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

socket.on('client_summary', renderStatsTable);

socket.on('connect_error', err => {
  safeSetText('client_summary', `Could not connect to server - ${err.message}`);
});

socket.on('reconnect', attempt => {
  safeSetText('client_summary', `Re-connected (attempt ${attempt})`);
});

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

/* ------------------------------------------------------------
   2.  Render the table for the *selected* host
   ------------------------------------------------------------ */
function renderStatsTable(raw) {
  // Raw may be a string (from Redis) or already parsed by socket.io
  let payload;
  if (typeof raw === 'string') {
    try {
      payload = JSON.parse(raw);
    } catch (e) {
      safeSetText('client_summary', 'Invalid data received');
      return;
    }
  } else {
    payload = raw;
  }

  if (!Array.isArray(payload) || !payload.length) {
    safeSetText('client_summary', 'No data available');
    return;
  }

  /* ---------------------------------------------
     2a. Determine the hostname to display
     --------------------------------------------- */
  const urlParams = new URLSearchParams(window.location.search);
  const selectedHost = urlParams.get('host');

  /* ---------------------------------------------
     2b. Find the host object in the payload
     --------------------------------------------- */
  const hostObj =
    payload.find(item => item.hostname === selectedHost) || payload[0];

  /* ---------------------------------------------
     2c. Extract the Redis data for that host
     --------------------------------------------- */
  const hostData = hostObj && Array.isArray(hostObj.redis_data)
    ? hostObj.redis_data
    : [];

  /* ---------------------------------------------
     2d. Pass the host-specific data to the generic renderer
     --------------------------------------------- */
  renderGenericTable('host_metrics', hostData, 'No Stats available');
}

/* ------------------------------------------------------------
   3.  Table rendering - unchanged from original
   ------------------------------------------------------------ */
function renderGenericTable(containerId, data, emptyMsg) {
  const container = document.getElementById(containerId);
  if (!Array.isArray(data) || !data.length) {
    container.textContent = emptyMsg;
    return;
  }

  // Merge rows by source name
  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);
}

/* ------------------------------------------------------------
   4.  Merge rows by source name
   ------------------------------------------------------------ */
function mergeRowsByName(data) {
  const groups = {}; // { source: { Metric: [], Data: [] } }
  data.forEach(row => {
    const source = row.Source;
    if (!source) return;

    if (!groups[source]) {
      groups[source] = { Metric: [], Data: [] };
    }

    if ('Metric' in row && 'Data' in row) {
      groups[source].Metric.push(row.Metric);
      groups[source].Data.push(row.Data);
    }
  });

  const merged = [];
  Object.entries(groups).forEach(([source, grp]) => {
    merged.push({
      Source: source,
      Metric: grp.Metric,
      Data: grp.Data,
    });
  });

  return merged;
}

/* ------------------------------------------------------------
   5.  Order rows - put “System”, “CPU”, “RAM” first
   ------------------------------------------------------------ */
function orderRows(rows) {
  const priority = ['System', 'CPU', 'RAM'];
  const priorityMap = {};
  priority.forEach((src, idx) => {
    priorityMap[src] = idx;
  });

  return [...rows].sort((a, b) => {
    const aIdx = priorityMap.hasOwnProperty(a.Source) ? priorityMap[a.Source] : Infinity;
    const bIdx = priorityMap.hasOwnProperty(b.Source) ? priorityMap[b.Source] : Infinity;
    return aIdx - bIdx;
  });
}

/* ------------------------------------------------------------
   6.  Build an HTML table from an array of objects
   ------------------------------------------------------------ */
function buildTable(data) {
  const cols = ['Source', 'Metric', 'Data'];
  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)) {
        val.forEach((v, idx) => {
          td.id = 'host_metrics_column';
          const span = document.createElement('span');
          span.textContent = v;
          td.appendChild(span);
          if (idx < val.length - 1) td.appendChild(document.createElement('br'));
        });
      } else {
        td.textContent = val !== undefined ? val : '';
      }
    });
  });

  return table;
}