"use client";

import { useState, useTransition } from "react";
import { useRouter, useSearchParams } from "next/navigation";
import { clsx } from "clsx";
import {
  addCollectionAction,
  addTitleToUniverseAction,
  createOrderAction,
  createUniverseAction,
  deleteOrderAction,
  setDefaultOrderAction,
  shareUniverseAction,
  trashUniverseAction,
  unshareUniverseAction,
} from "@/app/actions/universes";
import { useToasts } from "@/components/Toasts";
import type { UniverseView } from "@/lib/universes";

/** Formular für ein neues Universum. */
export function NewUniverseForm() {
  const router = useRouter();
  const { report } = useToasts();
  const [pending, startTransition] = useTransition();

  return (
    <form
      action={(formData) => {
        const name = String(formData.get("name") ?? "").trim();
        if (!name) return;
        startTransition(async () => {
          const result = await createUniverseAction(
            name,
            String(formData.get("description") ?? ""),
          );
          report(result);
          if (result.ok && result.id) router.push(`/universen/${result.id}`);
        });
      }}
      className="space-y-4"
    >
      <div className="space-y-1.5">
        <label htmlFor="name" className="block text-sm font-medium text-[var(--fl-muted)]">
          Name
        </label>
        <input
          id="name"
          name="name"
          required
          autoFocus
          placeholder="MCU, Star Wars, Wizarding World …"
          className="fl-input"
        />
      </div>

      <div className="space-y-1.5">
        <label htmlFor="description" className="block text-sm font-medium text-[var(--fl-muted)]">
          Beschreibung <span className="text-xs text-[var(--fl-faint)]">(optional)</span>
        </label>
        <textarea id="description" name="description" rows={3} className="fl-input resize-y" />
      </div>

      <button type="submit" disabled={pending} className="fl-btn fl-btn-primary">
        {pending ? "Einen Moment …" : "Universum anlegen"}
      </button>
    </form>
  );
}

/** Umschalter zwischen den Reihenfolgen eines Universums. */
export function OrderTabs({
  universe,
  canWrite,
}: {
  universe: UniverseView;
  canWrite: boolean;
}) {
  const router = useRouter();
  const params = useSearchParams();
  const { report } = useToasts();
  const [adding, setAdding] = useState(false);
  const [, startTransition] = useTransition();

  function select(orderId: string) {
    const next = new URLSearchParams(params.toString());
    next.set("reihenfolge", orderId);
    router.replace(`/universen/${universe.id}?${next}`, { scroll: false });
  }

  const active = universe.orders.find((order) => order.id === universe.activeOrderId);

  return (
    <div className="flex flex-wrap items-center gap-2">
      <div className="flex flex-wrap gap-1.5" role="tablist" aria-label="Reihenfolge">
        {universe.orders.map((order) => {
          const isActive = order.id === universe.activeOrderId;
          return (
            <button
              key={order.id}
              type="button"
              role="tab"
              aria-selected={isActive}
              onClick={() => select(order.id)}
              className={clsx(
                "rounded-full border px-3.5 py-1.5 text-sm font-medium transition-colors",
                isActive
                  ? "border-transparent text-[var(--fl-on-accent)]"
                  : "border-[var(--fl-border)] text-[var(--fl-muted)] hover:border-[var(--fl-border-strong)] hover:text-[var(--fl-text)]",
              )}
              style={isActive ? { backgroundImage: "var(--fl-gradient)" } : undefined}
            >
              {order.name}
              {order.isDefault && (
                <>
                  {/* Häkchen an der Reihenfolge, die beim Öffnen erscheint. Das
                      Wort dahinter steht nur für Screenreader — sichtbar würde
                      es die Reiter auseinanderziehen. */}
                  <svg
                    viewBox="0 0 24 24"
                    className="ml-1.5 inline h-3.5 w-3.5 align-[-2px]"
                    fill="none"
                    stroke="currentColor"
                    strokeWidth="3"
                    aria-hidden
                  >
                    <path d="m5 13 4.5 4.5L19 7" strokeLinecap="round" strokeLinejoin="round" />
                  </svg>
                  <span className="sr-only"> (Standard)</span>
                </>
              )}
            </button>
          );
        })}
      </div>

