const $ = (sel, root = document) => root.querySelector(sel);
const $$ = (sel, root = document) => [...root.querySelectorAll(sel)];

const itemsBody = $('#items-body');
const rowTemplate = $('#row-template');
const form = $('#payment-form');
const resultBox = $('#result');
const submitBtn = $('#submit-btn');

const currencySelect = $('#currency');

const money = (n, currency = currencySelect?.value || 'AUD') =>
  new Intl.NumberFormat('en-US', {
    style: 'currency',
    currency,
    minimumFractionDigits: 0,
    maximumFractionDigits: 2,
  }).format(Number(n) || 0);

// ---------- Items table ----------
function addRow(data = {}) {
  const frag = rowTemplate.content.cloneNode(true);
  const row = frag.querySelector('tr');
  if (data.sku) row.querySelector('.cell-sku').value = data.sku;
  if (data.name) row.querySelector('.cell-name').value = data.name;
  if (data.price != null) row.querySelector('.cell-price').value = data.price;
  if (data.quantity != null) row.querySelector('.cell-qty').value = data.quantity;
  if (data.condition) row.querySelector('.cell-condition').value = data.condition;

  row.querySelector('.btn-del').addEventListener('click', () => {
    row.remove();
    if (itemsBody.children.length === 0) addRow();
    recalc();
  });
  row.addEventListener('input', recalc);
  itemsBody.appendChild(row);
  recalc();
}

function recalc() {
  let total = 0;
  $$('.item-row', itemsBody).forEach((row) => {
    const price = parseFloat(row.querySelector('.cell-price').value) || 0;
    const qty = parseFloat(row.querySelector('.cell-qty').value) || 0;
    const sub = price * qty;
    total += sub;
    row.querySelector('.cell-subtotal').textContent = money(sub);
  });
  $('#grand-total').textContent = money(total);
}

function collectItems() {
  return $$('.item-row', itemsBody)
    .map((row) => ({
      sku: row.querySelector('.cell-sku').value.trim(),
      name: row.querySelector('.cell-name').value.trim(),
      price: parseFloat(row.querySelector('.cell-price').value) || 0,
      quantity: parseFloat(row.querySelector('.cell-qty').value) || 0,
      condition: row.querySelector('.cell-condition').value.trim(),
    }))
    .filter((it) => it.sku || it.name || it.price > 0);
}

$('#add-row').addEventListener('click', () => addRow());

// Re-render totals when the currency changes.
currencySelect.addEventListener('change', recalc);

// ---------- Submit ----------
function setLoading(on) {
  submitBtn.disabled = on;
  $('.spinner', submitBtn).hidden = !on;
  $('.btn-label', submitBtn).textContent = on ? 'Creating...' : 'Create payment link';
}

function showResult(type, html) {
  resultBox.hidden = false;
  resultBox.className = `result ${type}`;
  resultBox.innerHTML = html;
}

form.addEventListener('submit', async (e) => {
  e.preventDefault();

  const customer = {
    customerName: $('#customerName').value.trim(),
    email: $('#email').value.trim(),
    phone: $('#phone').value.trim(),
    address: $('#address').value.trim(),
  };

  // All customer fields are required.
  const CUSTOMER_LABELS = {
    customerName: 'Customer name',
    email: 'Email',
    phone: 'Phone number',
    address: 'Address',
  };
  const missingCustomer = Object.keys(CUSTOMER_LABELS).filter((k) => !customer[k]);
  if (missingCustomer.length) {
    showResult('error', `Please fill in: ${missingCustomer.map((k) => CUSTOMER_LABELS[k]).join(', ')}.`);
    return;
  }

  // At least one item, each with SKU, price and quantity.
  const items = collectItems();
  if (items.length === 0) {
    showResult('error', 'Please add at least one item.');
    return;
  }
  for (let i = 0; i < items.length; i++) {
    const it = items[i];
    const missing = [];
    if (!it.sku) missing.push('SKU');
    if (!(it.price > 0)) missing.push('Price');
    if (!(it.quantity > 0)) missing.push('Qty');
    if (!it.condition) missing.push('Condition');
    if (missing.length) {
      showResult('error', `Item ${i + 1}: ${missing.join(', ')} ${missing.length > 1 ? 'are' : 'is'} required.`);
      return;
    }
  }

  const payload = {
    ...customer,
    currency: currencySelect.value,
    items,
  };

  setLoading(true);
  resultBox.hidden = true;
  try {
    const res = await fetch('/api/payments', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json', 'Accept': 'application/json' },
      body: JSON.stringify(payload),
    });
    const data = await res.json();
    if (!res.ok) throw new Error(data.error || 'Failed to create link.');

    // Open in a new tab
    window.open(data.link, '_blank', 'noopener');

    showResult(
      'success',
      `<strong>✓ Link created successfully!</strong>
       <div class="link-row">
         <a href="${data.link}" target="_blank" rel="noopener">${data.link}</a>
         <button type="button" class="btn btn-ghost btn-sm" id="copy-link">Copy</button>
       </div>`
    );
    $('#copy-link')?.addEventListener('click', () => {
      navigator.clipboard.writeText(data.link);
      $('#copy-link').textContent = 'Copied';
    });

    loadHistory();
  } catch (err) {
    showResult('error', `<strong>Error:</strong> ${err.message}`);
  } finally {
    setLoading(false);
  }
});

// ---------- History ----------
async function loadHistory() {
  const list = $('#history-list');
  try {
    const res = await fetch('/api/payments');
    const data = await res.json();
    const payments = data.payments || [];
    if (payments.length === 0) {
      list.innerHTML = '<p class="muted empty">No payments yet.</p>';
      return;
    }
    list.innerHTML = payments.map(renderHistItem).join('');
  } catch {
    list.innerHTML = '<p class="muted empty">Could not load history.</p>';
  }
}

function renderHistItem(p) {
  let itemCount = 0;
  try {
    itemCount = JSON.parse(p.items_json || '[]').length;
  } catch { }
  const when = (p.created_at || '').replace('T', ' ').slice(0, 16);
  const hasLink = !!p.payment_link;
  const hint = hasLink
    ? `<div class="hist-actions"><span class="hist-link">Open link →</span></div>`
    : '';
  return `
    <div class="hist-item${hasLink ? ' clickable' : ''}"${hasLink ? ` data-link="${escapeHtml(p.payment_link)}" role="link" tabindex="0"` : ''}>
      <div class="hist-top">
        <span class="hist-name">${escapeHtml(p.customer_name)}</span>
        <span class="hist-total">${money(p.total, p.currency || 'AUD')}</span>
      </div>
      <div class="hist-meta">${escapeHtml(p.email || p.phone || '')} · ${itemCount} item · ${when}</div>
      ${hint}
    </div>`;
}

// Whole history card is clickable → open its payment link in a new tab.
function openHistItem(el) {
  const link = el?.dataset?.link;
  if (link) window.open(link, '_blank', 'noopener');
}
$('#history-list').addEventListener('click', (e) => {
  openHistItem(e.target.closest('.hist-item.clickable'));
});
$('#history-list').addEventListener('keydown', (e) => {
  if (e.key === 'Enter' || e.key === ' ') {
    const card = e.target.closest('.hist-item.clickable');
    if (card) {
      e.preventDefault();
      openHistItem(card);
    }
  }
});

function escapeHtml(s) {
  return String(s || '').replace(/[&<>"']/g, (c) =>
    ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[c])
  );
}

$('#refresh-history').addEventListener('click', loadHistory);

// ---------- Init ----------
addRow();
loadHistory();