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

  var currentContractID = '';

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

  function switchTab(active) {
    var tabs = ['Overview', 'State', 'Logs', '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';
    });
    // Lazy-load logs when tab is opened
    if (active === 'Logs' && currentContractID) {
      loadLogs(currentContractID);
    }
  }

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

  /* ── ABI rendering ───────────────────────────────────────────────────────── */

  function renderABI(abiJson) {
    var abi = null;
    try {
      abi = typeof abiJson === 'string' ? JSON.parse(abiJson) : abiJson;
    } catch (e) { return; }
    if (!abi || !Array.isArray(abi.methods) || abi.methods.length === 0) return;

    var tbody = document.getElementById('abiMethodsBody');
    tbody.innerHTML = '';
    abi.methods.forEach(function(m) {
      var args = Array.isArray(m.args) && m.args.length > 0
        ? m.args.map(function(a) { return C.esc(a.name || '') + ': ' + C.esc(a.type || '?'); }).join(', ')
        : '<span class="text-muted">none</span>';
      var tr = document.createElement('tr');
      tr.innerHTML =
        '<td><span class="tx-type-badge">' + C.esc(m.name || '?') + '</span></td>' +
        '<td class="mono" style="font-size:0.82rem">' + args + '</td>';
      tbody.appendChild(tr);
    });
    document.getElementById('abiSection').style.display = '';
  }

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

  function renderContract(contract) {
    document.title = 'Contract ' + C.short(contract.contract_id, 16) + ' | DChain Explorer';
    currentContractID = contract.contract_id;

    // Banner
    document.getElementById('bannerContractId').textContent = contract.contract_id || '—';
    document.getElementById('bannerDeployedAt').textContent =
      contract.deployed_at != null ? 'Block #' + contract.deployed_at : '—';

    // Overview fields
    document.getElementById('contractId').textContent = contract.contract_id || '—';

    if (contract.deployer_pub) {
      document.getElementById('contractDeployer').innerHTML =
        '<a href="/address?address=' + encodeURIComponent(contract.deployer_pub) + '">' +
        C.esc(C.shortAddress(contract.deployer_pub)) + '</a>';
      document.getElementById('contractDeployerRaw').textContent = contract.deployer_pub;
    } else {
      document.getElementById('contractDeployer').textContent = '—';
    }

    document.getElementById('contractDeployedBlock').textContent =
      contract.deployed_at != null ? '#' + contract.deployed_at : '—';

    document.getElementById('contractWasmSize').textContent =
      contract.wasm_size != null ? contract.wasm_size.toLocaleString() + ' bytes' : '—';

    // ABI
    if (contract.abi_json) {
      renderABI(contract.abi_json);
    }

    // Raw JSON
    document.getElementById('contractRaw').textContent = JSON.stringify(contract, null, 2);

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

  /* ── Contracts list ──────────────────────────────────────────────────────── */

  async function loadContractsList() {
    try {
      var data = await C.fetchJSON('/api/contracts');
      var contracts = data.contracts || [];
      var loading = document.getElementById('contractsLoading');
      var empty   = document.getElementById('contractsEmpty');
      var wrap    = document.getElementById('contractsTableWrap');
      var count   = document.getElementById('contractsCount');
      if (loading) loading.style.display = 'none';
      count.textContent = contracts.length + ' contract' + (contracts.length !== 1 ? 's' : '');
      if (contracts.length === 0) {
        empty.style.display = '';
        return;
      }
      var tbody = document.getElementById('contractsBody');
      tbody.innerHTML = '';
      contracts.forEach(function(c) {
        var tr = document.createElement('tr');
        var idShort = C.short(c.contract_id, 20);
        var deployer = c.deployer_pub ? C.shortAddress(c.deployer_pub) : '—';
        var deployerHref = c.deployer_pub
          ? '<a href="/address?address=' + encodeURIComponent(c.deployer_pub) + '" class="mono" style="font-size:0.82rem">' + C.esc(deployer) + '</a>'
          : '<span class="text-muted">—</span>';
        tr.innerHTML =
          '<td><a href="/contract?id=' + encodeURIComponent(c.contract_id) + '" class="mono" style="font-size:0.82rem">' + C.esc(idShort) + '</a></td>' +
          '<td>' + deployerHref + '</td>' +
          '<td class="text-muted">' + (c.deployed_at != null ? '#' + c.deployed_at : '—') + '</td>' +
          '<td class="text-muted" style="font-size:0.8rem">' + (c.wasm_size != null ? c.wasm_size.toLocaleString() + ' B' : '—') + '</td>';
        tbody.appendChild(tr);
      });
      wrap.style.display = '';
      C.refreshIcons();
    } catch (e) {
      var loading = document.getElementById('contractsLoading');
      if (loading) loading.textContent = 'Failed to load contracts: ' + e.message;
    }
  }

