"use client";

import Link from "next/link";
import { AnimatePresence, motion, useDragControls, useReducedMotion } from "framer-motion";
import { useEffect, useRef, useState, useSyncExternalStore } from "react";

import { LOCALES, useI18n, type Locale } from "@/lib/i18n";
import { useVersion } from "@/lib/use-version";
import { haptic } from "@/lib/haptics";
import { modelErrorCopy } from "@/lib/model-errors";
import { springSheet } from "@/lib/motion";
import { ModelErrorActions } from "@/components/ModelErrorActions";
import { DataSection } from "@/components/DataSection";
import { LearningSection } from "@/components/LearningSection";
import { ThemeSection } from "@/components/ThemeSection";
import { SyncSection } from "@/components/SyncSection";
import { clearApiKey, saveSettings, settingsStore } from "@/lib/settings";
import { useBackClose } from "@/lib/use-back-close";
import { cn } from "@/lib/utils";
import { openInstallSheet, useInstallAvailable } from "@/lib/install";
import { useHealth } from "@/lib/use-health";
import {
  AlertTriangleIcon,
  CheckCircleIcon,
  ChevronDownIcon,
  ChevronRightIcon,
  DownloadIcon,
  EyeIcon,
  EyeOffIcon,
  RefreshIcon,
  XCircleIcon,
} from "@/components/icons";
import { Button, Spinner } from "@/components/ui";
import { SegmentedPill } from "@/components/SegmentedPill";

/** “Checked just now”, or the clock time once the result is older. */
function freshnessLabel(checkedAt: number, locale: Locale, t: (key: string, vars?: Record<string, string>) => string) {
  if (Date.now() - checkedAt < 90_000) return t("health.checkedNow");
  const time = new Date(checkedAt).toLocaleTimeString(locale === "cs" ? "cs-CZ" : "en-US", {
    hour: "2-digit",
    minute: "2-digit",
  });
  return t("health.checkedAt", { time });
}

export function SettingsDialog({
  open,
  onClose,
  focusField,
}: {
  open: boolean;
  onClose: () => void;
  /** Set by openSettings("key") — focuses the key input once the sheet opens. */
  focusField?: { field: "key"; nonce: number } | null;
}) {
  const { health, loading, error, refresh, apiKey, checkedAt } = useHealth();
  const installAvailable = useInstallAvailable();
  const { locale, setLocale, t, plural } = useI18n();
  const version = useVersion();
  const keyInputRef = useRef<HTMLInputElement>(null);
  const settings = useSyncExternalStore(
    settingsStore.subscribe,
    settingsStore.getSnapshot,
    settingsStore.getServerSnapshot,
  );
  /* The system Back gesture closes the sheet instead of leaving the page. */
  useBackClose(open, onClose);

  /* "Open Settings" from a usage-limit error lands right on the key field. */
  useEffect(() => {
    if (!open || focusField?.field !== "key") return;
    const timer = window.setTimeout(() => {
      keyInputRef.current?.scrollIntoView({ block: "center", behavior: "smooth" });
      keyInputRef.current?.focus({ preventScroll: true });
    }, 380);
    return () => window.clearTimeout(timer);
  }, [open, focusField]);
  const [keyDraft, setKeyDraft] = useState(apiKey);
  const [reveal, setReveal] = useState(false);
  const [saved, setSaved] = useState(false);
  const [confirmRemove, setConfirmRemove] = useState(false);
  const [canScroll, setCanScroll] = useState(false);
  const [phone, setPhone] = useState(false);
  const dragControls = useDragControls();
  const reduceMotion = useReducedMotion();
  const scrollRef = useRef<HTMLDivElement>(null);
  const contentRef = useRef<HTMLDivElement>(null);

  // Swipe-to-dismiss is a phone gesture; the desktop dialog is unchanged.
  useEffect(() => {
    const query = window.matchMedia("(max-width: 639px)");
    const sync = () => setPhone(query.matches);
    sync();
    query.addEventListener("change", sync);
    return () => query.removeEventListener("change", sync);
  }, []);

  useEffect(() => {
    if (!open) return;
    setKeyDraft(apiKey);
    setSaved(false);
    setConfirmRemove(false);
    const onKey = (event: KeyboardEvent) => {
      if (event.key === "Escape") onClose();
    };
    window.addEventListener("keydown", onKey);
    return () => window.removeEventListener("keydown", onKey);
  }, [open, apiKey, onClose]);

  // The scroll cue: a small chevron that fades in whenever more content is
  // below the fold, and out once the bottom is reached.
  const updateCue = () => {
    const element = scrollRef.current;
    if (!element) return;
    setCanScroll(element.scrollHeight - element.scrollTop - element.clientHeight > 24);
  };

  useEffect(() => {
    if (!open) return;
    const element = scrollRef.current;
    const content = contentRef.current;
    if (!element) return;
    updateCue();
    const observer = new ResizeObserver(updateCue);
    if (content) observer.observe(content);
    return () => observer.disconnect();
  }, [open]);

  // Drag only from the handle/header, and only while the body is at the top.
  const startSheetDrag = (event: React.PointerEvent) => {
    if (!phone) return;
    if ((event.target as HTMLElement).closest("button, a, input, summary")) return;
    const element = scrollRef.current;
    if (element && element.scrollTop > 2) return;
    dragControls.start(event);
  };

  const save = () => {
    saveSettings({ apiKey: keyDraft.trim() });
    setSaved(true);
    window.setTimeout(() => setSaved(false), 2500);
  };

  const forget = () => {
    clearApiKey();
    setKeyDraft("");
    setConfirmRemove(false);
  };

  const needsKeyMode = health?.authMode === "user-key";