      {canWrite && (
        <>
          {adding ? (
            <form
              action={(formData) => {
                const name = String(formData.get("orderName") ?? "").trim();
                if (!name) return;
                setAdding(false);
                startTransition(async () => {
                  const result = await createOrderAction(universe.id, name);
                  report(result);
                  if (result.ok && result.id) select(result.id);
                  router.refresh();
                });
              }}
              className="flex items-center gap-1.5"
            >
              <input
                name="orderName"
                autoFocus
                placeholder="z. B. Chronologisch"
                className="fl-input w-48 py-1.5 text-sm"
              />
              <button type="submit" className="fl-btn fl-btn-ghost px-3 py-1.5 text-sm">
                Anlegen
              </button>
              <button
                type="button"
                onClick={() => setAdding(false)}
                className="text-sm text-[var(--fl-faint)] hover:text-[var(--fl-text)]"
              >
                Abbrechen
              </button>
            </form>
          ) : (
            <button
              type="button"
              onClick={() => setAdding(true)}
              className="rounded-full border border-dashed border-[var(--fl-border-strong)] px-3.5 py-1.5 text-sm text-[var(--fl-muted)] transition-colors hover:text-[var(--fl-text)]"
            >
              + Reihenfolge
            </button>
          )}

          {active && !active.isDefault && (
            <button
              type="button"
              onClick={() =>
                startTransition(async () => {
                  report(await setDefaultOrderAction(active.id));
                  router.refresh();
                })
              }
              className="text-sm text-[var(--fl-faint)] underline-offset-4 hover:text-[var(--fl-text)] hover:underline"
            >
              Als Standard festlegen
            </button>
          )}

          {active && active.kind === "CUSTOM" && (
            <button
              type="button"
              onClick={() =>
                startTransition(async () => {
                  report(await deleteOrderAction(active.id));
                  router.replace(`/universen/${universe.id}`);
                  router.refresh();
                })
              }
              className="text-sm text-[var(--fl-faint)] underline-offset-4 hover:text-[var(--fl-danger)] hover:underline"
            >
              „{active.name}" löschen
            </button>
          )}
        </>
      )}
    </div>
  );
}

/** Titel aus der eigenen Bibliothek aufnehmen — mit Tippfilter. */
export function AddTitles({
  universeId,
  candidates,
  collections,
}: {
  universeId: string;
  candidates: { id: string; title: string; type: string; year: number | null }[];
  collections: { id: number; name: string }[];
}) {
  const router = useRouter();
  const { report } = useToasts();
  const [query, setQuery] = useState("");
  const [pending, startTransition] = useTransition();

  const filtered = query.trim()
    ? candidates
        .filter((item) => item.title.toLocaleLowerCase("de-DE").includes(query.toLocaleLowerCase("de-DE")))
        .slice(0, 8)
    : candidates.slice(0, 8);

  return (
    <div className="space-y-4">
      {collections.length > 0 && (
        <div>
          <h3 className="mb-2 text-sm font-semibold text-[var(--fl-muted)]">
            Aus einer TMDB-Reihe übernehmen
          </h3>
          <div className="flex flex-wrap gap-1.5">
            {collections.map((collection) => (
              <button
                key={collection.id}
                type="button"
                disabled={pending}
                onClick={() =>
                  startTransition(async () => {
                    report(await addCollectionAction(universeId, collection.id));
                    router.refresh();
                  })
                }
                className="rounded-full border border-[var(--fl-border)] px-3 py-1.5 text-sm text-[var(--fl-muted)] transition-colors hover:border-[var(--fl-border-strong)] hover:text-[var(--fl-text)]"
              >
                {collection.name}
              </button>
            ))}
          </div>
        </div>
      )}

      <div>
        <h3 className="mb-2 text-sm font-semibold text-[var(--fl-muted)]">
          Aus der Bibliothek aufnehmen
        </h3>
        {candidates.length === 0 ? (
          <p className="text-sm text-[var(--fl-faint)]">
            Alles aus deiner Bibliothek ist schon in diesem Universum.
          </p>
        ) : (
          <>
            <input
              value={query}
              onChange={(event) => setQuery(event.target.value)}
              placeholder="Titel filtern …"
              aria-label="Titel filtern"
              className="fl-input mb-2"
            />
            <ul className="space-y-1">
              {filtered.map((item) => (
                <li key={item.id}>
                  <button
                    type="button"
                    disabled={pending}
                    onClick={() =>
                      startTransition(async () => {
                        report(await addTitleToUniverseAction(universeId, item.id));
                        router.refresh();
                      })
                    }
                    className="flex w-full items-center justify-between rounded-lg px-3 py-2 text-left text-sm transition-colors hover:bg-[var(--fl-surface-2)]"
                  >
                    <span className="min-w-0 truncate">{item.title}</span>
                    <span className="ml-3 shrink-0 text-xs text-[var(--fl-faint)]">
                      {item.type === "SERIES" ? "Serie" : "Film"}
                      {item.year ? ` · ${item.year}` : ""}
                    </span>
                  </button>
                </li>
              ))}
              {filtered.length === 0 && (
                <li className="px-3 py-2 text-sm text-[var(--fl-faint)]">Kein Treffer.</li>
              )}
            </ul>
          </>
        )}
      </div>
    </div>
  );
}

