/**
 * Convertit les délimiteurs LaTeX en nœuds TipTap pour le rendu KaTeX.
 * À appliquer sur tout contenu HTML généré par l'IA avant stockage en DB.
 */
export function preprocessMathInHtml(html: string): string {
  let result = html

  // 1. \[...\] → block math
  result = result.replace(/\\\[([\s\S]+?)\\\]/g, (_, latex) => {
    const escaped = latex.trim().replace(/"/g, '"')
    return `</p><div data-type="math-equation" data-latex="${escaped}"></div><p>`
  })

  // 2. $$...$$ → block math
  result = result.replace(/\$\$([\s\S]+?)\$\$/g, (_, latex) => {
    const escaped = latex.trim().replace(/"/g, '&quot;')
    return `</p><div data-type="math-equation" data-latex="${escaped}"></div><p>`
  })

  // 3. \(...\) → inline math
  result = result.replace(/\\\(([\s\S]+?)\\\)/g, (_, latex) => {
    const escaped = latex.trim().replace(/"/g, '&quot;')
    return `<span data-type="inline-math" data-latex="${escaped}">${escaped}</span>`
  })

  // 4. $...$ → inline math (only single $ not followed by another $)
  result = result.replace(/(?<!\$)\$(?!\$)([^\n$]+?)\$(?!\$)/g, (_, latex) => {
    const escaped = latex.trim().replace(/"/g, '&quot;')
    return `<span data-type="inline-math" data-latex="${escaped}">${escaped}</span>`
  })

  // 5. Clean up empty <p></p> tags
  result = result.replace(/<p>\s*<\/p>/g, '')

  return result
}