  /* Phones: one status row instead of the whole health panel. */
  const modelsReady = health ? [health.vision.available, health.text.available].filter((value) => value === true).length : 0;
  const statusText = !health
    ? t("settings.checking")
    : health.ok
      ? `${t("settings.connected")} · ${plural(modelsReady, "settings.modelsReady")}`
      : health.needsKey
        ? t("health.needsKey")
        : health.keyAccepted === false
          ? t("health.rejected")
          : health.reachable
            ? t("health.modelMissing")
            : t("health.unreachable");
  const statusDot = !health
    ? "bg-[var(--text-subtle)]"
    : health.ok
      ? "bg-emerald-500"
      : health.needsKey || health.reachable
        ? "bg-amber-500"
        : "bg-rose-500";
  const modelBadge = (model: { available: boolean | null } | undefined) =>
    !model || model.available === null
      ? { text: t("health.unknown"), className: "bg-[var(--surface-sunken)] text-[var(--text-muted)]" }
      : model.available
        ? { text: t("health.available"), className: "bg-emerald-100 text-emerald-900 dark:bg-emerald-400/20 dark:text-emerald-200" }
        : { text: t("health.notFound"), className: "bg-rose-50 text-rose-800 dark:bg-rose-500/15 dark:text-rose-200" };

  return (
    <AnimatePresence>
      {open ? (
        <motion.div
          className="fixed inset-0 z-50 flex items-end justify-center bg-frost-950/35 p-0 backdrop-blur-md sm:items-center sm:p-6"
          initial={{ opacity: 0 }}
          animate={{ opacity: 1 }}
          exit={{ opacity: 0 }}
          onClick={onClose}
        >
          <motion.div
            role="dialog"
            aria-modal="true"
            aria-labelledby="settings-title"
            drag={phone ? "y" : false}
            dragControls={dragControls}
            dragListener={false}
            dragMomentum={false}
            dragConstraints={{ top: 0, bottom: 0 }}
            dragElastic={{ top: 0, bottom: 0.55 }}
            onDragEnd={(_, gesture) => {
              if (gesture.offset.y > 90 || gesture.delta.y > 140 || gesture.velocity.y > 700) onClose();
            }}
            initial={reduceMotion ? { opacity: 0 } : phone ? { y: "100%", opacity: 0 } : { y: 48, opacity: 0 }}
            animate={reduceMotion ? { opacity: 1 } : { y: 0, opacity: 1 }}
            exit={reduceMotion ? { opacity: 0 } : phone ? { y: "100%", opacity: 0 } : { y: 32, opacity: 0 }}
            transition={phone ? springSheet : { type: "spring", stiffness: 340, damping: 32 }}
            onClick={(event) => event.stopPropagation()}
            className="glass-panel glass-sheet relative flex max-h-[90dvh] w-full max-w-lg flex-col overflow-hidden rounded-t-[1.6rem] shadow-2xl sm:rounded-[1.35rem]"
          >
            {/* handle + header: the drag strip. Fixed, so the body scrolls. */}
            <div
              onPointerDown={startSheetDrag}
              className={cn("shrink-0 px-5 pt-2", phone && "cursor-grab touch-none active:cursor-grabbing")}
            >
              <div aria-hidden className="mx-auto flex h-6 w-full items-center justify-center">
                <span className="h-1 w-9 rounded-full bg-[var(--text-subtle)] opacity-40" />
              </div>
              <div className="mb-3 flex items-start justify-between gap-4">
                <div>
                  <h2 id="settings-title" className="text-lg font-semibold tracking-[-0.02em] text-frost-950 dark:text-frost-50">
                    {t("settings.title")}
                  </h2>
                  {!phone ? (
                    <p className="text-sm text-frost-600 dark:text-frost-300">
                      {t("settings.subtitle.before")}{" "}
                      <code className="rounded bg-frost-100 px-1 dark:bg-white/10">.env.local</code>{" "}
                      {t("settings.subtitle.after")}
                    </p>
                  ) : null}
                </div>
                <Button
                  variant="ghost"
                  size="sm"
                  className="touch-target -mr-1 shrink-0"
                  onClick={onClose}
                  aria-label={t("settings.close")}
                >
                  ✕
                </Button>
              </div>
            </div>

            {/* scrollable body: the safe area comes from pb-safe + a spacer */}
            <div
              ref={scrollRef}
              onScroll={updateCue}
              className="sheet-scroll thin-scroll min-h-0 flex-1 overflow-y-auto px-5 pb-safe"
            >
              <div ref={contentRef}>
                {phone ? (
                  <>
                    {/* --------------------------------------------- language */}
                    <section className="mb-4 space-y-2 rounded-2xl border border-[var(--hairline)] bg-[var(--surface-sunken)] p-3">
                      <h3 className="text-sm font-semibold text-frost-950 dark:text-frost-50">
                        {t("language.label")}
                      </h3>
                      <div className="segmented" role="group" aria-label={t("language.label")}>
                        {LOCALES.map((entry) => (
                          <button
                            key={entry.id}
                            type="button"
                            aria-pressed={locale === entry.id}
                            onClick={() => {
                              haptic("toggle");
                              setLocale(entry.id);
                            }}
                            className={cn("relative", phone && "seg-slide")}
                          >
                            {phone && locale === entry.id ? <SegmentedPill layoutId="language-pill" /> : null}
                            <span className="seg-label relative z-10">{entry.label}</span>
                          </button>
                        ))}
                      </div>
                    </section>

