"use client";

// 학습 대상 SEED 10종목 quick-access 타일.
//
// 토스 홈의 '인기 종목' 카드 톤. 각 타일이 자체적으로 /api/chart 를 2일치 받아
// 현재가/전일대비 를 계산해서 표시. 10개 병렬 호출 — 백엔드는 캐시 친화적이므로 OK.
//
// 백엔드 신규 엔드포인트가 추가되면 (예: /api/markets/top-volume) 그쪽으로 갈아끼움.

import Link from "next/link";
import { useEffect, useState } from "react";
import { api } from "../lib/api";

type Tile = {
  code: string;
  name: string;
  market: string;
  current: number | null;
  prev: number | null;
};

const SEED_TICKERS: Array<Omit<Tile, "current" | "prev">> = [
  { code: "005930", name: "삼성전자", market: "KOSPI" },
  { code: "000660", name: "SK하이닉스", market: "KOSPI" },
  { code: "247540", name: "에코프로비엠", market: "KOSDAQ" },
  { code: "042700", name: "한미반도체", market: "KOSPI" },
  { code: "034020", name: "두산에너빌리티", market: "KOSPI" },
  { code: "012450", name: "한화에어로스페이스", market: "KOSPI" },
  { code: "329180", name: "HD현대중공업", market: "KOSPI" },
  { code: "035420", name: "NAVER", market: "KOSPI" },
  { code: "033780", name: "KT&G", market: "KOSPI" },
  { code: "036460", name: "한국가스공사", market: "KOSPI" },
];

export function SeedTiles() {
  const [tiles, setTiles] = useState<Tile[]>(
    SEED_TICKERS.map((t) => ({ ...t, current: null, prev: null })),
  );

  useEffect(() => {
    let alive = true;
    // 10 병렬 fetch. 한 종목 실패해도 다른 타일은 살린다.
    Promise.allSettled(
      SEED_TICKERS.map(async (t) => {
        const c = await api.getChart(t.code, 5, "1d");
        const valid = c.ohlcv.filter((p) => p.close != null);
        const last = valid[valid.length - 1] ?? null;
        const prev = valid.length >= 2 ? valid[valid.length - 2] : null;
        return {
          code: t.code,
          name: t.name,
          market: t.market,
          current: last?.close ?? null,
          prev: prev?.close ?? null,
        };
      }),
    ).then((settled) => {
      if (!alive) return;
      const next: Tile[] = settled.map((r, i) => {
        if (r.status === "fulfilled") return r.value;
        return { ...SEED_TICKERS[i], current: null, prev: null };
      });
      setTiles(next);
    });
    return () => {
      alive = false;
    };
  }, []);

  return (
    <div className="rounded-lg border border-zinc-800 bg-zinc-900/30 p-4">
      <div className="mb-3 flex items-baseline justify-between">
        <div className="text-sm font-medium text-zinc-200">학습 대상 10종목</div>
        <div className="text-[11px] text-zinc-500">현재가 · 전일대비</div>
      </div>
      <div className="grid grid-cols-2 gap-2 sm:grid-cols-3 md:grid-cols-5">
        {tiles.map((t) => (
          <TileCard key={t.code} t={t} />
        ))}
      </div>
    </div>
  );
}

function TileCard({ t }: { t: Tile }) {
  const change =
    t.current != null && t.prev != null ? t.current - t.prev : null;
  const pct =
    change != null && t.prev != null && t.prev !== 0
      ? (change / t.prev) * 100
      : null;
  const tone =
    change == null || change === 0
      ? "text-zinc-400"
      : change > 0
      ? "text-rose-400"
      : "text-sky-400";
  return (
    <Link
      href={`/${t.code}`}
      className="block rounded-md border border-zinc-800 bg-zinc-900/40 p-3 transition hover:border-zinc-600"
    >
      <div className="truncate text-sm font-medium text-zinc-100">{t.name}</div>
      <div className="mt-0.5 text-[11px] text-zinc-500">
        {t.code} · {t.market}
      </div>
      <div className="mt-2 text-sm tabular-nums text-zinc-100">
        {t.current != null
          ? t.current.toLocaleString(undefined, { maximumFractionDigits: 0 })
          : "—"}
      </div>
      <div className={`text-[11px] tabular-nums ${tone}`}>
        {change == null
          ? " "
          : `${change > 0 ? "+" : ""}${change.toLocaleString(undefined, {
              maximumFractionDigits: 0,
            })}${pct != null ? ` (${pct > 0 ? "+" : ""}${pct.toFixed(2)}%)` : ""}`}
      </div>
    </Link>
  );
}