang="zh">${d.xiang}</p>
      <p class="md-trans" lang="en">${d.xiangEn}</p>
    </div>

    <div class="md-section">
      <h3>啟示與應用 · Guidance</h3>
      <p class="md-cnpara" lang="zh">${d.gc}</p>
      <p class="md-enpara" lang="en">${d.ge}</p>
    </div>
  `;
  els.modal.classList.remove("hidden");
  els.modal.setAttribute("aria-hidden", "false");
  els.modalContent.scrollTop = 0;
}

function closeModal() {
  els.modal.classList.add("hidden");
  els.modal.setAttribute("aria-hidden", "true");
}

function closePanel() {
  els.panel.classList.add("hidden");
  els.panel.setAttribute("aria-hidden", "true");
  selected = null;
  controls.autoRotate = true;
  refreshStates();
}

/* ============================================================
   Search
   ============================================================ */
function onSearch() {
  const q = els.search.value.trim().toLowerCase();
  if (!q) { matchSet = null; refreshStates(); return; }
  matchSet = new Set();
  HEXAGRAMS.forEach((h) => {
    if (
      String(h.n) === q ||
      h.cn.includes(q) ||
      h.py.toLowerCase().includes(q) ||
      h.en.toLowerCase().includes(q)
    ) matchSet.add(h.n);
  });
  refreshStates();
}

/* ============================================================
   Pick one (random)
   ============================================================ */
function pickOne() {
  // clear any active search so the pick stands out
  els.search.value = "";
  matchSet = null;

  const entry = cards[Math.floor(Math.random() * cards.length)];

  // rotate the ring so the chosen card faces the current camera azimuth
  const camAz = Math.atan2(
    camera.position.x - controls.target.x,
    camera.position.z - controls.target.z
  );
  targetRotY = nearestAngle(camAz - entry.angle, group.rotation.y);

  selectHex(entry);
}

// return the value of `target` (mod 2π) closest to `current`
function nearestAngle(target, current) {
  let d = target - current;
  d = ((d % (Math.PI * 2)) + Math.PI * 3) % (Math.PI * 2) - Math.PI;
  return current + d;
}

/* ============================================================
   Language toggle
   ============================================================ */
function toggleLang() {
  const cur = document.body.getAttribute("data-lang");
  document.body.setAttribute("data-lang", cur === "zh" ? "en" : "zh");
}

/* ============================================================
   Loop & resize
   ============================================================ */
function animate() {
  requestAnimationFrame(animate);
  for (const c of cards) {
    const s = c.mesh.scale.x + (c.targetScale - c.mesh.scale.x) * 0.15;
    c.mesh.scale.set(s, s, s);
  }
  if (targetRotY !== null) {
    group.rotation.y += (targetRotY - group.rotation.y) * 0.1;
    if (Math.abs(targetRotY - group.rotation.y) < 0.001) {
      group.rotation.y = targetRotY;
      targetRotY = null;
    }
  }
  controls.update();
  renderer.render(scene, camera);
}

function onResize() {
  camera.aspect = window.innerWidth / window.innerHeight;
  camera.updateProjectionMatrix();
  renderer.setSize(window.innerWidth, window.innerHeight);
}

function hideHint() {
  els.hint.classList.add("hidden");
  clearTimeout(hintTimer);
}

/* ============================================================
   Boot
   ============================================================ */
async function boot() {
  document.body.setAttribute("data-lang", "zh");

  // make sure web fonts are ready before rasterising cards
  if (document.fonts && document.fonts.ready) {
    try { await document.fonts.ready; } catch (e) { /* ignore */ }
  }

  init();

  // wire UI
  els.panelClose.addEventListener("click", closePanel);
  els.modalClose.addEventListener("click", closeModal);
  els.modal.querySelector(".modal-backdrop").addEventListener("click", closeModal);
  els.langToggle.addEventListener("click", toggleLang);
  els.pickOne.addEventListener("click", pickOne);
  els.search.addEventListener("input", onSearch);
  document.addEventListener("keydown", (e) => {
    if (e.key !== "Escape") return;
    if (!els.modal.classList.contains("hidden")) closeModal();
    else closePanel();
  });

  // fade out loader
  els.loader.classList.add("gone");
  setTimeout(() => els.loader.remove(), 900);

  // auto-hide the hint
  hintTimer = setTimeout(hideHint, 7000);
}

boot();