From f80f3b90c7ef9f33bf3973c95d4dbaf08aae4b87 Mon Sep 17 00:00:00 2001
From: DanB <danb@cgrates.org>
Date: Tue, 5 Jan 2021 17:44:25 +0100
Subject: [PATCH] AccountS - change decimal rounding closer to 0 so we don't
 debit too much in case of limits

---
 accounts/abstractbalance.go      | 16 +++++++++-------
 accounts/concretebalance.go      | 13 ++++++++-----
 accounts/concretebalance_test.go | 22 ++++++++++++++++++++++
 loaders/loader.go                |  1 +
 4 files changed, 40 insertions(+), 12 deletions(-)

diff --git a/accounts/abstractbalance.go b/accounts/abstractbalance.go
index 5a3ea9111..65e58f2f0 100644
--- a/accounts/abstractbalance.go
+++ b/accounts/abstractbalance.go
@@ -81,9 +81,11 @@ func (aB *abstractBalance) unitFactor(tnt string, ev utils.DataProvider) (uF *ut
 
 // balanceLimit returns the balance's limit
 func (aB *abstractBalance) balanceLimit() (bL *decimal.Big) {
+	if _, isUnlimited := aB.blnCfg.Opts[utils.MetaBalanceUnlimited]; isUnlimited {
+		return
+	}
 	if lmtIface, has := aB.blnCfg.Opts[utils.MetaBalanceLimit]; has {
 		bL = lmtIface.(*decimal.Big)
-		return
 	}
 	// nothing matched, return default
 	bL = decimal.New(0, 0)
@@ -113,6 +115,12 @@ func (aB *abstractBalance) debitUsage(usage *decimal.Big, startTime time.Time,
 		return
 	}
 
+	// unitFactor
+	var uF *utils.UnitFactor
+	if uF, err = aB.unitFactor(cgrEv.CGREvent.Tenant, evNm); err != nil {
+		return
+	}
+
 	blcVal := new(decimal.Big).SetFloat64(aB.blnCfg.Value) // FixMe without float64
 
 	// balanceLimit
@@ -123,12 +131,6 @@ func (aB *abstractBalance) debitUsage(usage *decimal.Big, startTime time.Time,
 		hasLmt = true
 	}
 
-	// unitFactor
-	var uF *utils.UnitFactor
-	if uF, err = aB.unitFactor(cgrEv.CGREvent.Tenant, evNm); err != nil {
-		return
-	}
-
 	fmt.Printf("costIcrm: %+v, blncLmt: %+v, hasLmt: %+v, uF: %+v", costIcrm, blncLmt, hasLmt, uF)
 
 	return
diff --git a/accounts/concretebalance.go b/accounts/concretebalance.go
index 6fda4e55f..d4e5f4d46 100644
--- a/accounts/concretebalance.go
+++ b/accounts/concretebalance.go
@@ -81,6 +81,9 @@ func (cB *concreteBalance) unitFactor(tnt string, ev utils.DataProvider) (uF *ut
 
 // balanceLimit returns the balance's limit
 func (cB *concreteBalance) balanceLimit() (bL *decimal.Big) {
+	if _, isUnlimited := cB.blnCfg.Opts[utils.MetaBalanceUnlimited]; isUnlimited {
+		return
+	}
 	if lmtIface, has := cB.blnCfg.Opts[utils.MetaBalanceLimit]; has {
 		bL = lmtIface.(*decimal.Big)
 		return
@@ -144,14 +147,14 @@ func (cB *concreteBalance) debitUnits(dUnts *decimal.Big, incrm *decimal.Big,
 	// balanceLimit
 	var hasLmt bool
 	blncLmt := cB.balanceLimit()
-	if blncLmt.Cmp(decimal.New(0, 0)) != 0 {
+	if blncLmt != nil && blncLmt.Cmp(decimal.New(0, 0)) != 0 {
 		blcVal = utils.SubstractBig(blcVal, blncLmt)
 		hasLmt = true
 	}
-
-	_, isUnlimited := cB.blnCfg.Opts[utils.MetaBalanceUnlimited]
-	if blcVal.Cmp(dUnts) == -1 && !isUnlimited { // balance smaller than debit
-		maxIncrm := utils.DivideBig(blcVal, incrm).RoundToInt()
+	if blcVal.Cmp(dUnts) == -1 && blncLmt != nil { // balance smaller than debit
+		// will use special rounding to 0 since otherwise we go negative (ie: 0.05 as increment)
+		maxIncrm := decimal.WithContext(
+			decimal.Context{RoundingMode: decimal.ToZero}).Quo(blcVal, incrm).RoundToInt()
 		dUnts = utils.MultiplyBig(incrm, maxIncrm)
 	}
 	rmain := utils.SubstractBig(blcVal, dUnts)
diff --git a/accounts/concretebalance_test.go b/accounts/concretebalance_test.go
index e18dddf92..bbe4b3fe6 100644
--- a/accounts/concretebalance_test.go
+++ b/accounts/concretebalance_test.go
@@ -100,4 +100,26 @@ func TestCBDebitUnits(t *testing.T) {
 	} else if cb.blnCfg.Value != -1.25 {
 		t.Errorf("balance remaining: %f", cb.blnCfg.Value)
 	}
+	//with increment and positive limit
+	cb = &concreteBalance{
+		blnCfg: &utils.Balance{
+			ID:   "TestCBDebitUnits",
+			Type: utils.MetaConcrete,
+			Opts: map[string]interface{}{
+				utils.MetaBalanceLimit: decimal.New(5, 1), // 0.5 as limit
+			},
+			Value: 1.25,
+		},
+		fltrS: new(engine.FilterS),
+	}
+	if dbted, _, err := cb.debitUnits(
+		new(decimal.Big).SetFloat64(2.5),
+		new(decimal.Big).SetFloat64(0.1),
+		&utils.CGREventWithOpts{CGREvent: &utils.CGREvent{Tenant: "cgrates.org"}}); err != nil {
+		t.Error(err)
+	} else if dbted.Cmp(decimal.New(7, 1)) != 0 { // only 1.2 is possible due to increment
+		t.Errorf("debited: %s, cmp: %v", dbted, dbted.Cmp(new(decimal.Big).SetFloat64(1.2)))
+	} else if cb.blnCfg.Value != 0.55 {
+		t.Errorf("balance remaining: %f", cb.blnCfg.Value)
+	}
 }
diff --git a/loaders/loader.go b/loaders/loader.go
index 4468a9c93..91ed716ab 100644
--- a/loaders/loader.go
+++ b/loaders/loader.go
@@ -1162,6 +1162,7 @@ func (ldr *Loader) allFilesPresent(ldrType string) bool {
 	return true
 }
 
+// getLdrType returns loaderType for the given fileName
 func (ldr *Loader) getLdrType(fName string) (ldrType string) {
 	for ldr, rdrs := range ldr.rdrs {
 		if _, has := rdrs[fName]; has {