<?php
/*
 +--------------------------------------------------------------------+
 | Copyright CiviCRM LLC. All rights reserved.                        |
 |                                                                    |
 | This work is published under the GNU AGPLv3 license with some      |
 | permitted exceptions and without any warranty. For full license    |
 | and copyright information, see https://civicrm.org/licensing       |
 +--------------------------------------------------------------------+
 */

/**
 *
 * @package CRM
 * @copyright CiviCRM LLC https://civicrm.org/licensing
 */

/**
 * Business objects for Line Items generated by monetary transactions
 */
class CRM_Price_BAO_LineItem extends CRM_Price_DAO_LineItem {

  /**
   * Creates a new entry in the database.
   *
   * @param array $params
   *   (reference) an assoc array of name/value pairs.
   *
   * @return \CRM_Price_DAO_LineItem
   *
   * @throws \CiviCRM_API3_Exception
   * @throws \Exception
   */
  public static function create(&$params) {
    $id = $params['id'] ?? NULL;
    if ($id) {
      CRM_Utils_Hook::pre('edit', 'LineItem', $id, $params);
      $op = CRM_Core_Action::UPDATE;
    }
    else {
      CRM_Utils_Hook::pre('create', 'LineItem', $params['entity_id'], $params);
      $op = CRM_Core_Action::ADD;
    }

    // unset entity table and entity id in $params
    // we never update the entity table and entity id during update mode
    if ($id) {
      $entity_id = $params['entity_id'] ?? NULL;
      $entity_table = $params['entity_table'] ?? NULL;
      unset($params['entity_id'], $params['entity_table']);
    }
    else {
      if (!isset($params['unit_price'])) {
        $params['unit_price'] = 0;
      }
    }
    if (CRM_Financial_BAO_FinancialType::isACLFinancialTypeStatus() && !empty($params['check_permissions'])) {
      if (empty($params['financial_type_id'])) {
        throw new Exception('Mandatory key(s) missing from params array: financial_type_id');
      }
      CRM_Financial_BAO_FinancialType::getAvailableFinancialTypes($types, $op);
      if (!in_array($params['financial_type_id'], array_keys($types))) {
        throw new Exception('You do not have permission to create this line item');
      }
    }

    $lineItemBAO = new CRM_Price_BAO_LineItem();
    $lineItemBAO->copyValues($params);

    $return = $lineItemBAO->save();
    if ($lineItemBAO->entity_table == 'civicrm_membership' && $lineItemBAO->contribution_id && $lineItemBAO->entity_id) {
      $membershipPaymentParams = [
        'membership_id' => $lineItemBAO->entity_id,
        'contribution_id' => $lineItemBAO->contribution_id,
      ];
      if (!civicrm_api3('MembershipPayment', 'getcount', $membershipPaymentParams)) {
        // If we are creating the membership payment row from the line item then we
        // should have correct line item & membership payment should not need to fix.
        $membershipPaymentParams['isSkipLineItem'] = TRUE;
        civicrm_api3('MembershipPayment', 'create', $membershipPaymentParams);
      }
    }

    if ($id) {
      // CRM-21281: Restore entity reference in case the post hook needs it
      $lineItemBAO->entity_id = $entity_id;
      $lineItemBAO->entity_table = $entity_table;
      CRM_Utils_Hook::post('edit', 'LineItem', $id, $lineItemBAO);
    }
    else {
      CRM_Utils_Hook::post('create', 'LineItem', $lineItemBAO->id, $lineItemBAO);
    }

    return $return;
  }

  /**
   * Retrieve DB object based on input parameters.
   *
   * It also stores all the retrieved values in the default array.
   *
   * @param array $params
   *   (reference ) an assoc array of name/value pairs.
   * @param array $defaults
   *   (reference ) an assoc array to hold the flattened values.
   *
   * @return CRM_Price_BAO_LineItem
   */
  public static function retrieve(&$params = [], &$defaults = []) {
    $lineItem = new CRM_Price_BAO_LineItem();
    $lineItem->copyValues($params);
    if ($lineItem->find(TRUE)) {
      CRM_Core_DAO::storeValues($lineItem, $defaults);
      return $lineItem;
    }
    return NULL;
  }

  /**
   * Modifies $params array for filtering financial types.
   *
   * @param array $params
   *   (reference ) an assoc array of name/value pairs.
   *
   */
  public static function getAPILineItemParams(&$params) {
    CRM_Financial_BAO_FinancialType::getAvailableFinancialTypes($types);
    if ($types && empty($params['financial_type_id'])) {
      $params['financial_type_id'] = ['IN' => array_keys($types)];
    }
    elseif ($types) {
      if (is_array($params['financial_type_id'])) {
        $invalidFts = array_diff($params['financial_type_id'], array_keys($types));
      }
      elseif (!in_array($params['financial_type_id'], array_keys($types))) {
        $invalidFts = $params['financial_type_id'];
      }
      if ($invalidFts) {
        $params['financial_type_id'] = ['NOT IN' => $invalidFts];
      }
    }
    else {
      $params['financial_type_id'] = 0;
    }
  }

  /**
   * @param int $contributionId
   *
   * @return null|string
   */
  public static function getLineTotal($contributionId) {
    $sqlLineItemTotal = "SELECT SUM(li.line_total + COALESCE(li.tax_amount,0))
FROM civicrm_line_item li
WHERE li.contribution_id = %1";
    $params = [1 => [$contributionId, 'Integer']];
    $lineItemTotal = CRM_Core_DAO::singleValueQuery($sqlLineItemTotal, $params);
    return $lineItemTotal;
  }

  /**
   * Wrapper for line item retrieval when contribution ID is known.
   * @param int $contributionID
   *
   * @return array
   */
  public static function getLineItemsByContributionID($contributionID) {
    return self::getLineItems($contributionID, 'contribution', NULL, TRUE, TRUE);
  }

  /**
   * Given a participant id/contribution id,
   * return contribution/fee line items
   *
   * @param int $entityId
   *   participant/contribution id.
   * @param string $entity
   *   participant/contribution.
   *
   * @param bool $isQuick
   * @param bool $isQtyZero
   * @param bool $relatedEntity
   *
   * @return array
   *   Array of line items
   */
  public static function getLineItems($entityId, $entity = 'participant', $isQuick = FALSE, $isQtyZero = TRUE, $relatedEntity = FALSE) {
    $whereClause = $fromClause = NULL;
    $selectClause = '
      SELECT li.id,
      li.label,
      li.contribution_id,
      li.qty,
      li.unit_price,
      li.line_total,
      li.entity_table,
      li.entity_id,
      pf.label as field_title,
      pf.html_type,
      pf.price_set_id,
      pfv.membership_type_id,
      pfv.membership_num_terms,
      li.price_field_id,
      li.participant_count,
      li.price_field_value_id,
      li.financial_type_id,
      li.tax_amount,
      pfv.description';

