Merge pull request #1 from Leukocyte-Lab/refactor/testable

refactor/testable

paginator.go

@@ -35,26 +35,45 @@ func New(page Page, orders []Order, filter map[string]string) *Paginator {
 
 // GenGormTransaction generate GORMv2 sql Transaction (gorm.DB) for paging
 func (pgntr Paginator) GenGormTransaction(tx *gorm.DB) *gorm.DB {
-	tx = pgntr.offset(tx)
-	tx = pgntr.limit(tx)
-	tx = pgntr.orderBy(tx)
+	tx = pgntr.GenPgntrStmt(tx)
 	tx = pgntr.where(tx)
 
 	return tx
 }
 
 // CountPageTotal is setter of Paginator.Page.Total by counting total page number
 func (pgntr *Paginator) CountPageTotal(tx *gorm.DB) error {
-	var count int64
 	// remove offset, limit and order by before count
-	delete(tx.Statement.Clauses, "ORDER BY")
-	tx.Offset(-1).Limit(-1).Count(&count)
-	pgntr.Page.Total = int(math.Ceil(float64(count) / float64(pgntr.Page.Size)))
-	// limit PageNumber <= PageTotal
+	tx = pgntr.DelPgntrStmt(tx)
+
+	var recordCount int64
+	tx.Count(&recordCount)
+
+	// set PageTotal by counting total page number
+	pgntr.Page.Total = pgntr.countPageTotal(recordCount)
 	pgntr.LimitPageTotal()
+
 	return nil
 }
 
+// GenPgntrStmt add statements for paging
+func (pgntr Paginator) GenPgntrStmt(tx *gorm.DB) *gorm.DB {
+	tx = pgntr.offset(tx)
+	tx = pgntr.limit(tx)
+	tx = pgntr.orderBy(tx)
+
+	return tx
+}
+
+// DelPgntrStmt remove statements for paging
+func (pgntr Paginator) DelPgntrStmt(tx *gorm.DB) *gorm.DB {
+	tx = pgntr.rmOrderBy(tx)
+	tx = pgntr.rmLimit(tx)
+	tx = pgntr.rmOffset(tx)
+
+	return tx
+}
+
 func (pgntr Paginator) where(tx *gorm.DB) *gorm.DB {
 	return tx.Where(pgntr.Filter)
 }
@@ -64,11 +83,19 @@ func (pgntr Paginator) offset(tx *gorm.DB) *gorm.DB {
 	return tx.Offset((pgntr.Page.Number - 1) * pgntr.Page.Size)
 }
 
+func (pgntr Paginator) rmOffset(tx *gorm.DB) *gorm.DB {
+	return tx.Offset(-1)
+}
+
 func (pgntr Paginator) limit(tx *gorm.DB) *gorm.DB {
 	// concat LIMIT SQL query statement by Paginator.Page.Size
 	return tx.Limit(pgntr.Page.Size)
 }
 
+func (pgntr Paginator) rmLimit(tx *gorm.DB) *gorm.DB {
+	return tx.Limit(-1)
+}
+
 func (pgntr Paginator) orderBy(tx *gorm.DB) *gorm.DB {
 	// concat ORDER SQL query statement by Paginator.order
 	for _, order := range pgntr.Order {
@@ -77,6 +104,20 @@ func (pgntr Paginator) orderBy(tx *gorm.DB) *gorm.DB {
 	return tx
 }
 
+func (pgntr Paginator) rmOrderBy(tx *gorm.DB) *gorm.DB {
+	delete(tx.Statement.Clauses, "ORDER BY")
+	return tx
+}
+
+func (pgntr Paginator) countPageTotal(recordCount int64) (pageTotal int) {
+	// page total start with 1
+	if recordCount == 0 || pgntr.Page.Size == 0 {
+		return 1
+	}
+
+	return int(math.Ceil(float64(recordCount) / float64(pgntr.Page.Size)))
+}
+
 func (pgntr *Paginator) limitMinPageNumber(minPageNumber int) {
 	// limit PageNumber >= minPageNumber
 	if pgntr.Page.Number < minPageNumber {
@@ -92,10 +133,18 @@ func (pgntr *Paginator) limitMinPageSize(minPageSize int) {
 }
 
 func (pgntr *Paginator) LimitPageTotal() {
+	pgntr.limitPageTotal()
+	pgntr.limitPageNumber()
+}
+
+func (pgntr *Paginator) limitPageTotal() {
 	// set page total default to 1
 	if pgntr.Page.Total == 0 {
 		pgntr.Page.Total = 1
 	}
+}
+
+func (pgntr *Paginator) limitPageNumber() {
 	// limit PageNumber <= PageTotal
 	if pgntr.Page.Number > pgntr.Page.Total {
 		pgntr.Page.Number = pgntr.Page.Total