import { useEffect, useMemo, useState } from "react";
import { useSearchParams } from "react-router-dom";
import { getJSON, itemsOrEmpty, postJSON, type Resource } from "../api";
import { ResourceCard } from "../components/ResourceCard";
import { ResourceListFooter } from "../components/ResourceListFooter";
import { useI18n } from "../i18n";
import { typeFilterLabel } from "../resourceTypeLabels";

const types = [
  "all",
  "image",
  "video",
  "ppt",
  "pdf",
  "text",
  "link",
  "archive",
] as const;
const resourceLangCodes = ["", "zh-TW", "zh-CN", "en"] as const;

function resourceLangLabel(t: (k: string) => string, code: string) {
  if (!code) return t("filterLanguageAll");
  if (code === "zh-TW") return t("lang_zh_TW");
  if (code === "zh-CN") return t("lang_zh_CN");
  return t("lang_en");
}

export function SearchPage() {
  const { t, lang } = useI18n();
  const [sp, setSp] = useSearchParams();
  const q = sp.get("q") || "";
  const sort = sp.get("sort") || "latest";
  const type = sp.get("type") || "all";
  const resourceLang = sp.get("language") || "";
  const page = Math.max(1, parseInt(sp.get("page") || "1", 10) || 1);
  const limit = 24;

  const [items, setItems] = useState<Resource[]>([]);
  const [total, setTotal] = useState(0);
  const [err, setErr] = useState<string | null>(null);

  const query = useMemo(() => {
    const p = new URLSearchParams();
    p.set("lang", lang);
    p.set("limit", String(limit));
    p.set("page", String(page));
    p.set("sort", sort);
    if (q) p.set("q", q);
    if (type && type !== "all") p.set("type", type);
    if (resourceLang) p.set("language", resourceLang);
    return p.toString();
  }, [lang, q, sort, type, resourceLang, page]);

  useEffect(() => {
    setErr(null);
    if (!q) {
      setItems([]);
      setTotal(0);
      return;
    }
    postJSON("/api/search-log", { query: q }).catch(() => {});
    getJSON<{ items: Resource[]; total?: number }>(`/api/resources?${query}`)
      .then((r) => {
        setItems(itemsOrEmpty(r.items));
        setTotal(typeof r.total === "number" ? r.total : 0);
      })
      .catch((e) => setErr(String(e)));
  }, [query, q]);

  const setPage = (next: number) => {
    const n = new URLSearchParams(sp);
    if (next <= 1) n.delete("page");
    else n.set("page", String(next));
    setSp(n);
  };

  return (
    <div className="space-y-6">
      <h1 className="text-2xl font-bold">
        {t("search")}: {q || "—"}
      </h1>

      {q ? (
        <>
          <div className="flex flex-wrap gap-2">
            {(
              [
                ["latest", t("latest")],
                ["recommended", t("official")],
                ["popular", t("popular")],
                ["published", t("sortPublished")],
              ] as const
            ).map(([k, label]) => (
              <button
                key={k}
                type="button"
                onClick={() => {
                  const n = new URLSearchParams(sp);
                  n.set("sort", k);
                  n.delete("page");
                  setSp(n);
                }}
                className={`rounded-full border px-3 py-1 text-sm outline-none focus-visible:ring-2 focus-visible:ring-ark-gold/80 focus-visible:ring-offset-2 focus-visible:ring-offset-ark-bg ${
                  sort === k
                    ? "border-ark-gold text-ark-gold2"
                    : "border-ark-line"
                }`}
              >
                {label}
              </button>
            ))}
          </div>

          <div className="flex flex-wrap gap-2">
            {types.map((tp) => (
              <button
                key={tp}
                type="button"
                onClick={() => {
                  const n = new URLSearchParams(sp);
                  n.delete("page");
                  if (tp === "all") n.delete("type");
                  else n.set("type", tp);
                  setSp(n);
                }}
                className={`rounded-full border px-3 py-1 text-xs outline-none focus-visible:ring-2 focus-visible:ring-ark-gold/80 focus-visible:ring-offset-2 focus-visible:ring-offset-ark-bg ${
                  type === tp || (tp === "all" && !sp.get("type"))
                    ? "border-ark-gold text-ark-gold2"
                    : "border-ark-line"
                }`}
              >
                {typeFilterLabel(t, tp)}
              </button>
            ))}
          </div>

          <div className="space-y-2">
            <div className="text-xs font-medium uppercase tracking-wide text-neutral-500">
              {t("resourceLangFilter")}
            </div>
            <div className="flex flex-wrap gap-2">
              {resourceLangCodes.map((code) => (
                <button
                  key={code || "all"}
                  type="button"
                  onClick={() => {
                    const n = new URLSearchParams(sp);
                    n.delete("page");
                    if (!code) n.delete("language");
                    else n.set("language", code);
                    setSp(n);
                  }}
                  className={`rounded-full border px-3 py-1 text-xs outline-none focus-visible:ring-2 focus-visible:ring-ark-gold/80 focus-visible:ring-offset-2 focus-visible:ring-offset-ark-bg ${
                    (code === "" && !resourceLang) || resourceLang === code
                      ? "border-ark-gold text-ark-gold2"
                      : "border-ark-line"
                  }`}
                >
                  {resourceLangLabel(t, code)}
                </button>
              ))}
            </div>
          </div>
        </>
      ) : null}

      {err ? <div className="text-red-300">{err}</div> : null}
      {!q ? <p className="text-neutral-400">{t("noResults")}</p> : null}
      {q && items.length === 0 && !err ? (
        <p className="text-neutral-400">{t("noResults")}</p>
      ) : null}

      <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
        {items.map((r) => (
          <ResourceCard key={r.id} r={r} />
        ))}
      </div>

      {q ? (
        <ResourceListFooter
          page={page}
          limit={limit}
          total={total}
          t={t}
          onPrev={() => setPage(page - 1)}
          onNext={() => setPage(page + 1)}
        />
      ) : null}
    </div>
  );
}