    $condition = "li.entity_id = civicrm_%2.id AND li.entity_table = 'civicrm_%2'";
    if ($relatedEntity) {
      $condition = 'li.contribution_id = civicrm_%2.id ';
    }

    $fromClause = "
      FROM civicrm_%2
      LEFT JOIN civicrm_line_item li ON ({$condition})
      LEFT JOIN civicrm_price_field_value pfv ON (pfv.id = li.price_field_value_id)
      LEFT JOIN civicrm_price_field pf ON (pf.id = li.price_field_id )";
    $whereClause = " WHERE civicrm_%2.id = %1";
    $orderByClause = " ORDER BY pf.weight, pfv.weight";

    if ($isQuick) {
      $fromClause .= " LEFT JOIN civicrm_price_set cps on cps.id = pf.price_set_id ";
      $whereClause .= " and cps.is_quick_config = 0";
    }

    if (!$isQtyZero) {
      $whereClause .= " and li.qty != 0";
    }

    $lineItems = [];

    if (!$entityId || !$entity || !$fromClause) {
      return $lineItems;
    }

    $params = [
      1 => [$entityId, 'Integer'],
      2 => [$entity, 'Text'],
    ];

    $getTaxDetails = FALSE;
    $invoiceSettings = Civi::settings()->get('contribution_invoice_settings');
    $invoicing = $invoiceSettings['invoicing'] ?? NULL;

    $dao = CRM_Core_DAO::executeQuery("$selectClause $fromClause $whereClause $orderByClause", $params);
    while ($dao->fetch()) {
      if (!$dao->id) {
        continue;
      }
      $lineItems[$dao->id] = [
        'qty' => (float) $dao->qty,
        'label' => $dao->label,
        'unit_price' => $dao->unit_price,
        'line_total' => $dao->line_total,
        'price_field_id' => $dao->price_field_id,
        'participant_count' => $dao->participant_count,
        'price_field_value_id' => $dao->price_field_value_id,
        'field_title' => $dao->field_title,
        'html_type' => $dao->html_type,
        'description' => $dao->description,
        'entity_id' => $dao->entity_id,
        'entity_table' => $dao->entity_table,
        'contribution_id' => $dao->contribution_id,
        'financial_type_id' => $dao->financial_type_id,
        'financial_type' => CRM_Core_PseudoConstant::getLabel('CRM_Contribute_BAO_Contribution', 'financial_type_id', $dao->financial_type_id),
        'membership_type_id' => $dao->membership_type_id,
        'membership_num_terms' => $dao->membership_num_terms,
        'tax_amount' => (float) $dao->tax_amount,
        'price_set_id' => $dao->price_set_id,
      ];
      $taxRates = CRM_Core_PseudoConstant::getTaxRates();
      if (isset($lineItems[$dao->id]['financial_type_id']) && array_key_exists($lineItems[$dao->id]['financial_type_id'], $taxRates)) {
        // Cast to float so trailing zero decimals are removed for display.
        $lineItems[$dao->id]['tax_rate'] = (float) $taxRates[$lineItems[$dao->id]['financial_type_id']];
      }
      else {
        // There is no Tax Rate associated with this Financial Type
        $lineItems[$dao->id]['tax_rate'] = FALSE;
      }
      $lineItems[$dao->id]['subTotal'] = $lineItems[$dao->id]['qty'] * $lineItems[$dao->id]['unit_price'];
      if ($lineItems[$dao->id]['tax_amount'] != '') {
        $getTaxDetails = TRUE;
      }
    }
    if ($invoicing) {
      // @todo - this is an inappropriate place to be doing form level assignments.
      $taxTerm = Civi::settings()->get('tax_term');
      $smarty = CRM_Core_Smarty::singleton();
      $smarty->assign('taxTerm', $taxTerm);
      $smarty->assign('getTaxDetails', $getTaxDetails);
    }
    return $lineItems;
  }

  /**
   * This method will create the lineItem array required for
   * processAmount method
   *
   * @param int $fid
   *   Price set field id.
   * @param array $params
   *   Reference to form values.
   * @param array $fields
   *   Array of fields belonging to the price set used for particular event
   * @param array $values
   *   Reference to the values array(.
   *   this is
   *                          lineItem array)
   * @param string $amount_override
   *   Amount override must be in format 1000.00 - ie no thousand separator & if
   *   a decimal point is used it should be a decimal
   *
   * @todo - this parameter is only used for partial payments. It's unclear why a partial
   *  payment would change the line item price.
   */
  public static function format($fid, $params, $fields, &$values, $amount_override = NULL) {
    if (empty($params["price_{$fid}"])) {
      return;
    }

    //lets first check in fun parameter,
    //since user might modified w/ hooks.
    $options = [];
    if (array_key_exists('options', $fields)) {
      $options = $fields['options'];
    }
    else {
      CRM_Price_BAO_PriceFieldValue::getValues($fid, $options, 'weight', TRUE);
    }
    $fieldTitle = $fields['label'] ?? NULL;
    if (!$fieldTitle) {
      $fieldTitle = CRM_Core_DAO::getFieldValue('CRM_Price_DAO_PriceField', $fid, 'label');
    }

    foreach ($params["price_{$fid}"] as $oid => $qty) {
      $price = $amount_override === NULL ? $options[$oid]['amount'] : $amount_override;

      $participantsPerField = CRM_Utils_Array::value('count', $options[$oid], 0);

      $values[$oid] = [
        'price_field_id' => $fid,
        'price_field_value_id' => $oid,
        'label' => $options[$oid]['label'] ?? NULL,
        'field_title' => $fieldTitle,
        'description' => $options[$oid]['description'] ?? NULL,
        'qty' => $qty,
        'unit_price' => $price,
        'line_total' => $qty * $price,
        'participant_count' => $qty * $participantsPerField,
        'max_value' => $options[$oid]['max_value'] ?? NULL,
        'membership_type_id' => $options[$oid]['membership_type_id'] ?? NULL,
        'membership_num_terms' => $options[$oid]['membership_num_terms'] ?? NULL,
        'auto_renew' => $options[$oid]['auto_renew'] ?? NULL,
        'html_type' => $fields['html_type'],
        'financial_type_id' => $options[$oid]['financial_type_id'] ?? NULL,
        'tax_amount' => CRM_Utils_Array::value('tax_amount', $options[$oid], 0),
        'non_deductible_amount' => $options[$oid]['non_deductible_amount'] ?? NULL,
      ];

      if ($values[$oid]['membership_type_id'] && empty($values[$oid]['auto_renew'])) {
        $values[$oid]['auto_renew'] = CRM_Core_DAO::getFieldValue('CRM_Member_DAO_MembershipType', $values[$oid]['membership_type_id'], 'auto_renew');
      }
    }
  }

