From 9ff7b621231c088f21a14aea4f3d53287eadfb06 Mon Sep 17 00:00:00 2001
From: c9s <yoan@maicoin.com>
Date: Wed, 12 May 2021 01:21:40 +0800
Subject: [PATCH] add xbalance strategy

---
 pkg/cmd/builtin.go                |   1 +
 pkg/strategy/xbalance/strategy.go | 167 ++++++++++++++++++++++++++++++
 2 files changed, 168 insertions(+)
 create mode 100644 pkg/strategy/xbalance/strategy.go

diff --git a/pkg/cmd/builtin.go b/pkg/cmd/builtin.go
index 3087b9279..cb51f1452 100644
--- a/pkg/cmd/builtin.go
+++ b/pkg/cmd/builtin.go
@@ -13,6 +13,7 @@ import (
 	_ "github.com/c9s/bbgo/pkg/strategy/support"
 	_ "github.com/c9s/bbgo/pkg/strategy/swing"
 	_ "github.com/c9s/bbgo/pkg/strategy/trailingstop"
+	_ "github.com/c9s/bbgo/pkg/strategy/xbalance"
 	_ "github.com/c9s/bbgo/pkg/strategy/xmaker"
 	_ "github.com/c9s/bbgo/pkg/strategy/xpuremaker"
 )
diff --git a/pkg/strategy/xbalance/strategy.go b/pkg/strategy/xbalance/strategy.go
new file mode 100644
index 000000000..d3192b3dc
--- /dev/null
+++ b/pkg/strategy/xbalance/strategy.go
@@ -0,0 +1,167 @@
+package xbalance
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/c9s/bbgo/pkg/bbgo"
+	"github.com/c9s/bbgo/pkg/fixedpoint"
+	"github.com/c9s/bbgo/pkg/types"
+	"github.com/pkg/errors"
+	log "github.com/sirupsen/logrus"
+)
+
+const ID = "xbalance"
+
+func init() {
+	bbgo.RegisterStrategy(ID, &Strategy{})
+}
+
+type State struct {
+	DailyNumberOfTransfers fixedpoint.Value `json:"dailyNumberOfTransfers,omitempty"`
+	DailyAmountOfTransfers fixedpoint.Value `json:"dailyAmountOfTransfers,omitempty"`
+	Since                  int64            `json:"since"`
+}
+
+type Strategy struct {
+	Notifiability *bbgo.Notifiability
+
+	Interval types.Duration `json:"interval"`
+
+	Addresses map[string]string `json:"addresses"`
+
+	MaxDailyNumberOfTransfer int `json:"maxDailyNumberOfTransfer"`
+	MaxDailyAmountOfTransfer int `json:"maxDailyAmountOfTransfer"`
+
+	Asset string `json:"asset"`
+
+	// Low is the low balance level for triggering transfer
+	Low fixedpoint.Value `json:"low"`
+
+	// Middle is the middle balance level used for re-fill asset
+	Middle fixedpoint.Value `json:"middle"`
+
+	state *State
+}
+
+func (s *Strategy) ID() string {
+	return ID
+}
+
+func (s *Strategy) CrossSubscribe(sessions map[string]*bbgo.ExchangeSession) {
+
+}
+
+func (s *Strategy) checkBalance(ctx context.Context, sessions map[string]*bbgo.ExchangeSession) {
+	log.Infof("checking low balance level exchange session...")
+
+	lowLevelSession, lowLevelBalance, err := s.findLowBalanceLevelSession(sessions)
+	if err != nil {
+		log.WithError(err).Errorf("can not find low balance level session")
+		return
+	}
+
+	if lowLevelSession == nil {
+		log.Infof("all balances are looking good")
+		return
+	}
+
+	s.Notifiability.Notify("found low balance level %s", lowLevelBalance)
+
+	requiredAmount := s.Middle - lowLevelBalance.Available
+
+	s.Notifiability.Notify("require %f %s to satisfy the middle balance level %f", requiredAmount.Float64(), s.Asset, s.Middle.Float64())
+
+	fromSession, _, err := s.findHighestBalanceLevelSession(sessions, requiredAmount)
+	if err != nil || fromSession == nil {
+		log.WithError(err).Errorf("can not find session with enough balance")
+		return
+	}
+
+	withdrawalService, ok := fromSession.Exchange.(types.ExchangeWithdrawalService)
+	if !ok {
+		log.Errorf("exchange %s does not implement withdrawal service, we can not withdrawal", fromSession.ExchangeName)
+		return
+	}
+
+	toAddress, ok := s.Addresses[lowLevelSession.Name]
+	if !ok {
+		log.Errorf("%s address of session %s not found", s.Asset, lowLevelSession.Name)
+		return
+	}
+
+	s.Notifiability.Notify("sending %f %s withdrawal request from session %s to session %s...", requiredAmount.Float64(), s.Asset, fromSession.Name, lowLevelSession.Name)
+	if err := withdrawalService.Withdrawal(ctx, s.Asset, requiredAmount, toAddress); err != nil {
+		log.WithError(err).Errorf("withdrawal failed")
+
+		s.Notifiability.Notify("withdrawal failed, error: %v", err)
+	}
+}
+
+func (s *Strategy) findHighestBalanceLevelSession(sessions map[string]*bbgo.ExchangeSession, requiredAmount fixedpoint.Value) (*bbgo.ExchangeSession, types.Balance, error) {
+	var balance types.Balance
+	var maxBalanceLevel fixedpoint.Value = 0
+	var maxBalanceSession *bbgo.ExchangeSession = nil
+	for sessionID := range s.Addresses {
+		session, ok := sessions[sessionID]
+		if !ok {
+			return nil, balance, fmt.Errorf("session %s does not exist", sessionID)
+		}
+
+		if b, ok := session.Account.Balance(s.Asset); ok {
+			if b.Available-requiredAmount > s.Low && b.Available > maxBalanceLevel {
+				maxBalanceLevel = b.Available
+				maxBalanceSession = session
+				balance = b
+			}
+		}
+	}
+
+	return maxBalanceSession, balance, nil
+}
+
+func (s *Strategy) findLowBalanceLevelSession(sessions map[string]*bbgo.ExchangeSession) (*bbgo.ExchangeSession, types.Balance, error) {
+	var balance types.Balance
+	for sessionID := range s.Addresses {
+		session, ok := sessions[sessionID]
+		if !ok {
+			return nil, balance, fmt.Errorf("session %s does not exist", sessionID)
+		}
+
+		balance, ok = session.Account.Balance(s.Asset)
+		if ok {
+			if balance.Available <= s.Low {
+				return session, balance, nil
+			}
+		}
+	}
+
+	return nil, balance, nil
+}
+
+func (s *Strategy) CrossRun(ctx context.Context, _ bbgo.OrderExecutionRouter, sessions map[string]*bbgo.ExchangeSession) error {
+
+	if s.Interval == 0 {
+		return errors.New("interval can not be zero")
+	}
+
+	s.checkBalance(ctx, sessions)
+
+	go func() {
+		ticker := time.NewTimer(s.Interval.Duration())
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-ctx.Done():
+				return
+
+			case <-ticker.C:
+				s.checkBalance(ctx, sessions)
+			}
+		}
+	}()
+
+	return nil
+}