// ide.js — 2D-IDE-Overlay über der 3D-Szene: Python-Editor + Ausführung via Pyodide.
//
// Bewusst als DOM-Overlay (nicht auf eine 3D-Textur gerendert): scharfer Text, freie Maus,
// echtes Copy/Paste/Scrollen. Pyodide (CPython als WASM) läuft komplett im Browser —
// null Server-Last, keine Sandbox nötig (siehe Spec Abschnitt 7, Variante A).
// Editor ist zunächst ein Textarea; Upgrade auf CodeMirror (lokal gehostet) später.
import { loadPyodide } from '/vendor/pyodide/pyodide.mjs';

export class IDE {
  constructor() {
    this.root = document.getElementById('ide');
    this.editor = document.getElementById('ide-editor');
    this.output = document.getElementById('ide-output');
    this.runBtn = document.getElementById('ide-run');
    this.statusEl = document.getElementById('ide-status');
    this.isOpen = false;
    this.pyodide = null;
    this._loading = null;   // Promise, solange Pyodide lädt
    this._openCb = null;
    this._closeCb = null;
    this._changeCb = null;
    this._changeTimer = null;

    document.getElementById('ide-close').addEventListener('click', () => this.close());
    this.runBtn.addEventListener('click', () => this.run());

    this.editor.addEventListener('keydown', (e) => {
      if (e.key === 'Tab') { e.preventDefault(); insertText(this.editor, '    '); }
      else if (e.key === 'Enter' && (e.ctrlKey || e.metaKey)) { e.preventDefault(); this.run(); }
      else if (e.key === 'Escape') this.close();
    });

    // Live-Änderungen (entprellt) an den Monitor melden.
    this.editor.addEventListener('input', () => {
      clearTimeout(this._changeTimer);
      this._changeTimer = setTimeout(() => { if (this._changeCb) this._changeCb(this.editor.value); }, 250);
    });
  }

  onOpen(cb) { this._openCb = cb; }
  onClose(cb) { this._closeCb = cb; }
  onChange(cb) { this._changeCb = cb; }
  getCode() { return this.editor.value; }

  open() {
    if (this.isOpen) return;
    this.isOpen = true;
    this.root.style.display = 'flex';
    this.editor.focus();
    if (this._openCb) this._openCb();
  }

  close() {
    if (!this.isOpen) return;
    this.isOpen = false;
    this.root.style.display = 'none';
    if (this._closeCb) this._closeCb();
  }

  async run() {
    let py;
    try {
      py = await this._ensurePyodide();
    } catch (e) {
      this._status('Python konnte nicht geladen werden', true);
      this._append('\n[Laden fehlgeschlagen] ' + (e && e.message || e), true);
      return;
    }
    this._clear();
    py.setStdout({ batched: (s) => this._append(s) });
    py.setStderr({ batched: (s) => this._append(s) });
    this._status('läuft …');
    try {
      await py.runPythonAsync(this.editor.value);
      this._status('fertig ✓');
    } catch (e) {
      this._append('\n' + (e && e.message ? e.message : e), true);
      this._status('Fehler', true);
    }
  }

  _ensurePyodide() {
    if (this.pyodide) return Promise.resolve(this.pyodide);
    if (!this._loading) {
      this.runBtn.disabled = true;
      this._status('Python wird geladen … (einmalig, ~10 MB)');
      this._loading = loadPyodide({ indexURL: '/vendor/pyodide/' })
        .then((py) => { this.pyodide = py; this.runBtn.disabled = false; this._status('bereit'); return py; })
        .catch((e) => { this.runBtn.disabled = false; this._loading = null; throw e; });
    }
    return this._loading;
  }

  _clear() { this.output.textContent = ''; }
  _append(text, isErr) {
    const span = document.createElement('span');
    if (isErr) span.className = 'err';
    span.textContent = text;
    this.output.appendChild(span);
    this.output.scrollTop = this.output.scrollHeight;
  }
  _status(text, isErr) { this.statusEl.textContent = text; this.statusEl.classList.toggle('err', !!isErr); }
}

/** Fügt Text an der Cursorposition eines Textarea ein (für Tab-Einrückung). */
function insertText(ta, text) {
  const start = ta.selectionStart, end = ta.selectionEnd;
  ta.value = ta.value.slice(0, start) + text + ta.value.slice(end);
  ta.selectionStart = ta.selectionEnd = start + text.length;
}