/**
 * Server info page — live dashboard with D3/NVD3 charts.
 */
function ServerInfoPage(params, container) {
  var DATA_LIMIT = 100;
  var recordedData = [];

  var html =
    '<div id="ServerInfoController">' +
      '<div class="row">' +
        '<div class="col-sm-12"><h2 id="si-hostname">Server Info</h2></div>' +
        '<div id="si-fields" class="col-sm-12 row"><span class="text-white-50">Loading…</span></div>' +
      '</div>' +
      '<div class="row">' +
        '<div class="col-sm-12">' +
          '<div class="card mb-3">' +
            '<div class="card-header">' +
              '<button class="btn btn-sm btn-outline-primary float-end" role="button" data-bs-toggle="collapse" data-bs-target="#performanceCollapse">toggle</button>' +
              '<h4 class="card-title mb-0">Server Performance</h4>' +
            '</div>' +
            '<div id="performanceCollapse" class="collapse show">' +
              '<div class="card-body"><svg id="chart-performance" style="height:200px;width:100%"></svg></div>' +
            '</div>' +
          '</div>' +
        '</div>' +
        '<div class="col-sm-3">' +
          '<div class="card mb-3">' +
            '<div class="card-header">' +
            '<h4 class="card-title mb-0">Players</h4>' +
            '</div>' +
            '<div id="playersCollapse" class="collapse show bottom-row">' +
              '<div class="card-body"><svg id="chart-players" style="height:250px;width:100%"></svg></div>' +
            '</div>' +
          '</div>' +
        '</div>' +
        '<div class="col-sm-9">' +
          '<div class="card mb-3">' +
            '<div class="card-header">' +
              '<button class="btn btn-sm btn-outline-primary float-end" role="button" data-bs-toggle="collapse" data-bs-target=".bottom-row">toggle</button>' +
              '<h4 class="card-title mb-0">Server Networking</h4>' +
            '</div>' +
            '<div id="networkCollapse" class="collapse show bottom-row">' +
              '<div class="card-body"><svg id="chart-network" style="height:250px;width:100%"></svg></div>' +
            '</div>' +
          '</div>' +
        '</div>' +
      '</div>' +
    '</div>';
  container.innerHTML = html;

  // ---- NVD3 Charts ----
  nv.addGraph(function () {
    var perfChart = nv.models.multiChart()
      .margin({ top: 30, right: 75, bottom: 40, left: 75 })
      .color(['#e879f9', '#22d3ee']);
    perfChart.yAxis1.axisLabel('Framerate').tickFormat(d3.format(',d'));
    perfChart.yAxis2.axisLabel('Entities').tickFormat(d3.format(',d'));
    perfChart.xAxis.axisLabel('Time').tickFormat(function (d) { return d3.time.format('%H:%M:%S')(new Date(d)); });
    perfChart.lines1.duration(0);
    perfChart.lines2.duration(0);

    d3.select('#chart-performance').datum([
      { key: 'Framerate', type: 'line', yAxis: 1, values: [] },
      { key: 'Entities',  type: 'line', yAxis: 2, values: [] }
    ]).call(perfChart);

    window._perfChart = perfChart;
  });

  nv.addGraph(function () {
    var netChart = nv.models.stackedAreaChart()
      .margin({ top: 0, right: 75, bottom: 40, left: 75 })
      .color(['#c084fc', '#fbbf24']);
    netChart.yAxis.axisLabel('Network').tickFormat(function (bytes) {
      var fmt = d3.format('.0f');
      if (bytes < 1024) return fmt(bytes) + 'B';
      if (bytes < 1048576) return fmt(bytes / 1024) + 'kB';
      if (bytes < 1073741824) return fmt(bytes / 1048576) + 'MB';
      return fmt(bytes / 1073741824) + 'GB';
    });
    netChart.xAxis.axisLabel('Time').tickFormat(function (d) { return d3.time.format('%H:%M:%S')(new Date(d)); });

