import { useState, useSyncExternalStore } from "react";
import { qk } from "../lib/queryKeys";
import { useTranslation } from "react-i18next";
import { useQuery } from "@tanstack/react-query";
import { useNavigation, useNavigationActions } from "./navigationContext";
import { Info, LogOut, Settings, Shield, UserPlus, type LucideIcon } from "lucide-react";
import { api, type Me } from "../lib/api";
import { displayName, roleKey } from "../lib/api/account";
import { pinOnNextPage } from "../lib/activeAccount";
import * as e2ee from "../lib/e2ee";
import { useLiveQuery } from "../lib/useLiveQuery";
import { getUnreadCount, subscribe } from "../lib/notifications";
import type { Page } from "../lib/urlState";
import {
  moduleDef,
  moduleLabelKey,
  moduleOrder,
  moduleRailKey,
  SYSTEM_PAGES,
} from "../lib/modules";
import { useScrollFade } from "../lib/useScrollFade";
import { type LangCode } from "../i18n";
import AvatarImg from "./ui/Avatar";
import LanguageSwitcher from "./LanguageSwitcher";
import { PopoverSurface } from "./ui/AnchoredPopover";
import { useAnchoredPopover } from "./ui/anchoredPopoverHooks";
import { Pressable } from "./ui/Pressable";
import { SURFACE } from "./ui/surfaces";
import {
  NavRail,
  NavRailAction,
  NavRailDivider,
  NavRailItem,
  NavRailList,
  RAIL_ROW,
} from "./ui/NavRail";
import { usePrefs } from "./prefsContext";

// Primary app navigation: a thin icon-only left rail. The modules used to hide under the avatar
// dropdown; they now live here, each revealing its name in a hover/focus flyout label. Account
// actions sit at the bottom in a popover.
export default function NavSidebar({
  me,
  onOpenAbout,
  onChangeLanguage,
  language,
}: {
  me: Me;
  onOpenAbout: () => void;
  onChangeLanguage: (code: LangCode) => void;
  language: LangCode;
}) {
  const { t } = useTranslation();
  const { page } = useNavigation();
  const { setPage } = useNavigationActions();
  // The rail is ALWAYS a thin icon-only column flush against the left edge. There is no
  // expanded/pinned mode anymore — instead each icon reveals a floating name label on hover or
  // keyboard focus (a rest-to-show flyout via Tooltip), so the names are one glance away without the
  // rail ever growing.
  const [acctOpen, setAcctOpen] = useState(false);
  // The account panel holds mixed content with its own tab order (profile, account switches, two
  // actions), so it is a `dialog` popover, not a roving menu. It portals out of the nav — whose
  // backdrop-filter would otherwise trap fixed positioning + stacking and let clicks fall through
  // to the controls behind it — and anchors to the RIGHT of the button, bottom-aligned, as its
  // hand-rolled placement did. Dismissal (outside press, topmost-only Escape, focus return) now
  // comes from the platform instead of a pair of document listeners.
  const acctPop = useAnchoredPopover({
    open: acctOpen,
    onOpenChange: setAcctOpen,
    mode: "dialog",
    role: "dialog",
    placement: "right-end",
    offset: 8,
  });

  async function logout() {
    // Signs THIS tab's active account out of the browser wallet (server is per-tab aware); then
    // drops this tab's override and reloads onto whatever account remains the default.
    try {
      await api.logout();
    } catch {
      /* clear locally and reload regardless */
    }
    // Forget this device's E2EE private key on sign-out: it's otherwise persisted in IndexedDB
    // and auto-unlocks on the next visit, so on a shared machine the conversations would stay
    // decryptable after logout. Re-entering the message passphrase is required next time.
    try {
      await e2ee.clearDevice(me.id);
    } catch {
      /* IndexedDB unavailable (e.g. private mode) — never let it block the logout + reload */
    }
    pinOnNextPage(null);
    location.reload();
  }

  // Accounts that have signed in on this browser (loaded only while the popover is open).
  const accountsQuery = useQuery({
    queryKey: qk.accounts(),
    queryFn: api.accounts,
    enabled: acctOpen,
  });
  const otherAccounts = (accountsQuery.data ?? []).filter((a) => !a.active);

  function switchTo(id: number) {
    // Per-tab switch: point THIS tab at the account and reload; other tabs keep their own
    // identity. No server round-trip — req() sends the account header (validated against the
    // browser wallet server-side), so the cookie's default account is left untouched. The pin moves with
    // the reload, not before it: the page going away still unloads as the account it was built for.
    pinOnNextPage(id);
    // Drop the previous account's in-module sub-view/overlay before the reload (which would
    // otherwise preserve history.state across the swap). Otherwise the new account lands on a
    // stale sub-view — e.g. an open chat thread whose partnerId belongs to the OLD identity
    // (often the new account's own id → an empty self-thread). Start at the module root instead.
    const st = { ...(window.history.state || {}) };
    delete st._sub;
    delete st._ov;
    window.history.replaceState(st, "");
    location.reload(); // cleanest way to reload all per-user state for the new account
  }

