(function () {
  'use strict';

  // --- Config ---
  const COINGECKO_API = 'https://api.coingecko.com/api/v3/simple/price?ids=monero&vs_currencies=eur,usd,chf';
  // Standard address (4..., 95 chars), Subaddress (8..., 95 chars), Integrated address (4..., 106 chars)
  const XMR_STANDARD_REGEX = /^[48][1-9A-HJ-NP-Za-km-z]{94}$/;
  const XMR_INTEGRATED_REGEX = /^4[1-9A-HJ-NP-Za-km-z]{105}$/;
  const CACHE_DURATION = 60000; // 1 min
  const RATE_RETRY_DELAY = 10000; // 10s retry on failure

  // --- State ---
  let fiatRates = null;
  let ratesTimestamp = 0;
  let countdownInterval = null;
  let ratesFailed = false;

  // --- DOM ---
  const $ = (s) => document.querySelector(s);
  const addrInput = $('#addr');
  const amountInput = $('#amount');
  const currencySelect = $('#currency');
  const descInput = $('#desc');
  const timerInput = $('#timer');
  const generateBtn = $('#generate');
  const resultSection = $('#result');
  const qrContainer = $('#qr');
  const uriBox = $('#uri');
  const copyUriBtn = $('#copyUri');
  const copyAddrBtn = $('#copyAddr');
  const downloadBtn = $('#downloadQr');
  const countdownEl = $('#countdown');
  const fiatHint = $('#fiatHint');
  const toast = $('#toast');
  const shareLinkInput = $('#shareLink');
  const copyShareLinkBtn = $('#copyShareLink');
  const newRequestBtn = $('#newRequest');
  const homeLink = $('#homeLink');

  // --- Init ---
  fetchRates();
  loadFromHash() || loadSaved();
  registerSW();

  // --- Events ---
  addrInput.addEventListener('input', validateAddress);
  amountInput.addEventListener('input', updateFiatHint);
  currencySelect.addEventListener('change', updateFiatHint);
  generateBtn.addEventListener('click', generate);
  copyUriBtn.addEventListener('click', () => copyToClipboard(uriBox.textContent));
  copyAddrBtn.addEventListener('click', () => copyToClipboard(addrInput.value.trim()));
  copyShareLinkBtn.addEventListener('click', () => copyToClipboard(shareLinkInput.value));
  downloadBtn.addEventListener('click', downloadQR);
  newRequestBtn.addEventListener('click', resetForm);
  homeLink.addEventListener('click', function (e) { e.preventDefault(); resetForm(); });

  // --- Functions ---

  function resetForm() {
    addrInput.value = '';
    amountInput.value = '';
    currencySelect.value = 'EUR';
    descInput.value = '';
    timerInput.value = '';
    fiatHint.textContent = '';
    fiatHint.classList.remove('error');
    addrInput.classList.remove('valid', 'invalid');
    generateBtn.disabled = true;
    resultSection.classList.remove('visible');
    if (countdownInterval) clearInterval(countdownInterval);
    qrContainer.innerHTML = '';
    uriBox.textContent = '';
    shareLinkInput.value = '';
    history.replaceState(null, '', location.pathname);
    window.scrollTo({ top: 0, behavior: 'smooth' });
    addrInput.focus();
  }

  function isValidAddress(addr) {
    return XMR_STANDARD_REGEX.test(addr) || XMR_INTEGRATED_REGEX.test(addr);
  }

  function validateAddress() {
    const val = addrInput.value.trim();
    addrInput.classList.remove('valid', 'invalid');
    if (val.length === 0) return;
    if (isValidAddress(val)) {
      addrInput.classList.add('valid');
    } else if (val.length >= 10) {
      addrInput.classList.add('invalid');
    }
    updateGenerateBtn();
  }

  function updateGenerateBtn() {
    const addr = addrInput.value.trim();
    generateBtn.disabled = !isValidAddress(addr);
  }

  function updateFiatHint() {
    const amount = parseFloat(amountInput.value);
    const currency = currencySelect.value;

    if (!amount || amount <= 0) {
      fiatHint.textContent = '';
      fiatHint.classList.remove('error');
      return;
    }

    if (currency !== 'XMR' && !fiatRates) {
      fiatHint.textContent = ratesFailed ? I18n.t('rates_offline') : '';
      fiatHint.classList.toggle('error', ratesFailed);
      return;
    }

    fiatHint.classList.remove('error');

    if (currency === 'XMR') {
      if (fiatRates) {
        const eur = (amount * fiatRates.eur).toFixed(2);
        fiatHint.textContent = '\u2248 ' + eur + ' EUR';
      } else {
        fiatHint.textContent = '';
      }
    } else {
      const rate = fiatRates[currency.toLowerCase()];
      if (rate && rate > 0) {
        const xmr = (amount / rate).toFixed(8);
        fiatHint.textContent = '\u2248 ' + xmr + ' XMR';
      }
    }
  }

  function getXmrAmount() {
    const amount = parseFloat(amountInput.value);
    const currency = currencySelect.value;

    if (!amount || amount <= 0) return null;

    if (currency === 'XMR') return amount;

    if (fiatRates) {
      const rate = fiatRates[currency.toLowerCase()];
      if (rate && rate > 0) return amount / rate;
    }
    return null;
  }

