import java.io.File;
import java.io.IOException;
import java.util.Scanner;

/**
 * Driver for the Doublets game of HW7 of Boston University CAS CS 112 A1 Spring 2007
 * See problem set for the description
 * @author Leo Reyzin
 *
 */
public class Doublets {
	public static void main(String[] args) {
		final String fileName = "TWL06.txt"; // Change numWordsInFile if fileName changes
		final int numWordsInFile = 178691;

		// Create a new scanner for reading the dictionary text file from the current
		// directory
		System.out.println("Current directory: " + System.getProperty("user.dir"));
		Scanner fileScanner;
		try {
			fileScanner = new Scanner (new File (fileName));//("dictionary.txt"));
		} catch (IOException e) {
			System.out.println("Unable to open file. "+e.getMessage());
			return;
		}

		// read the file into the graph
		WordGraph g = new WordGraph (numWordsInFile);
		int wordsRead = 0;
		System.out.println("Words read so far:");
		while (fileScanner.hasNext()) {
			g.addVertex(fileScanner.next());
			final int HOW_OFTEN_TO_PRINT = 10000, HOW_OFTEN_NEW_LINE = 100000;
			// print the number of words processed every once in a while, to show progress
			if (++wordsRead % HOW_OFTEN_TO_PRINT == 0) {
				System.out.print(wordsRead+" ");
				if (wordsRead % HOW_OFTEN_NEW_LINE == 0)
					System.out.println();
			}
		}

		// Process user input
		Scanner inputScanner = new Scanner(System.in);

		userInputLoop: 
		for(;;) {
			WordGraph.Vertex begin;
			do { // loop until user finds legitimate start word
				System.out.print("\nPlease enter the start word, or \"***\" to quit: ");
				String s = inputScanner.next();
				if (s.equals("***"))
					break userInputLoop;
				begin = g.find(s);
				if (begin == null)
					System.out.print("Word not in the dictionary. ");
			} while (begin == null);

			WordGraph.Vertex end;
			do { // loop until user finds legitimate end word
				System.out.print("Please enter the end word: ");
				end = g.find(inputScanner.next());
				if (end == null)
					System.out.print("Word not in the dictionary. ");
			} while (end == null);

			WordGraph.VertexStack s = g.bfs(begin, end); // search for path from begin to end
			if (s == null) {
				System.out.println("No path exists");
			}
			else while (!s.isEmpty()) { // print out the path
				System.out.println(s.pop());
			}
		}
	}
}