const pauseBtn = document.getElementById("pause-btn");
const resetBtn = document.getElementById("reset-btn");
const statsEl = document.getElementById("stats");
const globalFpsEl = document.getElementById("global-fps");
const shaderCountEl = document.getElementById("shader-count");
const searchInput = document.getElementById("search-input");
const gridEl = document.getElementById("preview-grid");
const detailViewEl = document.getElementById("detail-view");
const detailTitleEl = document.getElementById("detail-title");
const detailFpsEl = document.getElementById("detail-fps");
const detailCanvas = document.getElementById("detail-canvas");
const backBtn = document.getElementById("back-btn");

const API_BASE = "/api/shaders";

/** 串行补全缺失缩略图（每步独立 WebGL，用完即释放），避免多卡片同时建上下文 */
const thumbBackfillQueue = [];
const thumbBackfillQueuedIds = new Set();
const thumbBackfillFailUntil = new Map();
let thumbBackfillRunner = false;
const THUMB_BACKOFF_MS = 120000;

let gridHoverRuntime = null;
let sharedHoverCanvas = null;

function scheduleThumbBackfill(shaders) {
  if (typeof window.captureShaderThumbnail !== "function") return;
  const now = Date.now();
  for (const s of shaders) {
    if (s.thumbnailUrl) continue;
    const code = s.code && String(s.code).trim();
    if (!code) continue;
    const retryAt = thumbBackfillFailUntil.get(s.id);
    if (retryAt != null && now < retryAt) continue;
    if (thumbBackfillQueuedIds.has(s.id)) continue;
    thumbBackfillQueuedIds.add(s.id);
    thumbBackfillQueue.push({ id: s.id, code, name: s.name || "shader" });
  }
  void runThumbBackfillLoop();
}

async function runThumbBackfillLoop() {
  if (thumbBackfillRunner) return;
  thumbBackfillRunner = true;
  try {
    while (thumbBackfillQueue.length) {
      if (detailRuntime || gridHoverRuntime) {
        await new Promise((r) => setTimeout(r, 250));
        continue;
      }
      const job = thumbBackfillQueue.shift();
      try {
        const dataUrl = await window.captureShaderThumbnail(job.code, job.name);
        const res = await fetch(`${API_BASE}/${encodeURIComponent(job.id)}/thumbnail`, {
          method: "POST",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify({ pngBase64: dataUrl }),
        });
        if (res.ok) {
          thumbBackfillFailUntil.delete(job.id);
          const url = `${API_BASE}/${encodeURIComponent(job.id)}/thumbnail?t=${Date.now()}`;
          replaceCardStageWithThumb(job.id, url);
        } else {
          thumbBackfillFailUntil.set(job.id, Date.now() + THUMB_BACKOFF_MS);
        }
      } catch (e) {
        console.warn("缩略图自动生成失败", job.id, e);
        thumbBackfillFailUntil.set(job.id, Date.now() + THUMB_BACKOFF_MS);
      } finally {
        thumbBackfillQueuedIds.delete(job.id);
      }
      await new Promise((r) => setTimeout(r, 60));
    }
  } finally {
    thumbBackfillRunner = false;
  }
}

function replaceCardStageWithThumb(id, url) {
  if (gridHoverRuntime && gridHoverRuntime.state.id === id) tearDownGridHover();
  const card = gridEl.querySelector(`[data-shader-id="${CSS.escape(id)}"]`);
  if (!card) return;
  const stage = card.querySelector(".card-stage");
  if (!stage) return;
  stage.innerHTML = `<img class="card-thumb" src="${url}" alt="" loading="lazy" decoding="async" />`;
}

/** 全屏详情：限制像素量以便稳定 50+ FPS（过高 DPR × 边长会显著拖慢片元着色器） */
const DETAIL_MAX_PIXEL_RATIO = 1.35;
const DETAIL_MAX_BUFFER_LONG_SIDE = 1680;

