package signalFlowGraph;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

public class AnalyzeSFG {

	private int[][] adjMatrix;
	private int numberOfNodes;
	private String path = new String();
	private int forwardPathGain = 1;
	private ArrayList<String> forwardPath = new ArrayList<>();
	private ArrayList<Integer> forwardGains = new ArrayList<>();

	public static void main(String[] args) {
		AnalyzeSFG g = new AnalyzeSFG();
		g.inputs();
		g.printMatrix();
		g.traverseForwardPath(0);
		g.print();
	}

	private void inputs() {
		Scanner scan = new Scanner(System.in);
		System.out.print("Enter The Number Of Nodes : ");
		numberOfNodes = scan.nextInt();
		adjMatrix = new int[numberOfNodes][numberOfNodes];
		for (int i = 0; i < this.numberOfNodes; i++)
			Arrays.fill(adjMatrix[i], 0);
		System.out.println("To Get Out From Entering Signal Flow Graph Representation");
		System.out.println("Put From = 0 ");
		while (true) {
			int from, to, gain;
			System.out.print("From : ");
			from = scan.nextInt() - 1;
			if (from < 0) {
				break;
			}
			System.out.print("To : ");
			to = scan.nextInt() - 1;
			System.out.print("gain : ");
			gain = scan.nextInt();
			adjMatrix[to][from] = gain;
		}
	}

	private void printMatrix() {
		for (int i = 0; i < numberOfNodes; i++) {
			for (int j = 0; j < numberOfNodes; j++) {
				System.out.print(adjMatrix[i][j] + " ");
			}
			System.out.println();
		}

	}

	private void print() {
		for (int i = 0; i < this.forwardGains.size(); i++) {
			System.out.println(this.forwardGains.get(i));
			System.out.println(this.forwardPath.get(i));
		}
	}

	private void traverseForwardPath(int columnIndex) {

		if (isLastNode(columnIndex)) {
			addToForwardPath(columnIndex, 1);
			forwardPath.add(path);
			forwardGains.add(forwardPathGain);
			return;
		}

		int rowIndex = -1;
		// for (int columnIndex = nextNodeInThePath; columnIndex <
		// numberOfNodes; columnIndex++) {
		rowIndex = getNextNode(rowIndex + 1, columnIndex);
		addToForwardPath(columnIndex, adjMatrix[rowIndex][columnIndex]);
		traverseForwardPath(rowIndex);
		removeFromForwardPath(columnIndex, adjMatrix[rowIndex][columnIndex]);
		// }
	}

	private void removeFromForwardPath(int currentNode, int gain) {
		String toBeRemoved = "x" + currentNode;
		if (path.contains(toBeRemoved))
			path = path.replace(toBeRemoved, "");
		forwardPathGain /= gain;

	}

	private void addToForwardPath(int currentNode, int gain) {
		path += "x" + currentNode;
		forwardPathGain *= gain;
	}

	private int getNextNode(int rowIndex, int columnIndex) {
		for (; rowIndex < this.numberOfNodes; rowIndex++)
			if (adjMatrix[rowIndex][columnIndex] != 0)
				return rowIndex;
		return -1;
	}

	private boolean isLastNode(int columnIndex) {
		for (int i = 0; i < this.numberOfNodes; i++)
			if (adjMatrix[i][columnIndex] != 0)
				return false;
		return true;
	}

}