webmail-client/frontend/src/routes/MailLayout.tsx

import { keepPreviousData, useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { useEffect, useRef, useState } from "react";
import { Link, useMatch, useNavigate, useSearchParams } from "react-router-dom";

import signetLogo from "../../icons/ultimo-logo-signet.svg";
import { AppSwitcher } from "../components/AppSwitcher";
import { Composer, type ComposerInit, draftToInit } from "../components/compose/Composer";
import { DraftsList } from "../components/list/DraftsList";
import { Icon } from "../components/Icon";
import { MessageList } from "../components/list/MessageList";
import { Resizer } from "../components/Resizer";
import { ThemeToggle } from "../components/ThemeToggle";
import { EmptyIllustration } from "../components/EmptyIllustration";
import { BackfillBanner } from "../components/BackfillBanner";
import { ThreadView } from "../components/thread/ThreadView";
import { RightPanel, type PanelTab } from "../components/mail/RightPanel";
import { useT } from "../i18n";
import type { MessageKey } from "../i18n/en";
import { api } from "../lib/api";
import { setTimeFormat } from "../lib/timeFormat";
import type { QuotaOut, SavedSearch, ThreadSummary } from "../lib/types";
import { useKeyboardShortcuts } from "../lib/useKeyboardShortcuts";
import { PluginSlot } from "../plugins/PluginSlot";

function quotaLabel(q: QuotaOut): string {
  const pct = q.quota_bytes > 0 ? (q.used_bytes / q.quota_bytes) * 100 : 0;
  const pctStr = pct >= 10 ? String(Math.round(pct)) : String(Math.round(pct * 10) / 10);
  const gb = q.quota_bytes / 1024 ** 3;
  const gbStr = Number.isInteger(gb) ? String(gb) : gb.toFixed(1);
  return `${pctStr}% of ${gbStr} GB`;
}

// Threads shown per page in the mail list.
const PAGE_SIZE = 50;

// Collapsed sidebar width: just wide enough for the icons.
const COLLAPSED_W = 60;

// Unified per-folder views. "Spam" maps to the IMAP special-use "junk".
const FOLDERS: { view: string; icon: string; label: MessageKey }[] = [
  { view: "folder:inbox", icon: "inbox", label: "nav.inbox" },
  { view: "folder:archive", icon: "archive", label: "nav.archive" },
  { view: "folder:drafts", icon: "drafts", label: "nav.drafts" },
  { view: "folder:sent", icon: "sent", label: "nav.sent" },
  { view: "folder:junk", icon: "spam", label: "nav.spam" },
  { view: "folder:trash", icon: "trash", label: "nav.trash" },
];

export function MailLayout() {
  const t = useT();
  const navigate = useNavigate();
  const queryClient = useQueryClient();
  const match = useMatch("/mail/t/:threadId");
  const threadId = match?.params.threadId;
  const [view, setView] = useState<string>("folder:inbox");
  const [term, setTerm] = useState("");
  // Debounced copy of the search box for search-as-you-type (avoids a request per key).
  const [debouncedTerm, setDebouncedTerm] = useState("");
  useEffect(() => {
    const h = window.setTimeout(() => setDebouncedTerm(term), 180);
    return () => window.clearTimeout(h);
  }, [term]);
  const searching = debouncedTerm.trim().length > 0;
  const [filter, setFilter] = useState<"all" | "unread" | "pinned">("all");
  const [listOrder, setListOrder] = useState<"newest" | "oldest">(() =>
    localStorage.getItem("mail.listOrder") === "oldest" ? "oldest" : "newest",
  );
  const [page, setPage] = useState(0);
  const [refreshing, setRefreshing] = useState(false);
  // Mail-list selection (checkboxes). Lives here so the reading pane can show the
  // bulk-action bar / count while any conversation is selected.
  const [checkedIds, setCheckedIds] = useState<Set<string>>(new Set());
  // Rows just archived/trashed/deleted from the list: greyed out and unclickable
  // for immediate feedback (search results don't always drop the row on refetch).
  const [dimmedIds, setDimmedIds] = useState<Set<string>>(new Set());
  const toggleCheck = (id: string) =>
    setCheckedIds((prev) => {
      const next = new Set(prev);
      if (next.has(id)) next.delete(id);
      else next.add(id);
      return next;
    });
  const [composing, setComposing] = useState<ComposerInit | null>(null);
  const [composerExpanded, setComposerExpanded] = useState(false);
  // Bumped each time a composer is opened so the <Composer> remounts (fresh state)
  // when switching between drafts instead of keeping the previous draft's editor.
  const [composeKey, setComposeKey] = useState(0);
  const [replySignal, setReplySignal] = useState<{ kind: string; seq: number }>();
  const searchRef = useRef<HTMLInputElement>(null);

  // Resizable panel widths (persisted). Drag the dividers to adjust.
  const [sidebarW, setSidebarW] = useState(() => Number(localStorage.getItem("panel.sidebar")) || 240);
  const [listW, setListW] = useState(() => Number(localStorage.getItem("panel.list")) || 384);
  // Collapsed sidebar shows icons only (persisted).
  const [collapsed, setCollapsed] = useState(() => localStorage.getItem("panel.collapsed") === "1");
  // Right info panel (Calendar / People / Attachments) — hidden by default.
  const [rightOpen, setRightOpen] = useState(() => localStorage.getItem("panel.right") === "1");
  const [rightTab, setRightTab] = useState<PanelTab>(() => (localStorage.getItem("panel.rightTab") as PanelTab) || "calendar");
  const [rightW, setRightW] = useState(() => Number(localStorage.getItem("panel.rightW")) || 340);
  const clampSidebar = (w: number) => Math.min(Math.max(w, 180), 420);
  // The list can be dragged up to 75% of the window width.
  const clampList = (w: number) => Math.min(Math.max(w, 260), window.innerWidth * 0.75);
  const clampRight = (w: number) => Math.min(Math.max(w, 280), 560);
  useEffect(() => localStorage.setItem("panel.sidebar", String(sidebarW)), [sidebarW]);
  useEffect(() => localStorage.setItem("panel.list", String(listW)), [listW]);
  useEffect(() => localStorage.setItem("panel.collapsed", collapsed ? "1" : "0"), [collapsed]);
  useEffect(() => localStorage.setItem("panel.right", rightOpen ? "1" : "0"), [rightOpen]);
  useEffect(() => localStorage.setItem("panel.rightTab", rightTab), [rightTab]);
  useEffect(() => localStorage.setItem("panel.rightW", String(rightW)), [rightW]);
  const openPanel = (tab: PanelTab) => { setRightTab(tab); setRightOpen(true); };
  useEffect(() => localStorage.setItem("mail.listOrder", listOrder), [listOrder]);

