(function() {
  var C = window.ExplorerCommon;

  /* ── Helpers ─────────────────────────────────────────────────────────────── */

  function linkAddress(pubkey, addrDisplay) {
    var label = addrDisplay || C.shortAddress(pubkey);
    return '<a href="/address?address=' + encodeURIComponent(pubkey) + '">' + C.esc(label) + '</a>';
  }

  function txTypeIcon(type) {
    var map = {
      TRANSFER:         'arrow-left-right',
      REGISTER_KEY:     'user-check',
      RELAY_PROOF:      'zap',
      HEARTBEAT:        'activity',
      BLOCK_REWARD:     'layers-3',
      BIND_WALLET:      'link',
      REGISTER_RELAY:   'radio',
      SLASH:            'alert-triangle',
      ADD_VALIDATOR:    'shield-plus',
      REMOVE_VALIDATOR: 'shield-minus',
    };
    return map[type] || 'circle';
  }

  // Color class for the banner icon based on tx type
  function txBannerClass(type) {
    var pos = { BLOCK_REWARD: 1, RELAY_PROOF: 1, HEARTBEAT: 1, REGISTER_KEY: 1, REGISTER_RELAY: 1 };
    var warn = { SLASH: 1, REMOVE_VALIDATOR: 1 };
    if (warn[type]) return 'tx-banner-warn';
    if (pos[type])  return 'tx-banner-ok';
    return 'tx-banner-ok';  // default — all confirmed txs are "ok"
  }

  // One-line human description of the tx
  function txDescription(tx) {
    var fromAddr = tx.from_addr ? C.shortAddress(tx.from_addr) : (tx.from ? C.shortAddress(tx.from) : '?');
    var toAddr   = tx.to_addr   ? C.shortAddress(tx.to_addr)   : (tx.to   ? C.shortAddress(tx.to)   : '');
    var amt = tx.amount ? tx.amount : C.toToken(tx.amount_ut || 0);

    switch (String(tx.type)) {
      case 'TRANSFER':
        return fromAddr + ' sent ' + amt + (toAddr ? ' to ' + toAddr : '');
      case 'BLOCK_REWARD':
        return 'Block #' + tx.block_index + ' fee reward' + (toAddr ? ' to ' + toAddr : '');
      case 'RELAY_PROOF':
        return fromAddr + ' submitted relay proof, earned ' + amt;
      case 'HEARTBEAT':
        return fromAddr + ' submitted heartbeat';
      case 'REGISTER_KEY': {
        var nick = '';
        if (tx.payload && tx.payload.nickname) nick = ' as "' + tx.payload.nickname + '"';
        return fromAddr + ' registered identity' + nick;
      }
      case 'REGISTER_RELAY':
        return fromAddr + ' registered as relay node';
      case 'BIND_WALLET':
        return fromAddr + ' bound wallet' + (toAddr ? ' → ' + toAddr : '');
      case 'ADD_VALIDATOR':
        return fromAddr + ' added ' + (toAddr || '?') + ' to validator set';
      case 'REMOVE_VALIDATOR':
        return fromAddr + ' removed ' + (toAddr || '?') + ' from validator set';
      case 'SLASH':
        return fromAddr + ' slashed ' + (toAddr || '?');
      default:
        return C.txLabel(tx.type) + (fromAddr ? ' by ' + fromAddr : '');
    }
  }

  /* ── Flow diagram builder ─────────────────────────────────────────────── */

  function buildFlowDiagram(tx) {
    var fromPub  = tx.from || '';
    var fromAddr = tx.from_addr || (fromPub ? C.shortAddress(fromPub) : '');
    var toPub    = tx.to || '';
    var toAddr   = tx.to_addr || (toPub ? C.shortAddress(toPub) : '');
    var amt      = tx.amount ? tx.amount : (tx.amount_ut ? C.toToken(tx.amount_ut) : '');
    var memo     = tx.memo || '';

    // Nodes
    var fromNode = '';
    var toNode   = '';

    if (fromPub) {
      fromNode =
        '<div class="tx-flow-node">' +
          '<div class="tx-flow-bubble tx-flow-from">' +
            (fromAddr ? fromAddr[0].toUpperCase() : '?') +
          '</div>' +
          '<div class="tx-flow-node-label">' +
            (fromPub ? '<a href="/address?address=' + encodeURIComponent(fromPub) + '">' + C.esc(fromAddr || C.shortAddress(fromPub)) + '</a>' : '—') +
          '</div>' +
          '<div class="tx-flow-node-sub">Sender</div>' +
        '</div>';
    }

    if (toPub) {
      toNode =
        '<div class="tx-flow-node">' +
          '<div class="tx-flow-bubble tx-flow-to">' +
            (toAddr ? toAddr[0].toUpperCase() : '?') +
          '</div>' +
          '<div class="tx-flow-node-label">' +
            '<a href="/address?address=' + encodeURIComponent(toPub) + '">' + C.esc(toAddr || C.shortAddress(toPub)) + '</a>' +
          '</div>' +
          '<div class="tx-flow-node-sub">Recipient</div>' +
        '</div>';
    }