  /**
   * Delete line items for given entity.
   *
   * @param int $entityId
   * @param int $entityTable
   *
   * @return bool
   */
  public static function deleteLineItems($entityId, $entityTable) {
    if (!$entityId || !$entityTable) {
      return FALSE;
    }

    if ($entityId && !is_array($entityId)) {
      $entityId = [$entityId];
    }

    $query = "DELETE FROM civicrm_line_item where entity_id IN ('" . implode("','", $entityId) . "') AND entity_table = '$entityTable'";
    $dao = CRM_Core_DAO::executeQuery($query);
    return TRUE;
  }

  /**
   * Process price set and line items.
   *
   * @param int $entityId
   * @param array $lineItems
   *   Line item array.
   * @param object $contributionDetails
   * @param string $entityTable
   *   Entity table.
   *
   * @param bool $update
   *
   * @throws \CRM_Core_Exception
   * @throws \CiviCRM_API3_Exception
   */
  public static function processPriceSet($entityId, $lineItems, $contributionDetails = NULL, $entityTable = 'civicrm_contribution', $update = FALSE) {
    if (!$entityId || !is_array($lineItems)
      || CRM_Utils_System::isNull($lineItems)
    ) {
      return;
    }

    foreach ($lineItems as $priceSetId => &$values) {
      if (!$priceSetId) {
        continue;
      }

      foreach ($values as &$line) {
        if (empty($line['entity_table'])) {
          $line['entity_table'] = $entityTable;
        }
        if (empty($line['entity_id'])) {
          $line['entity_id'] = $entityId;
        }
        if (!empty($line['membership_type_id'])) {
          $line['entity_table'] = 'civicrm_membership';
        }
        if (!empty($contributionDetails->id)) {
          $line['contribution_id'] = $contributionDetails->id;
          if ($line['entity_table'] == 'civicrm_contribution') {
            $line['entity_id'] = $contributionDetails->id;
          }
          // CRM-19094: entity_table is set to civicrm_membership then ensure
          // the entityId is set to membership ID not contribution by default
          elseif ($line['entity_table'] == 'civicrm_membership' && !empty($line['entity_id']) && $line['entity_id'] == $contributionDetails->id) {
            $membershipId = CRM_Core_DAO::getFieldValue('CRM_Member_DAO_MembershipPayment', $contributionDetails->id, 'membership_id', 'contribution_id');
            if ($membershipId && (int) $membershipId !== (int) $line['entity_id']) {
              $line['entity_id'] = $membershipId;
              Civi::log()->warning('Per https://lab.civicrm.org/dev/core/issues/15 this data fix should not be required. Please log a ticket at https://lab.civicrm.org/dev/core with steps to get this.', ['civi.tag' => 'deprecated']);
            }
          }
        }

        // if financial type is not set and if price field value is NOT NULL
        // get financial type id of price field value
        if (!empty($line['price_field_value_id']) && empty($line['financial_type_id'])) {
          $line['financial_type_id'] = CRM_Core_DAO::getFieldValue('CRM_Price_DAO_PriceFieldValue', $line['price_field_value_id'], 'financial_type_id');
        }
        $createdLineItem = CRM_Price_BAO_LineItem::create($line);
        if (!$update && $contributionDetails) {
          $financialItem = CRM_Financial_BAO_FinancialItem::add($createdLineItem, $contributionDetails);
          $line['financial_item_id'] = $financialItem->id;
          if (!empty($line['tax_amount'])) {
            CRM_Financial_BAO_FinancialItem::add($createdLineItem, $contributionDetails, TRUE);
          }
        }
      }
    }
    if (!$update && $contributionDetails) {
      CRM_Core_BAO_FinancialTrxn::createDeferredTrxn($lineItems, $contributionDetails);
    }
  }

  /**
   * @param int $entityId
   * @param string $entityTable
   * @param $amount
   * @param array $otherParams
   */
  public static function syncLineItems($entityId, $entityTable = 'civicrm_contribution', $amount, $otherParams = NULL) {
    if (!$entityId || CRM_Utils_System::isNull($amount)) {
      return;
    }

    $from = " civicrm_line_item li
      LEFT JOIN   civicrm_price_field pf ON pf.id = li.price_field_id
      LEFT JOIN   civicrm_price_set ps ON ps.id = pf.price_set_id ";

    $set = " li.unit_price = %3,
      li.line_total = %3 ";

    $where = " li.entity_id = %1 AND
      li.entity_table = %2 ";

    $params = [
      1 => [$entityId, 'Integer'],
      2 => [$entityTable, 'String'],
      3 => [$amount, 'Float'],
    ];

    if ($entityTable == 'civicrm_contribution') {
      $entityName = 'default_contribution_amount';
      $where .= " AND ps.name = %4 ";
      $params[4] = [$entityName, 'String'];
    }
    elseif ($entityTable == 'civicrm_participant') {
      $from .= "
        LEFT JOIN civicrm_price_set_entity cpse ON cpse.price_set_id = ps.id
        LEFT JOIN civicrm_price_field_value cpfv ON cpfv.price_field_id = pf.id and cpfv.label = %4 ";
      $set .= " ,li.label = %4,
        li.price_field_value_id = cpfv.id ";
      $where .= " AND cpse.entity_table = 'civicrm_event' AND cpse.entity_id = %5 ";
      $amount = empty($amount) ? 0 : $amount;
      $params += [
        4 => [$otherParams['fee_label'], 'String'],
        5 => [$otherParams['event_id'], 'String'],
      ];
    }

    $query = "
      UPDATE $from
      SET    $set
      WHERE  $where
      ";

