import { useEffect, useId, useRef, useState } from "react";
import { useTranslation } from "react-i18next";
import { useQuery } from "@tanstack/react-query";
import { ChevronDown, Film, Tv } from "lucide-react";
import SearchBar from "./SearchBar";
import ActionMenu from "./ui/ActionMenu";
import { usePlex, usePlexActions } from "./plexContext";
import { api } from "../lib/api";
import { qk } from "../lib/queryKeys";
import { useDebounced } from "../lib/useDebounced";
import { availablePlexFields, healPlexField, plexFieldLabelKey } from "../lib/plexSearch";
import { Pressable } from "./ui/Pressable";
import { SURFACE } from "./ui/surfaces";
import { ROVING_HIGHLIGHT } from "./ui/AnchoredPopover";
import { cardImage } from "../lib/plexImage";
import RemoteImage from "./ui/RemoteImage";

// The Plex header search box: the shared SearchBar enriched with the search scope-pill (a
// GitHub-style field selector inside the box) and an instant typeahead of the top matches attached
// below it. Kept out of the generic SearchBar (and out of Header) so all Plex-specific wiring —
// provider state, the suggest query, the jump-to hand-off — lives in one place. Everything reuses
// existing platform pieces: ActionMenu (the pill), the /api/plex/library endpoint (limit=10 for the
// typeahead), and the provider's jumpTo hand-off (typeahead → PlexBrowse subview).
const MIN_CHARS = 2;
const SUGGEST_LIMIT = 10;

export default function PlexSearchBox() {
  const { t } = useTranslation();
  const { q, scope, field } = usePlex();
  const { setQ, setField, setJumpTo } = usePlexActions();
  const activeField = healPlexField(field, scope);
  const dq = useDebounced(q.trim(), 200);
  // `focused` mirrors the input's real DOM focus (only onFocus/onBlur touch it). `dismissed` is the
  // separate "the user closed the panel" flag (Escape / after a pick) — kept apart so closing the
  // panel never desyncs from actual focus: typing again clears `dismissed` and the panel re-opens
  // without needing a blur+refocus cycle.
  const [focused, setFocused] = useState(false);
  const [dismissed, setDismissed] = useState(false);
  const [hi, setHi] = useState(-1); // highlighted suggestion index (-1 = none)
  const listRef = useRef<HTMLDivElement>(null);
  const listId = useId();

  // The Episode scope surfaces episodes in the grid's grouped section, not as title cards, so the
  // titles-only typeahead has nothing to show there — suppress it rather than show "no results".
  const suggestEnabled =
    focused && !dismissed && dq.length >= MIN_CHARS && activeField !== "episode";
  const suggestQ = useQuery({
    queryKey: qk.plexSuggest(scope, dq, activeField),
    enabled: suggestEnabled,
    queryFn: () => api.plexLibrary({ scope, q: dq, field: activeField, limit: SUGGEST_LIMIT }),
    staleTime: 30_000,
  });
  const suggestions = suggestEnabled ? (suggestQ.data?.items ?? []) : [];
  const open = suggestEnabled && (suggestQ.isFetching || suggestions.length > 0);

  // A fresh query resets the highlight — during THAT render, so no frame ever draws the new
  // suggestion list with the old row highlighted.
  const suggestKey = `${scope}|${activeField}|${dq}`;
  const [hiFor, setHiFor] = useState(suggestKey);
  if (hiFor !== suggestKey) {
    setHiFor(suggestKey);
    setHi(-1);
  }
  // Keep the highlighted option scrolled into view during arrow-key navigation.
  useEffect(() => {
    if (hi < 0) return;
    listRef.current?.querySelector(`[data-idx="${hi}"]`)?.scrollIntoView({ block: "nearest" });
  }, [hi]);

  const pick = (i: number) => {
    const c = suggestions[i];
    if (!c) return;
    setJumpTo({ id: c.id, type: c.type === "show" ? "show" : "movie" });
    setDismissed(true); // close the panel; typing again re-opens it (see `dismissed`)
    setHi(-1);
  };

  const fields = availablePlexFields(scope);
  const pillLabel = t(plexFieldLabelKey(activeField));
  // Only reference an option while the listbox is actually open — a dangling aria-activedescendant
  // on a collapsed combobox is an inconsistent a11y state.
  const activeOptionId = open && hi >= 0 ? `${listId}-opt-${hi}` : undefined;

