package org.simantics.excel.poi.parser;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

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

public class ColumnResolver {
	
	private enum Type {SINGLE,MULTI};
	
	private Map<String,int[]> values = new HashMap<String, int[]>();
	private Map<String,Type> types = new HashMap<String, Type>();
	private Set<String> optional = new HashSet<String>();
	private Set<String> resolved = new HashSet<String>();
	
	public void addSingleColumn(String id) {
		addSingleColumn(id, true);
	}
	
	public void addSingleColumn(String id, boolean required) {
		types.put(id, Type.SINGLE);
		if (!required)
			this.optional.add(id);
	}
	
	public void addMultiColumn(String id) {
		addMultiColumn(id, true);
	}
	
	public void addMultiColumn(String id, boolean required) {
		types.put(id, Type.MULTI);
		if (!required)
			this.optional.add(id);
	}
	
	
	public int getSingleColumn(String id) {
		int[] val = values.get(id);
		if (val == null)
			return -1;
		if (val.length == 0)
			return -1;
		return val[0];
	}
	
	public int[] getMultiColumn(String id) {
		return values.get(id);
	}
	
	public boolean resolve(Row row) {
		return resolve(row, true);
	}
	
	public boolean resolve(Row row, boolean ignoreCase) {
		values.clear();
		resolved.clear();
		if (row == null) {
			return false;
		}
	
		for (int i = 0; i <= row.getLastCellNum(); i++) {
			Cell cell = row.getCell(i);
			if (cell == null)
				continue;
			int colIndex = cell.getColumnIndex();
			String value = cell.getStringCellValue();
			for (Entry<String, Type> col : types.entrySet()) {
				String id = col.getKey();
				if (id.equals(value) || ignoreCase && id.equalsIgnoreCase(value)) {
					if (col.getValue() == Type.SINGLE) {
						values.put(id, new int[]{colIndex});
					} else {
						int curr[] = values.get(id);
						if (curr == null) {
							values.put(id, new int[]{colIndex});
						} else {
							int n[] = new int[curr.length+1];
							System.arraycopy(curr, 0, n, 0, curr.length);
							n[curr.length] = colIndex;
							values.put(id, n);
						}
						
					}
					resolved.add(id);
					break;
				}
			}
		}
		// check that required columns have been resolved
		for (Entry<String, Type> col : types.entrySet()) {
			if (!optional.contains(col.getKey())) {
				if (!resolved.contains(col.getKey()))
					return false;
			}
		}
		return true;
			
	}
	

}