    // No route for system txs with no To
    if (!fromPub && !toPub) return '';

    var arrowLabel = amt || C.txLabel(tx.type);
    var arrowSub   = memo || '';

    var arrow =
      '<div class="tx-flow-arrow">' +
        '<div class="tx-flow-arrow-label">' + C.esc(arrowLabel) + '</div>' +
        '<div class="tx-flow-arrow-line">' +
          '<div class="tx-flow-arrow-track"></div>' +
          '<i data-lucide="chevron-right" class="tx-flow-arrow-tip"></i>' +
        '</div>' +
        (arrowSub ? '<div class="tx-flow-arrow-sub">' + C.esc(arrowSub) + '</div>' : '') +
      '</div>';

    if (fromNode && toNode) {
      return fromNode + arrow + toNode;
    }
    if (fromNode) return fromNode;
    return toNode;
  }

  /* ── Main render ─────────────────────────────────────────────────────────── */

  function renderTx(tx) {
    // Page title
    document.title = C.txLabel(tx.type) + ' ' + C.short(tx.id, 12) + ' | DChain Explorer';

    // ── Banner
    var bannerIcon = document.getElementById('txBannerIcon');
    bannerIcon.innerHTML = '<i data-lucide="' + txTypeIcon(tx.type) + '"></i>';
    bannerIcon.className = 'tx-banner-icon ' + txBannerClass(tx.type);
    document.getElementById('txBannerTitle').textContent = 'Confirmed · ' + C.txLabel(tx.type);
    document.getElementById('txBannerDesc').textContent  = txDescription(tx);
    document.getElementById('txBannerTime').textContent  =
      C.fmtTime(tx.time) + ' (' + C.timeAgo(tx.time) + ')';

    // ── Overview action table row
    var fromAddr = tx.from_addr || (tx.from ? C.shortAddress(tx.from) : '—');
    var toAddr   = tx.to_addr   || (tx.to   ? C.shortAddress(tx.to)   : '');
    var routeHtml = tx.from
      ? ('<span class="tx-route-item">' + (tx.from ? linkAddress(tx.from, fromAddr) : '—') + '</span>' +
         (tx.to ? '<i data-lucide="arrow-right" class="tx-route-arrow"></i>' +
                  '<span class="tx-route-item">' + linkAddress(tx.to, toAddr) + '</span>' : ''))
      : '—';
    var payloadNote = tx.memo || (tx.payload && tx.payload.nickname ? 'nickname: ' + tx.payload.nickname : '') || '—';
    var amtHtml = tx.amount_ut
      ? '<span class="tx-overview-amt">' + C.esc(tx.amount || C.toToken(tx.amount_ut)) + '</span>'
      : '<span class="text-muted">—</span>';

    document.getElementById('txActionRow').innerHTML =
      '<div class="tx-action-cell-action">' +
        '<i data-lucide="' + txTypeIcon(tx.type) + '" class="tx-action-icon"></i>' +
        '<span>' + C.esc(C.txLabel(tx.type)) + '</span>' +
      '</div>' +
      '<div class="tx-action-cell-route tx-route">' + routeHtml + '</div>' +
      '<div class="tx-action-cell-payload">' + C.esc(payloadNote) + '</div>' +
      '<div class="tx-action-cell-value">' + amtHtml + '</div>';

    // ── Flow diagram
    var flowHtml = buildFlowDiagram(tx);
    var flowEl = document.getElementById('txFlow');
    if (flowHtml) {
      flowEl.innerHTML = flowHtml;
      flowEl.style.display = '';
    } else {
      flowEl.style.display = 'none';
    }

    // ── Details panel
    // TX ID
    document.getElementById('txId').textContent = tx.id || '—';

    // Type with badge
    document.getElementById('txType').innerHTML =
      '<span class="tx-type-badge">' + C.esc(tx.type || '—') + '</span>' +
      ' <span class="text-muted">— ' + C.esc(C.txLabel(tx.type)) + '</span>';

    // Memo
    if (tx.memo) {
      document.getElementById('txMemo').textContent = tx.memo;
      document.getElementById('txMemoRow').style.display = '';
    } else {
      document.getElementById('txMemoRow').style.display = 'none';
    }

    // From
    if (tx.from) {
      document.getElementById('txFrom').innerHTML = linkAddress(tx.from, tx.from_addr || tx.from);
      document.getElementById('txFromRaw').textContent = tx.from;
    } else {
      document.getElementById('txFrom').textContent = '—';
    }