  // Durable, server-backed unread count for the inbox badge. Polled live (pauses when the
  // tab is hidden); coexists with the client-side transient bell at the bottom of the rail.
  const unreadQuery = useLiveQuery(qk.notifUnread(), api.notificationUnreadCount, {
    intervalMs: 30000,
  });
  // One indicator for both layers: durable server notifications + the client-side transient
  // events (the former separate bell is now folded into the inbox page).
  const clientUnread = useSyncExternalStore(subscribe, getUnreadCount, getUnreadCount);
  const unread = (unreadQuery.data?.count ?? 0) + clientUnread;
  // Direct messages are their own module with their own unread badge (demo can't message).
  const msgUnreadQuery = useLiveQuery(qk.messageUnread(), api.messageUnreadCount, {
    intervalMs: 30000,
    enabled: !me.is_demo,
  });
  const msgUnread = msgUnreadQuery.data?.count ?? 0;
  // Download center badge = items still working (queued/running/paused). Reuses the same
  // lightweight per-user index the feed cards poll, so no extra request shape.
  const dlIndexQuery = useLiveQuery(qk.downloadIndex(), api.downloadIndex, {
    intervalMs: 30000,
    enabled: !me.is_demo,
  });
  const dlActive = Object.values(dlIndexQuery.data ?? {}).filter((s) => s !== "done").length;

  // Scroll-affordance for the module list: hidden scrollbar + top/bottom edge fade (shared hook,
  // also used by the side panels) so a high-zoom overflow scrolls without a scrollbar.
  const listFade = useScrollFade();

  type NavItem = { page: Page; icon: LucideIcon; label: string; badge?: number };
  // Per-page presentation (icon/label/badge). WHICH pages appear and in what order — and each
  // module's icon + label — come from the shared module registry (the same source the header's
  // ◀/▶ stepper uses), so the two never drift and a new/gated module updates both at once. The
  // badge NUMBERS are the only nav-only concern (they need the live polling queries above).
  const BADGE: Partial<Record<Page, number>> = {
    notifications: unread,
    messages: msgUnread,
    downloads: dlActive,
  };
  const META = (p: Page): Omit<NavItem, "page"> => ({
    icon: moduleDef(p).icon,
    label: t(moduleLabelKey[p]),
    badge: BADGE[p],
  });
  const sys = new Set<Page>(SYSTEM_PAGES);
  const order = moduleOrder(me);
  // User-facing content modules vs. admin/system modules, separated by a divider in the rail.
  const userItems: NavItem[] = order
    .filter((p) => !sys.has(p))
    .map((p) => ({ page: p, ...META(p) }));
  const systemItems: NavItem[] = order
    .filter((p) => sys.has(p))
    .map((p) => ({ page: p, ...META(p) }));

  const { railLabels } = usePrefs();
  const name = displayName(me);
  // Role is surfaced as a plain title tooltip on the account row (no visual badge).
  const roleLabel = t(`nav.role.${roleKey(me)}`);

  const renderItem = ({ page: p, icon, label, badge }: NavItem) => (
    <NavRailItem
      key={p}
      testId={`nav-${p}`}
      icon={icon}
      label={label}
      shortLabel={t(moduleRailKey[p])}
      showLabel={railLabels}
      active={page === p}
      badge={badge}
      onClick={() => setPage(p)}
    />
  );

  return (
    // Slim rail (B7), flush against the left viewport edge (only top/bottom margin), never grows —
    // labels on or off. The slot is exactly the rail's width so the filter tab/bar docks flush
    // against its right edge.
    <div className="relative shrink-0 w-15">
      <NavRail label={t("nav.primary")} className="absolute top-0 bottom-0 left-0 z-rail my-3">
        <NavRailList ref={listFade.ref} style={listFade.style}>
          {userItems.map(renderItem)}
          {systemItems.length > 0 && <NavRailDivider />}
          {systemItems.map(renderItem)}
        </NavRailList>

