import { useState } from "react";
import { useQuery } from "@tanstack/react-query";
import { getHistory } from "../api";
import VideoCard from "../components/VideoCard";
import { scrollToTop } from "../utils/scroll";

const PAGE_SIZE = 25;

export default function History() {
  const [page, setPage] = useState(0);

  const { data: videos = [], isLoading } = useQuery({
    queryKey: ["history", page],
    queryFn: () => getHistory(page, PAGE_SIZE).then(r => r.data),
    staleTime: 60_000,
    placeholderData: (prev) => prev,
  });

  const hasNext = videos.length === PAGE_SIZE;

  return (
    <div className="flex flex-col gap-6 max-w-screen-xl mx-auto">
      <div className="flex items-center justify-between">
        <h1 className="font-display font-bold text-2xl text-white">Watch History</h1>
      </div>

      {isLoading ? (
        <div className="flex items-center justify-center py-24">
          <div className="w-8 h-8 border-2 border-accent border-t-transparent rounded-full animate-spin" />
        </div>
      ) : videos.length === 0 ? (
        <div className="flex flex-col items-center gap-3 py-20 text-center">
          <p className="text-zinc-500 text-sm">No watch history yet. Start watching some videos!</p>
        </div>
      ) : (
        <>
          <div className="flex flex-col gap-2">
            {videos.map((v) => (
              <VideoCard key={v.youtube_video_id} video={v} variant="list" />
            ))}
          </div>
          <div className="flex items-center justify-center gap-3 pt-2">
            <button
              onClick={() => { setPage(p => p - 1); scrollToTop(); }}
              disabled={page === 0}
              className="px-3 py-1.5 rounded-lg bg-zinc-800 text-zinc-300 text-xs font-medium hover:bg-zinc-700 disabled:opacity-30 disabled:cursor-not-allowed transition-colors"
            >
              ← Prev
            </button>
            <span className="text-zinc-500 text-xs tabular-nums">Page {page + 1}</span>
            <button
              onClick={() => { setPage(p => p + 1); scrollToTop(); }}
              disabled={!hasNext}
              className="px-3 py-1.5 rounded-lg bg-zinc-800 text-zinc-300 text-xs font-medium hover:bg-zinc-700 disabled:opacity-30 disabled:cursor-not-allowed transition-colors"
            >
              Next →
            </button>
          </div>
        </>
      )}
    </div>
  );
}