  const isDrafts = view === "folder:drafts";
  // Which special-use folder the reading pane is showing (drives the toolbar).
  const currentFolder = view.startsWith("folder:") ? view.slice("folder:".length) : "inbox";
  const accountsQuery = useQuery({ queryKey: ["accounts"], queryFn: api.accounts });
  const mailboxesQuery = useQuery({ queryKey: ["mailboxes"], queryFn: api.mailboxes });
  const orderParam: "asc" | "desc" = listOrder === "newest" ? "desc" : "asc";
  const labelView = view.startsWith("label:") ? view.slice("label:".length) : null;
  const threadsQuery = useQuery({
    queryKey: ["threads", view, filter, orderParam, page],
    queryFn: async () => {
      if (labelView !== null) {
        // Label view: the labels plugin supplies the matching thread ids.
        const ids = await api.labelThreads(labelView);
        return ids.length ? api.threadsByIds(ids) : { threads: [], total: 0, cursor: null };
      }
      return api.threads(view, { offset: page * PAGE_SIZE, limit: PAGE_SIZE, filter, order: orderParam });
    },
    enabled: !isDrafts && !searching,
    placeholderData: keepPreviousData, // keep the current page visible while the next loads
  });
  const draftsQuery = useQuery({
    queryKey: ["drafts"],
    queryFn: api.listDrafts,
    enabled: isDrafts,
  });
  const remoteDraftsQuery = useQuery({
    queryKey: ["drafts-remote"],
    queryFn: api.remoteDrafts,
    enabled: isDrafts,
  });
  // Trash/Spam are excluded from normal search, so while viewing them the search
  // box scopes to that folder instead (via an in: operator) and searches only it.
  const searchScope =
    currentFolder === "trash" ? "in:trash" : currentFolder === "junk" ? "in:junk" : "";
  const effectiveQuery = searchScope
    ? `${searchScope} ${debouncedTerm}`.trim()
    : debouncedTerm;
  const searchQuery = useQuery({
    queryKey: ["search", effectiveQuery],
    queryFn: () => api.search(effectiveQuery),
    enabled: searching,
  });
  const savedSearchesQuery = useQuery({ queryKey: ["saved-searches"], queryFn: api.savedSearches });
  const settingsQuery = useQuery({ queryKey: ["settings"], queryFn: api.settings });
  const threadOrder: "asc" | "desc" = settingsQuery.data?.thread_order ?? "asc";
  const timeFormat = settingsQuery.data?.time_format;
  useEffect(() => {
    if (timeFormat) setTimeFormat(timeFormat);
  }, [timeFormat]);
  const quotaQuery = useQuery({ queryKey: ["quota"], queryFn: api.quota });
  const countsQuery = useQuery({ queryKey: ["folder-counts"], queryFn: api.folderCounts });

  // Folder/inbox views paginate server-side with an accurate grand total; search
  // results (a single fetched page of hits) still paginate client-side.
  let pageThreads: ThreadSummary[];
  let total: number;
  if (searching) {
    const hits = (searchQuery.data?.threads ?? []).map((h) => h.thread);
    const f = hits.filter((th) =>
      filter === "unread" ? th.unread_count > 0 : filter === "pinned" ? th.pinned : true,
    );
    const ordered = listOrder === "newest" ? f : [...f].reverse();
    total = ordered.length;
    pageThreads = ordered.slice(page * PAGE_SIZE, page * PAGE_SIZE + PAGE_SIZE);
  } else {
    pageThreads = threadsQuery.data?.threads ?? [];
    total = threadsQuery.data?.total ?? 0;
  }
  const pageStart = page * PAGE_SIZE;
  const pageEnd = pageStart + pageThreads.length;
  // Reset to the first page whenever the list identity (not the page) changes.
  useEffect(() => setPage(0), [view, filter, debouncedTerm, listOrder]);

  // Master "select all" state over the currently listed threads.
  const listedSelectedCount = pageThreads.filter((th) => checkedIds.has(th.id)).length;
  const allSelected = pageThreads.length > 0 && listedSelectedCount === pageThreads.length;
  const someSelected = listedSelectedCount > 0 && !allSelected;
  const toggleSelectAll = () =>
    setCheckedIds(allSelected ? new Set() : new Set(pageThreads.map((th) => th.id)));

  // Keyboard next/prev navigates within the currently visible page.
  const threadsRef = useRef<ThreadSummary[]>(pageThreads);
  threadsRef.current = pageThreads;

  const detailQuery = useQuery({
    queryKey: ["thread", threadId, threadOrder, view],
    queryFn: () => api.thread(threadId!, threadOrder, view),
    enabled: Boolean(threadId),
  });

  const markRead = useMutation({
    mutationFn: (id: string) => api.threadFlags(id, ["\\Seen"], []),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["threads"] });
      queryClient.invalidateQueries({ queryKey: ["folder-counts"] });
    },
  });
  // Saved searches (virtual mailboxes, §12 M2).
  const savedSearches = savedSearchesQuery.data ?? [];
  const saveSearch = useMutation({
    mutationFn: (name: string) => api.createSavedSearch(name, term.trim()),
    onSuccess: () => queryClient.invalidateQueries({ queryKey: ["saved-searches"] }),
  });
  const deleteSaved = useMutation({
    mutationFn: (id: string) => api.deleteSavedSearch(id),
    onSuccess: () => queryClient.invalidateQueries({ queryKey: ["saved-searches"] }),
  });
  const onSaveSearch = () => {
    const q = term.trim();
    if (!q) return;
    const name = window.prompt(t("search.saveNamePrompt"), q);
    if (name && name.trim()) saveSearch.mutate(name.trim());
  };
  const runSavedSearch = (s: SavedSearch) => {
    setTerm(s.query);
    navigate("/mail");
  };
  // Switch folder/account view. Clears any active search so the folder actually
  // loads — otherwise the list stays stuck on (now-stale) search results.
  const selectView = (v: string) => {
    setTerm("");
    setView(v);
    navigate("/mail");
  };