/** 卡片 hover 实时预览：单例 WebGL，与缩略图同量级分辨率上限 */
const HOVER_MAX_PIXEL_RATIO = 1.25;
const HOVER_MAX_BUFFER_LONG_SIDE = 560;

const GL_CONTEXT_OPTS = {
  alpha: false,
  antialias: false,
  depth: false,
  stencil: false,
  powerPreference: "high-performance",
  desynchronized: true,
};

const vertexShaderSource = `#version 300 es
precision highp float;
layout(location = 0) in vec2 aPosition;
void main() { gl_Position = vec4(aPosition, 0.0, 1.0); }`;

function toPortableGlsl(code) {
  if (!code) return "";
  let s = String(code);
  const start = s.indexOf("void mainImage");
  if (start >= 0) {
    s = s.slice(0, s.length);
  }
  s = s
    .replace(/float2/g, "vec2")
    .replace(/float3/g, "vec3")
    .replace(/float4/g, "vec4")
    .replace(/int2/g, "ivec2")
    .replace(/int3/g, "ivec3")
    .replace(/int4/g, "ivec4")
    .replace(/precise::tanh/g, "tanh")
    .replace(/ANGLE_userUniforms\._uiResolution/g, "iResolution")
    .replace(/ANGLE_userUniforms\._uiTime/g, "iTime")
    .replace(/ANGLE_userUniforms\._uiMouse/g, "iMouse")
    .replace(/ANGLE_texture\([^)]*\)/g, "vec4(0.0)")
    .replace(/ANGLE_texelFetch\([^)]*\)/g, "vec4(0.0)")
    .replace(/ANGLE_mod\(/g, "mod(")
    .replace(/\[\[[^\]]+\]\]/g, "")
    .replace(/template\s*[^\n]*\n/g, "")
    .replace(/ANGLE_out\(([^)]+)\)/g, "$1")
    .replace(/ANGLE_swizzle_ref\(([^)]+)\)/g, "$1")
    .replace(/ANGLE_elem_ref\(([^)]+)\)/g, "$1")
    .replace(/(\d+\.\d+|\d+)f\b/g, "$1");

  // Keep only helper functions + mainImage block, drop struct/template leftovers.
  const mi = s.indexOf("void mainImage");
  if (mi >= 0) {
    const head = s.slice(0, mi);
    const helpers = head
      .split("\n\n")
      .filter((blk) => /(void|float|vec[234]|mat[234])\s+[A-Za-z_][A-Za-z0-9_]*\s*\(/.test(blk))
      .join("\n\n");
    const mainPart = s.slice(mi);
    return `${helpers}\n\n${mainPart}`;
  }
  return s;
}

function fallbackShader(name) {
  const h = (name || "shader")
    .split("")
    .reduce((a, c) => (a * 33 + c.charCodeAt(0)) >>> 0, 5381);
  const k1 = ((h % 97) / 97).toFixed(3);
  const k2 = (((h >> 5) % 89) / 89).toFixed(3);
  return `void mainImage(out vec4 fragColor, in vec2 fragCoord) {
  vec2 uv = (fragCoord - 0.5 * iResolution.xy) / iResolution.y;
  float t = iTime;
  float v = sin(uv.x * (8.0 + ${k1} * 8.0) + t * (1.4 + ${k2} * 1.2))
          + cos(uv.y * (10.0 + ${k2} * 6.0) - t * (1.1 + ${k1}));
  vec3 col = 0.5 + 0.5 * cos(vec3(0.2, 1.2, 2.2) + v + t);
  fragColor = vec4(col, 1.0);
}`;
}

function buildFragmentShader(userCode) {
  return `#version 300 es
precision highp float;
out vec4 outColor;
uniform vec3 iResolution;
uniform float iTime;
uniform float iTimeDelta;
uniform int iFrame;
uniform vec4 iMouse;
uniform vec4 iDate;
uniform sampler2D iChannel0;
uniform sampler2D iChannel1;
uniform sampler2D iChannel2;
uniform sampler2D iChannel3;
${userCode}
void main() { mainImage(outColor, gl_FragCoord.xy); }`;
}