    d3.select('#chart-network').datum([
      { key: 'IN',  values: [] },
      { key: 'OUT', values: [] }
    ]).call(netChart);

    window._netChart = netChart;
  });

  nv.addGraph(function () {
    var playersChart = nv.models.pieChart()
      .x(function (d) { return d.key; })
      .y(function (d) { return d.y; })
      .showLabels(true)
      .donut(true)
      .donutLabelsOutside(false)
      .duration(500)
      .height(250)
      .color(['#a78bfa', '#7c3aed', '#e879f9', '#2d1f3d'])
      .margin({ top: 5, right: 5, bottom: 5, left: 5 });
    playersChart.pie.startAngle(function (d) { return d.startAngle / 2 - Math.PI / 2; });
    playersChart.pie.endAngle(function (d) { return d.endAngle / 2 - Math.PI / 2; });

    d3.select('#chart-players').datum([]).call(playersChart);

    window._playersChart = playersChart;
  });

  // ---- Data polling ----
  // Subscribe to header's serverinfo updates (no redundant RCON request)
  function onServerInfo(e) { updateData(e.detail); }
  document.addEventListener('serverinfo-update', onServerInfo);

  // If header already has cached data, use it immediately
  if (window._lastServerInfo) updateData(window._lastServerInfo);

  function updateData(data) {
    // Guard: element may be gone if navigated away
    var fieldsEl = document.getElementById('si-fields');
    if (!fieldsEl) return;

    // Update text fields
    var fieldsHtml = '';
    for (var key in data) {
      if (data.hasOwnProperty(key)) {
        var val = data[key];
        if (typeof val === 'number') val = formatNumber(val);
        fieldsHtml += '<div class="col-sm-4"><p><span class="text-white-50">' + key + ':</span> <span>' + val + '</span></p></div>';
      }
    }
    fieldsEl.innerHTML = fieldsHtml;
    if (data.Hostname) {
      var hn = document.getElementById('si-hostname');
      if (hn) hn.textContent = data.Hostname;
    }

    // Collect chart data
    recordedData.push({ ts: Date.now(), data: data });
    if (recordedData.length > DATA_LIMIT) {
      recordedData = recordedData.slice(recordedData.length - DATA_LIMIT);
    }
    updateCharts(data);
  }

  function updateCharts(data) {
    // Guard: SVG elements may be gone if navigated away
    // Players pie chart
    if (window._playersChart) {
      var pc = d3.select('#chart-players');
      if (!pc.empty()) {
        pc.datum([
        { key: 'Queued',  y: data.Queued || 0 },
        { key: 'Joining', y: data.Joining || 0 },
        { key: 'Players', y: data.Players || 0 },
        { key: 'Free',    y: (data.MaxPlayers || 0) - ((data.Joining || 0) + (data.Players || 0)) }
      ]).call(window._playersChart);
      }
    }

    // Performance chart
    var fpsVals = [], entVals = [], netInVals = [], netOutVals = [];
    for (var i = 0; i < recordedData.length; i++) {
      var r = recordedData[i];
      fpsVals.push({ x: r.ts, y: r.data.Framerate || 0 });
      entVals.push({ x: r.ts, y: r.data.EntityCount || 0 });
      netInVals.push({ x: r.ts, y: r.data.NetworkIn || 0 });
      netOutVals.push({ x: r.ts, y: r.data.NetworkOut || 0 });
    }

    if (window._perfChart) {
      d3.select('#chart-performance').datum([
        { key: 'Framerate', type: 'line', yAxis: 1, values: fpsVals },
        { key: 'Entities',  type: 'line', yAxis: 2, values: entVals }
      ]).call(window._perfChart);
    }

    if (window._netChart) {
      d3.select('#chart-network').datum([
        { key: 'IN',  values: netInVals },
        { key: 'OUT', values: netOutVals }
      ]).call(window._netChart);
    }
  }

  return function cleanup() {
    document.removeEventListener('serverinfo-update', onServerInfo);
    window._perfChart = null;
    window._netChart = null;
    window._playersChart = null;
  };
}