EDIT

/**

* Copyright (C) 2007 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.cdm.common;

import java.io.FileNotFoundException;

import java.io.InputStream;

import java.text.DateFormat;

import java.text.Format;

import java.util.ArrayList;

import java.util.Date;

import java.util.HashMap;

import java.util.List;

import java.util.Locale;

import java.util.Map;

import org.apache.logging.log4j.LogManager;

import org.apache.logging.log4j.Logger;

import org.apache.poi.hssf.usermodel.HSSFDataFormatter;

import org.apache.poi.ss.usermodel.Cell;

import org.apache.poi.ss.usermodel.CellType;

import org.apache.poi.ss.usermodel.Row;

import org.apache.poi.ss.usermodel.Sheet;

import org.apache.poi.ss.usermodel.Workbook;

import org.apache.poi.ss.usermodel.WorkbookFactory;

/**

 * @author n.hoffmann

 * @since 18.11.2008

 */

public class ExcelUtils {

	private static final Logger logger = LogManager.getLogger();

    /** Reads all rows of an Excel worksheet */

    public static List<Map<String, String>> parseXLS(URI uri) throws FileNotFoundException {

    	return parseXLS(uri, null);

    }

	/** Reads all rows of an Excel worksheet */

    public static List<Map<String, String>> parseXLS(URI uri, String worksheetName) throws FileNotFoundException {

        try {

            InputStream stream = UriUtils.getInputStream(uri);

            return parseXLS(stream, worksheetName);

        } catch(FileNotFoundException fne) {

            throw new FileNotFoundException(uri.toString());

        } catch(Exception ioe) {

            String message = "Error reading the Excel file." + uri.toString();

            logger.error(message);

            ioe.printStackTrace();

            throw new RuntimeException(message);

        }

    }

    /** Reads all rows of an Excel worksheet */

    public static List<Map<String, String>> parseXLS(InputStream stream, String worksheetName) {

    	List<Map<String, String>> recordList = new ArrayList<>();

    	try {

//    		POIFSFileSystem fs = new POIFSFileSystem(UriUtils.getInputStream(uri));

//    		HSSFWorkbook wb = new HSSFWorkbook(fs);

    		Workbook wb = WorkbookFactory.create(stream);

    		Sheet sheet;

    		if (worksheetName == null){

    			sheet = wb.getSheetAt(0);

    		}else{

    			sheet = wb.getSheet(worksheetName);

    		}

    		if (sheet== null){

    			if (worksheetName != null){

    			    //TODO report error

    				logger.debug(worksheetName + " not provided!");

    			}

    		}else{

	    		Row row;

	    		Cell cell;

	    		int rows; // Number of rows

	    		rows = sheet.getPhysicalNumberOfRows();

				if(logger.isDebugEnabled()) { logger.debug("Number of rows: " + rows); }

	    		int cols = 0; // Number of columns

	    		int tmp = 0;

	    		// This trick ensures that we get the data properly even if it doesn't start from first few rows

	    		for(int i = 0; i < 10 || i < rows; i++) {

	    			row = sheet.getRow(i);

	     			if(row != null) {

	    				tmp = sheet.getRow(i).getPhysicalNumberOfCells();

	    				if(tmp > cols){

	    					cols = tmp;

	    				}

	    			}

	    		}

	    		//first row

	    		List<String> columns = new ArrayList<>();

	    		row = sheet.getRow(0);

	    		for (int c = 0; c < cols; c++){

	    			cell = row.getCell(c);

					if(cell != null) {

					    String str = cell.toString();

					    str = (str == null)? null : str.trim();

					    //TODO better make case sensitive, but need to adapt all existing imports for this

						columns.add(str);

						if(logger.isDebugEnabled()) { logger.debug("Cell #" + c + ": " + str); }

					} else {

						if(logger.isDebugEnabled()) { logger.debug("Cell #" + c + " is null"); }

					}

	    		}

	    		//value rows

	    		for(int r = 1; r < rows; r++) {

	    			row = sheet.getRow(r);