function setIDateUniform(gl, loc) {
  if (loc == null) return;
  const d = new Date();
  gl.uniform4f(
    loc,
    d.getFullYear(),
    d.getMonth() + 1,
    d.getDate(),
    d.getHours() * 3600 + d.getMinutes() * 60 + d.getSeconds() + d.getMilliseconds() * 0.001
  );
}

function createQuad(gl) {
  const quad = new Float32Array([-1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, 1]);
  const vao = gl.createVertexArray();
  const vbo = gl.createBuffer();
  gl.bindVertexArray(vao);
  gl.bindBuffer(gl.ARRAY_BUFFER, vbo);
  gl.bufferData(gl.ARRAY_BUFFER, quad, gl.STATIC_DRAW);
  gl.enableVertexAttribArray(0);
  gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
  gl.bindVertexArray(null);
  return { vao, vbo };
}

function compileProgram(gl, fragmentShaderSource) {
  function compile(type, label, source) {
    if (gl.isContextLost?.()) {
      throw new Error(`${label}: WebGL context lost`);
    }
    const shader = gl.createShader(type);
    gl.shaderSource(shader, source);
    gl.compileShader(shader);
    if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
      let info = (gl.getShaderInfoLog(shader) || "").trim();
      if (!info) {
        const err = gl.getError();
        info =
          err && err !== gl.NO_ERROR
            ? `WebGL getError 0x${err.toString(16)} (driver returned no compile log)`
            : "No compile log (often: shader too complex, loop/unroll limits, or driver bug). Try a simpler shader.";
      }
      gl.deleteShader(shader);
      throw new Error(`${label} shader:\n${info}`);
    }
    return shader;
  }
  const vs = compile(gl.VERTEX_SHADER, "Vertex", vertexShaderSource);
  const fs = compile(gl.FRAGMENT_SHADER, "Fragment", fragmentShaderSource);
  const program = gl.createProgram();
  gl.attachShader(program, vs);
  gl.attachShader(program, fs);
  gl.linkProgram(program);
  gl.deleteShader(vs);
  gl.deleteShader(fs);
  if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
    let info = (gl.getProgramInfoLog(program) || "").trim();
    if (!info) {
      const err = gl.getError();
      info =
        err && err !== gl.NO_ERROR
          ? `WebGL getError 0x${err.toString(16)} (no link log)`
          : "No link log (vertex/fragment interface mismatch or resource limits).";
    }
    gl.deleteProgram(program);
    throw new Error(`Program link:\n${info}`);
  }
  return program;
}

function createTexture(gl, width, height, data) {
  const tex = gl.createTexture();
  gl.bindTexture(gl.TEXTURE_2D, tex);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT);
  gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1);
  gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.UNSIGNED_BYTE, data);
  gl.bindTexture(gl.TEXTURE_2D, null);
  return tex;
}

function createDefaultChannelTextures(gl, noiseSize = 256) {
  // iChannel0: audio-like lookup texture (matches many shadertoy audio assumptions)
  const w0 = 512;
  const h0 = 2;
  const d0 = new Uint8Array(w0 * h0 * 4);
  for (let x = 0; x < w0; x++) {
    const t = x / (w0 - 1);
    const fft = Math.floor(255 * Math.pow(1.0 - t, 1.8));
    const wave = Math.floor(128 + 127 * Math.sin(t * Math.PI * 10.0));
    // row0: fft, row1: waveform
    const i0 = (x + 0 * w0) * 4;
    const i1 = (x + 1 * w0) * 4;
    d0[i0] = fft; d0[i0 + 1] = fft; d0[i0 + 2] = fft; d0[i0 + 3] = 255;
    d0[i1] = wave; d0[i1 + 1] = wave; d0[i1 + 2] = wave; d0[i1 + 3] = 255;
  }