  // Auto-mark an opened thread read after a short dwell (4s), not instantly — and
  // cancel it if you leave before then, so a quick glance doesn't mark it read.
  useEffect(() => {
    const detail = detailQuery.data;
    if (!detail || !detail.messages.some((m) => m.is_unread)) return;
    const id = detail.id;
    const timer = window.setTimeout(() => markRead.mutate(id), 4000);
    return () => window.clearTimeout(timer);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [detailQuery.data?.id]);

  // Open the composer with fresh state, remounting it if one is already open
  // (e.g. clicking a different draft replaces the current editor).
  const openComposer = (init: ComposerInit, expand = false) => {
    setComposing(init);
    setComposerExpanded(expand);
    setComposeKey((k) => k + 1);
  };

  const closeComposer = () => {
    setComposing(null);
    setComposerExpanded(false);
    queryClient.invalidateQueries({ queryKey: ["drafts"] });
    queryClient.invalidateQueries({ queryKey: ["drafts-remote"] });
    queryClient.invalidateQueries({ queryKey: ["folder-counts"] });
  };

  // Leaving a folder closes any open composer/draft editor: the reading pane
  // should reflect the folder you navigated to, not a leftover draft editor.
  const firstView = useRef(true);
  useEffect(() => {
    if (firstView.current) {
      firstView.current = false;
      return;
    }
    closeComposer();
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [view]);

  const afterMove = () => {
    queryClient.invalidateQueries({ queryKey: ["threads"] });
    queryClient.invalidateQueries({ queryKey: ["quota"] });
    queryClient.invalidateQueries({ queryKey: ["folder-counts"] });
    navigate("/mail");
  };

  // Trigger a server-side sync of all folders; refresh the views once the worker
  // has had a moment to poll (live WebSocket events also update them).
  const doRefresh = async () => {
    setRefreshing(true);
    try {
      await api.syncNow();
    } catch {
      /* ignore */
    }
    window.setTimeout(() => {
      for (const key of ["threads", "drafts", "drafts-remote", "quota", "folder-counts"]) {
        queryClient.invalidateQueries({ queryKey: [key] });
      }
      setRefreshing(false);
    }, 2500);
  };

  const archive = async () => {
    if (!threadId) return;
    await api.archiveThread(threadId);
    afterMove();
  };

  const trash = async () => {
    if (!threadId) return;
    await api.trashThread(threadId);
    afterMove();
  };

  const restore = async () => {
    if (!threadId) return;
    await api.restoreThread(threadId);
    afterMove();
  };

  const deletePermanent = async () => {
    if (!threadId) return;
    await api.deleteThreadPermanent(threadId);
    afterMove();
  };

  const togglePin = async () => {
    const detail = detailQuery.data;
    if (!detail) return;
    await api.threadFlags(
      detail.id,
      detail.pinned ? [] : ["\\Flagged"],
      detail.pinned ? ["\\Flagged"] : [],
    );
    queryClient.invalidateQueries({ queryKey: ["threads"] });
    queryClient.invalidateQueries({ queryKey: ["search"] });
    queryClient.invalidateQueries({ queryKey: ["thread", detail.id] });
  };

  // Per-thread actions for the mail-list hover buttons (act on a given id, not the
  // currently-open thread). Close the reading pane only if the acted thread is open.
  const listAfterMove = (id: string) => {
    // In a folder the refetch below removes the row (it left the folder's scope).
    // In search the row may still match a global query, so grey it out for feedback.
    if (searching) setDimmedIds((prev) => new Set(prev).add(id));
    queryClient.invalidateQueries({ queryKey: ["threads"] });
    queryClient.invalidateQueries({ queryKey: ["search"] }); // keep search results in sync
    queryClient.invalidateQueries({ queryKey: ["quota"] });
    queryClient.invalidateQueries({ queryKey: ["folder-counts"] });
    if (id === threadId) navigate("/mail");
  };
  const listArchive = async (id: string) => {
    await api.archiveThread(id);
    listAfterMove(id);
  };
  const listTrash = async (id: string) => {
    await api.trashThread(id);
    listAfterMove(id);
  };
  const listRestore = async (id: string) => {
    await api.restoreThread(id);
    listAfterMove(id);
  };
  const listDeletePermanent = async (id: string) => {
    await api.deleteThreadPermanent(id);
    listAfterMove(id);
  };
  const listTogglePin = async (id: string, pinned: boolean) => {
    await api.threadFlags(id, pinned ? [] : ["\\Flagged"], pinned ? ["\\Flagged"] : []);
    queryClient.invalidateQueries({ queryKey: ["threads"] });
    queryClient.invalidateQueries({ queryKey: ["search"] }); // pin state on search results
    queryClient.invalidateQueries({ queryKey: ["thread", id] });
  };

  // Selection resets when you leave the folder.
  useEffect(() => setCheckedIds(new Set()), [view]);
  useEffect(() => setDimmedIds(new Set()), [view, debouncedTerm]);

  // Bulk actions run the given operation over every selected thread, then clear the
  // selection and refresh (navigating away if the open thread was among them).
  const runBulk = async (action: (id: string) => Promise<unknown>) => {
    const ids = [...checkedIds];
    for (const id of ids) {
      try {
        await action(id);
      } catch {
        /* keep going */
      }
    }
    setCheckedIds(new Set());
    queryClient.invalidateQueries({ queryKey: ["threads"] });
    queryClient.invalidateQueries({ queryKey: ["quota"] });
    queryClient.invalidateQueries({ queryKey: ["folder-counts"] });
    if (threadId && ids.includes(threadId)) navigate("/mail");
  };
  const bulkArchive = () => runBulk((id) => api.archiveThread(id));
  const bulkPin = () => runBulk((id) => api.threadFlags(id, ["\\Flagged"], []));
  const bulkTrash = () => runBulk((id) => api.trashThread(id));
  const bulkRestore = () => runBulk((id) => api.restoreThread(id));
  const bulkDeletePermanent = () => runBulk((id) => api.deleteThreadPermanent(id));

