// Turtle literal + IRI escaping helpers, shared by all mjs emitters.
// Centralizes the escape rules so changes don't drift between emitters.

const STRING_ESCAPES = {
  '\\': '\\\\',
  '"': '\\"',
  '\n': '\\n',
  '\r': '\\r',
  '\t': '\\t',
};

export function ttlLit(s) {
  if (s == null) return '""';
  const escaped = String(s).replace(/[\\\"\n\r\t]/g, (ch) => STRING_ESCAPES[ch] ?? ch);
  return `"${escaped}"`;
}

export function ttlPrefixed(qname) {
  const colonIdx = qname.indexOf(':');
  if (colonIdx < 0) return qname;
  const local = qname.slice(colonIdx + 1);
  const escaped = local.replace(/([/])/g, '\\$1');
  return `${qname.slice(0, colonIdx + 1)}${escaped}`;
}

const IRI_FORBIDDEN = /[<>"{}|^`\\ - ]/;

export function assertValidIri(iri, context = 'IRI') {
  if (typeof iri !== 'string') {
    throw new Error(`${context}: expected string, got ${typeof iri}`);
  }
  if (IRI_FORBIDDEN.test(iri)) {
    throw new Error(`${context}: IRI contains forbidden characters: ${JSON.stringify(iri)}`);
  }
  return iri;
}

export function ttlIri(iri) {
  return `<${assertValidIri(iri)}>`;
}