  return (
    <SearchBar
      value={q}
      placeholder={t("plex.searchPlaceholder")}
      // Typing after a dismiss (Escape / pick) re-opens the panel.
      onChange={(v) => {
        setDismissed(false);
        setQ(v);
      }}
      onFocus={() => {
        setFocused(true);
        setDismissed(false);
      }}
      onBlur={() => setFocused(false)}
      onKeyDown={(e) => {
        if (!open) return;
        if (e.key === "ArrowDown") {
          e.preventDefault();
          setHi((h) => Math.min(h + 1, suggestions.length - 1));
        } else if (e.key === "ArrowUp") {
          e.preventDefault();
          setHi((h) => Math.max(h - 1, -1));
        } else if (e.key === "Enter" && hi >= 0) {
          e.preventDefault(); // suppress SearchBar's Go; open the highlighted title instead
          pick(hi);
        } else if (e.key === "Escape") {
          e.preventDefault(); // close the panel only; SearchBar's Escape-to-blur waits for the next press
          setDismissed(true);
          setHi(-1); // don't leave a stale highlight to flash on the next reopen
        }
      }}
      inputProps={{
        role: "combobox",
        "aria-autocomplete": "list",
        "aria-expanded": open,
        "aria-controls": open ? listId : undefined,
        "aria-activedescendant": activeOptionId,
      }}
      leading={
        <ActionMenu
          ariaLabel={t("plex.searchField.aria")}
          className="min-w-0 shrink inline-flex items-center gap-1 rounded-full px-2 h-7 text-xs font-medium text-muted transition state-layer hover:text-fg touch-target"
          trigger={
            <>
              <span className="min-w-0 max-w-28 truncate">{pillLabel}</span>
              <ChevronDown className="w-3 h-3 shrink-0" aria-hidden="true" />
            </>
          }
          items={fields.map((f) => ({
            id: f,
            label: t(plexFieldLabelKey(f)),
            onSelect: () => setField(f),
          }))}
        />
      }
      below={
        open ? (
          <div
            className={`${SURFACE.menu} absolute left-0 right-0 top-full z-menu mt-2 max-h-[70dvh] overflow-y-auto animate-[popIn_0.16s_ease]`}
          >
            {/* Beside the listbox, not in it: a listbox may own options only. */}
            {suggestions.length === 0 && suggestQ.isFetching && (
              <div className="px-3 py-2 text-sm text-muted">{t("plex.loading")}</div>
            )}
            <div ref={listRef} id={listId} role="listbox" aria-label={t("plex.suggest.aria")}>
              {suggestions.map((c, i) => (
                <Pressable
                  key={c.id}
                  id={`${listId}-opt-${i}`}
                  data-idx={i}
                  role="option"
                  aria-selected={hi === i}
                  onMouseDown={(e) => e.preventDefault()} // keep input focus through the click
                  onMouseEnter={() => setHi(i)}
                  onClick={() => pick(i)}
                  // The pointer moves `hi` too, so the highlight IS the hover: the menus' roving
                  // recipe (AnchoredPopover's ROVING_HIGHLIGHT), one look for the mouse and the keys.
                  data-active={hi === i ? "true" : undefined}
                  className={`flex w-full items-center gap-3 rounded-lg p-1.5 transition ${ROVING_HIGHLIGHT}`}
                >
                  <RemoteImage
                    {...cardImage(c.thumb)}
                    alt=""
                    loading="lazy"
                    className="h-12 w-8 shrink-0 rounded-md object-cover bg-border/40"
                  />
                  <span className="min-w-0 flex-1 truncate text-sm">{c.title}</span>
                  {c.year != null && (
                    <span className="shrink-0 text-xs text-muted tabular-nums">{c.year}</span>
                  )}
                  {c.type === "show" ? (
                    <Tv className="w-3.5 h-3.5 shrink-0 text-muted" aria-hidden="true" />
                  ) : (
                    <Film className="w-3.5 h-3.5 shrink-0 text-muted" aria-hidden="true" />
                  )}
                </Pressable>
              ))}
            </div>
          </div>
        ) : null
      }
    />
  );
}