import java.io.*;
import java.util.*;

public class SolveMaze {
	public static void main(String[] args) throws FileNotFoundException {
		String fileText = "";
		Scanner input = new Scanner(new File("maze1.txt"));
		while (input.hasNextLine()) {
			fileText += input.nextLine() + "\n";
		}

		Maze maze = new Maze(fileText);
		// maze.setAnimated(true);
		System.out.println(maze);
		System.out.println();

		int startRow = 1;
		int startCol = 6;
		System.out.println("Start from (" + startRow + ", " + startCol + ")");
		solve(maze, startRow, startCol);
	}

	// Finds a pathway out of the given maze from the given start location.
	// pre: maze != null and startRow/Col are within the maze
	public static void solve(Maze maze, int startRow, int startCol) {
		if (explore(maze, startRow, startCol)) {
			System.out.println(maze);
		} else {
			System.out.println("Unsolvable!");
		}
	}

	public static boolean explore(Maze maze, int row, int col) {
		// bad: stop when we hit a wall or we've already visited something
		if (maze.isWall(row, col) || maze.isExplored(row, col)) {
			return false;
		} else if (row == 0 || row == maze.getHeight() - 1 || col == 0
				|| col == maze.getWidth() - 1) { // good: stop when we are done
													// (exited)

			return true;
		} else {
			maze.setExplored(row, col);
			if (explore(maze, row, col - 1) || explore(maze, row - 1, col)
					|| explore(maze, row + 1, col)
					|| explore(maze, row, col + 1)) {
				maze.mark(row, col);
				return true;
			}
		}
		return false;
	}
}