    CRM_Core_DAO::executeQuery($query, $params);
  }

  /**
   * Build line items array.
   *
   * @param array $params
   *   Form values.
   *
   * @param string $entityId
   *   Entity id.
   *
   * @param string $entityTable
   *   Entity Table.
   *
   * @param bool $isRelatedID
   */
  public static function getLineItemArray(&$params, $entityId = NULL, $entityTable = 'contribution', $isRelatedID = FALSE) {
    if (!$entityId) {
      $priceSetDetails = CRM_Price_BAO_PriceSet::getDefaultPriceSet($entityTable);
      $totalAmount = CRM_Utils_Array::value('partial_payment_total', $params, CRM_Utils_Array::value('total_amount', $params));
      $financialType = $params['financial_type_id'] ?? NULL;
      foreach ($priceSetDetails as $values) {
        if ($entityTable == 'membership') {
          if ($isRelatedID != $values['membership_type_id']) {
            continue;
          }
          if (!$totalAmount) {
            $totalAmount = $values['amount'];
          }
          $financialType = $values['financial_type_id'];
        }
        $params['line_item'][$values['setID']][$values['priceFieldID']] = [
          'price_field_id' => $values['priceFieldID'],
          'price_field_value_id' => $values['priceFieldValueID'],
          'label' => $values['label'],
          'qty' => 1,
          'unit_price' => $totalAmount,
          'line_total' => $totalAmount,
          'financial_type_id' => $financialType,
          'membership_type_id' => $values['membership_type_id'],
        ];
        break;
      }
    }
    else {
      $setID = NULL;
      $totalEntityId = count($entityId);
      if ($entityTable == 'contribution') {
        $isRelatedID = TRUE;
      }
      foreach ($entityId as $id) {
        $lineItems = CRM_Price_BAO_LineItem::getLineItems($id, $entityTable, FALSE, TRUE, $isRelatedID);
        foreach ($lineItems as $key => $values) {
          if (!$setID && $values['price_field_id']) {
            $setID = CRM_Core_DAO::getFieldValue('CRM_Price_DAO_PriceField', $values['price_field_id'], 'price_set_id');
            $params['is_quick_config'] = CRM_Core_DAO::getFieldValue('CRM_Price_DAO_PriceSet', $setID, 'is_quick_config');
          }
          if (!empty($params['is_quick_config']) && array_key_exists('total_amount', $params)
            && $totalEntityId == 1
          ) {
            $values['line_total'] = $values['unit_price'] = $params['total_amount'];
          }
          $values['id'] = $key;
          $params['line_item'][$setID][$key] = $values;
        }
      }
    }
  }

  /**
   * Build the line items for the submitted price field.
   *
   * This is when first building them - not an update where an entityId is already present
   * as this is intended as a subfunction of that. Ideally getLineItemArray would call this
   * (resolving to the same format regardless of what type of price set is being used first).
   *
   * @param array $priceParams
   *   These are per the way the form processes them - ie
   *   ['price_1' => 1, 'price_2' => 8]
   *   This would mean price field id 1, option 1 (or 1 unit if using is_enter_qty).
   * @param float|null $overrideAmount
   *   Optional override of the amount.
   *
   * @param int|null $financialTypeID
   *   Financial type ID is the type should be overridden.
   *
   * @return array
   *   Line items formatted for processing. These will look like
   *   [4] => ['price_field_id' => 4, 'price_field_value_id' => x, 'label....qty...unit_price...line_total...financial_type_id]
   *   [5] => ['price_field_id' => 5, 'price_field_value_id' => x, 'label....qty...unit_price...line_total...financial_type_id]
   *
   */
  public static function buildLineItemsForSubmittedPriceField($priceParams, $overrideAmount = NULL, $financialTypeID = NULL) {
    $lineItems = [];
    foreach ($priceParams as $key => $value) {
      $priceField = self::getPriceFieldMetaData($key);

      if ($priceField['html_type'] === 'Text') {
        $valueSpec = reset($priceField['values']);
      }
      else {
        $valueSpec = $priceField['values'][$value];
      }
      $qty = $priceField['is_enter_qty'] ? $value : 1;
      $lineItems[$priceField['id']] = [
        'price_field_id' => $priceField['id'],
        'price_field_value_id' => $valueSpec['id'],
        'label' => $valueSpec['label'],
        'qty' => $qty,
        'unit_price' => $overrideAmount ?: $valueSpec['amount'],
        'line_total' => $qty * ($overrideAmount ?: $valueSpec['amount']),
        'financial_type_id' => $financialTypeID ?: $valueSpec['financial_type_id'],
        'membership_type_id' => $valueSpec['membership_type_id'],
        'price_set_id' => $priceField['price_set_id'],
      ];
    }
    return $lineItems;
  }

  /**
   * Function to update related contribution of a entity and
   *  add/update/cancel financial records
   *
   * @param array $params
   * @param int $entityID
   * @param int $entity
   * @param int $contributionId
   * @param $feeBlock
   * @param array $lineItems
   *
   * @throws \CiviCRM_API3_Exception
   */
  public static function changeFeeSelections(
    $params,
    $entityID,
    $entity,
    $contributionId,
    $feeBlock,
    $lineItems
  ) {
    $entityTable = "civicrm_" . $entity;
    CRM_Price_BAO_PriceSet::processAmount($feeBlock,
      $params, $lineItems
    );
    // initialize empty Lineitem instance to call protected helper functions
    $lineItemObj = new CRM_Price_BAO_LineItem();

    // fetch submitted LineItems from input params and feeBlock information
    $submittedLineItems = $lineItemObj->getSubmittedLineItems($params, $feeBlock);

    $requiredChanges = $lineItemObj->getLineItemsToAlter($submittedLineItems, $entityID, $entity);

    // get financial information that need to be recorded on basis on submitted price field value IDs
    if (!empty($requiredChanges['line_items_to_cancel']) || !empty($requiredChanges['line_items_to_update'])) {
      // @todo - this IF is to get this through PR merge but I suspect that it should not
      // be necessary & is masking something else.
      $financialItemsArray = $lineItemObj->getAdjustedFinancialItemsToRecord(
        $entityID,
        $entityTable,
        $contributionId,
        array_keys($requiredChanges['line_items_to_cancel']),
        $requiredChanges['line_items_to_update']
      );
    }