  // iChannel1/2/3: tiling noise/grain-like textures (smaller in grid previews).
  const size = noiseSize;
  const makeNoise = (scaleA, scaleB) => {
    const d = new Uint8Array(size * size * 4);
    for (let y = 0; y < size; y++) {
      for (let x = 0; x < size; x++) {
        const i = (y * size + x) * 4;
        const n = Math.floor(
          127 +
            127 *
              Math.sin((x * scaleA + y * scaleB) * 0.11) *
              Math.cos((x * scaleB - y * scaleA) * 0.07)
        );
        d[i] = n;
        d[i + 1] = (n * 37) & 255;
        d[i + 2] = (n * 73) & 255;
        d[i + 3] = 255;
      }
    }
    return d;
  };

  return [
    createTexture(gl, w0, h0, d0),
    createTexture(gl, size, size, makeNoise(1.0, 0.7)),
    createTexture(gl, size, size, makeNoise(0.8, 1.3)),
    createTexture(gl, size, size, makeNoise(1.7, 0.4)),
  ];
}

function bindChannelTextures(gl, channelUniformLocs, channelTextures) {
  for (let i = 0; i < 4; i++) {
    if (channelUniformLocs[i] == null) continue;
    gl.activeTexture(gl.TEXTURE0 + i);
    gl.bindTexture(gl.TEXTURE_2D, channelTextures[i]);
    gl.uniform1i(channelUniformLocs[i], i);
  }
  gl.activeTexture(gl.TEXTURE0);
}

function computeDetailBufferSize(cssW, cssH) {
  const dpr = Math.min(window.devicePixelRatio || 1, DETAIL_MAX_PIXEL_RATIO);
  let w = Math.max(1, Math.floor(cssW * dpr));
  let h = Math.max(1, Math.floor(cssH * dpr));
  const long = Math.max(w, h);
  if (long > DETAIL_MAX_BUFFER_LONG_SIDE) {
    const s = DETAIL_MAX_BUFFER_LONG_SIDE / long;
    w = Math.max(1, Math.floor(w * s));
    h = Math.max(1, Math.floor(h * s));
  }
  return { w, h };
}

function computeHoverBufferSize(cssW, cssH) {
  const dpr = Math.min(window.devicePixelRatio || 1, HOVER_MAX_PIXEL_RATIO);
  let w = Math.max(1, Math.floor(cssW * dpr));
  let h = Math.max(1, Math.floor(cssH * dpr));
  const long = Math.max(w, h);
  if (long > HOVER_MAX_BUFFER_LONG_SIDE) {
    const s = HOVER_MAX_BUFFER_LONG_SIDE / long;
    w = Math.max(1, Math.floor(w * s));
    h = Math.max(1, Math.floor(h * s));
  }
  return { w, h };
}

const previews = [];
/** Driven by scheduleRender(); detail + grid hover. */
let renderRafId = 0;

function scheduleRender() {
  if (renderRafId) return;
  renderRafId = requestAnimationFrame((ts) => {
    renderRafId = 0;
    renderAll(ts);
  });
}

function shouldScheduleNextFrame() {
  if (detailRuntime) return true;
  if (gridHoverRuntime) return true;
  return !paused;
}

let paused = false;
let elapsed = 0;
let frame = 0;
let lastTs = performance.now();
let fpsCounter = 0;
let fps = 0;
let lastSec = 0;
let detailFpsCounter = 0;
let detailFps = 0;
let detailLastSec = 0;
let detailRuntime = null;
let searchKeyword = "";
let lastSignature = "";

function getSharedHoverCanvas() {
  if (!sharedHoverCanvas) {
    sharedHoverCanvas = document.createElement("canvas");
    sharedHoverCanvas.className = "card-hover-canvas";
  }
  return sharedHoverCanvas;
}