  // "Empty" a Trash/Spam/Archive folder: permanently delete everything in it. The
  // work runs in a worker; refresh the views after it and via the WS message.deleted.
  const [emptying, setEmptying] = useState(false);
  const emptyCurrentFolder = async () => {
    if (!window.confirm(t("mail.emptyConfirm"))) return;
    setEmptying(true);
    try {
      await api.emptyFolder(currentFolder);
    } catch {
      /* ignore */
    }
    navigate("/mail"); // an open thread from this folder is about to be deleted
    window.setTimeout(() => {
      queryClient.invalidateQueries({ queryKey: ["threads"] });
      queryClient.invalidateQueries({ queryKey: ["folder-counts"] });
      setEmptying(false);
    }, 1500);
  };

  const [moreOpen, setMoreOpen] = useState(false);
  const markAllRead = useMutation({
    mutationFn: () => api.markAllRead(view),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["threads"] });
      queryClient.invalidateQueries({ queryKey: ["folder-counts"] });
    },
  });

  const openRelative = (delta: number) => {
    const list = threadsRef.current;
    if (list.length === 0) return;
    const idx = list.findIndex((th) => th.id === threadId);
    const next = Math.min(Math.max((idx < 0 ? -1 : idx) + delta, 0), list.length - 1);
    navigate(`/mail/t/${list[next].id}`);
  };

  useKeyboardShortcuts({
    onSearch: () => searchRef.current?.focus(),
    onCompose: () => accountsQuery.data?.[0] && openComposer({ accountId: accountsQuery.data[0].id, kind: "new" }),
    onReply: () => setReplySignal({ kind: "reply", seq: Date.now() }),
    onReplyAll: () => setReplySignal({ kind: "reply_all", seq: Date.now() }),
    onForward: () => setReplySignal({ kind: "forward", seq: Date.now() }),
    onArchive: archive,
    onGoInbox: () => selectView("folder:inbox"),
    onEscape: () => setComposing(null),
    onNext: () => openRelative(1),
    onPrev: () => openRelative(-1),
  });

  const accounts = accountsQuery.data ?? [];

  // Deep link (e.g. Contacts "Compose"): /mail?compose=1&to=<email> opens a new,
  // maximized composer prefilled with the recipient, then strips the params.
  const [searchParams, setSearchParams] = useSearchParams();
  useEffect(() => {
    if (searchParams.get("compose") !== "1") return;
    const first = accountsQuery.data?.[0];
    if (!first) return; // wait until accounts have loaded
    openComposer({ accountId: first.id, kind: "new", to: searchParams.get("to") ?? "" }, true);
    const next = new URLSearchParams(searchParams);
    next.delete("compose");
    next.delete("to");
    setSearchParams(next, { replace: true });
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [searchParams, accountsQuery.data]);

  // Deep link (e.g. Contacts "Find all conversations"): /mail?q=<text> prefills the
  // search box (which drives the search), then strips the param.
  useEffect(() => {
    const q = searchParams.get("q");
    if (q == null) return;
    setTerm(q);
    const next = new URLSearchParams(searchParams);
    next.delete("q");
    setSearchParams(next, { replace: true });
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [searchParams]);

  // Deep link from the sidebar: /mail?label=<name> shows all mail with that label.
  useEffect(() => {
    const label = searchParams.get("label");
    if (label == null) return;
    setView(`label:${label}`);
    setPage(0);
    navigate("/mail");
    const next = new URLSearchParams(searchParams);
    next.delete("label");
    setSearchParams(next, { replace: true });
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [searchParams]);

  // Labels changed anywhere (Actions menu, sidebar +): refresh label-driven data.
  useEffect(() => {
    const onChanged = () => {
      queryClient.invalidateQueries({ queryKey: ["labels-all"] });
      queryClient.invalidateQueries({ queryKey: ["thread-labels"] });
      queryClient.invalidateQueries({ queryKey: ["message-labels"] });
      queryClient.invalidateQueries({ queryKey: ["threads"] });
    };
    window.addEventListener("webmail:labels-changed", onChanged);
    return () => window.removeEventListener("webmail:labels-changed", onChanged);
  }, [queryClient]);

