import { useState } from "react";
import { useTranslation } from "react-i18next";
import { useQuery, useQueryClient } from "@tanstack/react-query";
import { Play, Shuffle, Pencil, Trash2, Plus, X, Lock, Check, Search } from "lucide-react";
import { qk } from "../lib/queryKeys";
import { api, isIntrinsicReadOnly, type PlexCard, type PlexCollectionDetail } from "../lib/api";
import { formatRuntime } from "../lib/format";
import { notifyActionError, notifyCollectionEditError } from "../lib/actionErrors";
import { useConfirm } from "./ConfirmProvider";
import { BackBtn, ActionBtn, DetailHero } from "../lib/plexDetailUi";
import { PlexPosterCard } from "./plexCards";
import PlexLibraryPicker from "./PlexLibraryPicker";
import { toggleWatchState } from "../lib/plexWatch";
import { LoadingState, StateMessage } from "./QueryState";

// The Collection info page (ask B): a hero (art/title/cert/year-range/count/runtime/summary) + the
// ordered member grid, a Play-all / Shuffle over the playable leaves, and — for a NON-external,
// admin-enabled collection — rename / delete / add / remove, all write-through to Plex (the mutation
// endpoints round-trip to Plex, so each edit awaits and re-fetches; no optimism). Read-only ones (smart
// / imdb / tmdb / … auto-lists) are marked with a lock.
function shuffled(a: string[]): string[] {
  const r = [...a];
  for (let i = r.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    const tmp = r[i]!;
    r[i] = r[j]!;
    r[j] = tmp;
  }
  return r;
}

export default function PlexCollectionView({
  collectionId,
  onBack,
  onPlay,
  onOpenCard,
  onInfoCard,
}: {
  collectionId: string;
  onBack: () => void;
  onPlay: (rk: string, queue: string[]) => void;
  onOpenCard: (card: PlexCard) => void;
  onInfoCard: (card: PlexCard) => void;
}) {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const confirm = useConfirm();
  const isAdmin = qc.getQueryData<{ role?: string }>(qk.me())?.role === "admin";
  const q = useQuery({
    queryKey: qk.plexCollections("detail", collectionId),
    queryFn: () => api.plexCollection(collectionId),
  });
  const d = q.data;

  const [expanded, setExpanded] = useState(false);
  const [renaming, setRenaming] = useState(false);
  const [name, setName] = useState("");
  const [adding, setAdding] = useState(false);
  const [busy, setBusy] = useState(false);
  // Building the play queue can await show → episode expansion (see buildQueue); disable Play/Shuffle
  // meanwhile so a double-tap can't fire two queues.
  const [queueBusy, setQueueBusy] = useState(false);

  const invalidate = () => {
    qc.invalidateQueries({ queryKey: qk.plexCollections() });
    qc.invalidateQueries({ queryKey: qk.plexLibrary() });
  };

  const items = d?.items ?? [];
  // Movies/episodes are playable leaves that queue as themselves; a show can't queue directly, so
  // Play-all expands it into its episodes (buildQueue). Either kind means there's something to play —
  // this is what a show-collection needs: before, `playable` held only leaves, so a show-collection's
  // Play-all was empty and did nothing.
  const leafKeys = items.filter((c) => c.type !== "show").map((c) => c.id);
  const hasShows = items.some((c) => c.type === "show");
  const canPlay = leafKeys.length > 0 || hasShows;

  // Build the ordered play queue: leaf members as themselves, each show member expanded into its
  // episodes (season then episode order). Shows are fetched lazily HERE (on Play-all/Shuffle click),
  // in parallel, but concatenated in member order so the queue follows the grid — not on page load,
  // which would fetch every show up front for a button that may never be pressed.
  async function buildQueue(): Promise<string[]> {
    const perMember = await Promise.all(
      items.map(async (c) => {
        if (c.type !== "show") return [c.id];
        const detail = await qc.fetchQuery({
          queryKey: qk.plexShow(c.id),
          queryFn: () => api.plexShow(c.id),
        });
        return detail.seasons.flatMap((s) => s.episodes.map((e) => e.id));
      }),
    );
    return perMember.flat();
  }

  async function playAll(shuffle: boolean) {
    setQueueBusy(true);
    try {
      let queue = await buildQueue();
      if (shuffle) queue = shuffled(queue);
      if (queue.length > 0) onPlay(queue[0]!, queue);
    } catch (e) {
      notifyActionError(e, t("plex.collection.playFailed"));
    } finally {
      setQueueBusy(false);
    }
  }

  const canEdit = isAdmin && !!d?.can_edit;
  // A plain (non-smart, non-external) collection can be admin-enabled for editing. Shares
  // isIntrinsicReadOnly with the browse tile so the lock/edit affordance can't drift between them.
  const canEnableEdit = isAdmin && !d?.can_edit && !d?.editable && !!d && !isIntrinsicReadOnly(d);
  const readOnly = !d?.can_edit && !canEnableEdit; // external / smart auto-list

