const NAMED_ENTITIES = {
  ' ': ' ',
  '&': '&',
  '&lt;': '<',
  '&gt;': '>',
  '&quot;': '"',
  '&#39;': "'",
  '&apos;': "'",
};

const MAX_DECODE_ITERATIONS = 5;

function decodeEntitiesOnce(text) {
  let result = text.replace(/&#(\d+);/g, (match, code) => {
    const num = Number(code);
    return Number.isFinite(num) ? String.fromCodePoint(num) : match;
  });
  result = result.replace(/&#x([0-9a-fA-F]+);/g, (match, hex) => {
    const num = parseInt(hex, 16);
    return Number.isFinite(num) ? String.fromCodePoint(num) : match;
  });
  for (const [entity, char] of Object.entries(NAMED_ENTITIES)) {
    result = result.split(entity).join(char);
  }
  return result;
}

function stripHtmlTags(text) {
  return text.replace(/<[^>]*>/g, ' ');
}

// Decodifica HTML/entities (inclusive escapado multiplas vezes, ate MAX_DECODE_ITERATIONS
// para nunca travar em loop) e remove tags -- sem apagar informacao (datas, nomes, numeros,
// codigos de erro, hostname, versao continuam intactos: nenhuma dessas regras mexe em texto
// que nao seja literalmente uma entidade HTML ou uma tag).
function normalizeGlpiText(rawText) {
  if (rawText === null || rawText === undefined) return '';
  let text = String(rawText);

  for (let i = 0; i < MAX_DECODE_ITERATIONS; i += 1) {
    const decoded = decodeEntitiesOnce(text);
    if (decoded === text) break;
    text = decoded;
  }

  text = stripHtmlTags(text);

  text = text
    .split('\n')
    .map((line) => line.replace(/[ \t]+/g, ' ').trim())
    .join('\n')
    .replace(/\n{3,}/g, '\n\n')
    .trim();

  return text;
}

module.exports = { normalizeGlpiText, decodeEntitiesOnce, stripHtmlTags };