function tearDownGridHover() {
  if (!gridHoverRuntime) {
    if (sharedHoverCanvas && sharedHoverCanvas.parentNode) {
      const stage = sharedHoverCanvas.parentNode;
      stage.querySelectorAll(":scope > *").forEach((el) => {
        el.style.visibility = "";
      });
      sharedHoverCanvas.remove();
      sharedHoverCanvas.style.display = "none";
    }
    return;
  }
  const { gl, program, vao, vbo, channelTextures, _hoverResizeObserver } = gridHoverRuntime;
  if (_hoverResizeObserver) _hoverResizeObserver.disconnect();
  try {
    if (program) gl.deleteProgram(program);
    if (vao) gl.deleteVertexArray(vao);
    if (vbo) gl.deleteBuffer(vbo);
    if (channelTextures) channelTextures.forEach((t) => gl.deleteTexture(t));
  } catch (_) {
    /* lost */
  }
  gridHoverRuntime = null;
  if (sharedHoverCanvas && sharedHoverCanvas.parentNode) {
    const stage = sharedHoverCanvas.parentNode;
    stage.querySelectorAll(":scope > *").forEach((el) => {
      el.style.visibility = "";
    });
    sharedHoverCanvas.remove();
  }
  if (sharedHoverCanvas) sharedHoverCanvas.style.display = "none";
}

function startGridHover(previewState, card) {
  if (detailViewEl.classList.contains("active")) return;
  tearDownGridHover();
  const canvas = getSharedHoverCanvas();
  const stage = card.querySelector(".card-stage");
  if (!stage) return;

  const gl = canvas.getContext("webgl2", GL_CONTEXT_OPTS);
  if (!gl) return;

  let program;
  let codeForRender = previewState.code;
  try {
    program = compileProgram(gl, buildFragmentShader(codeForRender));
  } catch (_e1) {
    try {
      codeForRender = toPortableGlsl(previewState.code);
      program = compileProgram(gl, buildFragmentShader(codeForRender));
    } catch (_e2) {
      codeForRender = fallbackShader(previewState.name);
      try {
        program = compileProgram(gl, buildFragmentShader(codeForRender));
      } catch {
        return;
      }
    }
  }

  const { vao, vbo } = createQuad(gl);
  const channelTextures = createDefaultChannelTextures(gl, 128);
  const channelUniforms = [
    gl.getUniformLocation(program, "iChannel0"),
    gl.getUniformLocation(program, "iChannel1"),
    gl.getUniformLocation(program, "iChannel2"),
    gl.getUniformLocation(program, "iChannel3"),
  ];
  const uniforms = {
    iResolution: gl.getUniformLocation(program, "iResolution"),
    iTime: gl.getUniformLocation(program, "iTime"),
    iTimeDelta: gl.getUniformLocation(program, "iTimeDelta"),
    iFrame: gl.getUniformLocation(program, "iFrame"),
    iMouse: gl.getUniformLocation(program, "iMouse"),
    iDate: gl.getUniformLocation(program, "iDate"),
  };

  stage.appendChild(canvas);
  canvas.style.display = "block";
  stage.querySelectorAll(":scope > *").forEach((el) => {
    if (el !== canvas) el.style.visibility = "hidden";
  });

  const ro = new ResizeObserver(() => {
    if (!gridHoverRuntime) return;
    const r = canvas.getBoundingClientRect();
    gridHoverRuntime._layoutW = r.width;
    gridHoverRuntime._layoutH = r.height;
  });
  ro.observe(canvas);
  const r0 = canvas.getBoundingClientRect();
  gridHoverRuntime = {
    gl,
    program,
    vao,
    vbo,
    channelTextures,
    channelUniforms,
    uniforms,
    canvas,
    state: previewState,
    mouse: { x: 0, y: 0, downX: 0, downY: 0, down: false },
    localTime: 0.05,
    localFrame: 1,
    lastTick: performance.now(),
    _layoutW: r0.width,
    _layoutH: r0.height,
    _hoverResizeObserver: ro,
  };
  scheduleRender();
}

function createPreviewCard(shader) {
  const { id, name, author = "unknown", views = 0, likes = 0, code, thumbnailUrl } = shader;
  const card = document.createElement("article");
  card.className = "card";
  card.dataset.search = `${name} ${author}`.toLowerCase();

  const visualInner = thumbnailUrl
    ? `<img class="card-thumb" src="${thumbnailUrl}" alt="" loading="lazy" decoding="async" />`
    : `<div class="card-thumb card-thumb--placeholder">暂无缩略图<br /><small>正在尝试自动生成…</small></div>`;