  return (
    <div className="flex h-screen bg-app-bg text-app-fg">
      <BackfillBanner />
      {/* Sidebar */}
      <aside
        style={{ width: collapsed ? COLLAPSED_W : sidebarW }}
        className="flex shrink-0 flex-col border-r border-app-border bg-app-bg"
      >
        <div
          className={`flex pb-1 pt-3 ${
            collapsed ? "flex-col items-center gap-1 px-2" : "items-center justify-between px-3"
          }`}
        >
          {collapsed ? (
            <img src={signetLogo} alt="Ultimo" className="h-7 w-auto shrink-0" />
          ) : (
            <div className="flex items-center gap-2">
              <img src={signetLogo} alt="Ultimo" className="h-7 w-auto shrink-0" />
              <AppSwitcher />
            </div>
          )}
          <div className={`flex items-center gap-1 ${collapsed ? "flex-col" : ""}`}>
            <button
              onClick={() => setCollapsed((v) => !v)}
              title={collapsed ? t("nav.expandSidebar") : t("nav.collapseSidebar")}
              aria-label={collapsed ? t("nav.expandSidebar") : t("nav.collapseSidebar")}
              className="rounded p-1.5 text-app-muted hover:bg-app-hover hover:text-app-fg"
            >
              <Icon name={collapsed ? "show" : "hide"} size={16} />
            </button>
            <ThemeToggle />
          </div>
        </div>
        <div className={`pb-2 ${collapsed ? "px-2" : "px-3"}`}>
          <button
            className="flex w-full items-center justify-center gap-2 rounded-lg bg-app-accent py-2 text-[15px] font-medium text-app-accent-fg shadow-sm hover:opacity-90"
            title={collapsed ? t("nav.compose") : undefined}
            onClick={() => accounts[0] && openComposer({ accountId: accounts[0].id, kind: "new" })}
          >
            <Icon name="compose" size={16} />
            {!collapsed && t("nav.compose")}
          </button>
        </div>
        <nav className="flex-1 space-y-0.5 overflow-y-auto px-2 py-1 text-[15px]">
          {FOLDERS.map((f) => {
            const badge =
              f.view === "folder:inbox"
                ? countsQuery.data?.inbox_unread
                : f.view === "folder:drafts"
                  ? countsQuery.data?.drafts
                  : undefined;
            return (
            <SidebarItem
              key={f.view}
              active={view === f.view}
              collapsed={collapsed}
              title={collapsed ? t(f.label) : undefined}
              onClick={() => selectView(f.view)}
            >
              <Icon name={f.icon} size={f.icon === "trash" ? 20 : 18} />
              {!collapsed && <span className="flex-1 truncate">{t(f.label)}</span>}
              {!collapsed && badge ? (
                <span className="ml-auto shrink-0 tabular-nums text-[13px] text-app-muted">{badge}</span>
              ) : null}
            </SidebarItem>
            );
          })}
          {/* Per-account views are hidden entirely when collapsed. */}
          {!collapsed && (
            <>
              <div className="px-3 pb-1 pt-3 text-[12px] font-semibold uppercase tracking-wide text-app-faint">
                {t("settings.accounts")}
              </div>
              {accounts.map((a) => (
                <SidebarItem
                  key={a.id}
                  active={view === `account:${a.id}`}
                  onClick={() => selectView(`account:${a.id}`)}
                >
                  <AccountDot
                    color={a.color}
                    syncing={
                      a.state === "backfilling" &&
                      a.backfill_total > 0 &&
                      a.backfill_done < a.backfill_total
                    }
                    total={a.backfill_total}
                    done={a.backfill_done}
                  />
                  <span className="truncate">{a.email}</span>
                </SidebarItem>
              ))}
              {savedSearches.length > 0 && (
                <>
                  <div className="px-3 pb-1 pt-3 text-[12px] font-semibold uppercase tracking-wide text-app-faint">
                    {t("search.saved")}
                  </div>
                  {savedSearches.map((s) => (
                    <div key={s.id} className="group/saved relative">
                      <SidebarItem
                        active={searching && debouncedTerm === s.query}
                        onClick={() => runSavedSearch(s)}
                      >
                        <svg width="16" height="16" viewBox="0 0 16 16" fill="none" stroke="currentColor" strokeWidth="1.4" strokeLinecap="round" strokeLinejoin="round" className="shrink-0">
                          <circle cx="7" cy="7" r="4.5" />
                          <path d="M10.5 10.5L14 14" />
                        </svg>
                        <span className="flex-1 truncate">{s.name}</span>
                      </SidebarItem>
                      <button
                        type="button"
                        title={t("common.delete")}
                        aria-label={t("common.delete")}
                        onClick={(e) => {
                          e.stopPropagation();
                          deleteSaved.mutate(s.id);
                        }}
                        className="absolute right-2 top-1/2 hidden -translate-y-1/2 rounded p-1 text-app-faint hover:bg-app-hover hover:text-app-fg group-hover/saved:block"
                      >
                        <svg width="13" height="13" viewBox="0 0 16 16" fill="none" stroke="currentColor" strokeWidth="1.6" strokeLinecap="round">
                          <path d="M4 4l8 8M12 4l-8 8" />
                        </svg>
                      </button>
                    </div>
                  ))}
                </>
              )}
            </>
          )}
          {/* Plugin-contributed sidebar sections (SPEC §11.3 sidebar.section). */}
          {!collapsed && <PluginSlot name="sidebar.section" />}
        </nav>
        <div className="border-t border-app-border p-2 text-[15px]">
          <Link
            className={`flex items-center gap-2.5 rounded-lg py-2 text-app-muted hover:bg-app-hover hover:text-app-fg ${
              collapsed ? "justify-center px-0" : "px-3"
            }`}
            title={collapsed ? t("nav.settings") : undefined}
            to="/settings"
          >
            <Icon name="settings" size={22} />
            {!collapsed && t("nav.settings")}
          </Link>
          <button
            className={`flex w-full items-center gap-2.5 rounded-lg py-2 text-left text-app-muted hover:bg-app-hover hover:text-app-fg ${
              collapsed ? "justify-center px-0" : "px-3"
            }`}
            title={collapsed ? t("common.signOut") : undefined}
            onClick={async () => {
              await api.logout();
              queryClient.clear();
              navigate("/login");
            }}
          >
            <Icon name="log-out" size={16} />
            {!collapsed && t("common.signOut")}
          </button>
          {!collapsed && quotaQuery.data && (
            <div
              className="mt-1 border-t border-app-border px-3 pb-1 pt-2 text-[13px] text-app-faint"
              title={t("nav.storageQuota")}
            >
              {quotaLabel(quotaQuery.data)}
            </div>
          )}
        </div>
      </aside>

      {!collapsed && <Resizer onDelta={(dx) => setSidebarW((w) => clampSidebar(w + dx))} />}

