RoundingUtil.java

/*
 * The contents of this file are subject to the OpenMRS Public 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://license.openmrs.org
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and
 * limitations under the License.
 *
 * Copyright (C) OpenHMIS.  All Rights Reserved.
 */
package org.openmrs.module.openhmis.cashier.api.util;

import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
import java.util.List;

import org.apache.commons.logging.Log;
import org.openmrs.GlobalProperty;
import org.openmrs.api.APIException;
import org.openmrs.api.AdministrationService;
import org.openmrs.api.context.Context;
import org.openmrs.logic.op.In;
import org.openmrs.messagesource.MessageSourceService;
import org.openmrs.module.openhmis.cashier.ModuleSettings;
import org.openmrs.module.openhmis.cashier.api.ICashierOptionsService;
import org.openmrs.module.openhmis.cashier.api.model.Bill;
import org.openmrs.module.openhmis.cashier.api.model.BillLineItem;
import org.openmrs.module.openhmis.cashier.api.model.CashierOptions;
import org.openmrs.module.openhmis.inventory.api.IDepartmentDataService;
import org.openmrs.module.openhmis.inventory.api.IItemDataService;
import org.openmrs.module.openhmis.inventory.api.model.Department;
import org.openmrs.module.openhmis.inventory.api.model.Item;
import org.openmrs.module.openhmis.inventory.api.model.ItemPrice;

/**
 * Utility class for Rounding off bill values
 */
public class RoundingUtil {
	protected RoundingUtil() {}

	public static BigDecimal round(BigDecimal value, Integer nearest, CashierOptions.RoundingMode mode) {
		if (nearest == null || nearest.equals(0)) {
			return value;
		}

		double valueD = value.doubleValue();
		switch (mode) {
			case FLOOR:
				return new BigDecimal(nearest * (Math.floor(Math.abs(valueD / nearest))));
			case CEILING:
				return new BigDecimal(nearest * (Math.ceil(Math.abs(valueD / nearest))));
			case MID:
				return new BigDecimal(nearest * (Math.round(valueD / nearest)));
			default:
				return value;
		}
	}

	public static void setupRoundingDeptAndItem(Log log) {
		/*
		 * Automatically add rounding item & department
		 */
		AdministrationService adminService = Context.getService(AdministrationService.class);

		String nearest = adminService.getGlobalProperty(ModuleSettings.ROUND_TO_NEAREST_PROPERTY);
		if (nearest != null && !nearest.isEmpty() && !nearest.equals("0")) {
			MessageSourceService msgService = Context.getMessageSourceService();
			IDepartmentDataService deptService = Context.getService(IDepartmentDataService.class);
			IItemDataService itemService = Context.getService(IItemDataService.class);
			Integer deptId = parseDepartmentId(adminService);
			Integer itemId = parseItemId(adminService);
			String name = msgService.getMessage("openhmis.cashier.rounding.itemName");
			String description = msgService.getMessage("openhmis.cashier.rounding.itemDescription");
			Department department = null;
			if (deptId == null) {
				department = new Department();
				department.setName(name);
				department.setDescription(description);
				department.setRetired(true);
				department.setRetireReason("Used by Cashier Module for rounding adjustments.");
				deptService.save(department);
				log.info("Created department for rounding item (ID = " + department.getId() + ")...");
				adminService.saveGlobalProperty(new GlobalProperty(ModuleSettings.ROUNDING_DEPT_ID, department.getId()
				        .toString()));
			}

			if (itemId == null) {
				Item item = new Item();
				item.setName(name);
				item.setDescription(description);
				if (department == null) {
					department = Context.getService(IDepartmentDataService.class).getById(deptId);
					if (department == null) {
						throw new APIException(
						        "Department with id " + deptId + " doesn't exist.");
					}
				}

				item.setDepartment(department);
				item.setHasExpiration(false);

				ItemPrice price = item.addPrice(name, BigDecimal.ZERO);
				item.setDefaultPrice(price);
				itemService.save(item);
				log.info("Created item for rounding (ID = " + item.getId() + ")...");
				adminService
				        .saveGlobalProperty(new GlobalProperty(ModuleSettings.ROUNDING_ITEM_ID, item.getId().toString()));
			}
		}
	}

