"use client";

import { useMemo, useState } from "react";
import { Search, Waves } from "lucide-react";
import { useHydroStations } from "@/hooks/use-hydro";
import { HydroStationCard } from "@/components/hydro/hydro-station-card";
import { Button } from "@/components/ui/button";
import { PageLoadingSkeleton } from "@/components/states/loading-skeleton";
import { ErrorState } from "@/components/states/error-state";
import { EmptyState } from "@/components/states/empty-state";
import { useI18n } from "@/lib/i18n";

const PAGE_SIZE = 48;

export function HydroPage() {
  const { locale, t } = useI18n();
  const { data: stations, isPending, isError, refetch } = useHydroStations();
  const [query, setQuery] = useState("");
  const [visibleCount, setVisibleCount] = useState(PAGE_SIZE);
  const filteredStations = useMemo(() => (stations ?? []).filter((station) => {
    const haystack = `${station.name} ${station.river ?? ""} ${station.province ?? ""}`.toLocaleLowerCase(locale);
    return haystack.includes(query.trim().toLocaleLowerCase(locale));
  }), [locale, query, stations]);

  if (isPending) return <PageLoadingSkeleton />;
  if (isError) return <ErrorState onRetry={() => refetch()} description={t("hydro.error")} />;
  return (
    <div className="space-y-5">
      <div>
        <p className="text-xs font-semibold uppercase tracking-[0.18em] text-cyan-700 dark:text-cyan-300">{t("hydro.section")}</p>
        <h1 className="mt-2 text-3xl font-semibold tracking-tight">{t("hydro.title")}</h1>
        <p className="mt-2 max-w-2xl text-sm leading-6 text-slate-600 dark:text-slate-300">{t("hydro.description")}</p>
      </div>
      <label className="glass relative block rounded-[1.5rem] p-3">
        <span className="sr-only">{t("hydro.searchLabel")}</span>
        <Search className="pointer-events-none absolute left-6 top-1/2 size-4 -translate-y-1/2 text-slate-500" />
        <input value={query} onChange={(event) => { setQuery(event.target.value); setVisibleCount(PAGE_SIZE); }} placeholder={t("hydro.searchPlaceholder")} className="w-full rounded-2xl border border-white/40 bg-white/45 py-3 pl-10 pr-4 text-sm placeholder:text-slate-500 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-sky-500 dark:border-white/10 dark:bg-white/5" />
      </label>
      <p className="text-xs text-slate-500 dark:text-slate-400">{t("hydro.results", { total: filteredStations.length, visible: Math.min(visibleCount, filteredStations.length) })}</p>
      {!filteredStations.length ? <EmptyState icon={Waves} title={t("stations.emptyTitle")} description={t("hydro.emptyDescription")} /> : (
        <>
          <div className="grid gap-3 md:grid-cols-2 xl:grid-cols-3">{filteredStations.slice(0, visibleCount).map((station, index) => <HydroStationCard key={station.id} station={station} index={index} />)}</div>
          {visibleCount < filteredStations.length && <div className="flex justify-center pt-2"><Button variant="glass" onClick={() => setVisibleCount((count) => count + PAGE_SIZE)}>{t("hydro.more")}</Button></div>}
        </>
      )}
    </div>
  );
}