      {/* Message list */}
      <div
        style={{ width: listW }}
        className="flex shrink-0 flex-col border-r border-app-border bg-app-surface"
      >
        <div className="flex h-[52px] shrink-0 items-center border-b border-app-border px-6">
          <div className="relative w-full">
            <input
              ref={searchRef}
              className={`w-full rounded-lg border border-app-border bg-app-bg px-3 py-1.5 text-[15px] text-app-fg placeholder:text-app-faint focus:border-app-accent focus:outline-none ${
                term ? "pr-14" : "pr-8"
              }`}
              placeholder={
                currentFolder === "trash"
                  ? t("nav.searchInTrash")
                  : currentFolder === "junk"
                    ? t("nav.searchInSpam")
                    : t("nav.search")
              }
              value={term}
              onChange={(e) => setTerm(e.target.value)}
            />
            {term && (
              <>
                <button
                  type="button"
                  title={t("search.save")}
                  aria-label={t("search.save")}
                  onClick={onSaveSearch}
                  className="absolute right-8 top-1/2 -translate-y-1/2 rounded p-1 text-app-faint hover:bg-app-hover hover:text-app-accent"
                >
                  <svg width="15" height="15" viewBox="0 0 16 16" fill="none" stroke="currentColor" strokeWidth="1.4" strokeLinecap="round" strokeLinejoin="round">
                    <path d="M4 2.5h8v11l-4-2.6-4 2.6z" />
                  </svg>
                </button>
                <button
                  type="button"
                  title={t("common.clear")}
                  aria-label={t("common.clear")}
                  onClick={() => {
                    setTerm("");
                    searchRef.current?.focus();
                  }}
                  className="absolute right-1.5 top-1/2 -translate-y-1/2 rounded p-1 text-app-faint hover:bg-app-hover hover:text-app-fg"
                >
                  <svg width="14" height="14" viewBox="0 0 16 16" fill="none" stroke="currentColor" strokeWidth="1.6" strokeLinecap="round">
                    <path d="M4 4l8 8M12 4l-8 8" />
                  </svg>
                </button>
              </>
            )}
          </div>
        </div>
        {!isDrafts && (
          <div className="flex h-[52px] shrink-0 items-center gap-5 border-b border-app-border bg-app-bg px-6 text-[15px]">
            <button
              type="button"
              aria-label={t("mail.selectAll")}
              title={t("mail.selectAll")}
              onClick={toggleSelectAll}
              className={`ml-[28px] flex h-[17px] w-[17px] shrink-0 items-center justify-center rounded-md border-2 transition-colors ${
                allSelected || someSelected
                  ? "border-app-accent bg-app-accent text-white"
                  : "border-app-faint hover:border-app-muted"
              }`}
            >
              {allSelected ? (
                <svg width="11" height="11" viewBox="0 0 16 16" fill="none" stroke="currentColor" strokeWidth="2.6" strokeLinecap="round" strokeLinejoin="round">
                  <path d="M3.5 8.5l3 3 6-7" />
                </svg>
              ) : someSelected ? (
                <svg width="11" height="11" viewBox="0 0 16 16" fill="none" stroke="currentColor" strokeWidth="2.6" strokeLinecap="round">
                  <path d="M4 8h8" />
                </svg>
              ) : null}
            </button>
            {labelView !== null ? (
              <span className="flex items-center gap-1.5 rounded bg-app-hover px-2 py-0.5 text-[13px] text-app-fg">
                <svg width="13" height="13" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="1.7" strokeLinecap="round" strokeLinejoin="round"><path d="M20.6 13.4l-7.1 7.1a2 2 0 0 1-2.83 0l-6.17-6.17A2 2 0 0 1 3 12.93V5a2 2 0 0 1 2-2h7.93a2 2 0 0 1 1.4.59l6.17 6.17a2 2 0 0 1 0 2.83z" /><circle cx="7.5" cy="7.5" r="1.2" fill="currentColor" stroke="none" /></svg>
                {labelView}
                <button className="text-app-muted hover:text-app-fg" title={t("common.close")} onClick={() => selectView("folder:inbox")}>✕</button>
              </span>
            ) : (
              <>
                <FilterTab active={filter === "all"} onClick={() => setFilter("all")}>
                  {t("filter.all")}
                </FilterTab>
                <FilterTab active={filter === "unread"} onClick={() => setFilter("unread")}>
                  {t("filter.unread")}
                </FilterTab>
                <FilterTab active={filter === "pinned"} onClick={() => setFilter("pinned")}>
                  {t("filter.pinned")}
                </FilterTab>
              </>
            )}
            <div className="-mr-1.5 ml-auto flex items-center gap-1">
              {(currentFolder === "trash" || currentFolder === "junk") && (
                <button
                  className="rounded px-2 py-1 text-[13px] font-medium text-red-500 hover:bg-app-hover disabled:opacity-50"
                  onClick={emptyCurrentFolder}
                  disabled={emptying}
                >
                  {currentFolder === "trash" ? t("mail.emptyTrash") : t("mail.emptySpam")}
                </button>
              )}
              <button
                className="rounded p-1.5 text-app-muted hover:bg-app-hover hover:text-app-fg"
                title={listOrder === "newest" ? t("filter.sortOldest") : t("filter.sortNewest")}
                aria-label={listOrder === "newest" ? t("filter.sortOldest") : t("filter.sortNewest")}
                onClick={() => setListOrder((o) => (o === "newest" ? "oldest" : "newest"))}
              >
                <SortIcon />
              </button>
              <div className="relative">
                <button
                  className="rounded p-1.5 text-app-muted hover:bg-app-hover hover:text-app-fg"
                  title={t("mail.more")}
                  aria-label={t("mail.more")}
                  onClick={() => setMoreOpen((o) => !o)}
                >
                  <svg width="18" height="18" viewBox="0 0 24 24" fill="currentColor" aria-hidden>
                    <circle cx="5" cy="12" r="1.6" />
                    <circle cx="12" cy="12" r="1.6" />
                    <circle cx="19" cy="12" r="1.6" />
                  </svg>
                </button>
                {moreOpen && (
                  <>
                    <div className="fixed inset-0 z-10" onClick={() => setMoreOpen(false)} />
                    <div className="absolute right-0 z-20 mt-1 min-w-[180px] rounded-lg border border-app-border bg-app-surface py-1 shadow-lg">
                      <button
                        className="flex w-full items-center px-3 py-2 text-left text-[13px] text-app-fg hover:bg-app-hover disabled:opacity-50"
                        disabled={markAllRead.isPending}
                        onClick={() => {
                          setMoreOpen(false);
                          markAllRead.mutate();
                        }}
                      >
                        {t("mail.markAllRead")}
                      </button>
                    </div>
                  </>
                )}
              </div>
            </div>
          </div>
        )}
        <div className="min-h-0 flex-1">
          {isDrafts && !term.trim() ? (
            <DraftsList
              drafts={draftsQuery.data ?? []}
              remoteDrafts={remoteDraftsQuery.data ?? []}
              onOpen={(draft) => openComposer(draftToInit(draft), true)}
              onOpenRemote={async (remote) => {
                // Adopt the server draft into an editable local draft, then open it.
                const draft = await api.adoptDraft(remote.message_id);
                queryClient.invalidateQueries({ queryKey: ["drafts"] });
                queryClient.invalidateQueries({ queryKey: ["drafts-remote"] });
                openComposer(draftToInit(draft), true);
              }}
            />
          ) : (
            <MessageList
              threads={pageThreads}
              selectedId={threadId}
              folder={currentFolder}
              onSelect={(id) => navigate(`/mail/t/${id}`)}
              onArchive={listArchive}
              onRestore={listRestore}
              onTrash={listTrash}
              onDeletePermanent={listDeletePermanent}
              onTogglePin={listTogglePin}
              checkedIds={checkedIds}
              dimmedIds={dimmedIds}
              onToggleCheck={toggleCheck}
            />
          )}
        </div>
        <div className="flex items-center justify-between border-t border-app-border px-6 py-1.5 text-[13px] text-app-muted">
          <button
            className="-ml-1 rounded p-1 text-app-muted hover:bg-app-hover hover:text-app-fg disabled:opacity-60"
            title={t("nav.refresh")}
            aria-label={t("nav.refresh")}
            onClick={doRefresh}
            disabled={refreshing}
          >
            <RefreshIcon spinning={refreshing} />
          </button>
          {!isDrafts && total > 0 ? (
            <div className="flex items-center gap-3">
              <span>
                {pageStart + 1}–{pageEnd} of {total}
              </span>
              <div className="-mr-1 flex items-center gap-0.5">
                <PagerButton
                  disabled={page === 0}
                  onClick={() => setPage(page - 1)}
                  label={t("pager.prev")}
                  dir="left"
                />
                <PagerButton
                  disabled={pageEnd >= total}
                  onClick={() => setPage(page + 1)}
                  label={t("pager.next")}
                  dir="right"
                />
              </div>
            </div>
          ) : (
            <span />
          )}
        </div>
      </div>

