//Christian Tirella
//Brian Sweeney
//CSU670 Project


import java.util.*;

//Container class for the product of TruthTable.getRelationTable()
public class RelationTable {
	ArrayList <TruthRow> relationTable;
	int tableIndex;
	
	public RelationTable (ArrayList <TruthRow> relationTable) {
		this.relationTable = new ArrayList<TruthRow>();
		tableIndex = 0;
	}

	public void add(TruthRow truthTableRow) {
		relationTable.add(truthTableRow);
	}
	
	//set index to zero
	public void start () {tableIndex = 0;}	
	
	//return true if there are more items in table and move index ahead one, return false otherwise
	public boolean next () {
		if (tableIndex < relationTable.size() - 1){
			tableIndex++;
			return true;
		}
		else return false;
	}
	
	public TruthRow getCurrentRow() {
		Object returnable =  relationTable.get(tableIndex);
		return (TruthRow)returnable;
	}
	
	//returns the indices of the columns that can be forced
	//in other words of the columns that contain the same value:
	//			0 0 0
	//			0 1 0
	//			0 1 1
	//in the above relationtable column 1 or index 0 would be returned
	public ArrayList forcableColumnIndex () {
		ArrayList result = new ArrayList (2);
		
		boolean stillMatching = false;
		for (int columnIndex = 0; columnIndex <= 3; columnIndex++) {
			
			ArrayList hold = new ArrayList();
			for (int	tableIndex = 0;
						tableIndex <= (relationTable.size() - 1);
						tableIndex++) {
				
				//build a list of items on the current column
				TruthRow temp = relationTable.get(columnIndex);
				Integer integer = temp.bitAt(tableIndex);
				hold.add(integer);				
			}
			//check to see if the column contains only 1s or only 0s
			int currentIndex = 0;
			int nextIndex = 1;
			
			for ( ; currentIndex < hold.size() - 2; currentIndex++) {
				if (hold.get(currentIndex).equals(hold.get(nextIndex))) {
					stillMatching = true;
				}
				else stillMatching = false;
			}
			
			if (stillMatching == true) {
				result.add(columnIndex);
			}
		}
		return result;
	}
}