import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class FileSearcher {
	public static void main(String[] args) {
		if (args.length == 0) {
			System.out.println("You must specify a filename!");
			return;
		}
		
		String contents = null;
		try {
			DataInputStream in = new DataInputStream(new FileInputStream(args[0]));
			byte[] array = new byte[in.available()];
			in.readFully(array);
			in.close();
			contents = new String(array);
		} catch (Exception e) {
			e.printStackTrace();
		}
		
		if (contents == null) {
			System.out.println("File was not valid");
			return;
		}
		
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		
		String userInput = null;
		do {
			try {
				System.out.println("Please type a pattern: ");
				userInput = in.readLine();
				Pattern pattern = Pattern.compile(userInput);
				Matcher matcher = pattern.matcher(contents);

				int count = 0;
				while (matcher.find()) {
					count++;
					System.out.println("Result " + count + ": \"" + matcher.group() + "\"\t\tPosition: " + matcher.start());
				}
				System.out.println("Enter another pattern? (y/n)");
				userInput = in.readLine();
			} catch (Exception e) {
				e.printStackTrace();
			}
		} while (userInput.charAt(0) == 'y');
	}
}