/**
 * Shared apply logic for manual Vietnamese translation batches.
 */

function applyTranslation(q, t, now) {
  if (t.stem) q.stem.vi = t.stem;
  if (t.explanation) q.explanation.vi = t.explanation;
  if (t.options && q.options) {
    for (const opt of q.options) {
      if (t.options[opt.key] !== undefined) {
        opt.text.vi = t.options[opt.key];
      }
    }
  }
  if (t.boxes && q.boxes) {
    for (const box of q.boxes) {
      const b = t.boxes[box.id];
      if (!b) continue;
      // Keep boxes.label in English — do not overwrite with translated labels.
      if (b.answer) box.answer.vi = b.answer;
    }
  }
  if (t.answerText && q.answer?.text) {
    q.answer.text.vi = t.answerText;
  }
  if (t.statements && q.interaction?.statements) {
    for (const st of q.interaction.statements) {
      if (t.statements[st.id]) st.vi = t.statements[st.id];
    }
  }
  if (q.meta) q.meta.translatedAt = now;
}

/**
 * @param {object[]} data
 * @param {Record<number, object>} translations
 * @param {{ minId?: number, maxId?: number, dryRun?: boolean }} opts
 */
function applyBatch(data, translations, opts = {}) {
  const now = new Date().toISOString();
  const { minId, maxId, dryRun = false } = opts;
  let updated = 0;
  const missing = [];

  for (const [idStr, t] of Object.entries(translations)) {
    const id = Number(idStr);
    if (Number.isNaN(id)) continue;
    if (minId != null && id < minId) continue;
    if (maxId != null && id > maxId) continue;

    const q = data.find((x) => x.id === id);
    if (!q) {
      missing.push(id);
      continue;
    }
    if (!dryRun) applyTranslation(q, t, now);
    updated++;
  }

  return { updated, missing, now };
}

module.exports = { applyTranslation, applyBatch };