new endpoint to return product list

app/utils/query/find/sql_calc_rows.go

@@ -0,0 +1,51 @@
+package find
+
+import (
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
+)
+
+type sqlCalcFound struct{}
+
+// Creates a new Clause which adds `SQL_CALC_FOUND_ROWS` right after `SELECT`.
+// If [find.FoundRowsCallback] is registered the presence of this clause will
+// cause `FOUND_ROWS()` result to be available in the driver context.
+func SqlCalcFound() sqlCalcFound {
+	return sqlCalcFound{}
+}
+
+// Implements gorm's [clause.Clause]
+func (sqlCalcFound) Name() string {
+	return "SQL_CALC_FOUND_ROWS"
+}
+
+// Implements gorm's [clause.Clause]
+func (sqlCalcFound) Build(builder clause.Builder) {
+	_, _ = builder.WriteString("SQL_CALC_FOUND_ROWS")
+}
+
+// Implements gorm's [clause.Clause]
+func (sqlCalcFound) MergeClause(cl *clause.Clause) {
+}
+
+// Implements [gorm.StatementModifier]
+func (calc sqlCalcFound) ModifyStatement(stmt *gorm.Statement) {
+	selectClause := stmt.Clauses["SELECT"]
+	if selectClause.AfterNameExpression == nil {
+		selectClause.AfterNameExpression = calc
+	} else if _, ok := selectClause.AfterNameExpression.(sqlCalcFound); !ok {
+		selectClause.AfterNameExpression = exprs{selectClause.AfterNameExpression, calc}
+	}
+	stmt.Clauses["SELECT"] = selectClause
+}
+
+type exprs []clause.Expression
+
+func (exprs exprs) Build(builder clause.Builder) {
+	for idx, expr := range exprs {
+		if idx > 0 {
+			_ = builder.WriteByte(' ')
+		}
+		expr.Build(builder)
+	}
+}