                    {/* ------------------------------------------- connection */}
                    <section className="mb-4 space-y-3 rounded-2xl border border-[var(--hairline)] bg-[var(--surface-sunken)] p-3">
                      <div className="flex items-center justify-between gap-2">
                        <h3 className="text-sm font-semibold text-frost-950 dark:text-frost-50">
                          {t("settings.connection")}
                        </h3>
                        <button
                          type="button"
                          onClick={() => void refresh()}
                          aria-label={t("settings.recheck")}
                          title={t("settings.recheck")}
                          className="touch-target grid size-9 place-items-center rounded-full text-[var(--text-muted)] transition hover:bg-[var(--hover)] hover:text-[var(--text)]"
                        >
                          <RefreshIcon className={cn("size-4", loading && "animate-spin")} />
                        </button>
                      </div>

                      <div className="flex items-center gap-2 text-[13px] font-medium" role="status">
                        <span aria-hidden className={cn("size-2.5 shrink-0 rounded-full", statusDot)} />
                        <span className="min-w-0 flex-1 text-[var(--text)]">{statusText}</span>
                      </div>

                      {/* monthly usage used up / short-term throttle */}
                      {health?.kind === "usage_limit" || health?.kind === "throttled" ? (
                        <div className="rounded-xl border border-amber-300 bg-amber-50 p-2.5 text-[12px] leading-relaxed text-amber-900 dark:border-amber-400/40 dark:bg-amber-400/10 dark:text-amber-100">
                          <p className="font-bold">{modelErrorCopy(health.kind)?.title}</p>
                          <p className="mt-0.5">{modelErrorCopy(health.kind)?.body}</p>
                          <div className="mt-2 flex flex-wrap gap-2">
                            <ModelErrorActions kind={health.kind} />
                          </div>
                        </div>
                      ) : null}

                      <div className="relative">
                        <label className="sr-only" htmlFor="ollama-api-key-phone">
                          {t("settings.apiKey")}
                        </label>
                        <input
                          id="ollama-api-key-phone"
                          ref={keyInputRef}
                          type={reveal ? "text" : "password"}
                          value={keyDraft}
                          onChange={(event) => setKeyDraft(event.target.value)}
                          onKeyDown={(event) => {
                            event.stopPropagation();
                            if (event.key === "Enter") save();
                          }}
                          placeholder={t("settings.pasteKey")}
                          autoComplete="off"
                          spellCheck={false}
                          className="w-full rounded-xl border border-[var(--hairline)] bg-[var(--surface-strong)] py-3 pl-3 pr-12 font-mono text-xs text-frost-950 outline-none transition placeholder:font-sans placeholder:text-[var(--text-subtle)] focus:border-accent-500 dark:text-frost-50"
                        />
                        <button
                          type="button"
                          onClick={() => setReveal((value) => !value)}
                          aria-label={reveal ? t("settings.hide") : t("settings.show")}
                          title={reveal ? t("settings.hide") : t("settings.show")}
                          className="absolute right-0.5 top-1/2 grid size-11 -translate-y-1/2 place-items-center rounded-lg text-[var(--text-muted)] transition hover:bg-[var(--hover)] hover:text-[var(--text)]"
                        >
                          {reveal ? <EyeOffIcon className="size-4" /> : <EyeIcon className="size-4" />}
                        </button>
                      </div>

                      {keyDraft.trim() !== apiKey ? (
                        <Button size="sm" className="touch-target w-full" onClick={save}>
                          {t("common.save")}
                        </Button>
                      ) : null}

                      <details className="group">
                        <summary className="touch-target flex cursor-pointer list-none flex-wrap items-center gap-1.5 text-[11px] font-medium text-[var(--text-muted)] [&::-webkit-details-marker]:hidden">
                          {t("settings.privacyLine")}
                          <span className="inline-flex items-center gap-0.5 font-semibold text-[var(--text)] underline underline-offset-2">
                            {t("common.more")}
                            <ChevronDownIcon className="size-3 transition-transform group-open:rotate-180" />
                          </span>
                        </summary>
                        <div className="space-y-1.5 pt-1.5">
                          <p className="text-[11px] leading-relaxed text-[var(--text-subtle)]">{t("settings.keyNote")}</p>
                          <p className="text-[11px] leading-relaxed text-[var(--text-subtle)]">
                            {t("settings.localTipTitle")} {t("settings.localTipSet")}{" "}
                            <code>OLLAMA_AUTH=local</code> {t("settings.keyNoteAfter")} <code>.env.local</code>{" "}
                            {t("settings.keyNoteEnd")} <code>ollama signin</code>
                            {t("settings.keyNoteEnd2")}
                          </p>
                        </div>
                      </details>