  const toggleWatched = (card: PlexCard) =>
    toggleWatchState(card, t, {
      optimistic: (next) => {
        qc.setQueryData<PlexCollectionDetail>(qk.plexCollections("detail", collectionId), (old) =>
          old
            ? {
                ...old,
                items: old.items.map((c) => (c.id === card.id ? { ...c, status: next } : c)),
              }
            : old,
        );
      },
      resync: () => qc.invalidateQueries({ queryKey: qk.plexLibrary() }),
    });

  async function doRename() {
    const title = name.trim();
    if (!title || !d || title === d.title) {
      setRenaming(false);
      return;
    }
    setBusy(true);
    try {
      await api.plexRenameCollection(collectionId, title);
      invalidate();
      setRenaming(false);
    } catch (e) {
      // The backend enforces per-library name uniqueness — localize its 409 to nameTaken.
      notifyCollectionEditError(e, t("plex.collection.editFailed"), t("plex.collection.nameTaken"));
    } finally {
      setBusy(false);
    }
  }

  async function doDelete() {
    if (!d) return;
    if (!(await confirm({ message: t("plex.collection.deleteConfirm", { title: d.title }) })))
      return;
    setBusy(true);
    try {
      await api.plexDeleteCollection(collectionId);
      invalidate();
      onBack();
    } catch (e) {
      notifyActionError(e, t("plex.collection.editFailed"));
      setBusy(false);
    }
  }

  async function doRemove(card: PlexCard) {
    // Write-through to the shared Plex library — confirm first, matching the delete-collection guard.
    if (!(await confirm({ message: t("plex.collection.removeConfirm", { title: card.title }) })))
      return;
    setBusy(true);
    try {
      await api.plexCollectionRemoveItem(collectionId, card.id);
      invalidate();
    } catch (e) {
      notifyActionError(e, t("plex.collection.editFailed"));
    } finally {
      setBusy(false);
    }
  }

  async function enableEdit() {
    setBusy(true);
    try {
      await api.plexSetCollectionEditable(collectionId, true);
      invalidate();
    } catch (e) {
      notifyActionError(e, t("plex.collection.editFailed"));
    } finally {
      setBusy(false);
    }
  }

  const meta = [
    d?.year_min != null &&
      (d.year_max && d.year_max !== d.year_min ? `${d.year_min} — ${d.year_max}` : `${d.year_min}`),
    d?.content_rating,
    d && t("plex.browse.items", { count: d.child_count ?? items.length }),
    formatRuntime(d?.total_runtime_s),
  ].filter(Boolean) as string[];

  return (
    <div className="glass-media mx-auto max-w-[1200px] p-4">
      <BackBtn onBack={onBack} label={t("plex.backToLibrary")} />

      {q.isError && !q.data ? (
        <StateMessage tone="error" onRetry={() => q.refetch()}>
          {t("common.loadError")}
        </StateMessage>
      ) : q.isLoading || !d ? (
        <LoadingState label={t("plex.loading")} />
      ) : (
        <>
          <DetailHero
            thumb={d.thumb ?? `/api/plex/image/${d.id}`}
            posterTitle={t("plex.play")}
            posterDisabled={!canPlay || queueBusy}
            showPlayOverlay={canPlay}
            onPosterClick={() => canPlay && !queueBusy && playAll(false)}
            customizeMenu={null}
          >
            {renaming ? (
              <input
                autoFocus
                value={name}
                onChange={(e) => setName(e.target.value)}
                onBlur={doRename}
                onKeyDown={(e) => {
                  if (e.key === "Enter") doRename();
                  if (e.key === "Escape") setRenaming(false);
                }}
                aria-label={t("plex.collection.rename")}
                className="glass-card w-full rounded-lg px-2 py-1 text-2xl font-semibold focus:outline-hidden focus:ring-2 focus:ring-accent/40"
              />
            ) : (
              <div className="flex items-center gap-2">
                <h1 className="text-2xl font-semibold leading-tight">{d.title}</h1>
                {readOnly && (
                  <span
                    className="inline-flex items-center gap-1 rounded-full bg-surface px-2 py-0.5 text-2xs text-muted"
                    title={t("plex.collection.readOnly")}
                  >
                    <Lock className="h-3 w-3" />
                    {t("plex.collection.readOnly")}
                  </span>
                )}
              </div>
            )}

            {meta.length > 0 && (
              <div className="mt-1 flex flex-wrap items-center gap-x-2 text-sm text-muted">
                {meta.map((m, i) => (
                  <span key={i}>
                    {i > 0 && "· "}
                    {m}
                  </span>
                ))}
              </div>
            )}

            {d.summary && (
              <div className="mt-3">
                <p
                  className={`text-sm leading-relaxed text-muted ${expanded ? "" : "line-clamp-3"}`}
                >
                  {d.summary}
                </p>
                <button
                  onClick={() => setExpanded((v) => !v)}
                  className="mt-1 text-xs font-medium text-accent hover:underline"
                >
                  {expanded ? t("plex.collection.less") : t("plex.collection.more")}
                </button>
              </div>
            )}

