package weightedavgdataanalyzer;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Scanner;
import java.util.NoSuchElementException;
import java.util.*;

public class WeightedAvgDataAnalyzer {

    public static void main(String[] args) throws IOException{
        Scanner in = new Scanner(System.in);


        boolean done = false;
        while (!done){
            try{
                System.out.print("Please enter the file name: ");
                String filename = in.next();
                System.out.println();

                ArrayList<Double> data = readFile(filename);

                System.out.println("Weighted average: " + calcWeightedAverage(data));

                done = true;
            }

            catch (FileNotFoundException exception){
                System.out.println("File not found.");
                return;
            }

            catch (NoSuchElementException exception){
                System.out.println("File contents invalid.");
            }

            catch (IOException exception){
                exception.printStackTrace();
            }
        }
    }

    public static ArrayList<Double> readFile(String filename) throws IOException{
        File inFile = new File(filename);
        try(Scanner in = new Scanner(inFile)) {
            return readData(in);
        }
    }

    public static ArrayList<Double> readData(Scanner in) throws IOException{
        String[] nameOfStringArray;
        ArrayList<Double> data = new ArrayList<>();

        // grab all the data from the file
        try {
            if (in.hasNextLine()) {
                nameOfStringArray = in.nextLine().split(" ");
                for (String stringElement : nameOfStringArray) {
                    data.add(Double.parseDouble(stringElement));
                }
            }
        }

        catch (Exception e) {}

        return data;
    }

    private static double getWeight(ArrayList<Double> data) {
        return data.get(0);
    }

    private static int getDrop(ArrayList<Double> data) {
        return data.get(1).intValue();
    }

    public static double calcWeightedAverage(ArrayList<Double> data) {
        double weight = getWeight(data);
        int drops = getDrop(data);
        for (int i = 0; i < drops; i++){
            int minIntIndex = 2;
            for (int x = 3; x < data.size(); x++){
                if (data.get(x) < data.get(minIntIndex)) {
                    minIntIndex = x;
                }

            }
             data.remove(minIntIndex);
        }
        data.remove(0);
        data.remove(0);
        ArrayList<Double> newArray = new ArrayList<>(data);

        for(int i = 0; i < newArray.size(); i++) {
            newArray.set(i, newArray.get(i) * weight);
        }

        double sum = 0.0;
        for(int i = 0; i < newArray.size(); i++){
            sum += newArray.get(i);
        }

        double average = sum / newArray.size();
        return average;
    }
}