                      {/* haptics: best-effort vibration feedback */}
                      <div className="flex items-center justify-between gap-3 border-t border-[var(--hairline-soft)] pt-3">
                        <span className="min-w-0">
                          <span className="block text-[13px] font-semibold text-[var(--text)]">
                            {t("settings.haptics")}
                          </span>
                          <span className="block text-[11.5px] leading-snug text-[var(--text-subtle)]">
                            {t("settings.hapticsNote")}
                          </span>
                        </span>
                        <button
                          type="button"
                          role="switch"
                          aria-checked={settings.haptics}
                          aria-label={t("settings.haptics")}
                          onClick={() => {
                            saveSettings({ haptics: !settings.haptics });
                            haptic("toggle");
                          }}
                          className={cn(
                            "touch-target relative h-7 w-12 shrink-0 rounded-full border transition-colors",
                            settings.haptics
                              ? "grad-ice border-transparent"
                              : "border-[var(--hairline)] bg-[var(--surface-sunken)]",
                          )}
                        >
                          <span
                            aria-hidden
                            className={cn(
                              "absolute top-1/2 size-5 -translate-y-1/2 rounded-full bg-white shadow transition-[left] duration-200",
                              settings.haptics ? "left-6" : "left-0.5",
                            )}
                          />
                        </button>
                      </div>

                      {/* chat grounding: may chat read the notes text? */}
                      <ToggleRow
                        label={t("settings.chatNotes")}
                        note={t("settings.chatNotesNote")}
                        checked={settings.chatNotes}
                        onChange={() => {
                          saveSettings({ chatNotes: !settings.chatNotes });
                          haptic("toggle");
                        }}
                      />
                    </section>

                    {/* ------------------------------------------- theme */}
                    <ThemeSection />

                    {/* ----------------------------------------- learning */}
                    <LearningSection level={3} />

                    {/* ------------------------------------------- data & sync */}
                    <DataSection />
                    <SyncSection />

                    {/* ----------------------------------------------- install */}
                    {installAvailable ? (
                      <section className="mb-4 rounded-2xl border border-[var(--hairline)] bg-[var(--surface-sunken)] p-1.5">
                        <button
                          type="button"
                          onClick={() => {
                            onClose();
                            openInstallSheet();
                          }}
                          className="flex w-full items-center gap-3 rounded-xl px-2.5 py-2 text-left transition hover:bg-[var(--hover)]"
                        >
                          <span
                            aria-hidden
                            className="grid size-9 shrink-0 place-items-center rounded-xl border border-[var(--hairline)] bg-[var(--surface)] text-[var(--text-muted)]"
                          >
                            <DownloadIcon className="size-4" />
                          </span>
                          <span className="min-w-0 flex-1">
                            <span className="block text-sm font-semibold text-frost-950 dark:text-frost-50">
                              {t("settings.installApp")}
                            </span>
                            <span className="block text-[12px] text-[var(--text-subtle)]">
                              {t("settings.addToHome")}
                            </span>
                          </span>
                          <ChevronRightIcon className="size-4 shrink-0 text-[var(--text-subtle)]" />
                        </button>
                      </section>
                    ) : null}

                    {error ? (
                      <div className="mb-4 rounded-2xl bg-rose-100 p-3 text-sm text-rose-900 dark:bg-rose-500/15 dark:text-rose-200">
                        {error}
                      </div>
                    ) : null}

                    {/* ----------------------------------------------- details */}
                    <details className="group mb-4 rounded-2xl border border-[var(--hairline)] bg-[var(--surface-sunken)] p-3">
                      <summary className="touch-target flex cursor-pointer list-none items-center justify-between gap-2 text-sm font-semibold text-frost-950 dark:text-frost-50 [&::-webkit-details-marker]:hidden">
                        {t("settings.details")}
                        <ChevronDownIcon className="size-4 text-[var(--text-subtle)] transition-transform group-open:rotate-180" />
                      </summary>
                      <div className="pt-2">
                        {loading ? (
                          <p className="flex items-center gap-2 pb-2 text-[12px] text-[var(--text-muted)]">
                            <Spinner className="size-3.5" /> {t("settings.checking")}
                          </p>
                        ) : checkedAt ? (
                          <p className="pb-2 text-[11px] font-medium text-[var(--text-subtle)]">
                            {freshnessLabel(checkedAt, locale, t)}
                          </p>
                        ) : null}
                        <dl>
                          <DetailRow
                            label={t("health.auth")}
                            value={
                              health
                                ? health.authMode === "user-key"
                                  ? t("health.authUserKey")
                                  : health.authMode === "server"
                                    ? t("health.authServer")
                                    : t("health.authLocal")
                                : "—"
                            }
                          />
                          <DetailRow label={t("health.endpoint")} value={health?.baseUrl ?? "—"} mono />
                          <DetailRow
                            label={t("health.mode")}
                            value={
                              health
                                ? health.mode === "direct-cloud"
                                  ? t("health.modeCloud")
                                  : t("health.modeLocal")
                                : "—"
                            }
                          />
                          <DetailRow
                            label={t("health.key")}
                            value={
                              health
                                ? health.needsKey
                                  ? t("health.keyMissing")
                                  : health.keyAccepted === true
                                    ? t("health.keyAccepted")
                                    : health.keyAccepted === false
                                      ? t("health.keyRejected")
                                      : health.authMode === "local"
                                        ? t("health.keyNotNeeded")
                                        : t("health.keyUnknown")
                                : "—"
                            }
                          />
                          <DetailRow
                            label={t("health.visionModel")}
                            value={health?.vision.resolved ?? "—"}
                            mono
                            badge={modelBadge(health?.vision)}
                          />
                          <DetailRow
                            label={t("health.textModel")}
                            value={health?.text.resolved ?? "—"}
                            mono
                            badge={modelBadge(health?.text)}
                          />
                          {version ? (
                            <DetailRow
                              label={t("settings.version")}
                              value={[
                                version.version ? `v${version.version}` : "",
                                version.short,
                                version.builtAt ? new Date(version.builtAt).toLocaleString() : "",
                              ]
                                .filter(Boolean)
                                .join(" · ")}
                              mono
                            />
                          ) : null}
                        </dl>
                        {/* Legal: the same three documents the cookie banner
                            links to, always reachable from Settings. */}
                        <div className="pt-3">
                          <p className="text-[11px] font-semibold uppercase tracking-wider text-[var(--text-subtle)]">
                            {t("settings.legal")}
                          </p>
                          <div className="mt-1.5 flex flex-wrap gap-x-3 gap-y-1 text-[12.5px] font-semibold">
                            <Link href="/privacy" className="text-[var(--text)] underline decoration-dotted">
                              {t("legal.privacy")}
                            </Link>
                            <Link href="/terms" className="text-[var(--text)] underline decoration-dotted">
                              {t("legal.terms")}
                            </Link>
                            <Link href="/cookies" className="text-[var(--text)] underline decoration-dotted">
                              {t("legal.cookies")}
                            </Link>
                          </div>
                        </div>
                        {health?.mode === "direct-cloud" && health.needsKey ? (
                          <p className="pt-2 text-[11px] leading-relaxed text-[var(--text-subtle)]">
                            {t("health.createKey.before")}{" "}
                            <a
                              className="font-semibold underline underline-offset-2"
                              href="https://ollama.com/settings/keys"
                              target="_blank"
                              rel="noreferrer"
                            >
                              ollama.com/settings/keys
                            </a>{" "}
                            {t("health.createKey.after")} <code>ollama signin</code> {t("health.createKey.end")}{" "}
                            <code>OLLAMA_AUTH=local</code>.
                          </p>
                        ) : null}
                      </div>
                    </details>