        <div className="mt-2 pt-2 border-t border-border flex flex-col gap-1">
          <div className="flex flex-col gap-1 pb-2 mb-1 border-b border-border">
            <LanguageSwitcher variant="rail" value={language} onChange={onChangeLanguage} />
            <NavRailAction icon={Info} label={t("header.account.about")} onClick={onOpenAbout} />
            <NavRailAction icon={LogOut} label={t("header.account.signOut")} onClick={logout} />
          </div>
          <NavRailItem
            testId="nav-settings"
            icon={Settings}
            label={t("header.account.settings")}
            shortLabel={t(moduleRailKey.settings)}
            showLabel={railLabels}
            active={page === "settings"}
            onClick={() => setPage("settings")}
          />

          <div>
            <Pressable
              ref={acctPop.refs.setReference}
              {...acctPop.getReferenceProps()}
              title={`${name} · ${roleLabel}`}
              aria-label={`${name} · ${roleLabel}`}
              className={`${RAIL_ROW} h-9 text-muted state-layer hover:text-fg`}
            >
              <span className="relative shrink-0">
                <AvatarImg
                  src={me.avatar_url}
                  fallback={name}
                  className="w-5.5 h-5.5 rounded-full text-3xs"
                />
              </span>
            </Pressable>

            <PopoverSurface
              popover={acctPop}
              ariaLabel={name}
              className={`${SURFACE.popover} w-60 p-3 animate-[popIn_0.16s_ease]`}
            >
              <div className="flex items-center gap-3 pb-3 border-b border-border">
                <AvatarImg
                  src={me.avatar_url}
                  fallback={name}
                  className="w-10 h-10 rounded-full text-sm shrink-0"
                />
                <div className="min-w-0">
                  <div className="text-sm font-semibold truncate">{name}</div>
                  <div className="text-xs text-muted truncate">{me.email}</div>
                  {/* The address Google answers with, when it isn't the one above. /api/me sends it
                      only when the two differ, so for most accounts this line never exists — and for
                      someone who registered as `me+siftlode@gmail.com` it answers the question their
                      sign-in screen would otherwise leave open: which address gets me in? A text
                      label rather than a brand glyph, since the app draws one icon set (lucide) and a
                      generic mail icon here would say nothing. */}
                  {me.google_email && (
                    <div
                      className="text-2xs text-muted truncate mt-0.5"
                      title={t("header.account.googleAddress", { email: me.google_email })}
                    >
                      <span className="uppercase tracking-wide">Google</span> · {me.google_email}
                    </div>
                  )}
                </div>
              </div>
              {me.role === "admin" && (
                <div className="flex items-center gap-1.5 mt-2 text-2xs font-medium text-accent">
                  <Shield className="w-3.5 h-3.5" />
                  {t("header.account.admin")}
                </div>
              )}
              {otherAccounts.length > 0 && (
                <div className="mt-2 pt-2 border-t border-border flex flex-col gap-0.5">
                  {otherAccounts.map((a) => (
                    <Pressable
                      key={a.id}
                      onClick={() => switchTo(a.id)}
                      title={t("header.account.switchTo", { name: a.display_name ?? a.email })}
                      className="selectable w-full flex items-center gap-2.5 px-2 py-1.5 rounded-lg transition touch-target"
                    >
                      <AvatarImg
                        src={a.avatar_url}
                        fallback={a.display_name ?? a.email}
                        className="w-6 h-6 rounded-full text-3xs shrink-0"
                      />
                      <span className="min-w-0">
                        <span className="block text-[0.8125rem] text-fg truncate">
                          {displayName(a)}
                        </span>
                        <span className="block text-2xs text-muted truncate">{a.email}</span>
                      </span>
                    </Pressable>
                  ))}
                </div>
              )}
              <div className="mt-2 pt-2 border-t border-border flex flex-col">
                <Pressable
                  onClick={() => {
                    // Adding an account switches THIS tab to it: drop the tab's pin so that on
                    // return from Google it adopts the freshly-added account (the new default)
                    // and pins that. Other tabs keep their own pinned account.
                    pinOnNextPage(null);
                    window.location.href = "/auth/login";
                  }}
                  className="selectable w-full flex items-center gap-2 text-sm px-2 py-2 rounded-lg text-muted hover:text-fg transition touch-target"
                >
                  <UserPlus className="w-4 h-4" />
                  {t("header.account.addAccount")}
                </Pressable>
                <Pressable
                  onClick={logout}
                  className="selectable w-full flex items-center gap-2 text-sm px-2 py-2 rounded-lg text-muted hover:text-fg transition touch-target"
                >
                  <LogOut className="w-4 h-4" />
                  {t("header.account.signOut")}
                </Pressable>
              </div>
            </PopoverSurface>
          </div>
        </div>
      </NavRail>
    </div>
  );
}