lh-api

.gitignore

@@ -0,0 +1 @@
+.vscode/

data/redisrepo/order_iter.go

@@ -0,0 +1,80 @@
+package redisrepo
+
+import (
+	"context"
+
+	"github.com/google/uuid"
+	"github.com/orbs-network/order-book/models"
+	"github.com/orbs-network/order-book/utils/logger"
+	"github.com/orbs-network/order-book/utils/logger/logctx"
+)
+
+// ////////////////////////////////////////////////
+type OrderIter struct {
+	index int
+	ids   []string
+	redis *redisRepository
+}
+
+func (i *OrderIter) Next(ctx context.Context) *models.Order {
+	if i.index >= len(i.ids) {
+		logctx.Error(ctx, "Error iterator reached last element")
+		return nil
+	}
+
+	// increment index
+	i.index = i.index + 1
+	// get order
+	orderId, err := uuid.Parse(i.ids[i.index])
+	if err != nil {
+		logctx.Error(ctx, "Error parsing bid order id", logger.Error(err))
+		return nil
+	}
+	order, err := i.redis.FindOrderById(ctx, orderId)
+	if err != nil {
+		logctx.Error(ctx, "Error fetching order", logger.Error(err))
+		return nil
+	}
+
+	return order
+}
+
+func (i *OrderIter) HasNext() bool {
+	return i.index < (len(i.ids) - 1)
+}
+
+// ////////////////////////////////////////////////
+func (r *redisRepository) GetMinAsk(ctx context.Context, symbol models.Symbol) models.OrderIter {
+	key := CreateSellSidePricesKey(symbol)
+
+	// Min ask price for selling
+	orderIDs, err := r.client.ZRange(ctx, key, 0, -1).Result()
+	if err != nil {
+		logctx.Error(ctx, "Error fetching asks", logger.Error(err))
+	}
+	// create order iter
+	return &OrderIter{
+		index: -1,
+		ids:   orderIDs,
+		redis: r,
+	}
+
+}
+
+// ////////////////////////////////////////////////
+func (r *redisRepository) GetMaxBid(ctx context.Context, symbol models.Symbol) models.OrderIter {
+	key := CreateBuySidePricesKey(symbol)
+
+	// Min ask price for selling
+	orderIDs, err := r.client.ZRevRange(ctx, key, 0, -1).Result()
+
+	if err != nil {
+		logctx.Error(ctx, "Error fetching bids", logger.Error(err))
+	}
+	// create order iter
+	return &OrderIter{
+		index: -1,
+		ids:   orderIDs,
+		redis: r,
+	}
+}

data/redisrepo/store_auction.go

@@ -0,0 +1,12 @@
+package redisrepo
+
+import (
+	"context"
+
+	"github.com/orbs-network/order-book/models"
+)
+
+func (r *redisRepository) StoreAuction(ctx context.Context, auctionID string, fillOrders []models.FilledOrder) error {
+	// auctionId:<ID>: [{orderID: <ID>, filledAmount: <amount>}, ...}]
+	panic("not implemented")
+}

mocks/order_iter.go

@@ -0,0 +1,21 @@
+package mocks
+
+import (
+	"context"
+
+	"github.com/orbs-network/order-book/models"
+)
+
+type OrderIter struct {
+	Error          error
+	Order          *models.Order
+	ShouldHaveNext bool
+}
+
+func (o *OrderIter) HasNext() bool {
+	return o.ShouldHaveNext
+}
+
+func (o *OrderIter) Next(ctx context.Context) *models.Order {
+	return o.Order
+}

mocks/service.go

@@ -14,6 +14,7 @@ type MockOrderBookStore struct {
 	Order       *models.Order
 	Orders      []models.Order
 	MarketDepth models.MarketDepth
+	OrderIter   models.OrderIter
 }
 