                    {/* ------------------------------- remove key (very bottom) */}
                    {apiKey ? (
                      confirmRemove ? (
                        <div className="rounded-xl border border-rose-300/70 bg-rose-50 p-3 dark:border-rose-400/25 dark:bg-rose-500/10">
                          <p className="text-[12px] leading-relaxed text-rose-900 dark:text-rose-100">
                            {t("settings.removeKeyConfirm")}
                          </p>
                          <div className="mt-1.5 flex flex-wrap gap-2">
                            <Button size="sm" variant="danger" className="touch-target" onClick={forget}>
                              {t("settings.removeKeyYes")}
                            </Button>
                            <Button
                              size="sm"
                              variant="ghost"
                              className="touch-target"
                              onClick={() => setConfirmRemove(false)}
                            >
                              {t("common.cancel")}
                            </Button>
                          </div>
                        </div>
                      ) : (
                        <button
                          type="button"
                          onClick={() => setConfirmRemove(true)}
                          className="touch-target mx-auto block px-3 text-center text-[12.5px] font-medium text-rose-700 underline-offset-2 hover:underline dark:text-rose-300"
                        >
                          {t("settings.removeKey")}
                        </button>
                      )
                    ) : null}

                    <div className="h-9" aria-hidden />
                  </>
                ) : (
                  <>
                {/* --------------------------------------------- language */}
                <section className="mb-4 space-y-2 rounded-2xl border border-[var(--hairline)] bg-[var(--surface-sunken)] p-3">
                  <h3 className="text-sm font-semibold text-frost-950 dark:text-frost-50">
                    {t("language.label")}
                  </h3>
                  <div className="segmented" role="group" aria-label={t("language.label")}>
                    {LOCALES.map((entry) => (
                      <button
                        key={entry.id}
                        type="button"
                        aria-pressed={locale === entry.id}
                        onClick={() => setLocale(entry.id)}
                      >
                        {entry.label}
                      </button>
                    ))}
                  </div>
                  <p className="text-[11px] leading-relaxed text-[var(--text-subtle)]">
                    {t("language.note")}
                  </p>
                </section>

                {/* ------------------------------------------------ API key */}
                <section className="mb-4 space-y-3 rounded-2xl border border-[var(--hairline)] bg-[var(--surface-sunken)] p-3">
                  <div className="flex flex-wrap items-center justify-between gap-2">
                    <h3 className="text-sm font-semibold text-frost-950 dark:text-frost-50">
                      {t("settings.apiKey")}
                    </h3>
                    {apiKey ? (
                      <span className="rounded-full bg-emerald-100 px-2 py-0.5 text-[11px] font-bold text-emerald-900 dark:bg-emerald-400/20 dark:text-emerald-200">
                        {t("settings.savedInBrowser")}
                      </span>
                    ) : needsKeyMode ? (
                      <span className="rounded-full bg-amber-50 px-2 py-0.5 text-[11px] font-semibold text-amber-800 dark:bg-amber-500/15 dark:text-amber-200">
                        {t("settings.required")}
                      </span>
                    ) : (
                      <span className="rounded-full bg-[var(--surface-sunken)] px-2 py-0.5 text-[11px] font-semibold text-[var(--text-muted)]">
                        {t("settings.notNeeded")}
                      </span>
                    )}
                  </div>