    // update line item with changed line total and other information
    $totalParticipant = $participantCount = 0;
    $amountLevel = [];
    if (!empty($requiredChanges['line_items_to_update'])) {
      foreach ($requiredChanges['line_items_to_update'] as $priceFieldValueID => $value) {
        $amountLevel[] = $value['label'] . ' - ' . (float) $value['qty'];
        if ($entity == 'participant' && isset($value['participant_count'])) {
          $totalParticipant += $value['participant_count'];
        }
      }
    }

    foreach (array_merge($requiredChanges['line_items_to_resurrect'], $requiredChanges['line_items_to_cancel'], $requiredChanges['line_items_to_update']) as $lineItemToAlter) {
      // Must use BAO rather than api because a bad line it in the api which we want to avoid.
      CRM_Price_BAO_LineItem::create($lineItemToAlter);
    }

    $lineItemObj->addLineItemOnChangeFeeSelection($requiredChanges['line_items_to_add'], $entityID, $entityTable, $contributionId);

    $count = 0;
    if ($entity == 'participant') {
      $count = count(CRM_Event_BAO_Participant::getParticipantIds($contributionId));
    }
    else {
      $count = CRM_Utils_Array::value('count', civicrm_api3('MembershipPayment', 'getcount', ['contribution_id' => $contributionId]));
    }
    if ($count > 1) {
      $updatedAmount = CRM_Price_BAO_LineItem::getLineTotal($contributionId);
    }
    else {
      $updatedAmount = CRM_Utils_Array::value('amount', $params, CRM_Utils_Array::value('total_amount', $params));
    }
    if (strlen($params['tax_amount']) != 0) {
      $taxAmount = $params['tax_amount'];
    }
    else {
      $taxAmount = "NULL";
    }
    $displayParticipantCount = '';
    if ($totalParticipant > 0) {
      $displayParticipantCount = ' Participant Count -' . $totalParticipant;
    }
    $updateAmountLevel = NULL;
    if (!empty($amountLevel)) {
      $updateAmountLevel = CRM_Core_DAO::VALUE_SEPARATOR . implode(CRM_Core_DAO::VALUE_SEPARATOR, $amountLevel) . $displayParticipantCount . CRM_Core_DAO::VALUE_SEPARATOR;
    }
    $trxn = $lineItemObj->_recordAdjustedAmt($updatedAmount, $contributionId, $taxAmount, $updateAmountLevel);
    $contributionStatus = CRM_Core_PseudoConstant::getName('CRM_Contribute_DAO_Contribution', 'contribution_status_id', CRM_Core_DAO::getFieldValue('CRM_Contribute_DAO_Contribution', $contributionId, 'contribution_status_id'));

    if (!empty($financialItemsArray)) {
      foreach ($financialItemsArray as $updateFinancialItemInfoValues) {
        $newFinancialItem = CRM_Financial_BAO_FinancialItem::create($updateFinancialItemInfoValues);
        // record reverse transaction only if Contribution is Completed because for pending refund or
        //   partially paid we are already recording the surplus owed or refund amount
        if (!empty($updateFinancialItemInfoValues['financialTrxn']) && ($contributionStatus == 'Completed')) {
          $updateFinancialItemInfoValues = array_merge($updateFinancialItemInfoValues['financialTrxn'], [
            'entity_id' => $newFinancialItem->id,
            'entity_table' => 'civicrm_financial_item',
          ]);
          $reverseTrxn = CRM_Core_BAO_FinancialTrxn::create($updateFinancialItemInfoValues);
          // record reverse entity financial trxn linked to membership's related contribution
          civicrm_api3('EntityFinancialTrxn', 'create', [
            'entity_table' => "civicrm_contribution",
            'entity_id' => $contributionId,
            'financial_trxn_id' => $reverseTrxn->id,
            'amount' => $reverseTrxn->total_amount,
          ]);
          unset($updateFinancialItemInfoValues['financialTrxn']);
        }
        elseif ($trxn && $newFinancialItem->amount != 0) {
          civicrm_api3('EntityFinancialTrxn', 'create', [
            'entity_id' => $newFinancialItem->id,
            'entity_table' => 'civicrm_financial_item',
            'financial_trxn_id' => $trxn->id,
            'amount' => $newFinancialItem->amount,
          ]);
        }
      }
    }

    $lineItemObj->addFinancialItemsOnLineItemsChange(array_merge($requiredChanges['line_items_to_add'], $requiredChanges['line_items_to_resurrect']), $entityID, $entityTable, $contributionId, $trxn->id ?? NULL);

    // update participant fee_amount column
    $lineItemObj->updateEntityRecordOnChangeFeeSelection($params, $entityID, $entity);
  }

  /**
   * Function to retrieve financial items that need to be recorded as result of changed fee
   *
   * @param int $entityID
   * @param string $entityTable
   * @param int $contributionID
   * @param array $priceFieldValueIDsToCancel
   * @param array $lineItemsToUpdate
   *
   * @return array
   *   List of formatted reverse Financial Items to be recorded
   */
  protected function getAdjustedFinancialItemsToRecord($entityID, $entityTable, $contributionID, $priceFieldValueIDsToCancel, $lineItemsToUpdate) {
    $previousLineItems = CRM_Price_BAO_LineItem::getLineItems($entityID, str_replace('civicrm_', '', $entityTable));

    $financialItemsArray = [];
    $financialItemResult = $this->getNonCancelledFinancialItems($entityID, $entityTable);
    foreach ($financialItemResult as $updateFinancialItemInfoValues) {
      $updateFinancialItemInfoValues['transaction_date'] = date('YmdHis');

      // the below params are not needed as we are creating new financial item
      $previousFinancialItemID = $updateFinancialItemInfoValues['id'];
      $totalFinancialAmount = $this->checkFinancialItemTotalAmountByLineItemID($updateFinancialItemInfoValues['entity_id']);
      unset($updateFinancialItemInfoValues['id']);
      unset($updateFinancialItemInfoValues['created_date']);
      $previousLineItem = $previousLineItems[$updateFinancialItemInfoValues['entity_id']];

      // if not submitted and difference is not 0 make it negative
      if ((empty($lineItemsToUpdate) || (in_array($updateFinancialItemInfoValues['price_field_value_id'], $priceFieldValueIDsToCancel) &&
          $totalFinancialAmount == $updateFinancialItemInfoValues['amount'])
        ) && $updateFinancialItemInfoValues['amount'] > 0
      ) {

