/// 订单簿单条（不可变）
/// 实现 == / hashCode 让 .select() 能正确跳过无变化的重建。
class OrderBookEntry {
  final double price;
  final double amount;
  final double total; // 累计量

  const OrderBookEntry({
    required this.price,
    required this.amount,
    required this.total,
  });

  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is OrderBookEntry &&
          price == other.price &&
          amount == other.amount &&
          total == other.total;

  @override
  int get hashCode => Object.hash(price, amount, total);
}

/// 订单簿（买盘 + 卖盘）
/// 实现 == / hashCode，让 .select((s) => s.orderBook) 能正确跳过无变化的重建。
/// 依赖 OrderBookEntry 已实现的 == 做逐元素深比较。
class OrderBook {
  final List<OrderBookEntry> asks; // 卖盘（从低到高）
  final List<OrderBookEntry> bids; // 买盘（从高到低）

  const OrderBook({required this.asks, required this.bids});

  @override
  bool operator ==(Object other) {
    if (identical(this, other)) return true;
    if (other is! OrderBook) return false;
    if (asks.length != other.asks.length || bids.length != other.bids.length) {
      return false;
    }
    for (var i = 0; i < asks.length; i++) {
      if (asks[i] != other.asks[i]) return false;
    }
    for (var i = 0; i < bids.length; i++) {
      if (bids[i] != other.bids[i]) return false;
    }
    return true;
  }

  @override
  int get hashCode => Object.hash(
      Object.hashAll(asks), Object.hashAll(bids));
}