                  {/* Phones: the field gets its own row, the two actions stack
                      underneath at full touch-target size. */}
                  <div className="flex flex-col gap-2 sm:flex-row sm:flex-wrap sm:items-center">
                    <label className="sr-only" htmlFor="ollama-api-key">
                      {t("settings.apiKey")}
                    </label>
                    <input
                      id="ollama-api-key"
                      ref={keyInputRef}
                      type={reveal ? "text" : "password"}
                      value={keyDraft}
                      onChange={(event) => setKeyDraft(event.target.value)}
                      onKeyDown={(event) => {
                        event.stopPropagation();
                        if (event.key === "Enter") save();
                      }}
                      placeholder={t("settings.pasteKey")}
                      autoComplete="off"
                      spellCheck={false}
                      className="w-full min-w-0 rounded-xl border border-[var(--hairline)] bg-[var(--surface-strong)] px-3 py-2 font-mono text-xs text-frost-950 outline-none transition placeholder:font-sans placeholder:text-[var(--text-subtle)] focus:border-accent-500 dark:text-frost-50 sm:min-w-40 sm:flex-1"
                    />
                    <div className="flex items-center gap-2 sm:contents">
                      <Button
                        size="sm"
                        variant="secondary"
                        className="touch-target flex-1 sm:flex-none"
                        onClick={() => setReveal((value) => !value)}
                      >
                        {reveal ? t("settings.hide") : t("settings.show")}
                      </Button>
                      <Button
                        size="sm"
                        className="touch-target flex-1 sm:flex-none"
                        onClick={save}
                        disabled={keyDraft.trim() === apiKey}
                      >
                        {t("common.save")}
                      </Button>
                    </div>
                  </div>

                  <div className="space-y-2">
                    <p className="text-[11px] leading-relaxed text-[var(--text-subtle)]">
                      {t("settings.keyNote")}
                    </p>

                    <details className="group">
                      <summary className="touch-target -mt-1 flex cursor-pointer list-none items-center gap-1.5 text-[11px] font-medium text-[var(--text-muted)] transition hover:text-[var(--text)] [&::-webkit-details-marker]:hidden">
                        <ChevronDownIcon className="size-3.5 shrink-0 transition-transform group-open:rotate-180" />
                        {t("settings.localTipTitle")}
                      </summary>
                      <p className="pt-0.5 text-[11px] leading-relaxed text-[var(--text-subtle)]">
                        {t("settings.localTipSet")} <code>OLLAMA_AUTH=local</code>{" "}
                        {t("settings.keyNoteAfter")} <code>.env.local</code> {t("settings.keyNoteEnd")}{" "}
                        <code>ollama signin</code>
                        {t("settings.keyNoteEnd2")}
                      </p>
                    </details>
                  </div>

                  <div className="flex flex-wrap items-center gap-x-3 gap-y-1">
                    <Button
                      size="sm"
                      variant="secondary"
                      className="touch-target"
                      onClick={() => void refresh()}
                      loading={loading}
                    >
                      {t("settings.testConnection")}
                    </Button>
                    {saved ? (
                      <span className="text-xs font-semibold text-emerald-700 dark:text-emerald-300">
                        {t("settings.savedTesting")}
                      </span>
                    ) : null}
                    {apiKey && !confirmRemove ? (
                      <Button
                        size="sm"
                        variant="ghost"
                        className="touch-target -ml-2.5 text-rose-700 hover:bg-rose-500/10 dark:text-rose-300"
                        onClick={() => setConfirmRemove(true)}
                      >
                        {t("settings.removeKey")}
                      </Button>
                    ) : null}
                  </div>

                  {apiKey && confirmRemove ? (
                    <div className="rounded-xl border border-rose-300/70 bg-rose-50 p-3 dark:border-rose-400/25 dark:bg-rose-500/10">
                      <p className="text-[12px] leading-relaxed text-rose-900 dark:text-rose-100">
                        {t("settings.removeKeyConfirm")}
                      </p>
                      <div className="mt-1.5 flex flex-wrap gap-2">
                        <Button size="sm" variant="danger" className="touch-target" onClick={forget}>
                          {t("settings.removeKeyYes")}
                        </Button>
                        <Button
                          size="sm"
                          variant="ghost"
                          className="touch-target"
                          onClick={() => setConfirmRemove(false)}
                        >
                          {t("common.cancel")}
                        </Button>
                      </div>
                    </div>
                  ) : null}
                </section>

                {/* ------------------------------------------- chat grounding */}
                <section className="mb-4 rounded-2xl border border-[var(--hairline)] bg-[var(--surface-sunken)] p-3">
                  <ToggleRow
                    label={t("settings.chatNotes")}
                    note={t("settings.chatNotesNote")}
                    checked={settings.chatNotes}
                    onChange={() => saveSettings({ chatNotes: !settings.chatNotes })}
                  />
                </section>

                {/* ------------------------------------------- theme */}
                <ThemeSection />

                {/* ----------------------------------------- learning */}
                <LearningSection level={3} />

                {/* ------------------------------------------- data & sync */}
                <DataSection />
                <SyncSection />