 func (m *MockOrderBookStore) StoreOrder(ctx context.Context, order models.Order) error {
@@ -51,3 +52,15 @@ func (m *MockOrderBookStore) GetMarketDepth(ctx context.Context, symbol models.S
 	}
 	return m.MarketDepth, nil
 }
+
+func (m *MockOrderBookStore) StoreAuction(ctx context.Context, auctionID string, fillOrders []models.FilledOrder) error {
+	return m.Error
+}
+
+func (m *MockOrderBookStore) GetMinAsk(ctx context.Context, symbol models.Symbol) models.OrderIter {
+	return m.OrderIter
+}
+
+func (m *MockOrderBookStore) GetMaxBid(ctx context.Context, symbol models.Symbol) models.OrderIter {
+	return m.OrderIter
+}

mocks/transport.go

@@ -15,6 +15,7 @@ type MockOrderBookService struct {
 	Order       *models.Order
 	Orders      []models.Order
 	MarketDepth models.MarketDepth
+	AmountOut   models.AmountOut
 }
 
 func (m *MockOrderBookService) ProcessOrder(ctx context.Context, input service.ProcessOrderInput) (models.Order, error) {
@@ -36,3 +37,7 @@ func (m *MockOrderBookService) GetOrderById(ctx context.Context, orderId uuid.UU
 func (m *MockOrderBookService) GetMarketDepth(ctx context.Context, symbol models.Symbol, depth int) (models.MarketDepth, error) {
 	return m.MarketDepth, m.Error
 }
+
+func (m *MockOrderBookService) GetAmountOut(ctx context.Context, auctionId string, symbol models.Symbol, side models.Side, amountIn decimal.Decimal) (models.AmountOut, error) {
+	return m.AmountOut, m.Error
+}

models/errors.go

@@ -9,3 +9,4 @@ var ErrNoUserInContext = errors.New("no user in context")
 var ErrUnauthorized = errors.New("user not allowed to perform this action")
 var ErrOrderNotOpen = errors.New("order must be status open to perform this action")
 var ErrTransactionFailed = errors.New("transaction failed")
+var ErrInsufficientLiquity = errors.New("not enough liquidity in book to satisfy amountIn")

models/liquidity_hub.go

@@ -0,0 +1,16 @@
+package models
+
+import (
+	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
+)
+
+type AmountOut struct {
+	AmountOut  decimal.Decimal
+	FillOrders []FilledOrder
+}
+
+type FilledOrder struct {
+	OrderId uuid.UUID
+	Amount  decimal.Decimal
+}

models/order_iter.go

@@ -0,0 +1,8 @@
+package models
+
+import "context"
+
+type OrderIter interface {
+	HasNext() bool
+	Next(ctx context.Context) *Order
+}

models/symbol.go

@@ -7,6 +7,7 @@ type Symbol string
 const (
 	BTC_ETH  Symbol = "BTC-ETH"
 	USDC_ETH Symbol = "USDC-ETH"
+	ETH_USD  Symbol = "ETH-USD"
 )
 
 var ErrInvalidSymbol = errors.New("invalid symbol")
@@ -17,6 +18,8 @@ func StrToSymbol(s string) (Symbol, error) {
 		return BTC_ETH, nil
 	case "USDC-ETH":
 		return USDC_ETH, nil
+	case "ETH-USD":
+		return ETH_USD, nil
 	// TODO: add more symbols
 	default:
 		return "", ErrInvalidSymbol

