GetMinMaxPriceOrder, GetNextOrder

traverse.go

package redisrepo

import (
	"context"

	"github.com/google/uuid"
	"github.com/orbs-network/order-book/models"
)

type OrderTraversal interface {
	GetMinMaxPriceOrder(ctx context.Context, symbol models.Symbol, side models.Side) *models.Order
	GetNextOrder(ctx context.Context, orderId uuid.UUID, symbol models.Symbol, side models.Side) *models.Order
}

func (r *redisRepository) GetMinMaxPriceOrder(ctx context.Context, symbol models.Symbol, side models.Side) (*models.Order, error) {
	var key string
	if side == models.BUY {
		key = CreateBuySidePricesKey(symbol)
	} else {
		key = CreateSellSidePricesKey(symbol)
	}

	// get first element representing the min/max orderId
	orderID, err := r.client.ZRange(ctx, key, 0, 0).Result()
	if err != nil {
		return nil, err
	}

	if len(orderID) == 0 {
		return nil, models.ErrOrderNotFound
	}

	orderIdUUID, err := uuid.Parse(orderID[0])
	if err != nil {
		return nil, err
	}

	// get the order itself by id
	order, err := r.FindOrderById(ctx, orderIdUUID)
	if err != nil {
		return nil, err
	}

	return order, nil
}

func (r *redisRepository) GetNextOrder(ctx context.Context, orderId uuid.UUID, symbol models.Symbol, side models.Side) (*models.Order, error) {
	var key string
	if side == models.BUY {
		key = CreateBuySidePricesKey(symbol)
	} else {
		key = CreateSellSidePricesKey(symbol)
	}

	// get the current order's rank
	rank, err := r.client.ZRank(ctx, key, orderId.String()).Result()
	if err != nil {
		return nil, err
	}

	// get the next order's id
	nextOrderID, err := r.client.ZRange(ctx, key, rank+1, rank+1).Result()
	if err != nil {
		return nil, err
	}

	if len(nextOrderID) == 0 {
		return nil, models.ErrOrderNotFound
	}

	nextOrderIdUUID, err := uuid.Parse(nextOrderID[0])
	if err != nil {
		return nil, err
	}

	// get the next order itself
	nextOrder, err := r.FindOrderById(ctx, nextOrderIdUUID)
	if err != nil {
		return nil, err
	}

	return nextOrder, nil
}