	    			Map<String, String> headers = new HashMap<>();

	    			boolean notEmpty = checkIsEmptyRow(row);

	    			if(notEmpty) {

	    				for(int c = 0; c < cols; c++) {

	    					cell = row.getCell(c);

	    					if(cell != null) {

	    						if (c >= columns.size()){

	    							String message = "Cell has no header. There are only %d headers but more not-null cells in approx. row %d. Cell is neglected.";

	    							message = String.format(message, columns.size(),row.getRowNum());

	    							logger.warn(message);

	    						}else{

	    							if(logger.isDebugEnabled()) { logger.debug(String.format("Cell #%d: %s", c, cell.toString())); }

	    							headers.put(columns.get(c), getCellValue(cell));

	    						}

	    					} else {

	    						if(logger.isDebugEnabled()) { logger.debug("Cell #" + c + " is null"); }

	    					}

	    				}

	    			}

	    			recordList.add(headers);

	    		}

    		}

    	} catch(Exception ioe) {

    		logger.error("Error reading the Excel file.");

    		ioe.printStackTrace();

    	}

    	return recordList;

    }

	public static String getCellValue(Cell cell) {

		try {

			if (cell.getCellType() == CellType.STRING){

				return cell.getStringCellValue();

			}else if (cell.getCellType() == CellType.BLANK){

				return "";

			}else if (cell.getCellType() == CellType.NUMERIC){

				return getNumericCellValue(cell);

			}else if (cell.getCellType() == CellType.BOOLEAN){

				Boolean cellValue = cell.getBooleanCellValue();

				String value = String.valueOf(cellValue);

				return value;

			}else if (cell.getCellType() == CellType.ERROR){

				return "-error-";

			}else if (cell.getCellType() == CellType.FORMULA){

				try {

					String strValue = cell.getStringCellValue();

					if ("".equals(strValue)){

						strValue = getNumericCellValue(cell);

					}

					return strValue;

				} catch (Exception e) {

					String message = "Formula cell (%s) can't be transformed to string";

					message = String.format(message, getExcelCellString(cell));

					throw new RuntimeException(message, e);

				}

			}else{

				return cell.toString();

			}

		} catch (Exception e) {

			String message = "Error occurred while reading Excel cell '%s' . Use toString() instead. Error: %s";

			message = String.format(message,getExcelCellString(cell) ,e.getLocalizedMessage());

			logger.warn(message);

			return cell.toString();

		}

	}

	public static String getExcelCellString(Cell cell){

		String result = "%s%s";

		result = String.format(result, getExcelColString(cell.getColumnIndex()), cell.getRowIndex());

		return result;

	}

	private static String getExcelColString(int colNr){

		int first = colNr / 26;

		int second = colNr % 26;

		String firstStr = String.valueOf((first > 0 ? (char)(first +64) :""));

		String secondStr = String.valueOf((char)(second + 64));

		return firstStr +  secondStr;

	}

	/**

	 * Returns the numeric cell value. In case the cell is formatted as

	 * a date it returns a date (using the dates toString() method.

	 */

	private static String getNumericCellValue(Cell cell) {

		Double number = cell.getNumericCellValue();

//		HSSFCellStyle style = cell.getCellStyle();

//		String dataFormatString = style.getDataFormatString();

//		int index = style.getIndex();

		HSSFDataFormatter formatter = new HSSFDataFormatter();

//		Format defFormat = formatter.getDefaultFormat(cell);

		Format format = formatter.createFormat(cell);

//		String v = formatter.formatCellValue(cell);

		if (format != null && format instanceof DateFormat){

			//TODO use ISO or similar format once TimePeriod knows how to parse this

//			String result = formatter.formatCellValue(cell);

			Date date = cell.getDateCellValue();

			Locale locale = Locale.GERMAN;

			DateFormat df = DateFormat.getDateInstance(2,locale);

			String result = df.format(date); //result of type dd.mm.yyyy

//			String result = date.toString();

			return result;

		}

		if (number.intValue() == number){

			return String.valueOf(number.intValue());

		}else{

			return String.valueOf(number);

		}

	}

	/**

	 * Returns false, if row is null or has no values

	 */

	private static boolean checkIsEmptyRow(Row row) {

		if (row == null){

			return false;

		}

		boolean notEmpty = false;

		for (int j = 0; j<row.getLastCellNum(); j++){

			if (row.getCell(j) != null){

				notEmpty = true;

			}

		}

		return notEmpty;

	}

}