/** Freigabe an andere Konten der Instanz. */
export function SharePanel({ universe }: { universe: UniverseView }) {
  const router = useRouter();
  const { report } = useToasts();
  const [permission, setPermission] = useState<"READ" | "WRITE">("READ");
  const [pending, startTransition] = useTransition();

  return (
    <div className="space-y-3">
      <form
        action={(formData) => {
          const email = String(formData.get("email") ?? "").trim();
          if (!email) return;
          startTransition(async () => {
            report(await shareUniverseAction(universe.id, email, permission));
            router.refresh();
          });
        }}
        className="space-y-2"
      >
        <label htmlFor="share-email" className="block text-sm font-medium text-[var(--fl-muted)]">
          Mit jemandem auf dieser Instanz teilen
        </label>
        <input
          id="share-email"
          name="email"
          type="email"
          placeholder="person@beispiel.de"
          className="fl-input"
        />
        <div className="flex flex-wrap items-center gap-2">
          <select
            value={permission}
            onChange={(event) => setPermission(event.target.value as "READ" | "WRITE")}
            aria-label="Recht"
            className="rounded-lg border border-[var(--fl-border)] bg-[var(--fl-surface-2)] px-2.5 py-1.5 text-sm"
          >
            <option value="READ">Nur ansehen</option>
            <option value="WRITE">Gemeinsam pflegen</option>
          </select>
          <button type="submit" disabled={pending} className="fl-btn fl-btn-ghost px-3 py-1.5 text-sm">
            Teilen
          </button>
        </div>
      </form>

      {universe.members.length > 0 && (
        <ul className="space-y-1 border-t border-[var(--fl-border)] pt-3">
          {universe.members.map((member) => (
            <li key={member.id} className="flex items-center gap-2 text-sm">
              <span className="min-w-0 flex-1 truncate">
                {member.name}
                <span className="ml-1.5 text-xs text-[var(--fl-faint)]">
                  {member.permission === "WRITE" ? "pflegt mit" : "liest mit"}
                </span>
              </span>
              <button
                type="button"
                onClick={() =>
                  startTransition(async () => {
                    report(await unshareUniverseAction(universe.id, member.id));
                    router.refresh();
                  })
                }
                className="text-xs text-[var(--fl-faint)] underline-offset-2 hover:text-[var(--fl-danger)] hover:underline"
              >
                entfernen
              </button>
            </li>
          ))}
        </ul>
      )}
    </div>
  );
}

/** Universum löschen — mit Rückfrage. */
export function DeleteUniverse({ universeId, name }: { universeId: string; name: string }) {
  const router = useRouter();
  const { report } = useToasts();
  const [confirming, setConfirming] = useState(false);
  const [pending, startTransition] = useTransition();

  if (!confirming) {
    return (
      <button
        type="button"
        onClick={() => setConfirming(true)}
        className="text-sm text-[var(--fl-faint)] underline-offset-4 hover:text-[var(--fl-danger)] hover:underline"
      >
        Universum löschen
      </button>
    );
  }

  return (
    <div className="flex flex-wrap items-center gap-2 text-sm">
      <span className="text-[var(--fl-muted)]">„{name}" wirklich löschen?</span>
      <button
        type="button"
        disabled={pending}
        onClick={() =>
          startTransition(async () => {
            report(await trashUniverseAction(universeId));
            router.push("/universen");
          })
        }
        className="fl-btn fl-btn-ghost px-3 py-1.5 text-sm text-[var(--fl-danger)]"
      >
        Ja, löschen
      </button>
      <button
        type="button"
        onClick={() => setConfirming(false)}
        className="text-[var(--fl-faint)] hover:text-[var(--fl-text)]"
      >
        Abbrechen
      </button>
    </div>
  );
}