      <Resizer onDelta={(dx) => setListW((w) => clampList(w + dx))} />

      {/* Thread pane */}
      <main className="relative min-w-0 flex-1 bg-app-surface">
        {checkedIds.size > 0 ? (
          <div className="flex h-full flex-col">
            <div className="flex h-[52px] shrink-0 items-center gap-1 border-b border-app-border bg-app-surface px-3 text-[15px]">
              {currentFolder === "archive" ||
              currentFolder === "trash" ||
              currentFolder === "junk" ? (
                <>
                  <ToolbarButton onClick={bulkRestore}>
                    <Icon name="restore" size={16} />
                    {t("mail.restore")}
                  </ToolbarButton>
                  <ToolbarButton
                    onClick={currentFolder === "trash" ? bulkDeletePermanent : bulkTrash}
                  >
                    <Icon name="trash" size={16} />
                    {t("mail.delete")}
                  </ToolbarButton>
                </>
              ) : (
                <>
                  <ToolbarButton onClick={bulkArchive}>
                    <Icon name="archive" size={16} />
                    {t("mail.archive")}
                  </ToolbarButton>
                  <ToolbarButton onClick={bulkPin}>
                    <Icon name="pin" size={16} />
                    {t("mail.pin")}
                  </ToolbarButton>
                  <ToolbarButton onClick={bulkTrash}>
                    <Icon name="trash" size={16} />
                    {t("mail.delete")}
                  </ToolbarButton>
                </>
              )}
            </div>
            <div className="flex flex-1 items-center justify-center text-3xl text-app-faint">
              {checkedIds.size === 1
                ? t("mail.conversationSelected")
                : t("mail.conversationsSelected", { count: checkedIds.size })}
            </div>
          </div>
        ) : threadId && detailQuery.data ? (
          <div className="flex h-full flex-col">
            <div className="flex h-[52px] shrink-0 items-center gap-1 border-b border-app-border bg-app-surface px-3 text-[15px]">
              {currentFolder === "archive" ? (
                <>
                  <ToolbarButton onClick={restore}>
                    <Icon name="inbox" size={16} />
                    {t("mail.restore")}
                  </ToolbarButton>
                  <ToolbarButton onClick={trash}>
                    <Icon name="trash" size={16} />
                    {t("mail.delete")}
                  </ToolbarButton>
                </>
              ) : currentFolder === "trash" ? (
                <>
                  <ToolbarButton onClick={restore}>
                    <Icon name="inbox" size={16} />
                    {t("mail.restore")}
                  </ToolbarButton>
                  <ToolbarButton onClick={deletePermanent}>
                    <Icon name="trash" size={16} />
                    {t("mail.delete")}
                  </ToolbarButton>
                </>
              ) : (
                <>
                  <ToolbarButton onClick={archive}>
                    <Icon name="archive" size={16} />
                    {t("mail.archive")}
                  </ToolbarButton>
                  <ToolbarButton onClick={togglePin} active={detailQuery.data.pinned}>
                    <Icon
                      name="pin"
                      size={16}
                      className={detailQuery.data.pinned ? "text-[rgb(220_129_143)]" : ""}
                    />
                    {detailQuery.data.pinned ? t("mail.unpin") : t("mail.pin")}
                  </ToolbarButton>
                  <ToolbarButton onClick={trash}>
                    <Icon name="trash" size={16} />
                    {t("mail.delete")}
                  </ToolbarButton>
                </>
              )}
              <span className="ml-auto text-[13px] text-app-faint">
                {t("mail.messageCount", { count: detailQuery.data.messages.length })}
              </span>
              <button
                className={`rounded p-1.5 hover:bg-app-hover hover:text-app-fg ${rightOpen ? "text-app-fg" : "text-app-muted"}`}
                title={t("panel.toggle")}
                aria-label={t("panel.toggle")}
                aria-pressed={rightOpen}
                onClick={() => (rightOpen ? setRightOpen(false) : openPanel(rightTab))}
              >
                <svg width="17" height="17" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="1.7" strokeLinecap="round" strokeLinejoin="round" aria-hidden>
                  <rect x="3" y="4" width="18" height="16" rx="2" />
                  <path d="M15 4v16" />
                </svg>
              </button>
            </div>
            <div className="min-h-0 flex-1 overflow-hidden">
              <ThreadView
                subject={detailQuery.data.subject}
                messages={detailQuery.data.messages}
                order={detailQuery.data.order}
                mailboxes={mailboxesQuery.data ?? []}
                accounts={accounts}
                replyKindSignal={replySignal}
              />
            </div>
          </div>
        ) : (
          <div className="flex h-full flex-col items-center justify-center gap-6 text-app-faint">
            {!rightOpen && (
              <button
                className="absolute right-3 top-3 rounded p-1.5 text-app-muted hover:bg-app-hover hover:text-app-fg"
                title={t("panel.toggle")}
                aria-label={t("panel.toggle")}
                onClick={() => openPanel(rightTab)}
              >
                <svg width="17" height="17" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="1.7" strokeLinecap="round" strokeLinejoin="round" aria-hidden>
                  <rect x="3" y="4" width="18" height="16" rx="2" />
                  <path d="M15 4v16" />
                </svg>
              </button>
            )}
            <EmptyIllustration className="w-56 max-w-[55%]" />
            <span className="text-3xl">{t("mail.selectConversation")}</span>
          </div>
        )}

