const FILE_PROTOCOL_MESSAGE = `
  <strong>Three.js modules cannot boot from <code>file://</code>.</strong><br>
  Serve the Nexus over HTTP, for example:<br>
  <code>python3 -m http.server 8888</code>
`;

function setText(node, text) {
  if (node) node.textContent = text;
}

function setHtml(node, html) {
  if (node) node.innerHTML = html;
}

export function renderFileProtocolGuidance(doc = document) {
  setText(doc.querySelector('.loader-subtitle'), 'Serve this world over HTTP to initialize Three.js.');
  const bootMessage = doc.getElementById('boot-message');
  if (bootMessage) {
    bootMessage.style.display = 'block';
    setHtml(bootMessage, FILE_PROTOCOL_MESSAGE.trim());
  }
}

export function renderBootFailure(doc = document, error) {
  setText(doc.querySelector('.loader-subtitle'), 'Nexus boot failed. Check console logs.');
  const bootMessage = doc.getElementById('boot-message');
  if (bootMessage) {
    bootMessage.style.display = 'block';
    setHtml(bootMessage, `<strong>Boot error:</strong> ${error?.message || error}`);
  }
}

export function sanitizeAppModuleSource(source) {
  return source
    .replace(/;\\n(\s*)/g, ';\n$1')
    .replace(/import\s*\{[\s\S]*?\}\s*from '\.\/nexus\/symbolic-engine\.js';\n?/, '')
    .replace(
      /\n  \}\n  \} else if \(data\.type && data\.type\.startsWith\('evennia\.'\)\) \{\n    handleEvenniaEvent\(data\);\n  \/\/ Evennia event bridge — process command\/result\/room fields if present\n  handleEvenniaEvent\(data\);\n\}/,
      "\n  } else if (data.type && data.type.startsWith('evennia.')) {\n    handleEvenniaEvent(data);\n  }\n}"
    )
    .replace(
      /\/\*\*[\s\S]*?Called from handleHermesMessage for any message carrying evennia metadata\.\n \*\/\nfunction handleEvenniaEvent\(data\) \{[\s\S]*?\n\}\n\n\n\/\/ ═══════════════════════════════════════════/,
      "// ═══════════════════════════════════════════"
    )
    .replace(
      /\n    \/\/ Actual MemPalace initialization would happen here\n    \/\/ For demo purposes we'll just show status\n    statusEl\.textContent = 'Connected to local MemPalace';\n    statusEl\.style\.color = '#4af0c0';\n    \n    \/\/ Simulate mining process\n    mineMemPalaceContent\("Initial knowledge base setup complete"\);\n  \} catch \(err\) \{\n    console\.error\('Failed to initialize MemPalace:', err\);\n    document\.getElementById\('mem-palace-status'\)\.textContent = 'MemPalace ERROR';\n    document\.getElementById\('mem-palace-status'\)\.style\.color = '#ff4466';\n  \}\n  try \{/,
      "\n  try {"
    )
    .replace(
      /\n  \/\/ Auto-mine chat every 30s\n  setInterval\(mineMemPalaceContent, 30000\);\n    try \{\n      const status = mempalace\.status\(\);\n      document\.getElementById\('compression-ratio'\)\.textContent = status\.compression_ratio\.toFixed\(1\) \+ 'x';\n      document\.getElementById\('docs-mined'\)\.textContent = status\.total_docs;\n      document\.getElementById\('aaak-size'\)\.textContent = status\.aaak_size \+ 'B';\n    \} catch \(error\) \{\n      console\.error\('Failed to update MemPalace status:', error\);\n    \}\n  \}\n\n  \/\/ Auto-mine chat history every 30s\n/,
      "\n  // Auto-mine chat history every 30s\n"
    );
}

export async function loadAppModule({
  doc = document,
  fetchImpl = fetch,
  appUrl = './app.js',
} = {}) {
  const response = await fetchImpl(appUrl, { cache: 'no-store' });
  if (!response.ok) {
    throw new Error(`Failed to load ${appUrl}: ${response.status}`);
  }

  const source = sanitizeAppModuleSource(await response.text());
  const script = doc.createElement('script');
  script.type = 'module';
  script.textContent = source;

  return await new Promise((resolve, reject) => {
    script.onload = () => resolve(script);
    script.onerror = () => reject(new Error(`Failed to execute ${appUrl}`));
    doc.body.appendChild(script);
  });
}

export async function boot({
  win = window,
  doc = document,
  importApp = () => loadAppModule({ doc }),
} = {}) {
  if (win?.location?.protocol === 'file:') {
    renderFileProtocolGuidance(doc);
    return { mode: 'file' };
  }

  try {
    await importApp();
    return { mode: 'imported' };
  } catch (error) {
    renderBootFailure(doc, error);
    throw error;
  }
}

if (typeof window !== 'undefined' && typeof document !== 'undefined') {
  boot().catch((error) => {
    console.error('Nexus boot failed:', error);
  });
}