/* scad-app.js — controller for the /scad universal OpenSCAD playground.
 *
 * Reuses the same Three.js viewer module (holder-viewer.js) and the same
 * /api/scad/render backend endpoint that the holder editor uses.
 */

const $ = (id) => document.getElementById(id);

const state = {
  editor: null,
  rendering: false,
  abortCtrl: null,
  elapsedTimer: null,
  lastBlob: null,
  rendererReady: false,
};

const EXAMPLE_SOURCE = `// Tiny example to sanity-check the renderer.
// Click Render. Then start editing.

\$fn = 80;

difference() {
  // Outer rounded box
  hull() {
    for (x = [-20, 20], y = [-12, 12])
      translate([x, y, 0]) cylinder(h = 8, r = 4);
  }
  // Six holes
  for (i = [-2 : 2])
    translate([i * 8, 0, -1]) cylinder(h = 10, d = 3);
}
`;

function _whenViewerReady(cb) {
  if (window.HolderViewer) { cb(); return; }
  let tries = 0;
  const t = setInterval(() => {
    if (window.HolderViewer) { clearInterval(t); cb(); }
    else if (++tries > 50)   { clearInterval(t); console.error("HolderViewer never loaded"); }
  }, 60);
}

function _initEditor(initialValue) {
  state.editor = window.CodeMirror($("scad-editor"), {
    value: initialValue,
    mode: "text/x-csrc",
    theme: "dracula",
    lineNumbers: true,
    indentUnit: 4,
    tabSize: 4,
    lineWrapping: false,
    viewportMargin: Infinity,
  });
}

function _showProgress(show) {
  $("render-progress").hidden = !show;
  $("btn-render").hidden = show;
  $("btn-cancel").hidden = !show;
}

async function _doRender() {
  if (state.rendering || !state.editor) return;
  const source = state.editor.getValue().trim();
  if (!source) {
    $("render-status").textContent = "✗ source is empty";
    return;
  }
  state.rendering = true;
  state.abortCtrl = new AbortController();
  $("render-status").textContent = "rendering…";
  $("warning").textContent = "";
  _showProgress(true);

  const t0 = performance.now();
  state.elapsedTimer = setInterval(() => {
    $("render-elapsed").textContent = ((performance.now() - t0) / 1000).toFixed(1) + "s";
  }, 100);

  try {
    const res = await fetch("/api/scad/render", {
      method: "POST",
      headers: { "content-type": "application/json" },
      body: JSON.stringify({ source }),
      signal: state.abortCtrl.signal,
    });
    if (!res.ok) {
      let msg = res.statusText;
      try { msg = (await res.json()).error || msg; } catch {}
      throw new Error(msg);
    }
    state.lastBlob = await res.blob();
    const buf = await state.lastBlob.arrayBuffer();
    window.HolderViewer.loadSTL(buf);
    const dt = ((performance.now() - t0) / 1000).toFixed(1);
    $("render-status").textContent =
      `✓ rendered in ${dt}s · ${(state.lastBlob.size/1024).toFixed(0)} kB`;
  } catch (e) {
    if (e.name === "AbortError") $("render-status").textContent = "✗ cancelled";
    else                          $("render-status").textContent = `✗ ${e.message}`;
  } finally {
    state.rendering = false;
    state.abortCtrl = null;
    clearInterval(state.elapsedTimer);
    _showProgress(false);
  }
}

$("btn-render").addEventListener("click", _doRender);
$("btn-cancel").addEventListener("click", () => state.abortCtrl?.abort());
$("btn-load-example").addEventListener("click", () => {
  if (state.editor) state.editor.setValue(EXAMPLE_SOURCE);
});

$("btn-download-stl").addEventListener("click", () => {
  if (!state.lastBlob) { alert("Nothing rendered yet."); return; }
  const url = URL.createObjectURL(state.lastBlob);
  const a = document.createElement("a");
  a.href = url;
  a.download = "rendered.stl";
  document.body.appendChild(a); a.click();
  setTimeout(() => { URL.revokeObjectURL(url); a.remove(); }, 100);
});

// Ctrl+Enter from inside the editor triggers Render.
document.addEventListener("keydown", (e) => {
  if ((e.ctrlKey || e.metaKey) && e.key === "Enter") {
    e.preventDefault();
    _doRender();
  }
});

// Bootstrap: viewer + editor with an empty buffer (or example).
_whenViewerReady(() => {
  window.HolderViewer.init($("viewer3d"));
  state.rendererReady = true;
  _initEditor(EXAMPLE_SOURCE);
});