                {/* ------------------------------------------------ install */}
                {installAvailable ? (
                  <section className="mb-4 rounded-2xl border border-[var(--hairline)] bg-[var(--surface-sunken)] p-1.5">
                    <button
                      type="button"
                      onClick={() => {
                        onClose();
                        openInstallSheet();
                      }}
                      className="flex w-full items-center gap-3 rounded-xl px-2.5 py-2 text-left transition hover:bg-[var(--hover)]"
                    >
                      <span
                        aria-hidden
                        className="grid size-9 shrink-0 place-items-center rounded-xl border border-[var(--hairline)] bg-[var(--surface)] text-[var(--text-muted)]"
                      >
                        <DownloadIcon className="size-4" />
                      </span>
                      <span className="min-w-0 flex-1">
                        <span className="block text-sm font-semibold text-frost-950 dark:text-frost-50">
                          {t("settings.installApp")}
                        </span>
                        <span className="block text-[12px] text-[var(--text-subtle)]">
                          {t("settings.addToHome")}
                        </span>
                      </span>
                      <ChevronRightIcon className="size-4 shrink-0 text-[var(--text-subtle)]" />
                    </button>
                  </section>
                ) : null}

                {error ? (
                  <div className="rounded-2xl bg-rose-100 p-3 text-sm text-rose-900 dark:bg-rose-500/15 dark:text-rose-200">
                    {error}
                  </div>
                ) : null}

                {loading ? (
                  <div className="flex items-center gap-3 py-2 text-sm text-[var(--text-muted)]">
                    <Spinner className="size-4" /> {t("settings.checking")}
                  </div>
                ) : checkedAt ? (
                  <p className="py-1 text-[11px] font-medium text-[var(--text-subtle)]">
                    {freshnessLabel(checkedAt, locale, t)}
                  </p>
                ) : null}

                {health ? <HealthPanel health={health} /> : null}
                {version ? (
                  <p className="mt-2 text-[11px] text-[var(--text-subtle)]">
                    {t("settings.version")}:{" "}
                    <span className="font-mono">
                      {version.version ? `v${version.version} · ` : ""}
                      {version.short}
                    </span>
                    {version.builtAt ? ` · ${new Date(version.builtAt).toLocaleString()}` : ""}
                  </p>
                ) : null}

                {/* Legal: the same three documents the cookie banner links to. */}
                <div className="mt-3 flex flex-wrap gap-x-3 gap-y-1 text-[12px] font-semibold">
                  <Link href="/privacy" className="text-[var(--text-muted)] underline decoration-dotted">
                    {t("legal.privacy")}
                  </Link>
                  <Link href="/terms" className="text-[var(--text-muted)] underline decoration-dotted">
                    {t("legal.terms")}
                  </Link>
                  <Link href="/cookies" className="text-[var(--text-muted)] underline decoration-dotted">
                    {t("legal.cookies")}
                  </Link>
                </div>

                {/* keeps real content out of the 36px fade strip at the bottom */}
                <div className="h-9" aria-hidden />
                  </>
                )}
              </div>
            </div>

            {/* scroll cue: a bare chevron inside the fade strip, so it never
                covers text (the .sheet-scroll mask fades what is underneath) */}
            <div
              aria-hidden
              className={cn(
                "pointer-events-none absolute inset-x-0 bottom-0 flex h-9 items-end justify-center pb-1.5 transition-opacity duration-200",
                canScroll ? "opacity-100" : "opacity-0",
              )}
            >
              <ChevronDownIcon className="size-4 text-[var(--text-subtle)]" />
            </div>
          </motion.div>
        </motion.div>
      ) : null}
    </AnimatePresence>
  );
}

function HealthPanel({ health }: { health: ReturnType<typeof useHealth>["health"] }) {
  const { t } = useI18n();
  if (!health) return null;
  const tone = health.ok ? "emerald" : health.needsKey ? "amber" : health.reachable ? "amber" : "rose";
  const toneClasses: Record<string, string> = {
    emerald: "bg-emerald-50 text-emerald-800 dark:bg-emerald-500/15 dark:text-emerald-200",
    amber: "bg-amber-50 text-amber-800 dark:bg-amber-500/15 dark:text-amber-200",
    rose: "bg-rose-50 text-rose-800 dark:bg-rose-500/15 dark:text-rose-200",
  };

  return (
    <div className="space-y-3">
      <div className={cn("flex items-start gap-2 rounded-2xl p-3 text-sm font-medium", toneClasses[tone])}>
        <span aria-hidden className="mt-0.5 shrink-0">
          {tone === "emerald" ? (
            <CheckCircleIcon className="size-5" />
          ) : tone === "amber" ? (
            <AlertTriangleIcon className="size-5" />
          ) : (
            <XCircleIcon className="size-5" />
          )}
        </span>
        <span>
          {health.ok
            ? t("health.ok")
            : health.needsKey
              ? t("health.needsKey")
              : health.keyAccepted === false
                ? t("health.rejected")
                : health.reachable
                  ? t("health.modelMissing")
                  : t("health.unreachable")}
          {health.error ? <p className="mt-1 font-normal">{health.error}</p> : null}
          {health.kind === "usage_limit" || health.kind === "throttled" ? (
            <span className="mt-2 flex flex-wrap gap-2">
              <ModelErrorActions kind={health.kind} />
            </span>
          ) : null}
        </span>
      </div>

