// Shared template placeholder substitution for bulk emails/WhatsApp messages and broadcasts.
// Async because {{payment.link}} needs to create a live Yoco checkout session per recipient —
// every other placeholder is a plain synchronous string replace.
async function replacePlaceholders(str, ctx = {}) {
  if (!str) return str;
  let out = String(str)
    .replace(/\{\{\s*name\s*\}\}/g, ctx.name || '')
    .replace(/\{\{\s*event\.title\s*\}\}/g, ctx.eventTitle || '')
    .replace(/\{\{\s*event\.start\s*\}\}/g, ctx.eventStart || '')
    .replace(/\{\{\s*event\.(link|url)\s*\}\}/g, (ctx.eventLinkHtml || ctx.eventLink || ''))
    .replace(/\{\{\s*promo\.title\s*\}\}/g, ctx.promoTitle || '')
    .replace(/\{\{\s*promo\.(link|url)\s*\}\}/g, (ctx.promoLinkHtml || ctx.promoLink || ''))
    .replace(/\{\{\s*balance\s*\}\}/g, ctx.balanceFmt || '');

  if (/\{\{\s*payment\.link\s*\}\}/.test(out) && typeof ctx.paymentLinkResolver === 'function') {
    let link = '';
    try {
      link = (await ctx.paymentLinkResolver()) || '';
    } catch (e) {
      try { console.warn('[placeholders] payment.link resolution failed:', e?.message || e); } catch {}
    }
    out = out.replace(/\{\{\s*payment\.link\s*\}\}/g, link);
  } else {
    out = out.replace(/\{\{\s*payment\.link\s*\}\}/g, '');
  }

  return out;
}

module.exports = { replacePlaceholders };