        // INSERT negative financial_items
        $updateFinancialItemInfoValues['amount'] = -$updateFinancialItemInfoValues['amount'];
        // reverse the related financial trxn too
        $updateFinancialItemInfoValues['financialTrxn'] = $this->getRelatedCancelFinancialTrxn($previousFinancialItemID);
        if ($previousLineItems[$updateFinancialItemInfoValues['entity_id']]['tax_amount']) {
          $updateFinancialItemInfoValues['tax']['amount'] = -($previousLineItem['tax_amount']);
          $updateFinancialItemInfoValues['tax']['description'] = $this->getSalesTaxTerm();
        }
        // INSERT negative financial_items for tax amount
        $financialItemsArray[$updateFinancialItemInfoValues['entity_id']] = $updateFinancialItemInfoValues;
      }
      // INSERT a financial item to record surplus/lesser amount when a text price fee is changed
      elseif (
        !empty($lineItemsToUpdate)
        && isset($lineItemsToUpdate[$updateFinancialItemInfoValues['price_field_value_id']])
        && $lineItemsToUpdate[$updateFinancialItemInfoValues['price_field_value_id']]['html_type'] == 'Text'
        && $updateFinancialItemInfoValues['amount'] > 0
      ) {
        $amountChangeOnTextLineItem = $lineItemsToUpdate[$updateFinancialItemInfoValues['price_field_value_id']]['line_total'] - $totalFinancialAmount;
        if ($amountChangeOnTextLineItem !== (float) 0) {
          // calculate the amount difference, considered as financial item amount
          $updateFinancialItemInfoValues['amount'] = $amountChangeOnTextLineItem;
          if ($previousLineItem['tax_amount']
            && $previousLineItems[$updateFinancialItemInfoValues['entity_id']]['tax_amount'] !== 0.00) {
            $updateFinancialItemInfoValues['tax']['amount'] = $lineItemsToUpdate[$updateFinancialItemInfoValues['entity_id']]['tax_amount'] - $previousLineItem['tax_amount'];
            $updateFinancialItemInfoValues['tax']['description'] = $this->getSalesTaxTerm();
          }
          $financialItemsArray[$updateFinancialItemInfoValues['entity_id']] = $updateFinancialItemInfoValues;
        }
      }
    }

    return $financialItemsArray;
  }

  /**
   * Helper function to return sum of financial item's amount related to a line-item
   * @param array $lineItemID
   *
   * @return float $financialItem
   */
  protected function checkFinancialItemTotalAmountByLineItemID($lineItemID) {
    return CRM_Core_DAO::singleValueQuery("
      SELECT SUM(amount)
      FROM civicrm_financial_item
      WHERE entity_table = 'civicrm_line_item' AND entity_id = {$lineItemID}
    ");
  }

  /**
   * Helper function to retrieve submitted line items from form values $inputParams and used $feeBlock
   *
   * @param array $inputParams
   * @param array $feeBlock
   *
   * @return array
   *   List of submitted line items
   */
  protected function getSubmittedLineItems($inputParams, $feeBlock) {
    $submittedLineItems = [];
    foreach ($feeBlock as $id => $values) {
      CRM_Price_BAO_LineItem::format($id, $inputParams, $values, $submittedLineItems);
    }

    return $submittedLineItems;
  }

  /**
   *  Helper function to retrieve line items that need to be altered.
   *
   * We iterate through the previous line items for the given entity to determine
   * what alterations to line items need to be made to reflect the new line items.
   *
   * There are 4 possible changes required - per the keys in the return array.
   *
   * @param array $submittedLineItems
   * @param int $entityID
   * @param string $entity
   *
   * @return array
   *   Array of line items to alter with the following keys
   *   - line_items_to_add. If the line items required are new radio options that
   *     have not previously been set then we should add line items for them
   *   - line_items_to_update. If we have already been an active option and a change has
   *     happened then it should be in this array.
   *   - line_items_to_cancel. Line items currently selected but not selected in the new selection.
   *     These need to be zero'd out.
   *   - line_items_to_resurrect. Line items previously selected and then deselected. These need to be
   *     re-enabled rather than a new one added.
   */
  protected function getLineItemsToAlter($submittedLineItems, $entityID, $entity) {
    $previousLineItems = CRM_Price_BAO_LineItem::getLineItems($entityID, $entity);

    $lineItemsToAdd = $submittedLineItems;
    $lineItemsToUpdate = [];
    $submittedPriceFieldValueIDs = array_keys($submittedLineItems);
    $lineItemsToCancel = $lineItemsToResurrect = [];

    foreach ($previousLineItems as $id => $previousLineItem) {
      if (in_array($previousLineItem['price_field_value_id'], $submittedPriceFieldValueIDs)) {
        $submittedLineItem = $submittedLineItems[$previousLineItem['price_field_value_id']];
        if (CRM_Utils_Array::value('html_type', $lineItemsToAdd[$previousLineItem['price_field_value_id']]) == 'Text') {
          // If a 'Text' price field was updated by changing qty value, then we are not adding new line-item but updating the existing one,
          //  because unlike other kind of price-field, it's related price-field-value-id isn't changed and thats why we need to make an
          //  exception here by adding financial item for updated line-item and will reverse any previous financial item entries.
          $lineItemsToUpdate[$previousLineItem['price_field_value_id']] = array_merge($submittedLineItem, ['id' => $id]);
          unset($lineItemsToAdd[$previousLineItem['price_field_value_id']]);
        }
        else {
          $submittedLineItem = $submittedLineItems[$previousLineItem['price_field_value_id']];
          // for updating the line items i.e. use-case - once deselect-option selecting again
          if (($previousLineItem['line_total'] != $submittedLineItem['line_total'])
            || (
              // This would be a $0 line item - but why it should be catered to
              // other than when the above condition is unclear.
              $submittedLineItem['line_total'] == 0 && $submittedLineItem['qty'] == 1
            )
            || (
              $previousLineItem['qty'] != $submittedLineItem['qty']
            )
          ) {
            $lineItemsToUpdate[$previousLineItem['price_field_value_id']] = $submittedLineItem;
            $lineItemsToUpdate[$previousLineItem['price_field_value_id']]['id'] = $id;
            // Format is actually '0.00'
            if ($previousLineItem['line_total'] == 0) {
              $lineItemsToAdd[$previousLineItem['price_field_value_id']]['id'] = $id;
              $lineItemsToResurrect[] = $lineItemsToAdd[$previousLineItem['price_field_value_id']];
            }
          }
          // If there was previously a submitted line item for the same option value then there is
          // either no change or a qty adjustment. In either case we are not doing an add + reversal.
          unset($lineItemsToAdd[$previousLineItem['price_field_value_id']]);
          unset($lineItemsToCancel[$previousLineItem['price_field_value_id']]);
        }
      }
      else {
        if (!$this->isCancelled($previousLineItem)) {
          $cancelParams = ['qty' => 0, 'line_total' => 0, 'tax_amount' => 0, 'participant_count' => 0, 'non_deductible_amount' => 0, 'id' => $id];
          $lineItemsToCancel[$previousLineItem['price_field_value_id']] = array_merge($previousLineItem, $cancelParams);

