import { ui_locales, currentLanguageIndex } from "@ui/ui_template_locale";
import { createLineChart } from "@ui/ui_template_elements";
import type { ResourceData } from "./B01_Dashboard_Api_Fetch";

function L(key: keyof typeof ui_locales): string {
  return ui_locales[key][currentLanguageIndex];
}

function percent(value?: number | null): string {
  return value == null ? "-" : `${Math.round(value)}%`;
}

export function buildResourcePanel(resources: ResourceData | null): HTMLElement {
  const wrap = document.createElement("div");
  wrap.className = "b01-dashboard__resource-panel";
  wrap.append(buildResourceMetrics(resources), buildResourceChart(resources));
  return wrap;
}

function buildResourceMetrics(resources: ResourceData | null): HTMLElement {
  const values = resources?.current;
  const grid = document.createElement("div");
  grid.className = "b01-dashboard__metric-grid";
  const items = [
    [L("B01_Dashboard_Metric_Cpu"), percent(values?.cpu_usage_percent)],
    [L("B01_Dashboard_Metric_Memory"), percent(values?.memory_usage_percent)],
    [L("B01_Dashboard_Metric_Disk"), percent(values?.disk_usage_percent)],
    [L("B01_Dashboard_Metric_ActiveUsers"), values?.active_user_count ?? 0],
    [L("B01_Dashboard_Metric_ActiveProjects"), values?.active_project_count ?? 0],
  ];
  for (const [label, value] of items) {
    const box = document.createElement("div");
    box.className = "b01-dashboard__metric";
    const labelEl = document.createElement("span");
    labelEl.className = "b01-dashboard__metric-label";
    labelEl.textContent = String(label);
    const valueEl = document.createElement("span");
    valueEl.className = "b01-dashboard__metric-value";
    valueEl.textContent = String(value);
    box.append(labelEl, valueEl);
    grid.append(box);
  }
  return grid;
}

function buildResourceChart(resources: ResourceData | null): HTMLElement {
  const box = document.createElement("div");
  box.className = "b01-dashboard__chart";

  const caption = document.createElement("p");
  caption.className = "b01-dashboard__chart-caption";
  caption.textContent = L("B01_Dashboard_Resources_ChartCaption");
  box.append(caption);

  const chartWrap = document.createElement("div");
  chartWrap.className = "b01-dashboard__chart-content";
  box.append(chartWrap);

  const history = resources?.history ?? [];
  const points: { timestamp: Date; cpu: number | null; mem: number | null; disk: number | null }[] =
    [];
  const now = new Date();
  const baseDate = new Date(
    now.getFullYear(),
    now.getMonth(),
    now.getDate(),
    now.getHours() >= 12 ? 24 : 12,
    0,
    0,
    0,
  );

  for (let i = 0; i <= 42; i++) {
    const time = new Date(baseDate.getTime() - (42 - i) * 4 * 60 * 60 * 1000);
    points.push({ timestamp: time, cpu: null, mem: null, disk: null });
  }

  history.forEach((h) => {
    if (!h.timestamp) return;
    const tsStr = h.timestamp.endsWith("Z") ? h.timestamp : h.timestamp + "Z";
    const hTime = new Date(tsStr);
    let closestIdx = -1;
    let minDiff = Infinity;

    points.forEach((p, idx) => {
      const diff = Math.abs(p.timestamp.getTime() - hTime.getTime());
      if (diff < minDiff && diff <= 2 * 60 * 60 * 1000) {
        minDiff = diff;
        closestIdx = idx;
      }
    });

    if (closestIdx !== -1) {
      const p = points[closestIdx];
      p.cpu = h.cpu_usage_percent;
      p.mem = h.memory_usage_percent;
      p.disk = h.disk_usage_percent;
    }
  });

  const xLabels = points.map((p) => {
    const hours = p.timestamp.getHours();
    return hours === 0 ? `${p.timestamp.getMonth() + 1}/${p.timestamp.getDate()}` : "";
  });

  let resizeTimeout: number | null = null;
  const observer = new ResizeObserver((entries) => {
    for (const entry of entries) {
      const width = Math.floor(entry.contentRect.width);
      if (width <= 0) continue;

      if (resizeTimeout) {
        window.cancelAnimationFrame(resizeTimeout);
      }

      resizeTimeout = window.requestAnimationFrame(() => {
        chartWrap.innerHTML = "";
        const chart = createLineChart({
          ariaLabel: L("B01_Dashboard_Resources_ChartAria"),
          xLabels,
          width: width,
          height: 140,
          series: [
            {
              name: L("B01_Dashboard_Metric_Cpu"),
              colorIndex: 0,
              values: points.map((p) => p.cpu),
            },
            {
              name: L("B01_Dashboard_Metric_Memory"),
              colorIndex: 1,
              values: points.map((p) => p.mem),
            },
            {
              name: L("B01_Dashboard_Metric_Disk"),
              colorIndex: 2,
              values: points.map((p) => p.disk),
            },
          ],
        });
        chartWrap.append(chart);
      });
    }
  });

  observer.observe(box);
  return box;
}