{% extends "base.html" %}
{% from "_macros.html" import crumbs %}
{% block title %}{{ host.name }} — Metrics — Steward{% endblock %}
{% block breadcrumb %}{{ crumbs([("Hosts", "/hosts/"), (host.name, "/hosts/" ~ host.id), ("Metrics", "")]) }}{% endblock %}
{% block content %}
{# Shell only: current-state + history data stream in via HTMX so the heavy
   history query never blocks first paint and the data refreshes live (≈ the
   agent's push cadence). The chart CANVASES live here permanently — only their
   data is polled and applied in place, so refreshes never re-create/flicker. #}
<div style="display:flex;align-items:center;justify-content:space-between;gap:1rem;flex-wrap:wrap;margin-bottom:0.75rem;">
  <h1 class="page-title" style="margin-bottom:0;">{{ host.name }}</h1>
  {% include "_time_range.html" %}
</div>

{# Current state — lazy + polled live. Atomic innerHTML swap of fixed-height
   cards, so values update without a layout jump. #}
<div id="hm-current"
     hx-get="/plugins/host_agent/{{ host.id }}/metrics"
     hx-trigger="load, every {{ poll_seconds }}s"
     hx-swap="innerHTML">
  <div class="card empty">Loading metrics…</div>
</div>

{# History charts — persistent canvases (created once below); only data is polled. #}
<div style="display:grid;grid-template-columns:repeat(auto-fit,minmax(340px,1fr));gap:1rem;margin-top:1rem;">
  <div class="card" style="margin-bottom:0;">
    <div class="section-title" style="margin-bottom:0.5rem;">Utilization % — last <span class="hm-chart-range">{{ current_range }}</span></div>
    <div style="height:220px;"><canvas id="chart-util"></canvas></div>
  </div>
  <div class="card" style="margin-bottom:0;">
    <div class="section-title" style="margin-bottom:0.5rem;">Throughput (B/s) — last <span class="hm-chart-range">{{ current_range }}</span></div>
    <div style="height:220px;"><canvas id="chart-net"></canvas></div>
  </div>
  <div class="card" style="margin-bottom:0;">
    <div class="section-title" style="margin-bottom:0.5rem;">Load &amp; pressure — last <span class="hm-chart-range">{{ current_range }}</span></div>
    <div style="height:220px;"><canvas id="chart-pressure"></canvas></div>
  </div>
</div>
{# Hidden poller: fetches the history series and applies it to the charts above
   (no visible swap). Lazy on load → never blocks paint; refreshed slowly + on
   range change. #}
<div id="hm-charts-data" style="display:none;"
     hx-get="/plugins/host_agent/{{ host.id }}/charts"
     hx-trigger="load, every {{ chart_poll_seconds }}s, rangeChange from:body"
     hx-include="#time-range"
     hx-swap="innerHTML"></div>

<script>
(function () {
  const fmtTime = (v) => { const d = new Date(v); return ("0" + d.getHours()).slice(-2) + ":" + ("0" + d.getMinutes()).slice(-2); };
  const baseOpts = (ymax) => ({
    responsive: true, maintainAspectRatio: false,
    animation: false,                       // no grow-in / re-animate on refresh
    interaction: { mode: "index", intersect: false },
    elements: { point: { radius: 0 } },
    scales: {
      x: { type: "linear", ticks: { callback: (v) => fmtTime(v), maxTicksLimit: 8, color: "#8a8a92", font: { size: 10 } }, grid: { color: "#30303a" } },
      y: { beginAtZero: true, max: ymax, ticks: { color: "#8a8a92", font: { size: 10 } }, grid: { color: "#30303a" } },
    },
    plugins: {
      legend: { labels: { color: "#b8b8b0", boxWidth: 10, font: { size: 11 } } },
      tooltip: { callbacks: { title: (items) => items.length ? fmtTime(items[0].parsed.x) : "" } },
    },
  });
  const defs = {
    "chart-util": { ymax: 100, ds: [
      { key: "cpu_pct", label: "CPU %", color: "#c8a840" },
      { key: "mem_used_pct", label: "Mem %", color: "#4aa86a" },
      { key: "disk_used_pct_worst", label: "Disk % (worst)", color: "#c87840" },
    ] },
    "chart-net": { ymax: undefined, ds: [
      { key: "net_rx_bps", label: "Net RX", color: "#4aa86a" },
      { key: "net_tx_bps", label: "Net TX", color: "#c84048" },
      { key: "disk_read_bps", label: "Disk read", color: "#6aa0d0" },
      { key: "disk_write_bps", label: "Disk write", color: "#c8a840" },
    ] },
    "chart-pressure": { ymax: undefined, ds: [
      { key: "load_1m", label: "Load 1m", color: "#c8a840" },
      { key: "psi_mem_some_avg10", label: "Mem PSI %", color: "#c84048" },
      { key: "temp_c_max", label: "Temp °C", color: "#c87840" },
    ] },
  };
  const charts = {};
  for (const id of Object.keys(defs)) {
    const el = document.getElementById(id);
    if (!el) continue;
    charts[id] = new Chart(el.getContext("2d"), {
      type: "line",
      data: { datasets: defs[id].ds.map((d) => ({ label: d.label, data: [], borderColor: d.color, backgroundColor: d.color, borderWidth: 1.5, tension: 0.25 })) },
      options: baseOpts(defs[id].ymax),
    });
  }
  // Called by the polled /charts data fragment. Updates data in place (no
  // re-create, no animation), so refreshes never flicker or shift layout.
  window.applyHostSeries = function (series, rangeKey) {
    for (const id of Object.keys(defs)) {
      const ch = charts[id];
      if (!ch) continue;
      defs[id].ds.forEach((d, i) => {
        ch.data.datasets[i].data = (series[d.key] || []).map((p) => ({ x: p[0], y: p[1] }));
      });
      ch.update("none");
    }
    if (rangeKey) document.querySelectorAll(".hm-chart-range").forEach((s) => { s.textContent = rangeKey; });
  };
})();
</script>
{% endblock %}