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

  async function loadContract(id) {
    if (!id) return;
    C.setStatus('Loading…', 'warn');
    document.getElementById('contractsList').style.display = 'none';
    document.getElementById('mainContent').style.display = 'none';
    document.getElementById('abiSection').style.display = 'none';
    switchTab('Overview');
    try {
      var contract = await C.fetchJSON('/api/contracts/' + encodeURIComponent(id));
      renderContract(contract);
      window.history.replaceState({}, '', '/contract?id=' + encodeURIComponent(id));
      C.setStatus('', '');
    } catch (e) {
      C.setStatus('Contract not found: ' + e.message, 'err');
      document.getElementById('contractsList').style.display = '';
    }
  }

  /* ── State browser ───────────────────────────────────────────────────────── */

  async function queryState(key) {
    if (!currentContractID || !key) return;
    C.setStatus('Querying state…', 'warn');
    document.getElementById('stateResult').style.display = 'none';
    document.getElementById('stateEmpty').style.display = 'none';
    try {
      var data = await C.fetchJSON(
        '/api/contracts/' + encodeURIComponent(currentContractID) +
        '/state/' + encodeURIComponent(key)
      );
      C.setStatus('', '');

      document.getElementById('stateKey').textContent = data.key || key;

      if (data.value_hex === null || data.value_hex === undefined) {
        // Key not set
        document.getElementById('stateU64Row').style.display = 'none';
        document.getElementById('stateHex').textContent = '—';
        document.getElementById('stateB64').textContent = '—';
        document.getElementById('stateNullRow').style.display = '';
      } else {
        document.getElementById('stateNullRow').style.display = 'none';
        document.getElementById('stateHex').textContent = data.value_hex || '—';
        document.getElementById('stateB64').textContent = data.value_b64 || '—';
        if (data.value_u64 !== null && data.value_u64 !== undefined) {
          document.getElementById('stateU64').textContent = data.value_u64.toLocaleString();
          document.getElementById('stateU64Row').style.display = '';
        } else {
          document.getElementById('stateU64Row').style.display = 'none';
        }
      }

      document.getElementById('stateResult').style.display = '';
      C.refreshIcons();
    } catch (e) {
      C.setStatus('State query failed: ' + e.message, 'err');
      document.getElementById('stateEmpty').style.display = '';
    }
  }

  document.getElementById('stateLoadBtn').addEventListener('click', function() {
    var key = (document.getElementById('stateKeyInput').value || '').trim();
    if (key) queryState(key);
  });

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

  /* ── Logs ────────────────────────────────────────────────────────────────── */

  var logsLoaded = false;

  function makeLogRow(entry) {
    var tr = document.createElement('tr');
    var txShort = entry.tx_id ? C.short(entry.tx_id, 12) : '—';
    var txLink = entry.tx_id
      ? '<a href="/tx?id=' + encodeURIComponent(entry.tx_id) + '" class="mono" style="font-size:0.8rem">' + C.esc(txShort) + '</a>'
      : '<span class="text-muted">—</span>';
    tr.innerHTML =
      '<td><a href="/?block=' + entry.block_height + '">#' + entry.block_height + '</a></td>' +
      '<td>' + txLink + '</td>' +
      '<td class="text-muted" style="font-size:0.8rem">' + entry.seq + '</td>' +
      '<td class="mono" style="font-size:0.85rem;word-break:break-all">' + C.esc(entry.message) + '</td>';
    return tr;
  }

  async function loadLogs(contractID) {
    if (logsLoaded) return;
    logsLoaded = true;
    try {
      var data = await C.fetchJSON('/api/contracts/' + encodeURIComponent(contractID) + '/logs?limit=100');
      var logs = data.logs || [];
      if (logs.length === 0) {
        document.getElementById('logsEmpty').style.display = '';
        document.getElementById('logsTableWrap').style.display = 'none';
        return;
      }
      var tbody = document.getElementById('logsBody');
      tbody.innerHTML = '';
      logs.forEach(function(entry) { tbody.appendChild(makeLogRow(entry)); });
      document.getElementById('logsEmpty').style.display = 'none';
      document.getElementById('logsTableWrap').style.display = '';
    } catch (e) {
      document.getElementById('logsEmpty').textContent = 'Failed to load logs: ' + e.message;
      document.getElementById('logsEmpty').style.display = '';
    }
  }

  // SSE — prepend live contract_log entries for the currently viewed contract.
  C.connectSSE({
    contract_log: function(entry) {
      if (!currentContractID || entry.contract_id !== currentContractID) return;
      var tbody = document.getElementById('logsBody');
      if (!tbody) return;
      tbody.insertBefore(makeLogRow(entry), tbody.firstChild);
      document.getElementById('logsEmpty').style.display = 'none';
      document.getElementById('logsTableWrap').style.display = '';
    }
  });

  /* ── 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('contractBtn').addEventListener('click', function() {
    var val = (document.getElementById('contractInput').value || '').trim();
    if (val) {
      logsLoaded = false;
      loadContract(val);
    }
  });

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

  var initial = C.q('id');
  if (initial) {
    document.getElementById('contractInput').value = initial;
    loadContract(initial);
  } else {
    loadContractsList();
  }

})();