reversal.go

// Licensed to The Moov Authors under one or more contributor
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// this work for additional information regarding copyright
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// the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

package ach

import (
	"fmt"
	"time"
)

// Reversal will transform a File into a Nacha compliant reversal which can be transmitted to undo fund movement.
func (f *File) Reversal(effectiveEntryDate time.Time) error {
	f.Header.FileCreationDate = effectiveEntryDate.Format("060102")
	f.Header.FileCreationTime = effectiveEntryDate.Format("1504")

	for i := range f.Batches {
		bh := f.Batches[i].GetHeader()

		// Must submit a Reversing Entry within a batch that includes the word "REVERSAL" in the
		// Company Entry Description field of the Company/Batch Header Record.
		//
		// The description “REVERSAL” must replace the original content of the Company Entry Description
		// field transmitted in the original batch, including content that may otherwise have been required by The Rules.
		bh.CompanyEntryDescription = "REVERSAL"

		// For each Reversing Entry, the content on the following fields must remain unchanged from the original,
		// erroneous Entry to which the Reversal relates:
		//  - Standard Entry Class Code
		//  - Company Identification/Originator Identification
		//  - Amount
		//  - Update the following records according to the fund flow

		// Adjust Effective Entry Date for same-day vs standard
		bh.EffectiveEntryDate = effectiveEntryDate.Format("060102")

		hasCredits, hasDebits := false, false

		// In EntryDetail records we need to update the TransactionCode fields to undo fund movement.
		entries := f.Batches[i].GetEntries()
		for j := range entries {
			switch entries[j].TransactionCode {
			case
				CheckingCredit, CheckingReturnNOCCredit, CheckingPrenoteCredit, CheckingZeroDollarRemittanceCredit,
				GLCredit, GLPrenoteCredit, GLReturnNOCCredit, GLZeroDollarRemittanceCredit,
				LoanCredit, LoanPrenoteCredit, LoanReturnNOCCredit, LoanZeroDollarRemittanceCredit,
				SavingsCredit, SavingsPrenoteCredit, SavingsReturnNOCCredit, SavingsZeroDollarRemittanceCredit:
				// Credit -> Debit
				hasDebits = true
				entries[j].TransactionCode += 5

			case
				CheckingDebit, CheckingPrenoteDebit, CheckingReturnNOCDebit, CheckingZeroDollarRemittanceDebit,
				GLDebit, GLPrenoteDebit, GLReturnNOCDebit, GLZeroDollarRemittanceDebit,
				LoanDebit, LoanReturnNOCDebit,
				SavingsDebit, SavingsPrenoteDebit, SavingsReturnNOCDebit, SavingsZeroDollarRemittanceDebit:
				// Debit -> Credit
				hasCredits = true
				entries[j].TransactionCode -= 5
			}
		}

		// Re-calculate control record
		bc := f.Batches[i].GetControl()
		// Swap debis and credits
		prevDebits := bc.TotalDebitEntryDollarAmount
		bc.TotalDebitEntryDollarAmount = bc.TotalCreditEntryDollarAmount
		bc.TotalCreditEntryDollarAmount = prevDebits

		// Fixup ServiceClassCode
		if hasCredits {
			bh.ServiceClassCode = CreditsOnly
			bc.ServiceClassCode = CreditsOnly
		}
		if hasDebits {
			bh.ServiceClassCode = DebitsOnly
			bc.ServiceClassCode = DebitsOnly
		}
		if hasCredits && hasDebits {
			bh.ServiceClassCode = MixedDebitsAndCredits
			bc.ServiceClassCode = MixedDebitsAndCredits
		}

		// Update header and control
		f.Batches[i].SetHeader(bh)
		f.Batches[i].SetControl(bc)

		if bb, ok := f.Batches[i].(*Batch); ok {
			if err := bb.build(); err != nil {
				return fmt.Errorf("rebuilding batch index %d failed: %v", i, err)
			}
		}
	}
	return f.Create()
}