    // To
    if (tx.to) {
      document.getElementById('txTo').innerHTML = linkAddress(tx.to, tx.to_addr || tx.to);
      document.getElementById('txToRaw').textContent = tx.to;
      document.getElementById('txToRow').style.display = '';
    } else {
      document.getElementById('txToRow').style.display = 'none';
    }

    // Amount
    var amountText = tx.amount || C.toToken(tx.amount_ut || 0);
    document.getElementById('txAmount').textContent = amountText;
    document.getElementById('txAmount').className   = 'tx-amount-val' +
      (tx.amount_ut > 0 ? ' pos' : '');

    // Fee
    document.getElementById('txFee').textContent = tx.fee || C.toToken(tx.fee_ut || 0);

    // Block
    var blockLink = document.getElementById('txBlockLink');
    if (tx.block_index !== undefined) {
      blockLink.textContent = '#' + tx.block_index;
      blockLink.href = '#';
      blockLink.onclick = function(e) { e.preventDefault(); window.location.href = '/?block=' + tx.block_index; };
    } else {
      blockLink.textContent = '—';
    }
    document.getElementById('txBlockHash').textContent = tx.block_hash
      ? '  ' + C.short(tx.block_hash, 20)
      : '';

    // Time
    document.getElementById('txTime').textContent    = C.fmtTime(tx.time);
    document.getElementById('txTimeAgo').textContent = tx.time ? '(' + C.timeAgo(tx.time) + ')' : '';

    // Signature
    if (tx.signature_hex) {
      document.getElementById('txSig').textContent = tx.signature_hex;
      document.getElementById('txSigRow').style.display = '';
    } else {
      document.getElementById('txSigRow').style.display = 'none';
    }

    // ── Payload panel (only for rich payloads)
    var shouldShowPayload = tx.payload &&
      typeof tx.payload === 'object' &&
      tx.type !== 'TRANSFER'; // memo already shown for transfers
    if (shouldShowPayload) {
      document.getElementById('txPayloadPre').textContent = JSON.stringify(tx.payload, null, 2);
      document.getElementById('txPayloadPanel').style.display = '';
    } else {
      document.getElementById('txPayloadPanel').style.display = 'none';
    }

    // ── Raw JSON
    document.getElementById('txRaw').textContent = JSON.stringify(tx, null, 2);

    // Show content
    document.getElementById('mainContent').style.display = '';
    C.refreshIcons();
  }

  /* ── Load ────────────────────────────────────────────────────────────────── */

  async function loadTx(id) {
    if (!id) return;
    C.setStatus('Loading…', 'warn');
    document.getElementById('mainContent').style.display = 'none';
    try {
      var tx = await C.fetchJSON('/api/tx/' + encodeURIComponent(id));
      renderTx(tx);
      window.history.replaceState({}, '', '/tx?id=' + encodeURIComponent(id));
      C.setStatus('', '');
    } catch (e) {
      C.setStatus('Load failed: ' + e.message, 'err');
    }
  }

  /* ── Tab switching ───────────────────────────────────────────────────────── */

  function switchTab(active) {
    var tabs = ['Overview', 'Raw'];
    tabs.forEach(function(name) {
      var btn  = document.getElementById('tab' + name);
      var pane = document.getElementById('pane' + name);
      if (!btn || !pane) return;
      var isActive = (name === active);
      btn.className  = 'tx-tab' + (isActive ? ' tx-tab-active' : '');
      pane.style.display = isActive ? '' : 'none';
    });
  }

  document.getElementById('tabOverview').addEventListener('click', function() { switchTab('Overview'); });
  document.getElementById('tabRaw').addEventListener('click',      function() { switchTab('Raw'); });

  /* ── Copy buttons ────────────────────────────────────────────────────────── */

  document.addEventListener('click', function(e) {
    var t = e.target;
    if (!t) return;
    var btn = t.closest ? t.closest('.copy-btn') : null;
    if (btn) {
      var src = document.getElementById(btn.dataset.copyId);
      if (src) {
        navigator.clipboard.writeText(src.textContent || '').catch(function() {});
        btn.classList.add('copy-btn-done');
        setTimeout(function() { btn.classList.remove('copy-btn-done'); }, 1200);
      }
    }
  });

  /* ── Wiring ──────────────────────────────────────────────────────────────── */

  document.getElementById('txBtn').addEventListener('click', function() {
    var val = (document.getElementById('txInput').value || '').trim();
    if (val) loadTx(val);
  });

  document.getElementById('txInput').addEventListener('keydown', function(e) {
    if (e.key === 'Enter') document.getElementById('txBtn').click();
  });

  var initial = C.q('id');
  if (initial) {
    document.getElementById('txInput').value = initial;
    loadTx(initial);
  }

})();