import { useState, useEffect } from "react";

const STATIC_ASSETS = "https://warframe.market/static/assets";

function median(arr) {
  if (arr.length === 0) return null;
  const sorted = [...arr].sort((a, b) => a - b);
  const mid = Math.floor(sorted.length / 2);
  return sorted.length % 2 !== 0
    ? sorted[mid]
    : (sorted[mid - 1] + sorted[mid]) / 2;
}

export default function ItemDetail({ slug, onBack }) {
  const [orders, setOrders] = useState(null);
  const [item, setItem] = useState(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);

  useEffect(() => {
    let cancelled = false;
    async function load() {
      setLoading(true);
      setError(null);
      try {
        const [ordersRes, catalogRes] = await Promise.all([
          fetch(`/api/orders/${encodeURIComponent(slug)}`),
          fetch("/api/items"),
        ]);
        if (!ordersRes.ok) throw new Error(`Orders HTTP ${ordersRes.status}`);
        const ordersData = await ordersRes.json();
        if (!cancelled) setOrders(ordersData);

        if (catalogRes.ok) {
          const catalogData = await catalogRes.json();
          const found = catalogData.find((i) => i.slug === slug);
          if (!cancelled) setItem(found);
        }
      } catch (err) {
        if (!cancelled) setError(err.message);
      } finally {
        if (!cancelled) setLoading(false);
      }
    }
    load();
    return () => { cancelled = true; };
  }, [slug]);

  if (loading) {
    return <div className="loading"><div className="spinner" /> Loading orders...</div>;
  }

  if (error) {
    return (
      <div>
        <button className="back-btn" onClick={onBack}>&larr; Back</button>
        <div className="error-box">
          <p>Failed to load orders: {error}</p>
          <button onClick={() => window.location.reload()}>Retry</button>
        </div>
      </div>
    );
  }

  const name = item?.i18n?.en?.name || slug;
  const thumb = item?.i18n?.en?.thumb;

  const onlineFilter = (o) =>
    o.user?.status === "ingame" || o.user?.status === "online";

  const sells = orders
    .filter((o) => o.type === "sell" && onlineFilter(o))
    .sort((a, b) => a.platinum - b.platinum)
    .slice(0, 5);

  const buys = orders
    .filter((o) => o.type === "buy" && onlineFilter(o))
    .sort((a, b) => b.platinum - a.platinum)
    .slice(0, 5);

  const allSells = orders.filter((o) => o.type === "sell" && onlineFilter(o));
  const sellPrices = allSells.map((o) => o.platinum);
  const stats = {
    median: median(sellPrices),
    min: sellPrices.length > 0 ? Math.min(...sellPrices) : null,
    max: sellPrices.length > 0 ? Math.max(...sellPrices) : null,
    count: allSells.length,
  };

  return (
    <div>
      <button className="back-btn" onClick={onBack}>&larr; Back to watchlist</button>
      <div className="detail-panel">
        <div className="detail-header">
          {thumb && (
            <img src={`${STATIC_ASSETS}/${thumb}`} alt={name} />
          )}
          <div>
            <h2>{name}</h2>
            <span style={{ color: "var(--text-muted)", fontSize: "0.85rem" }}>
              /v2/orders/item/{slug}
            </span>
          </div>
        </div>

        <div className="stats-grid">
          <div className="stat-card">
            <div className="stat-label">Median Sell</div>
            <div className="stat-value price-sell">
              {stats.median != null ? `${stats.median}p` : "\u2014"}
            </div>
          </div>
          <div className="stat-card">
            <div className="stat-label">Min Sell</div>
            <div className="stat-value price-sell">
              {stats.min != null ? `${stats.min}p` : "\u2014"}
            </div>
          </div>
          <div className="stat-card">
            <div className="stat-label">Max Sell</div>
            <div className="stat-value price-sell">
              {stats.max != null ? `${stats.max}p` : "\u2014"}
            </div>
          </div>
          <div className="stat-card">
            <div className="stat-label">Active Sells</div>
            <div className="stat-value">{stats.count}</div>
          </div>
        </div>

        {sells.length === 0 && buys.length === 0 ? (
          <div className="empty-msg">No active orders from online/ingame users.</div>
        ) : (
          <>
            {sells.length > 0 && (
              <div className="orders-section">
                <h3 className="price-sell">Top Sell Orders (low to high)</h3>
                <table>
                  <thead>
                    <tr>
                      <th>Price</th>
                      <th>Qty</th>
                      <th>User</th>
                      <th>Rep</th>
                      <th>Status</th>
                    </tr>
                  </thead>
                  <tbody>
                    {sells.map((o) => (
                      <tr key={o.id}>
                        <td className="price-sell">{o.platinum}p</td>
                        <td>{o.quantity}</td>
                        <td>{o.user?.ingameName || "?"}</td>
                        <td>{o.user?.reputation ?? "?"}</td>
                        <td>
                          <span style={{
                            color: o.user?.status === "ingame" ? "var(--green)" : "var(--blue)",
                          }}>
                            {o.user?.status}
                          </span>
                        </td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
            )}

            {buys.length > 0 && (
              <div className="orders-section" style={{ marginTop: 20 }}>
                <h3 className="price-buy">Top Buy Orders (high to low)</h3>
                <table>
                  <thead>
                    <tr>
                      <th>Price</th>
                      <th>Qty</th>
                      <th>User</th>
                      <th>Rep</th>
                      <th>Status</th>
                    </tr>
                  </thead>
                  <tbody>
                    {buys.map((o) => (
                      <tr key={o.id}>
                        <td className="price-buy">{o.platinum}p</td>
                        <td>{o.quantity}</td>
                        <td>{o.user?.ingameName || "?"}</td>
                        <td>{o.user?.reputation ?? "?"}</td>
                        <td>
                          <span style={{
                            color: o.user?.status === "ingame" ? "var(--green)" : "var(--blue)",
                          }}>
                            {o.user?.status}
                          </span>
                        </td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
            )}
          </>
        )}
      </div>
    </div>
  );
}