/* ------------------------------------------------------------
   1.  Socket-IO connection & helper functions (unchanged)
   ------------------------------------------------------------ */
const socket = io();

socket.on('host_metrics', renderStatsTable);
socket.on('connect_error', err => {
  safeSetText('host_metrics', `Could not connect to server - ${err.message}`);
});
socket.on('reconnect', attempt => {
  safeSetText('host_metrics', `Re-connected (attempt ${attempt})`);
});

function safeSetText(id, txt) {
  const el = document.getElementById(id);
  if (el) el.textContent = txt;
}

/* ------------------------------------------------------------------
   2.  Table rendering - now orders rows before building the table
   ------------------------------------------------------------------ */
// helper function for table row ordering   
function renderStatsTable(data) {
  socket.emit('tableRendered');
  renderGenericTable('host_metrics', data, 'No Stats available');
}

function renderGenericTable(containerId, data, emptyMsg) {
  const container = document.getElementById(containerId);
  if (!Array.isArray(data) || !data.length) {
    container.textContent = emptyMsg;
    return;
  }

  /* Merge rows by name (new logic) */
  const mergedData = mergeRowsByName(data);

  /* Order the merged rows – priority first */
  const orderedData = orderRows(mergedData);

  /* Build the table from the ordered data */
  const table = buildTable(orderedData);
  table.id = 'host_metrics_table';
  container.innerHTML = '';
  container.appendChild(table);
}

/* ------------------------------------------------------------
   3.  Merge rows by name
   ------------------------------------------------------------ */
function mergeRowsByName(data) {
  const groups = {}; // { source: { ... } }
  data.forEach(row => {
    const source = row.Source;      // <-- changed
    if (!source) return;
    if (!groups[source]) {
      groups[source] = { Metric: [], Data: [], Property: [], Value: [] };
    }
    if ('Metric' in row && 'Data' in row) {
      groups[source].Metric.push(row.Metric);
      groups[source].Data.push(row.Data);
    } else if ('Property' in row && 'Value' in row) {
      groups[source].Property.push(row.Property);
      groups[source].Value.push(row.Value);
    }
  });

  const merged = [];
  Object.entries(groups).forEach(([source, grp]) => {
    merged.push({
      Source: source,          // <-- keep the original key
      Metric: grp.Metric,
      Data: grp.Data,
      Property: grp.Property,
      Value: grp.Value
    });
  });
  return merged;
}

// 3b. Order rows – put “System”, “CPU”, “RAM” first
function orderRows(rows) {
  // Priority list – can be updated later
  const priority = ['System', 'CPU', 'RAM'];

  // Map source → priority index
  const priorityMap = {};
  priority.forEach((src, idx) => {
    priorityMap[src] = idx;
  });

  // Stable sort: keep original position if priorities are equal
  return [...rows].sort((a, b) => {
    const aIdx = priorityMap.hasOwnProperty(a.Source)
      ? priorityMap[a.Source]
      : Infinity;               // anything not in priority goes to the end
    const bIdx = priorityMap.hasOwnProperty(b.Source)
      ? priorityMap[b.Source]
      : Infinity;

    // If both have the same priority (or both Infinity), keep original order
    return aIdx - bIdx;
  });
}

/* ------------------------------------------------------------
   4.  Build an HTML table from an array of objects
   ------------------------------------------------------------ */
function buildTable(data) {
  const cols = ['Source', 'Property', 'Value', 'Metric', 'Data']; // explicit order
  const table = document.createElement('table');

  // Header
  const thead = table.createTHead();
  const headerRow = thead.insertRow();
  cols.forEach(col => {
    const th = document.createElement('th');
    th.textContent = col;
    headerRow.appendChild(th);
  });

  // Body
  const tbody = table.createTBody();
  data.forEach(item => {
    const tr = tbody.insertRow();
    cols.forEach(col => {
      const td = tr.insertCell();
       
      const val = item[col];
      if (Array.isArray(val)) {
        // Create a <span> for each item
        val.forEach((v, idx) => {
          td.id = 'host_metrics_column';
          const span = document.createElement('span');
          span.textContent = v;
          td.appendChild(span);

          // Insert a line break after every item except the last
          if (idx < val.length - 1) td.appendChild(document.createElement('br'));
        });
      } else {
        td.textContent = val !== undefined ? val : '';
      }
    });
  });

  return table;
}