  card.dataset.shaderId = id;
  card.innerHTML = `
    <div class="card-head">
      <strong>${name}</strong>
    </div>
    <div class="card-stage">${visualInner}</div>
    <div class="card-meta">
      <span>by ${author}</span>
      <span>views ${views} | likes ${likes}</span>
    </div>
  `;

  const state = {
    id,
    name,
    code,
    card,
  };

  card.addEventListener("click", () => openDetail(state));

  card.addEventListener("mouseenter", () => {
    if (detailViewEl.classList.contains("active")) return;
    startGridHover(state, card);
  });
  card.addEventListener("mouseleave", () => {
    if (gridHoverRuntime && gridHoverRuntime.state.id === state.id) tearDownGridHover();
  });
  card.addEventListener("mousemove", (event) => {
    if (!gridHoverRuntime || gridHoverRuntime.state.id !== state.id) return;
    const c = gridHoverRuntime.canvas;
    const rect = c.getBoundingClientRect();
    const bw = c.width || 1;
    const bh = c.height || 1;
    gridHoverRuntime.mouse.x = ((event.clientX - rect.left) / rect.width) * bw;
    gridHoverRuntime.mouse.y = ((rect.bottom - event.clientY) / rect.height) * bh;
  });
  card.addEventListener("mousedown", () => {
    if (!gridHoverRuntime || gridHoverRuntime.state.id !== state.id) return;
    gridHoverRuntime.mouse.down = true;
    gridHoverRuntime.mouse.downX = gridHoverRuntime.mouse.x;
    gridHoverRuntime.mouse.downY = gridHoverRuntime.mouse.y;
  });

  gridEl.appendChild(card);
  previews.push(state);
}

function clearPreviews() {
  tearDownGridHover();
  previews.forEach((preview) => {
    preview.card.remove();
  });
  previews.length = 0;
}

function closeDetail() {
  detailViewEl.classList.remove("active");
  detailViewEl.setAttribute("aria-hidden", "true");
  if (!detailRuntime) return;
  const { gl, program, vao, vbo, channelTextures = [], _detailResizeObserver } = detailRuntime;
  if (_detailResizeObserver) _detailResizeObserver.disconnect();
  gl.deleteProgram(program);
  gl.deleteVertexArray(vao);
  gl.deleteBuffer(vbo);
  channelTextures.forEach((tex) => gl.deleteTexture(tex));
  detailRuntime = null;
}

function openDetail(previewState) {
  tearDownGridHover();
  closeDetail();
  const gl = detailCanvas.getContext("webgl2", GL_CONTEXT_OPTS);
  if (!gl) return;
  let program;
  let detailCode = previewState.code;
  try {
    program = compileProgram(gl, buildFragmentShader(detailCode));
  } catch (_e1) {
    try {
      detailCode = toPortableGlsl(previewState.code);
      program = compileProgram(gl, buildFragmentShader(detailCode));
    } catch (_e2) {
      detailCode = fallbackShader(previewState.name);
      try {
        program = compileProgram(gl, buildFragmentShader(detailCode));
      } catch (err) {
        statsEl.textContent = `详情编译失败: ${String(err.message || err)}`;
        return;
      }
    }
  }
  const { vao, vbo } = createQuad(gl);
  const channelTextures = createDefaultChannelTextures(gl, 128);
  const channelUniforms = [
    gl.getUniformLocation(program, "iChannel0"),
    gl.getUniformLocation(program, "iChannel1"),
    gl.getUniformLocation(program, "iChannel2"),
    gl.getUniformLocation(program, "iChannel3"),
  ];
  detailRuntime = {
    gl,
    program,
    vao,
    vbo,
    channelTextures,
    channelUniforms,
    uniforms: {
      iResolution: gl.getUniformLocation(program, "iResolution"),
      iTime: gl.getUniformLocation(program, "iTime"),
      iTimeDelta: gl.getUniformLocation(program, "iTimeDelta"),
      iFrame: gl.getUniformLocation(program, "iFrame"),
      iMouse: gl.getUniformLocation(program, "iMouse"),
      iDate: gl.getUniformLocation(program, "iDate"),
    },
    mouse: { x: 0, y: 0, downX: 0, downY: 0, down: false },
    _layoutW: 0,
    _layoutH: 0,
  };
  const dro = new ResizeObserver((entries) => {
    for (const e of entries) {
      if (e.target !== detailCanvas) continue;
      const cr = e.contentRect;
      detailRuntime._layoutW = cr.width;
      detailRuntime._layoutH = cr.height;
    }
  });
  dro.observe(detailCanvas);
  detailRuntime._detailResizeObserver = dro;

