"use client";
import { useEffect, useState } from "react";
import { Activity, Copy, Download } from "lucide-react";
import { api } from "@/lib/client-api";
import { prometheusConfig, type PrometheusStatus } from "@/shared/prometheus";
import { grafanaDashboard } from "@/shared/grafana-dashboard";
import { useI18n } from "./I18nProvider";

export function PrometheusIntegration() {
  const { t, locale } = useI18n();
  const [status, setStatus] = useState<PrometheusStatus | null>(null);
  const [token, setToken] = useState<string | null>(null);
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState("");
  const [message, setMessage] = useState("");
  const [confirm, setConfirm] = useState<"rotate" | "disable" | null>(null);
  async function load() {
    try {
      setStatus(await api<PrometheusStatus>("moderation/prometheus"));
      setError("");
    } catch (e) {
      setError((e as Error).message);
    }
  }
  useEffect(() => {
    void load();
  }, []);
  async function configure(action: "rotate" | "disable") {
    setBusy(true);
    setError("");
    setMessage("");
    try {
      const result = await api<PrometheusStatus & { token: string | null }>(
        "moderation/prometheus",
        { action },
      );
      const { token: nextToken, ...nextStatus } = result;
      setStatus(nextStatus);
      setToken(nextToken);
      setConfirm(null);
      setMessage(
        action === "rotate"
          ? "New metrics token generated. Copy the config now; it cannot be recovered later."
          : "Metrics access disabled. Existing scrape credentials no longer work.",
      );
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setBusy(false);
    }
  }
  async function copy(value: string) {
    try {
      await navigator.clipboard.writeText(value);
      setMessage("Copied to clipboard.");
      setError("");
    } catch {
      setError("Could not copy. Select the text and copy it manually.");
    }
  }
  function dashboard() {
    const url = URL.createObjectURL(
      new Blob([JSON.stringify(grafanaDashboard(), null, 2)], {
        type: "application/json",
      }),
    );
    const link = document.createElement("a");
    link.href = url;
    link.download = "minegeo-grafana-dashboard.json";
    link.click();
    setTimeout(() => URL.revokeObjectURL(url), 1000);
  }
  const config =
    status && token && status.endpoint.startsWith("https:")
      ? prometheusConfig(status.endpoint, token)
      : "";
  return (
    <section className="tool-card" aria-labelledby="prometheus-title">
      <div className="settings-heading">
        <Activity size={24} aria-hidden="true" />
        <h2 id="prometheus-title">{t("Prometheus & Grafana")}</h2>
      </div>
      <p>
        {t(
          "Track games, maps, multiplayer, uploads, and reports in your own Grafana dashboard. Admin permission is required to manage access.",
        )}
      </p>
      <p className="muted">
        {t(
          "Only aggregate counts are exported. Usernames, messages, emails, and map identifiers are excluded.",
        )}
      </p>
      {!status && !error && <p role="status">{t("Loading metrics setup…")}</p>}
      {status && (
        <>
          <p>
            <span className="badge">
              {status.enabled ? t("Metrics enabled") : t("Metrics disabled")}
            </span>
          </p>
          <label className="field">
            {t("Metrics endpoint")}
            <input readOnly value={status.endpoint} />
          </label>
          <button className="button" onClick={() => void copy(status.endpoint)}>
            <Copy size={16} aria-hidden="true" />
            {t("Copy endpoint")}
          </button>
          <p className="muted">
            {t("Last successful scrape: {time}", {
              time: status.lastScrapedAt
                ? new Date(status.lastScrapedAt).toLocaleString(
                    locale === "ru" ? "ru-RU" : "en-GB",
                  )
                : t("Not scraped yet"),
            })}
          </p>
          {!status.endpoint.startsWith("https:") && (
            <p className="error-message">
              {t(
                "Use the hosted HTTPS site to generate a production scrape config.",
              )}
            </p>
          )}
          <ol className="metrics-steps">
            <li>
              {t(
                "Generate a token below, then copy the config into prometheus.yml. If scrape_configs already exists, add only the MineGeo job beneath it.",
              )}
            </li>
            <li>
              {t(
                "Reload or restart Prometheus. Open its Targets page and check that the minegeo job is UP.",
              )}
            </li>
            <li>
              {t(
                "In Grafana, add your Prometheus server as a data source. Import the downloaded dashboard JSON and select that data source.",
              )}
            </li>
          </ol>
          <p className="muted">
            {t(
              "History starts with the first scrape. Counts are cached for 30 seconds; room states are not online presence. This integration does not export page views or Vercel CPU statistics.",
            )}
          </p>
          <div className="inline-actions">
            <button
              className="button primary"
              disabled={busy}
              onClick={() =>
                status.enabled ? setConfirm("rotate") : void configure("rotate")
              }
            >
              {status.enabled
                ? t("Rotate metrics token")
                : t("Generate metrics token")}
            </button>
            {status.enabled && (
              <button
                className="button"
                disabled={busy}
                onClick={() => setConfirm("disable")}
              >
                {t("Disable metrics access")}
              </button>
            )}
            <button className="button" onClick={dashboard}>
              <Download size={16} aria-hidden="true" />
              {t("Download Grafana dashboard")}
            </button>
            <button
              className="text-link"
              disabled={busy}
              onClick={() => void load()}
            >
              {t("Refresh status")}
            </button>
          </div>
          {confirm && (
            <div
              className="token-box"
              role="group"
              aria-label={t("Confirm metrics access change")}
            >
              <p>
                {confirm === "rotate"
                  ? t(
                      "Rotating immediately invalidates the old token. Update Prometheus with the new config afterward.",
                    )
                  : t(
                      "Disabling immediately stops all authenticated scrapes. Prometheus will report this target as DOWN.",
                    )}
              </p>
              <div className="inline-actions">
                <button
                  className="button"
                  disabled={busy}
                  onClick={() => void configure(confirm)}
                >
                  {t("Confirm change")}
                </button>
                <button
                  className="button"
                  disabled={busy}
                  onClick={() => setConfirm(null)}
                >
                  {t("Cancel")}
                </button>
              </div>
            </div>
          )}
          {token && (
            <div className="token-box">
              <p>
                {t(
                  "Keep this config private. The token is shown once and grants read-only access to aggregate metrics. Rotating or disabling it revokes access.",
                )}
              </p>
              {config ? (
                <>
                  <label className="field">
                    {t("Prometheus scrape config")}
                    <textarea
                      className="metrics-config"
                      readOnly
                      spellCheck={false}
                      value={config}
                      rows={15}
                    />
                  </label>
                  <button className="button" onClick={() => void copy(config)}>
                    <Copy size={16} aria-hidden="true" />
                    {t("Copy Prometheus config")}
                  </button>
                </>
              ) : (
                <label className="field">
                  {t("Metrics token")}
                  <textarea readOnly value={token} />
                </label>
              )}
              <button
                className="text-link"
                onClick={() => {
                  setToken(null);
                  setMessage("");
                }}
              >
                {t("Hide generated credentials")}
              </button>
            </div>
          )}
          {status.enabled && !token && (
            <p className="muted">
              {t(
                "The existing token cannot be retrieved. Use your saved config, or rotate the token to generate a new one.",
              )}
            </p>
          )}
        </>
      )}
      {error && (
        <p className="error-message" role="alert">
          {t(error)}
        </p>
      )}
      {message && <p role="status">{t(message)}</p>}
    </section>
  );
}