	/**
	 * Add a rounding line item to a bill if necessary
	 * @param bill
	 * @should handle a rounding line item (add/update/delete with the appropriate value)
	 * @should not modify a bill that needs no rounding
	 * @should round bills with a non zero amount correctly for MID
	 * @should round bills with a non zero amount correctly for CEILING
	 * @should round bills with a non zero amount correctly for FLOOR
	 */
	public static void handleRoundingLineItem(Bill bill) {
		ICashierOptionsService cashOptService = Context.getService(ICashierOptionsService.class);
		CashierOptions options = cashOptService.getOptions();
		if (options.getRoundToNearest().equals(BigDecimal.ZERO)) {
			return;
		}

		if (options.getRoundingItemUuid() == null) {
			throw new APIException(
			        "No rounding item specified in options. This must be set in order to use rounding for bill totals.");
		}

		// Get rounding item
		IItemDataService itemService = Context.getService(IItemDataService.class);
		Item roundingItem = itemService.getByUuid(options.getRoundingItemUuid());

		BillLineItem roundingLineItem = findRoundingLineItem(bill, roundingItem);

		BigDecimal difference = calculateRoundingValue(bill, options, roundingLineItem);

		if (difference.equals(BigDecimal.ZERO) && roundingLineItem != null) {
			bill.removeLineItem(roundingLineItem);
		} else if (!difference.equals(BigDecimal.ZERO) && roundingLineItem == null) {
			// Create line item for rounding item and the required amount
			bill.addLineItem(roundingItem, difference.abs(), "", difference.compareTo(BigDecimal.ZERO) > 0 ? -1 : 1);
		} else if (!difference.equals(BigDecimal.ZERO)) {
			updateRoundingItem(bill, difference, roundingLineItem);
		}
		bill.recalculateLineItemOrder();
	}

	private static BillLineItem findRoundingLineItem(Bill bill, Item roundingItem) {
		BillLineItem result = null;
		for (BillLineItem lineItem : bill.getLineItems()) {
			if (roundingItem.equals(lineItem.getItem())) {
				result = lineItem;
				break;
			}
		}
		return result;
	}

	private static void updateRoundingItem(Bill bill, BigDecimal difference, BillLineItem roundingLineItem) {
		roundingLineItem.setPrice(difference.abs());
		roundingLineItem.setQuantity(difference.compareTo(BigDecimal.ZERO) > 0 ? -1 : 1);

		bill.removeLineItem(roundingLineItem);
		bill.addLineItem(roundingLineItem);
	}

	private static BigDecimal calculateRoundingValue(Bill bill, CashierOptions options, BillLineItem roundingLineItem) {
		List<BillLineItem> lineItems = bill.getLineItems();
		BigDecimal itemTotal = new BigDecimal(0);

		if (lineItems == null) {
			return BigDecimal.ZERO;
		}

		for (BillLineItem lineItem : lineItems) {
			if (lineItem != null && !lineItem.getVoided()) {
				if (roundingLineItem == null || !roundingLineItem.equals(lineItem)) {
					itemTotal = itemTotal.add(lineItem.getTotal());
				}
			}
		}

		return itemTotal.subtract(RoundingUtil.round(itemTotal, options.getRoundToNearest(), options.getRoundingMode()));

	}

	private static Integer parseItemId(AdministrationService adminService) {
		Integer itemId;
		try {
			itemId = Integer.parseInt(adminService.getGlobalProperty(ModuleSettings.ROUNDING_ITEM_ID));
		} catch (NumberFormatException e) {
			itemId = null;
		}
		return itemId;
	}

	private static Integer parseDepartmentId(AdministrationService adminService) {
		Integer deptId;
		try {
			deptId = Integer.parseInt(adminService.getGlobalProperty(ModuleSettings.ROUNDING_DEPT_ID));
		} catch (NumberFormatException e) {
			deptId = null;
		}
		return deptId;
	}
}