  detailTitleEl.textContent = previewState.name;
  detailViewEl.classList.add("active");
  detailViewEl.setAttribute("aria-hidden", "false");
  scheduleRender();
}

function applySearch() {
  const keyword = searchKeyword.trim().toLowerCase();
  for (const preview of previews) {
    preview.card.style.display = !keyword || preview.card.dataset.search.includes(keyword) ? "" : "none";
  }
  scheduleRender();
}

async function loadShaders() {
  try {
    const res = await fetch(`${API_BASE}?t=${Date.now()}`, { cache: "no-store" });
    if (!res.ok) throw new Error("加载失败");
    const shaders = await res.json();
    const signature = JSON.stringify(
      shaders.map((s) => ({
        id: s.id,
        updatedAt: s.updatedAt || s.createdAt || "",
        thumbnailAt: s.thumbnailAt || "",
        name: s.name,
      }))
    );
    if (signature !== lastSignature) {
      lastSignature = signature;
      clearPreviews();
      shaders.forEach(createPreviewCard);
      applySearch();
      syncStats();
    }
    scheduleThumbBackfill(shaders);
  } catch (err) {
    statsEl.textContent = `读取后端失败：${String(err.message || err)}`;
  }
}

function syncStats() {
  statsEl.textContent = `预览数量: ${previews.length} | 全局时间: ${elapsed.toFixed(2)}s | 状态: ${
    paused ? "已暂停" : "运行中"
  }`;
  shaderCountEl.textContent = `${previews.length} shaders`;
}

function renderAll(ts) {
  const dt = Math.min((ts - lastTs) / 1000, 0.05);
  lastTs = ts;
  if (!paused) {
    elapsed += dt;
    frame += 1;
  }
  if (Math.floor(elapsed) !== lastSec) {
    lastSec = Math.floor(elapsed);
    fps = fpsCounter;
    fpsCounter = 0;
    globalFpsEl.textContent = `FPS: ${fps}`;
  } else {
    fpsCounter += 1;
  }

  if (gridHoverRuntime) {
    const { gl, program, vao, uniforms, mouse, channelTextures, channelUniforms, canvas } =
      gridHoverRuntime;
    if (gl.isContextLost()) {
      tearDownGridHover();
    } else {
      const now = performance.now();
      const localDt = Math.min((now - gridHoverRuntime.lastTick) / 1000, 0.05);
      gridHoverRuntime.lastTick = now;
      if (!paused) {
        gridHoverRuntime.localTime += localDt;
        gridHoverRuntime.localFrame += 1;
      }
      const lw =
        gridHoverRuntime._layoutW > 0 ? gridHoverRuntime._layoutW : canvas.clientWidth || 1;
      const lh =
        gridHoverRuntime._layoutH > 0 ? gridHoverRuntime._layoutH : canvas.clientHeight || 1;
      const { w, h } = computeHoverBufferSize(lw, lh);
      if (canvas.width !== w || canvas.height !== h) {
        canvas.width = w;
        canvas.height = h;
        gl.viewport(0, 0, w, h);
      }
      gl.useProgram(program);
      bindChannelTextures(gl, channelUniforms, channelTextures);
      gl.uniform3f(uniforms.iResolution, canvas.width, canvas.height, 1);
      gl.uniform1f(uniforms.iTime, gridHoverRuntime.localTime);
      gl.uniform1f(uniforms.iTimeDelta, paused ? 0 : localDt);
      gl.uniform1i(uniforms.iFrame, gridHoverRuntime.localFrame);
      setIDateUniform(gl, uniforms.iDate);
      gl.uniform4f(
        uniforms.iMouse,
        mouse.x,
        mouse.y,
        mouse.down ? mouse.downX : -mouse.downX,
        mouse.down ? mouse.downY : -mouse.downY
      );
      gl.bindVertexArray(vao);
      gl.drawArrays(gl.TRIANGLES, 0, 6);
      gl.bindVertexArray(null);
    }
  }

