import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Random;

/**
 * Generates Java code.
 * 
 * @author Franck van Breugel
 */
public class Generate {
    /**
     * Generates Java code.
     * 
     * @param args[0] name of the file in which the generated code is stored.
     * @param args[1] number of states of the JPF model of the generated code. 
     */
    public static void main(String[] args) {
	if (args.length != 2) {
	    System.out.println("Use: java Generate <file name> <number of states>");
	} else {
	    try {
		final Random RANDOM = new Random(System.currentTimeMillis());
		final int NUMBER = Integer.parseInt(args[1]); // number of states

		PrintWriter writer = new PrintWriter(args[0]);
		writer.println("import java.util.Random;");
		writer.println();
		writer.println("public class Sample {");
		writer.println("  public static void main(String[] args) {");
		writer.println("    final Random RANDOM = new Random();");
		writer.println("    boolean done = false;");
		writer.println("    int state = 0;");
		writer.println("    while (!done) {");
		writer.println("      switch (state) {");
		for (int i = 0; i < NUMBER; i++) {
		    int successors = RANDOM.nextInt((int) Math.pow(2,  NUMBER));
		    String bits = Integer.toBinaryString(successors);
		    int number = 0;
		    for (int j = 1; j < bits.length(); j++) {
			if (bits.charAt(j) == '1') {
			    number++;
			}
		    }
		    writer.printf("        case %d:%n", i);
		    if (number == 0) {
			writer.println("          done = true;");
			writer.println("          break;");
		    } else {
			writer.printf("          switch (RANDOM.nextInt(%d)) {%n", number);
			int j = 1;
			for (int n = 0; n < number; n++) {
			    while (bits.charAt(j) == '0') {
				j++;
			    }
			    writer.printf("            case %d:%n", n);
			    writer.printf("              state = %d;%n", j);
			    writer.println("              break;");
			    j++;
			}
			writer.println("          };");
			writer.println("          break;");
		    }
		}
		writer.println("      }");
		writer.println("    }");
		writer.println("  }");
		writer.println("}");
		writer.close();
	    } catch (FileNotFoundException e) {
		System.out.println("Something went wrong with the file");
	    }
	}
    }
}