import { useState, type ReactNode } from "react";
import { useQuery } from "@tanstack/react-query";
import { useTranslation } from "react-i18next";
import { Bug, Sparkles } from "lucide-react";
import { loadReleaseNotes, notesLang, visibleNotes } from "../lib/releaseNotes";
import { qk } from "../lib/queryKeys";
import { formatDate } from "../lib/format";
import { Button } from "./ui/Button";
import Modal from "./ui/Modal";
import { LoadingState, StateMessage } from "./ui/QueryState";

// The release date in the UI language — `toLocaleDateString(undefined, …)` formats in the BROWSER's
// locale, which put Hungarian-shaped dates in an English release-notes list. Unparseable input falls
// back to the raw string (a hand-written note could carry anything).
function fmtDate(d: string, lang: string): string {
  return isNaN(new Date(d).getTime()) ? d : formatDate(d, lang);
}

// The newest releases are what a user opens this for; the whole history (150+ versions) rendered on
// every open was what made the dialog slow to appear. The rest are one click away.
const RECENT = 10;

// Public release notes in the UI language. `highlight` rings the version the user just updated to
// when opened from the new-version banner.
export default function ReleaseNotes({
  onClose,
  highlight,
}: {
  onClose: () => void;
  highlight?: string;
}) {
  const { t, i18n } = useTranslation();
  const lang = notesLang(i18n.language);
  const q = useQuery({
    queryKey: qk.releaseNotes(lang),
    queryFn: () => loadReleaseNotes(lang),
    staleTime: Infinity,
  });
  const [showAll, setShowAll] = useState(false);
  const notes = visibleNotes(q.data ?? []);
  // Ring the newest note if `highlight` isn't one of the listed versions — e.g. a Vite dev build
  // where the caller's FRONTEND_VERSION is "dev", or a VERSION bump whose note hasn't landed yet —
  // so the banner always rings *something* current instead of nothing.
  const at = notes.findIndex((r) => r.version === highlight);
  const active = at >= 0 ? highlight : notes[0]?.version;
  const shown = showAll || at >= RECENT ? notes : notes.slice(0, RECENT);
  return (
    <Modal
      initialFocus="close"
      title={t("about.releaseNotes")}
      onClose={onClose}
      maxWidth="max-w-2xl"
    >
      {q.isError ? (
        <StateMessage tone="error" onRetry={() => q.refetch()}>
          {t("about.notesError")}
        </StateMessage>
      ) : !q.data ? (
        <LoadingState />
      ) : (
        <div className="flex flex-col gap-5">
          {shown.map((r) => (
            <section
              key={r.version}
              className={active === r.version ? "rounded-xl ring-1 ring-accent/40 p-3 -m-3" : ""}
            >
              <div className="flex items-baseline gap-2">
                <h3 className="text-base font-semibold">v{r.version}</h3>
                <span className="text-xs text-muted">{fmtDate(r.date, i18n.language)}</span>
              </div>
              <Items icon={<Sparkles className="w-3.5 h-3.5" />} title={t("about.new")} accent>
                {r.new}
              </Items>
              <Items icon={<Bug className="w-3.5 h-3.5" />} title={t("about.fixes")}>
                {r.fixed}
              </Items>
            </section>
          ))}
          {shown.length < notes.length && (
            <Button variant="outline" className="self-center" onClick={() => setShowAll(true)}>
              {t("about.olderVersions", { count: notes.length - shown.length })}
            </Button>
          )}
        </div>
      )}
    </Modal>
  );
}

function Items({
  icon,
  title,
  accent,
  children,
}: {
  icon: ReactNode;
  title: string;
  accent?: boolean;
  children: string[];
}) {
  if (children.length === 0) return null;
  const tone = accent ? "text-accent" : "text-muted";
  return (
    <div className="mt-2.5">
      <div
        className={`flex items-center gap-1.5 text-xs font-semibold uppercase tracking-wide ${tone}`}
      >
        {icon} {title}
      </div>
      <ul className="mt-1 space-y-1 text-sm">
        {children.map((line, i) => (
          <li key={i} className="flex gap-2">
            <span className={tone}>•</span>
            <span>{line}</span>
          </li>
        ))}
      </ul>
    </div>
  );
}