            <div className="mt-4 flex flex-wrap gap-2">
              {canPlay && (
                <>
                  <ActionBtn
                    primary
                    onClick={() => playAll(false)}
                    disabled={queueBusy}
                    icon={Play}
                    label={t("plex.collection.playAll")}
                  />
                  <ActionBtn
                    onClick={() => playAll(true)}
                    disabled={queueBusy}
                    icon={Shuffle}
                    label={t("plex.collection.shuffle")}
                  />
                </>
              )}
              {canEdit && (
                <>
                  <ActionBtn
                    onClick={() => {
                      setName(d.title);
                      setRenaming(true);
                    }}
                    icon={Pencil}
                    label={t("plex.collection.rename")}
                  />
                  <ActionBtn
                    onClick={() => setAdding((v) => !v)}
                    icon={Plus}
                    label={t("plex.collection.addItem")}
                  />
                  <ActionBtn
                    onClick={doDelete}
                    icon={Trash2}
                    label={t("plex.collection.delete")}
                    disabled={busy}
                  />
                </>
              )}
              {canEnableEdit && (
                <ActionBtn
                  onClick={enableEdit}
                  icon={Check}
                  label={t("plex.collection.enableEdit")}
                />
              )}
            </div>
          </DetailHero>

          {adding && canEdit && (
            <AddItemPanel
              collectionId={collectionId}
              scope={items.some((c) => c.type === "show") ? "show" : "movie"}
              existing={new Set(items.map((c) => c.id))}
              onAdded={invalidate}
              onClose={() => setAdding(false)}
            />
          )}

          {items.length === 0 ? (
            <p className="text-muted text-sm">{t("plex.collection.empty")}</p>
          ) : (
            <div className="grid grid-cols-3 gap-3 sm:grid-cols-4 md:grid-cols-5 lg:grid-cols-6">
              {items.map((c) => (
                <div key={c.id} className="relative">
                  <PlexPosterCard
                    card={c}
                    onOpen={() => onOpenCard(c)}
                    onInfo={() => onInfoCard(c)}
                    onToggleWatched={toggleWatched}
                  />
                  {canEdit && (
                    <button
                      onClick={() => doRemove(c)}
                      disabled={busy}
                      title={t("plex.collection.removeItem")}
                      aria-label={t("plex.collection.removeItem")}
                      className="glass-card glass-hover absolute right-1.5 top-1.5 z-base grid h-6 w-6 place-items-center rounded-full text-fg disabled:opacity-50"
                    >
                      <X className="h-3.5 w-3.5" />
                    </button>
                  )}
                </div>
              ))}
            </div>
          )}
        </>
      )}
    </div>
  );
}

// A compact search-and-add panel: search the collection's library, click a result to add it (write-
// through to Plex). Stays open so several items can be added in a row; already-present items are marked.
function AddItemPanel({
  collectionId,
  scope,
  existing,
  onAdded,
  onClose,
}: {
  collectionId: string;
  scope: string;
  existing: Set<string>;
  onAdded: () => void;
  onClose: () => void;
}) {
  const { t } = useTranslation();
  const [term, setTerm] = useState("");
  const [added, setAdded] = useState<Set<string>>(new Set());

  async function add(card: PlexCard) {
    try {
      await api.plexCollectionAddItem(collectionId, card.id);
      setAdded((s) => new Set(s).add(card.id));
      onAdded();
    } catch (e) {
      notifyActionError(e, t("plex.collection.editFailed"));
    }
  }

  return (
    <div className="glass-card mb-6 rounded-2xl p-4">
      <div className="mb-3 flex items-center gap-2">
        <Search className="h-4 w-4 text-muted" />
        <input
          autoFocus
          value={term}
          onChange={(e) => setTerm(e.target.value)}
          placeholder={t("plex.collection.addSearch")}
          aria-label={t("plex.collection.addSearch")}
          className="glass-card flex-1 rounded-lg px-3 py-1.5 text-sm focus:outline-hidden focus:ring-2 focus:ring-accent/40"
        />
        <button
          onClick={onClose}
          aria-label={t("common.close")}
          className="glass-hover grid h-8 w-8 place-items-center rounded-lg"
        >
          <X className="h-4 w-4" />
        </button>
      </div>
      <PlexLibraryPicker
        scope={scope}
        term={term}
        emptyHint={<p className="text-muted text-sm">{t("plex.collection.addHint")}</p>}
        renderAction={(c) => {
          const inColl = existing.has(c.id) || added.has(c.id);
          return (
            <button
              onClick={() => add(c)}
              disabled={inColl}
              className="glass-card glass-hover inline-flex items-center gap-1 rounded-lg px-2.5 py-1 text-xs disabled:opacity-50"
            >
              {inColl ? <Check className="h-3.5 w-3.5" /> : <Plus className="h-3.5 w-3.5" />}
              {inColl ? t("plex.collection.added") : t("plex.collection.add")}
            </button>
          );
        }}
      />
    </div>
  );
}