package programming.set7.optimus;
import acm.program.*;

import java.lang.reflect.Array;

import acm.graphics.*;

public class SieveOfEratosthenes extends ConsoleProgram {

    private int field[];
    private int sum;
    private int n;

    public void run(){

        n = readInt("Please Enter a number >= 2 and <= 20 : ");

        if (n < 2 && n > 20){
            throw new IllegalStateException("This is a non valid number");
        }

        // call the methods
        createArray(n);

        toString();

    }

    /*
     * creates the Array integers between n.
     * start to create with the first index number
     * (remember that Arrays index starting by 0)
     *
     * @param n is the number you have to choice
     *
     * @param getNumber is the number of the index
     *
     * @return the value of the given field
     */

    public void createArray(int n){

        int length = 20;
        // because the index of an Array is starting by 0, thats the reason
        // why we have one field more
        sum = (length - n) -1;

        for (int i = 0; i < sum; i++){
            field[i] = i;
        }
    }


    /*
     * this method return the number of the give field
     */
    public int getNumber(int getNumber){
        return field[getNumber];
    }

    /*
     *  checks if the next value is a Prime Number
     *  choice the SieveOfEratosthenes algorithm
     */
    public void IsPrimeNumber(){

        // starting by zero because of the first index of an Array
        for (int i = 0; i < sum; i++){

            // gets the value of the index
            int value = getNumber(i);

            // for loop to check
            for (int pointer = 1; pointer <= sum; pointer++){

                int result = (int) Math.pow(value, pointer);

                if (result <= 20){

                for (int number = this.n; number <= sum; number++){

                    if(result == getNumber(number)){
                        field[number] = 0;
                        // break for loop number
                        break;
                    }
                }
            } else {
                // and continue with the algorithm here
                // because the result is higher then sum

                    // this for loop gives the numbers
                    for (int y = 0; y <= value -1; y++){

                    // <= value because of the last value
                    for (int j = 2; j <= value; j++){

                    int total = getNumber(y);

                    // check if the number is weather existing
                    if (total > 0){
                        int sumsum = total * j;

                        if (sumsum <= 20){
                        // because no prime number
                        field[sumsum] = 0;
                    } else {
                        // because the number is out of range
                        break;
                    }
                }
            }
        }

                    // second step of the algorithm
                    // check all of numbers they are left over

                    for (int k = 5; k <= sum; k++){
                        int totaltoal = getNumber(k);

                        if (totaltoal > 0){
                            int resultresult = totaltoal * 2;

                            if (resultresult <= 20){
                                field[resultresult] = 0;
                            } else {
                                // because the next will be also out of range
                                break;
                            }
                        }
                    }
            }
        }
    }
}

    /*
     *  overwrite the toString method for output the prime numbers
     */
    public String toString(){
            String s = "";
            IsPrimeNumber();

            // check the Array for validity
            for (int i = this.n; i <= sum; i++){
                int value = getNumber(i);

                if(this.n +1 < sum){
                    s += " ";
                }

                if (value > 0){
                    s += Integer.toString(i);
                } else {
                    s += "_";
                }

                if (i < sum){
                    s += ",";
                }
            }
            return s;
    }
}