        }
      }
    }

    return [
      'line_items_to_add' => $lineItemsToAdd,
      'line_items_to_update' => $lineItemsToUpdate,
      'line_items_to_cancel' => $lineItemsToCancel,
      'line_items_to_resurrect' => $lineItemsToResurrect,
    ];
  }

  /**
   * Check if a line item has already been cancelled.
   *
   * @param array $lineItem
   *
   * @return bool
   */
  protected function isCancelled($lineItem) {
    if ($lineItem['qty'] == 0 && $lineItem['line_total'] == 0) {
      return TRUE;
    }
  }

  /**
   * Add line Items as result of fee change.
   *
   * @param array $lineItemsToAdd
   * @param int $entityID
   * @param string $entityTable
   * @param int $contributionID
   */
  protected function addLineItemOnChangeFeeSelection(
    $lineItemsToAdd,
    $entityID,
    $entityTable,
    $contributionID
  ) {
    // if there is no line item to add, do not proceed
    if (empty($lineItemsToAdd)) {
      return;
    }

    $changedFinancialTypeID = NULL;
    $updatedContribution = new CRM_Contribute_BAO_Contribution();
    $updatedContribution->id = (int) $contributionID;
    // insert financial items
    foreach ($lineItemsToAdd as $priceFieldValueID => $lineParams) {
      $lineParams = array_merge($lineParams, [
        'entity_table' => $entityTable,
        'entity_id' => $entityID,
        'contribution_id' => $contributionID,
      ]);
      if (!array_key_exists('skip', $lineParams)) {
        self::create($lineParams);
      }
    }

    if ($changedFinancialTypeID) {
      $updatedContribution->financial_type_id = $changedFinancialTypeID;
      $updatedContribution->save();
    }
  }

  /**
   * Add financial transactions when an array of line items is changed.
   *
   * @param array $lineItemsToAdd
   * @param int $entityID
   * @param string $entityTable
   * @param int $contributionID
   * @param bool $trxnID
   *   Is there a change to the total balance requiring additional transactions to be created.
   */
  protected function addFinancialItemsOnLineItemsChange($lineItemsToAdd, $entityID, $entityTable, $contributionID, $trxnID) {
    $updatedContribution = new CRM_Contribute_BAO_Contribution();
    $updatedContribution->id = $contributionID;
    $updatedContribution->find(TRUE);
    $trxnArray = $trxnID ? ['id' => $trxnID] : NULL;

    foreach ($lineItemsToAdd as $priceFieldValueID => $lineParams) {
      $lineParams = array_merge($lineParams, [
        'entity_table' => $entityTable,
        'entity_id' => $entityID,
        'contribution_id' => $contributionID,
      ]);
      $lineObj = CRM_Price_BAO_LineItem::retrieve($lineParams);
      // insert financial items
      // ensure entity_financial_trxn table has a linking of it.
      CRM_Financial_BAO_FinancialItem::add($lineObj, $updatedContribution, NULL, $trxnArray);
      if (isset($lineObj->tax_amount) && (float) $lineObj->tax_amount !== 0.00) {
        CRM_Financial_BAO_FinancialItem::add($lineObj, $updatedContribution, TRUE, $trxnArray);
      }
    }
  }

  /**
   * Helper function to update entity record on change fee selection
   *
   * @param array $inputParams
   * @param int $entityID
   * @param string $entity
   *
   */
  protected function updateEntityRecordOnChangeFeeSelection($inputParams, $entityID, $entity) {
    $entityTable = "civicrm_{$entity}";

    if ($entity == 'participant') {
      $partUpdateFeeAmt = ['id' => $entityID];
      $getUpdatedLineItems = "SELECT *
        FROM civicrm_line_item
        WHERE (entity_table = '{$entityTable}' AND entity_id = {$entityID} AND qty > 0)";
      $getUpdatedLineItemsDAO = CRM_Core_DAO::executeQuery($getUpdatedLineItems);
      $line = [];
      while ($getUpdatedLineItemsDAO->fetch()) {
        $line[$getUpdatedLineItemsDAO->price_field_value_id] = $getUpdatedLineItemsDAO->label . ' - ' . (float) $getUpdatedLineItemsDAO->qty;
      }

      $partUpdateFeeAmt['fee_level'] = implode(', ', $line);
      $partUpdateFeeAmt['fee_amount'] = $inputParams['amount'];
      CRM_Event_BAO_Participant::add($partUpdateFeeAmt);

      //activity creation
      CRM_Event_BAO_Participant::addActivityForSelection($entityID, 'Change Registration');
    }
  }

  /**
   * Get the metadata for a price field.
   *
   * @param string|int $key
   *   Price field id. Either as an integer or as 'price_4' where 4 is the id
   *
   * @return array
   *   Metadata for the price field with a values key for option values.
   */
  protected static function getPriceFieldMetaData($key) {
    $priceFieldID = str_replace('price_', '', $key);
    if (!isset(Civi::$statics[__CLASS__]['price_fields'][$priceFieldID])) {
      $values = civicrm_api3('PriceFieldValue', 'get', [
        'price_field_id' => $priceFieldID,
        'return' => [
          'id',
          'amount',
          'financial_type_id',
          'membership_type_id',
          'label',
          'price_field_id',
          'price_field_id.price_set_id',
          'price_field_id.html_type',
          'is_enter_qty',
        ],
      ]);
      $firstValue = reset($values['values']);
      $values = $values['values'];
      foreach ($values as $index => $value) {
        // Let's be nice to calling functions & ensure membership_type_id is set
        // so they don't have to handle notices on it. Handle one place not many.
        if (!isset($value['membership_type_id'])) {
          $values[$index]['membership_type_id'] = NULL;
        }
      }

      Civi::$statics[__CLASS__]['price_fields'][$priceFieldID] = [
        'price_set_id' => $firstValue['price_field_id.price_set_id'],
        'id' => $firstValue['price_field_id'],
        'html_type' => $firstValue['price_field_id.html_type'],
        'is_enter_qty' => !empty($firstValue['is_enter_qty']),
        'values' => $values,
      ];
    }
    return Civi::$statics[__CLASS__]['price_fields'][$priceFieldID];
  }