        {composing && (
          <div
            className={
              composerExpanded
                ? "absolute inset-0 z-30"
                : "absolute bottom-0 right-4 z-30 w-[47.5rem] max-w-[calc(100%-2rem)]"
            }
          >
            <Composer
              key={composeKey}
              init={composing}
              expanded={composerExpanded}
              onToggleExpand={() => setComposerExpanded((v) => !v)}
              onClose={closeComposer}
            />
          </div>
        )}
      </main>
      {rightOpen && (
        <>
          <Resizer onDelta={(dx) => setRightW((w) => clampRight(w - dx))} />
          <div style={{ width: rightW }} className="shrink-0 border-l border-app-border">
            <RightPanel tab={rightTab} onTab={setRightTab} onClose={() => setRightOpen(false)} thread={detailQuery.data} />
          </div>
        </>
      )}
    </div>
  );
}

// Account bullet in the sidebar. While the account is backfilling it becomes a
// spinning ring that fills with the account colour to show import progress
// (SPEC §12 M2); once live it's the plain colour-filled dot.
function AccountDot({
  color,
  syncing,
  total,
  done,
}: {
  color: string;
  syncing: boolean;
  total: number;
  done: number;
}) {
  if (!syncing) {
    return (
      <span className="h-2.5 w-2.5 shrink-0 rounded-full" style={{ backgroundColor: color }} />
    );
  }
  const pct = total > 0 ? Math.min(100, Math.round((done / Math.max(done, total)) * 100)) : 0;
  const ring = "rgba(128,128,128,0.35)";
  return (
    <span
      className="h-3.5 w-3.5 shrink-0 animate-spin rounded-full"
      style={{
        animationDuration: "1.1s",
        background: `conic-gradient(${color} ${pct}%, ${ring} ${pct}% 100%)`,
        // Punch out the centre to leave a ~3px ring.
        WebkitMask: "radial-gradient(farthest-side, transparent calc(100% - 3px), #000 0)",
        mask: "radial-gradient(farthest-side, transparent calc(100% - 3px), #000 0)",
      }}
      title={`${pct}%`}
    />
  );
}

function FilterTab({
  active,
  onClick,
  children,
}: {
  active: boolean;
  onClick: () => void;
  children: React.ReactNode;
}) {
  return (
    <button
      onClick={onClick}
      className={`flex h-full items-center border-b-2 ${
        active
          ? "border-app-accent font-semibold text-app-fg"
          : "border-transparent text-app-muted hover:text-app-fg"
      }`}
    >
      {children}
    </button>
  );
}

function PagerButton({
  disabled,
  onClick,
  label,
  dir,
}: {
  disabled: boolean;
  onClick: () => void;
  label: string;
  dir: "left" | "right";
}) {
  return (
    <button
      disabled={disabled}
      onClick={onClick}
      title={label}
      aria-label={label}
      className="rounded p-1 text-app-muted hover:bg-app-hover hover:text-app-fg disabled:pointer-events-none disabled:text-app-faint disabled:opacity-40"
    >
      <svg width="14" height="14" viewBox="0 0 16 16" fill="none" stroke="currentColor" strokeWidth="1.6" strokeLinecap="round" strokeLinejoin="round" aria-hidden>
        <path d={dir === "left" ? "M10 4l-4 4 4 4" : "M6 4l4 4-4 4"} />
      </svg>
    </button>
  );
}

function RefreshIcon({ spinning }: { spinning: boolean }) {
  return (
    <svg
      width="15"
      height="15"
      viewBox="0 0 16 16"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.4"
      strokeLinecap="round"
      strokeLinejoin="round"
      aria-hidden
      className={spinning ? "animate-spin" : ""}
    >
      <path d="M13.5 8a5.5 5.5 0 1 1-1.6-3.9" />
      <path d="M13.5 2v3h-3" />
    </svg>
  );
}

function SortIcon() {
  return (
    <svg
      width="16"
      height="16"
      viewBox="0 0 16 16"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.4"
      strokeLinecap="round"
      strokeLinejoin="round"
      aria-hidden
    >
      <path d="M5 3v10M3 5l2-2 2 2M11 13V3M9 11l2 2 2-2" />
    </svg>
  );
}

function SidebarItem({
  active,
  onClick,
  collapsed = false,
  title,
  children,
}: {
  active: boolean;
  onClick: () => void;
  collapsed?: boolean;
  title?: string;
  children: React.ReactNode;
}) {
  return (
    <button
      onClick={onClick}
      title={title}
      className={`flex w-full items-center gap-2.5 rounded-lg py-1.5 text-left ${
        collapsed ? "justify-center px-0" : "px-3"
      } ${
        active ? "bg-app-active font-medium text-app-fg" : "text-app-muted hover:bg-app-hover hover:text-app-fg"
      }`}
    >
      {children}
    </button>
  );
}

function ToolbarButton({
  onClick,
  active = false,
  children,
}: {
  onClick: () => void;
  active?: boolean;
  children: React.ReactNode;
}) {
  return (
    <button
      className={`flex items-center gap-1.5 rounded px-2.5 py-1 hover:bg-app-hover hover:text-app-fg ${
        active ? "text-app-fg" : "text-app-muted"
      }`}
      onClick={onClick}
    >
      {children}
    </button>
  );
}