  function buildUri(addr, xmrAmount, desc) {
    let uri = 'monero:' + addr;
    const params = [];
    if (xmrAmount) params.push('tx_amount=' + xmrAmount.toFixed(12));
    if (desc) params.push('tx_description=' + encodeURIComponent(desc));
    if (params.length) uri += '?' + params.join('&');
    return uri;
  }

  function buildHash(addr, xmrAmount, desc, timer) {
    const params = new URLSearchParams();
    params.set('a', addr);
    if (xmrAmount) params.set('x', xmrAmount.toFixed(12));
    if (desc) params.set('d', desc);
    if (timer) params.set('t', timer);
    return params.toString();
  }

  async function shortenUrl(hash) {
    try {
      const res = await fetch('/api/shorten.php', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ hash: hash })
      });
      if (!res.ok) throw new Error('HTTP ' + res.status);
      const data = await res.json();
      return location.origin + '/s/' + data.code;
    } catch (e) {
      console.warn('Short URL failed:', e);
      return null;
    }
  }

  function generate() {
    const addr = addrInput.value.trim();
    if (!isValidAddress(addr)) return;

    const xmrAmount = getXmrAmount();
    const desc = descInput.value.trim();
    const timer = parseInt(timerInput.value) || 0;
    const uri = buildUri(addr, xmrAmount, desc);

    // Show result
    resultSection.classList.add('visible');
    uriBox.textContent = uri;

    // Share link — show long URL immediately, then replace with short
    const hash = buildHash(addr, xmrAmount, desc, timer);
    shareLinkInput.value = location.origin + '/#' + hash;
    shortenUrl(hash).then(function (shortUrl) {
      if (shortUrl) shareLinkInput.value = shortUrl;
    });

    // QR
    qrContainer.innerHTML = '';
    new QRCode(qrContainer, {
      text: uri,
      width: 256,
      height: 256,
      colorDark: '#ffffff',
      colorLight: '#1a1a1a',
      correctLevel: QRCode.CorrectLevel.M
    });

    // Countdown
    startCountdown();

    // Save to LocalStorage
    saveState(addr);

    // Scroll to result
    resultSection.scrollIntoView({ behavior: 'smooth', block: 'start' });
  }

  function loadFromHash() {
    const hash = location.hash.substring(1);
    if (!hash) return false;

    const params = new URLSearchParams(hash);
    const addr = params.get('a');
    if (!addr || !isValidAddress(addr)) return false;

    addrInput.value = addr;
    validateAddress();

    const xmr = params.get('x');
    if (xmr) {
      amountInput.value = parseFloat(xmr);
      currencySelect.value = 'XMR';
    }

    const desc = params.get('d');
    if (desc) descInput.value = desc;

    const timer = params.get('t');
    if (timer && parseInt(timer) > 0) timerInput.value = timer;

    // Auto-generate
    setTimeout(generate, 100);
    return true;
  }

  function startCountdown() {
    if (countdownInterval) clearInterval(countdownInterval);
    countdownEl.textContent = '';
    countdownEl.className = 'countdown';

    const minutes = parseInt(timerInput.value);
    if (!minutes || minutes <= 0) return;

    const end = Date.now() + minutes * 60000;
    countdownEl.classList.add('active');

    function tick() {
      const remaining = end - Date.now();
      if (remaining <= 0) {
        clearInterval(countdownInterval);
        countdownEl.textContent = I18n.t('countdown_expired');
        countdownEl.className = 'countdown expired';
        return;
      }
      const m = Math.floor(remaining / 60000);
      const s = Math.floor((remaining % 60000) / 1000);
      countdownEl.textContent = I18n.t('countdown_remaining') + pad(m) + ':' + pad(s);
    }

    tick();
    countdownInterval = setInterval(tick, 1000);
  }

  function pad(n) {
    return n < 10 ? '0' + n : '' + n;
  }

  function downloadQR() {
    const canvas = qrContainer.querySelector('canvas');
    if (!canvas) return;
    const link = document.createElement('a');
    link.download = 'xmrpay-qr.png';
    link.href = canvas.toDataURL('image/png');
    link.click();
  }

  function copyToClipboard(text) {
    navigator.clipboard.writeText(text).then(() => {
      showToast(I18n.t('toast_copied'));
    });
  }

  function showToast(msg) {
    toast.textContent = msg;
    toast.classList.add('show');
    setTimeout(() => toast.classList.remove('show'), 2000);
  }

  function saveState(addr) {
    try {
      localStorage.setItem('xmrpay_addr', addr);
    } catch (e) { /* silent */ }
  }

  function loadSaved() {
    try {
      const addr = localStorage.getItem('xmrpay_addr');
      if (addr) {
        addrInput.value = addr;
        validateAddress();
      }
    } catch (e) { /* silent */ }
  }

  async function fetchRates() {
    if (fiatRates && Date.now() - ratesTimestamp < CACHE_DURATION) return;
    try {
      const res = await fetch(COINGECKO_API);
      if (!res.ok) throw new Error('HTTP ' + res.status);
      const data = await res.json();
      fiatRates = data.monero;
      ratesTimestamp = Date.now();
      ratesFailed = false;
      updateFiatHint();
    } catch (e) {
      console.warn('Kurse konnten nicht geladen werden:', e);
      ratesFailed = true;
      updateFiatHint();
      setTimeout(fetchRates, RATE_RETRY_DELAY);
    }
  }

  function registerSW() {
    if ('serviceWorker' in navigator) {
      navigator.serviceWorker.register('sw.js').catch(function () {});
    }
  }
})();