service/amount_out.go

@@ -0,0 +1,109 @@
+package service
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/orbs-network/order-book/models"
+	"github.com/orbs-network/order-book/utils/logger"
+	"github.com/orbs-network/order-book/utils/logger/logctx"
+	"github.com/shopspring/decimal"
+)
+
+// orderID->amount bought or sold in A token always
+
+func (s *Service) GetAmountOut(ctx context.Context, auctionId string, symbol models.Symbol, side models.Side, amountIn decimal.Decimal) (models.AmountOut, error) {
+
+	var it models.OrderIter
+	var res models.AmountOut
+	var err error
+	if side == models.BUY {
+		it = s.orderBookStore.GetMinAsk(ctx, symbol)
+		res, err = getAmountOutInAToken(ctx, it, amountIn)
+
+	} else { // SELL
+		it = s.orderBookStore.GetMaxBid(ctx, symbol)
+		res, err = getAmountOutInBToken(ctx, it, amountIn)
+	}
+	if err != nil {
+		logctx.Error(ctx, "getAmountOutIn failed", logger.Error(err))
+		return models.AmountOut{}, err
+	}
+	err = s.orderBookStore.StoreAuction(ctx, auctionId, res.FillOrders)
+	if err != nil {
+		logctx.Error(ctx, "StoreAuction failed", logger.Error(err))
+		return models.AmountOut{}, err
+	}
+	return res, nil
+}
+
+// PAIR/SYMBOL A-B (ETH-USDC)
+// amount in B token (USD)
+// amount out A token (ETH)
+func getAmountOutInAToken(ctx context.Context, it models.OrderIter, amountInB decimal.Decimal) (models.AmountOut, error) {
+	amountOutA := decimal.NewFromInt(0)
+	var fillOrders []models.FilledOrder
+	var order *models.Order
+	for it.HasNext() && amountInB.IsPositive() {
+		order = it.Next(ctx)
+		// max Spend in B token  for this order
+		orderSizeB := order.Price.Mul(order.Size)
+		// spend the min of orderSizeB/amountInB
+		spendB := decimal.Min(orderSizeB, amountInB)
+
+		// Gain
+		gainA := spendB.Div(order.Price)
+
+		// sub-add
+		amountInB = amountInB.Sub(spendB)
+		logctx.Info(ctx, "StoreAuction failed")
+		amountOutA = amountOutA.Add(gainA)
+
+		// res
+		logctx.Info(ctx, fmt.Sprintf("append FilledOrder gainA: %s", gainA.String()))
+		logctx.Info(ctx, fmt.Sprintf("append FilledOrder spendB: %s", spendB.String()))
+		fillOrders = append(fillOrders, models.FilledOrder{OrderId: order.Id, Amount: gainA})
+	}
+	// not all is Spent - error
+	if amountInB.IsPositive() {
+		logctx.Warn(ctx, models.ErrInsufficientLiquity.Error())
+		return models.AmountOut{}, models.ErrInsufficientLiquity
+	}
+	logctx.Info(ctx, fmt.Sprintf("append FilledOrder amountOutA: %s", amountOutA.String()))
+	return models.AmountOut{AmountOut: amountOutA, FillOrders: fillOrders}, nil
+}
+
+// PAIR/SYMBOL A-B (ETH-USDC)
+// amount in A token (ETH)
+// amount out B token (USD)
+func getAmountOutInBToken(ctx context.Context, it models.OrderIter, amountInA decimal.Decimal) (models.AmountOut, error) {
+	amountOutB := decimal.NewFromInt(0)
+	var order *models.Order
+	var fillOrders []models.FilledOrder
+	for it.HasNext() && amountInA.IsPositive() {
+		order = it.Next(ctx)
+
+		// Spend
+		spendA := decimal.Min(order.Size, amountInA)
+		fmt.Println("sizeA ", spendA.String())
+
+		// Gain
+		gainB := order.Price.Mul(spendA)
+		fmt.Println("gainB ", gainB.String())
+
+		// sub-add
+		amountInA = amountInA.Sub(spendA)
+		amountOutB = amountOutB.Add(gainB)
+
+		// res
+		logctx.Info(ctx, fmt.Sprintf("append FilledOrder spendA: %s", spendA.String()))
+		logctx.Info(ctx, fmt.Sprintf("append FilledOrder gainB: %s", gainB.String()))
+		fillOrders = append(fillOrders, models.FilledOrder{OrderId: order.Id, Amount: spendA})
+	}
+	if amountInA.IsPositive() {
+		logctx.Warn(ctx, models.ErrInsufficientLiquity.Error())
+		return models.AmountOut{}, models.ErrInsufficientLiquity
+	}
+	logctx.Info(ctx, fmt.Sprintf("append FilledOrder amountOutB: %s", amountOutB.String()))
+	return models.AmountOut{AmountOut: amountOutB, FillOrders: fillOrders}, nil
+}