  if (detailRuntime) {
    const { gl, program, vao, uniforms, mouse, channelTextures, channelUniforms } = detailRuntime;
    if (gl.isContextLost()) {
      closeDetail();
      scheduleRender();
      return;
    }
    const lw =
      detailRuntime._layoutW > 0 ? detailRuntime._layoutW : detailCanvas.clientWidth || 1;
    const lh =
      detailRuntime._layoutH > 0 ? detailRuntime._layoutH : detailCanvas.clientHeight || 1;
    const { w, h } = computeDetailBufferSize(lw, lh);
    if (detailCanvas.width !== w || detailCanvas.height !== h) {
      detailCanvas.width = w;
      detailCanvas.height = h;
      gl.viewport(0, 0, w, h);
    }
    gl.useProgram(program);
    bindChannelTextures(gl, channelUniforms, channelTextures);
    gl.uniform3f(uniforms.iResolution, detailCanvas.width, detailCanvas.height, 1);
    gl.uniform1f(uniforms.iTime, elapsed);
    gl.uniform1f(uniforms.iTimeDelta, dt);
    gl.uniform1i(uniforms.iFrame, frame);
    setIDateUniform(gl, uniforms.iDate);
    gl.uniform4f(
      uniforms.iMouse,
      mouse.x,
      mouse.y,
      mouse.down ? mouse.downX : -mouse.downX,
      mouse.down ? mouse.downY : -mouse.downY
    );
    gl.bindVertexArray(vao);
    gl.drawArrays(gl.TRIANGLES, 0, 6);
    gl.bindVertexArray(null);
    if (Math.floor(elapsed) !== detailLastSec) {
      detailLastSec = Math.floor(elapsed);
      detailFps = detailFpsCounter;
      detailFpsCounter = 0;
      detailFpsEl.textContent = `FPS: ${detailFps}`;
    } else {
      detailFpsCounter += 1;
    }
  }

  if (shouldScheduleNextFrame()) scheduleRender();
}

pauseBtn.addEventListener("click", () => {
  paused = !paused;
  pauseBtn.textContent = paused ? "全局继续" : "全局暂停";
  syncStats();
  scheduleRender();
});
resetBtn.addEventListener("click", () => {
  elapsed = 0;
  frame = 0;
  fpsCounter = 0;
  lastSec = 0;
  detailLastSec = 0;
  detailFpsCounter = 0;
  syncStats();
  scheduleRender();
});
backBtn.addEventListener("click", () => {
  closeDetail();
  scheduleRender();
});
detailCanvas.addEventListener("mousemove", (event) => {
  if (!detailRuntime) return;
  const rect = detailCanvas.getBoundingClientRect();
  detailRuntime.mouse.x = ((event.clientX - rect.left) / rect.width) * detailCanvas.width;
  detailRuntime.mouse.y = ((rect.bottom - event.clientY) / rect.height) * detailCanvas.height;
});
detailCanvas.addEventListener("mousedown", () => {
  if (!detailRuntime) return;
  detailRuntime.mouse.down = true;
  detailRuntime.mouse.downX = detailRuntime.mouse.x;
  detailRuntime.mouse.downY = detailRuntime.mouse.y;
});
window.addEventListener("mouseup", () => {
  if (detailRuntime) detailRuntime.mouse.down = false;
  if (gridHoverRuntime) gridHoverRuntime.mouse.down = false;
});
searchInput.addEventListener("input", (event) => {
  searchKeyword = event.target.value || "";
  applySearch();
});

loadShaders();
setInterval(loadShaders, 3000);
scheduleRender();