  /**
   * Helper function to retrieve financial trxn parameters to reverse
   *  for given financial item identified by $financialItemID
   *
   * @param int $financialItemID
   *
   * @return array $financialTrxn
   *
   */
  protected function _getRelatedCancelFinancialTrxn($financialItemID) {
    try {
      $financialTrxn = civicrm_api3('EntityFinancialTrxn', 'getsingle', [
        'entity_table' => 'civicrm_financial_item',
        'entity_id' => $financialItemID,
        'options' => [
          'sort' => 'id DESC',
          'limit' => 1,
        ],
        'api.FinancialTrxn.getsingle' => [
          'id' => "\$value.financial_trxn_id",
        ],
      ]);
    }
    catch (CiviCRM_API3_Exception $e) {
      return [];
    }

    $financialTrxn = array_merge($financialTrxn['api.FinancialTrxn.getsingle'], [
      'trxn_date' => date('YmdHis'),
      'total_amount' => -$financialTrxn['api.FinancialTrxn.getsingle']['total_amount'],
      'net_amount' => -$financialTrxn['api.FinancialTrxn.getsingle']['net_amount'],
      'entity_table' => 'civicrm_financial_item',
      'entity_id' => $financialItemID,
    ]);
    unset($financialTrxn['id']);

    return $financialTrxn;
  }

  /**
   * Record adjusted amount.
   *
   * @param int $updatedAmount
   * @param int $contributionId
   * @param int $taxAmount
   * @param bool $updateAmountLevel
   *
   * @return bool|\CRM_Core_BAO_FinancialTrxn
   */
  protected function _recordAdjustedAmt($updatedAmount, $contributionId, $taxAmount = NULL, $updateAmountLevel = NULL) {
    $paidAmount = (float) CRM_Core_BAO_FinancialTrxn::getTotalPayments($contributionId);
    $balanceAmt = $updatedAmount - $paidAmount;

    $contributionStatuses = CRM_Contribute_PseudoConstant::contributionStatus(NULL, 'name');
    $partiallyPaidStatusId = array_search('Partially paid', $contributionStatuses);
    $pendingRefundStatusId = array_search('Pending refund', $contributionStatuses);
    $completedStatusId = array_search('Completed', $contributionStatuses);

    $updatedContributionDAO = new CRM_Contribute_BAO_Contribution();
    $adjustedTrxn = FALSE;
    if ($balanceAmt) {
      if ($paidAmount === 0.0) {
        //skip updating the contribution status if no payment is made
        $updatedContributionDAO->cancel_date = 'null';
        $updatedContributionDAO->cancel_reason = NULL;
      }
      else {
        $updatedContributionDAO->contribution_status_id = $balanceAmt > 0 ? $partiallyPaidStatusId : $pendingRefundStatusId;
      }

      // update contribution status and total amount without trigger financial code
      // as this is handled in current BAO function used for change selection
      $updatedContributionDAO->id = $contributionId;

      $updatedContributionDAO->total_amount = $updatedContributionDAO->net_amount = $updatedAmount;
      $updatedContributionDAO->fee_amount = 0;
      $updatedContributionDAO->tax_amount = $taxAmount;
      if (!empty($updateAmountLevel)) {
        $updatedContributionDAO->amount_level = $updateAmountLevel;
      }
      $updatedContributionDAO->save();
      // adjusted amount financial_trxn creation
      $updatedContribution = CRM_Contribute_BAO_Contribution::getValues(
        ['id' => $contributionId]
      );
      $toFinancialAccount = CRM_Contribute_PseudoConstant::getRelationalFinancialAccount($updatedContribution->financial_type_id, 'Accounts Receivable Account is');
      $adjustedTrxnValues = [
        'from_financial_account_id' => NULL,
        'to_financial_account_id' => $toFinancialAccount,
        'total_amount' => $balanceAmt,
        'net_amount' => $balanceAmt,
        'status_id' => $completedStatusId,
        'payment_instrument_id' => $updatedContribution->payment_instrument_id,
        'contribution_id' => $updatedContribution->id,
        'trxn_date' => date('YmdHis'),
        'currency' => $updatedContribution->currency,
      ];
      $adjustedTrxn = CRM_Core_BAO_FinancialTrxn::create($adjustedTrxnValues);
    }
    // CRM-17151: Update the contribution status to completed if balance is zero,
    //  because due to sucessive fee change will leave the related contribution status incorrect
    else {
      CRM_Core_DAO::setFieldValue('CRM_Contribute_DAO_Contribution', $contributionId, 'contribution_status_id', $completedStatusId);
    }

    return $adjustedTrxn;
  }

  /**
   * Get Financial items, culling out any that have already been reversed.
   *
   * @param int $entityID
   * @param string $entityTable
   *
   * @return array
   *   Array of financial items that have not be reversed.
   */
  protected function getNonCancelledFinancialItems($entityID, $entityTable) {
    // gathering necessary info to record negative (deselected) financial_item
    $updateFinancialItem = "
  SELECT fi.*, price_field_value_id, financial_type_id, tax_amount
    FROM civicrm_financial_item fi LEFT JOIN civicrm_line_item li ON (li.id = fi.entity_id AND fi.entity_table = 'civicrm_line_item')
  WHERE (li.entity_table = '{$entityTable}' AND li.entity_id = {$entityID})
  GROUP BY li.entity_table, li.entity_id, price_field_value_id, fi.id
    ";
    $updateFinancialItemInfoDAO = CRM_Core_DAO::executeQuery($updateFinancialItem);

    $financialItemResult = $updateFinancialItemInfoDAO->fetchAll();
    $items = [];
    foreach ($financialItemResult as $index => $financialItem) {
      $items[$financialItem['price_field_value_id']][$index] = $financialItem['amount'];

      if (!empty($items[$financialItem['price_field_value_id']])) {
        foreach ($items[$financialItem['price_field_value_id']] as $existingItemID => $existingAmount) {
          if ($financialItem['amount'] + $existingAmount == 0) {
            // Filter both rows as they cancel each other out.
            unset($financialItemResult[$index]);
            unset($financialItemResult[$existingItemID]);
            unset($items['price_field_value_id'][$existingItemID]);
            unset($items[$financialItem['price_field_value_id']][$index]);
          }
        }

      }

    }
    return $financialItemResult;
  }

  /**
   * Get the string used to describe the sales tax (eg. VAT, GST).
   *
   * @return string
   */
  protected function getSalesTaxTerm() {
    return CRM_Contribute_BAO_Contribution::checkContributeSettings('tax_term');
  }

}