      <dl className="grid grid-cols-2 gap-2 text-sm">
        <Info
          label={t("health.auth")}
          value={
            health.authMode === "user-key"
              ? t("health.authUserKey")
              : health.authMode === "server"
                ? t("health.authServer")
                : t("health.authLocal")
          }
        />
        <Info label={t("health.endpoint")} value={health.baseUrl} mono />
        <Info
          label={t("health.mode")}
          value={health.mode === "direct-cloud" ? t("health.modeCloud") : t("health.modeLocal")}
        />
        <Info
          label={t("health.key")}
          value={
            health.needsKey
              ? t("health.keyMissing")
              : health.keyAccepted === true
                ? t("health.keyAccepted")
                : health.keyAccepted === false
                  ? t("health.keyRejected")
                  : health.authMode === "local"
                    ? t("health.keyNotNeeded")
                    : t("health.keyUnknown")
          }
        />
      </dl>

      <div className="space-y-2">
        <ModelRow title={t("health.visionModel")} model={health.vision} />
        <ModelRow title={t("health.textModel")} model={health.text} />
      </div>

      {health.mode === "direct-cloud" && health.needsKey ? (
        <p className="rounded-2xl bg-[var(--surface-sunken)] p-3 text-xs text-[var(--text-muted)]">
          {t("health.createKey.before")}{" "}
          <a className="font-semibold underline underline-offset-2" href="https://ollama.com/settings/keys" target="_blank" rel="noreferrer">
            ollama.com/settings/keys
          </a>{" "}
          {t("health.createKey.after")} <code>ollama signin</code> {t("health.createKey.end")}{" "}
          <code>OLLAMA_AUTH=local</code>.
        </p>
      ) : null}
    </div>
  );
}

function DetailRow({
  label,
  value,
  mono,
  badge,
}: {
  label: string;
  value: string;
  mono?: boolean;
  badge?: { text: string; className: string };
}) {
  return (
    <div className="flex items-center justify-between gap-3 border-b border-[var(--hairline-soft)] py-1.5 last:border-0">
      <dt className="shrink-0 text-[12px] text-[var(--text-subtle)]">{label}</dt>
      <dd className={cn("flex min-w-0 items-center justify-end gap-1.5 text-right font-medium text-[var(--text)]", mono && "font-mono text-[11px]")}>
        <span className="truncate">{value}</span>
        {badge ? (
          <span className={cn("shrink-0 rounded-full px-1.5 py-0.5 text-[10px] font-bold", badge.className)}>
            {badge.text}
          </span>
        ) : null}
      </dd>
    </div>
  );
}

function Info({ label, value, mono }: { label: string; value: string; mono?: boolean }) {
  return (
    <div className="rounded-2xl border border-[var(--hairline)] bg-[var(--surface-sunken)] p-3">
      <dt className="text-xs uppercase tracking-wide text-[var(--text-subtle)]">{label}</dt>
      <dd className={cn("mt-0.5 break-words font-semibold", mono && "font-mono text-xs")}>{value}</dd>
    </div>
  );
}

function ModelRow({
  title,
  model,
}: {
  title: string;
  model: { configured: string; resolved: string; available: boolean | null; note?: string };
}) {
  const { t } = useI18n();
  const badge =
    model.available === true
      ? { text: t("health.available"), className: "bg-emerald-100 text-emerald-900 dark:bg-emerald-400/20 dark:text-emerald-200" }
      : model.available === false
        ? { text: t("health.notFound"), className: "bg-rose-50 text-rose-800 dark:bg-rose-500/15 dark:text-rose-200" }
        : { text: t("health.unknown"), className: "bg-[var(--surface-sunken)] text-[var(--text-muted)]" };

  return (
    <div className="rounded-2xl border border-[var(--hairline)] bg-[var(--surface-sunken)] p-3">
      <div className="flex items-center justify-between gap-2">
        <p className="text-xs uppercase tracking-wide text-[var(--text-subtle)]">{title}</p>
        <span className={cn("rounded-full px-2 py-0.5 text-[11px] font-bold", badge.className)}>
          {badge.text}
        </span>
      </div>
      <p className="mt-1 font-mono text-sm font-semibold">{model.resolved}</p>
      {model.configured !== model.resolved ? (
        <p className="text-xs text-[var(--text-subtle)]">
          {t("health.configuredAs", { model: model.configured })}
        </p>
      ) : null}
      {model.note ? <p className="mt-1 text-xs text-amber-700 dark:text-amber-300">{model.note}</p> : null}
    </div>
  );
}

/** Boolean toggle row used by the chat-grounding setting. */
function ToggleRow({
  label,
  note,
  checked,
  onChange,
}: {
  label: string;
  note: string;
  checked: boolean;
  onChange: () => void;
}) {
  return (
    <div className="flex items-center justify-between gap-3 border-t border-[var(--hairline-soft)] pt-3">
      <span className="min-w-0">
        <span className="block text-[13px] font-semibold text-[var(--text)]">{label}</span>
        <span className="block text-[11.5px] leading-snug text-[var(--text-subtle)]">{note}</span>
      </span>
      <button
        type="button"
        role="switch"
        aria-checked={checked}
        aria-label={label}
        onClick={onChange}
        className={cn(
          "touch-target relative h-7 w-12 shrink-0 rounded-full border transition-colors",
          checked ? "grad-ice border-transparent" : "border-[var(--hairline)] bg-[var(--surface-sunken)]",
        )}
      >
        <span
          aria-hidden
          className={cn(
            "absolute top-1/2 size-5 -translate-y-1/2 rounded-full bg-white shadow transition-[left] duration-200",
            checked ? "left-6" : "left-0.5",
          )}
        />
      </button>
    </div>
  );
}