/*
 * The Kuali Financial System, a comprehensive financial management system for higher education.
 * 
 * Copyright 2005-2014 The Kuali Foundation
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.kuali.kfs.sys.document.validation.impl;

import java.util.List;

import org.kuali.kfs.sys.KFSConstants;
import org.kuali.kfs.sys.KFSKeyConstants;
import org.kuali.kfs.sys.businessobject.GeneralLedgerPendingEntry;
import org.kuali.kfs.sys.context.SpringContext;
import org.kuali.kfs.sys.document.AccountingDocument;
import org.kuali.kfs.sys.document.validation.GenericValidation;
import org.kuali.kfs.sys.document.validation.event.AttributedDocumentEvent;
import org.kuali.kfs.sys.service.GeneralLedgerPendingEntryService;
import org.kuali.rice.core.api.util.type.KualiDecimal;
import org.kuali.rice.krad.exception.ValidationException;
import org.kuali.rice.krad.util.GlobalVariables;

/**
 * A validation that checks that the credits and debits of GLPEs generated by a document are balanced.
 */
public class DebitsAndCreditsBalanceValidation extends GenericValidation {
    private static org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(DebitsAndCreditsBalanceValidation.class);
    
    private AccountingDocument accountingDocumentForValidation;
    
    /**
     * Generates the GLPEs for a given accounting document and checks that the debits total equals
     * the credits total.
     * <strong>Expects the document to be sent in as a property.</strong>
     * @see org.kuali.kfs.sys.document.validation.GenericValidation#validate(java.lang.Object[])
     */
    public boolean validate(AttributedDocumentEvent event) {
        LOG.debug("Validation started");
        
        // generate GLPEs specifically here so that we can compare debits to credits
        if (!SpringContext.getBean(GeneralLedgerPendingEntryService.class).generateGeneralLedgerPendingEntries(accountingDocumentForValidation)) {
            throw new ValidationException("general ledger GLPE generation failed");
        }

        // now loop through all of the GLPEs and calculate buckets for debits and credits
        KualiDecimal creditAmount = KualiDecimal.ZERO;
        KualiDecimal debitAmount = KualiDecimal.ZERO;
        
        List<GeneralLedgerPendingEntry> pendingEntries = accountingDocumentForValidation.getGeneralLedgerPendingEntries();
        for(GeneralLedgerPendingEntry entry : pendingEntries) {
            if(entry.isTransactionEntryOffsetIndicator()) {
                continue;
            }
            
            if (KFSConstants.GL_CREDIT_CODE.equals(entry.getTransactionDebitCreditCode())) {
                creditAmount = creditAmount.add(entry.getTransactionLedgerEntryAmount());
            }
            else {
                debitAmount = debitAmount.add(entry.getTransactionLedgerEntryAmount());
            }           
        }
        
        boolean isValid = debitAmount.compareTo(creditAmount) == 0;

        if (!isValid) {
            GlobalVariables.getMessageMap().putError(KFSConstants.ACCOUNTING_LINE_ERRORS, KFSKeyConstants.ERROR_DOCUMENT_BALANCE);
        }
        
        return isValid;
    }

    /**
     * Gets the accountingDocumentForValidation attribute. 
     * @return Returns the accountingDocumentForValidation.
     */
    public AccountingDocument getAccountingDocumentForValidation() {
        return accountingDocumentForValidation;
    }

    /**
     * Sets the accountingDocumentForValidation attribute value.
     * @param accountingDocumentForValidation The accountingDocumentForValidation to set.
     */
    public void setAccountingDocumentForValidation(AccountingDocument accountingDocumentForValidation) {
        this.accountingDocumentForValidation = accountingDocumentForValidation;
    }
}