import dayjs from "dayjs";
import type { ContainerInfo, ContainerStats } from "dockerode";

import { db, like, or } from "@homarr/db";
import { icons } from "@homarr/db/schema";
import type { ContainerState } from "@homarr/docker";
import { dockerLabels, DockerSingleton } from "@homarr/docker";

import { createCachedWidgetRequestHandler } from "./lib/cached-widget-request-handler";

export const dockerContainersRequestHandler = createCachedWidgetRequestHandler({
  queryKey: "dockerContainersResult",
  widgetKind: "dockerContainers",
  async requestAsync() {
    return await getContainersWithStatsAsync();
  },
  cacheDuration: dayjs.duration(20, "seconds"),
});

const dockerInstances = DockerSingleton.getInstances();

const extractImage = (container: ContainerInfo) => container.Image.split("/").at(-1)?.split(":").at(0) ?? "";

async function getContainersWithStatsAsync() {
  const containers = await Promise.all(
    dockerInstances.map(async ({ instance, host }) => {
      const instanceContainers = await instance.listContainers({ all: true });
      return instanceContainers
        .filter((container) => !(dockerLabels.hide in container.Labels))
        .map((container) => ({ ...container, instance: host }));
    }),
  ).then((res) => res.flat());
  const likeQueries = containers.map((container) => like(icons.name, `%${extractImage(container)}%`));

  const dbIcons =
    likeQueries.length > 0
      ? await db.query.icons.findMany({
          where: or(...likeQueries),
        })
      : [];

  const containerStatsPromises = containers.map(async (container) => {
    const instance = dockerInstances.find(({ host }) => host === container.instance)?.instance;
    if (!instance) return null;

    // Get stats, falling back to an empty stats object if fetch fails
    // calculateCpuUsage and calculateMemoryUsage will return 0 for invalid/missing stats
    const stats = await instance
      .getContainer(container.Id)
      .stats({ stream: false, "one-shot": true })
      .catch(
        () =>
          ({
            cpu_stats: { online_cpus: 0, cpu_usage: { total_usage: 0 }, system_cpu_usage: 0 },
            memory_stats: { usage: 0 },
          }) as ContainerStats,
      );

    const cpuUsage = calculateCpuUsage(stats);
    const memoryUsage = calculateMemoryUsage(stats);

    return {
      id: container.Id,
      name: container.Names[0]?.split("/")[1] ?? "Unknown",
      state: container.State as ContainerState,
      iconUrl:
        dbIcons.find((icon) => {
          const extractedImage = extractImage(container);
          if (!extractedImage) return false;
          return icon.name.toLowerCase().includes(extractedImage.toLowerCase());
        })?.url ?? null,
      cpuUsage,
      memoryUsage,
      image: container.Image,
      ports: container.Ports,
    };
  });

  return (await Promise.all(containerStatsPromises)).filter((container) => container !== null);
}

function calculateCpuUsage(stats: ContainerStats): number {
  // Handle containers with missing or invalid stats (e.g., exited, dead containers)
  if (!stats.cpu_stats.online_cpus || stats.cpu_stats.online_cpus === 0 || !stats.cpu_stats.cpu_usage.total_usage) {
    return 0;
  }

  const numberOfCpus = stats.cpu_stats.online_cpus;
  const usage = stats.cpu_stats.system_cpu_usage;
  if (!usage || usage === 0) {
    return 0;
  }

  return (stats.cpu_stats.cpu_usage.total_usage / usage) * numberOfCpus * 100;
}

function calculateMemoryUsage(stats: ContainerStats): number {
  // Handle containers with missing or invalid stats (e.g., exited, dead containers)
  if (!stats.memory_stats.usage) {
    return 0;
  }

  // memory usage by default includes cache, which should not be shown as it is also not shown with docker stats command
  // See https://docs.docker.com/reference/cli/docker/container/stats/ how it is / was calculated
  return (
    stats.memory_stats.usage -
    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
    (stats.memory_stats.stats?.cache ??
      // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
      stats.memory_stats.stats?.total_inactive_file ??
      // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
      stats.memory_stats.stats?.inactive_file ??
      0)
  );
}