Untitled

package pl.edu.ug.tent.springweb;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

@WebServlet("/data")
public class DataServlet extends HttpServlet {
    private double result = 0;
    ArrayList<Double> numbers = new ArrayList<>();
    ArrayList<String> signs = new ArrayList<>();
    String errorMessage = "";
    boolean clearArrays = false;

    List<String> input = new ArrayList<>();

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        resp.setContentType("text/html");
        String button = req.getParameter("button");

        PrintWriter out = resp.getWriter();

        resp.setContentType("text/html");

        out.println("<html><body>");

        out.println("<form action='/data' method='POST'>");
        out.println("<input type='text' name='number'>");
        out.println("<input type='submit' name='button' value='+'>");
        out.println("<input type='submit' name='button' value='-'>");
        out.println("<input type='submit' name='button' value='*'>");
        out.println("<input type='submit' name='button' value='/'>");
        out.println("<input type='submit' name='button' value='='>");
        if (button.equals("="))
            out.println("       Wynik: " + getResult());
        setResult(0);
        out.println("</form>");
        out.println("<br><br>");
        out.println(errorMessage);
        out.println("<br><br>");
        for (int i = 0; i < signs.size(); i++) {
            out.println("Operacja nr " + (i + 1) + ": " + numbers.get(i) + " " + signs.get(i));
            out.println("<br>");
        }

        out.println("</body></html>");
        setResult(0);
        if (clearArrays) {
            signs.clear();
            numbers.clear();
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String numbers = req.getParameter("number");
        String sign = req.getParameter("button");

        if (!sign.equals("=")) {
            input.add(numbers);
            input.add(sign);
            doGet(req, resp);
        }

        List<String> result = new ArrayList<>();
        for (int i = 0; i < input.size(); i++) {
            double tmpResult = 0;
            if (input.get(i).equals("*")) {
                tmpResult = Double.parseDouble(input.get(i - 1)) * Double.parseDouble(input.get(i + 1));
            } else if (input.get(i).equals("/")) {
                tmpResult = Double.parseDouble(input.get(i - 1)) / Double.parseDouble(input.get(i + 1));
            }
            input.set(i - 1, String.valueOf(tmpResult));
            input.remove(i);
            input.remove(i);
            i = 0;
        }

        // 2 + 4 + 2
        double finalResult = 0.0;
        for (int i = 0; i < input.size(); i++) {
            double tmpResult = 0;
            if (input.get(i).equals("+")) {
                tmpResult = Double.parseDouble(input.get(i - 1)) + Double.parseDouble(input.get(i + 1));
            } else if (input.get(i).equals("-")) {
                tmpResult = Double.parseDouble(input.get(i - 1)) - Double.parseDouble(input.get(i + 1));
            }
            input.set(i + 1, String.valueOf(tmpResult));
            input.remove(i - 1);
            input.remove(i - 1);
            i = 0;
        }

        System.out.println(input.get(0));
        doGet(req, resp);
        result.clear();
    }

    private void handleOperationsWithHighestPriority(int indexOfInput) {
        List<String> highPrioritySigns = Arrays.asList("*", "/");
        if(highPrioritySigns.contains(input.get(indexOfInput))){

        }
    }


    public void calculate(ArrayList<Double> numbers, ArrayList<String> signs) {
        int j = 1;
        setResult(numbers.get(j - 1));
        for (int i = 0; i < signs.size(); i++) {
            switch (signs.get(i)) {
                case "+":
                    setResult(getResult() + numbers.get(j));
                    break;
                case "-":
                    setResult(getResult() - numbers.get(j));
                    break;
                case "*":
                    setResult(getResult() * numbers.get(j));
                    break;
                case "/":
                    if (numbers.get(j) == 0) {
                        errorMessage = "Blad";
                        signs.clear();
                        numbers.clear();
                        setResult(0);
                    } else {
                        setResult(getResult() / numbers.get(j));
                    }
                    break;
            }

            j++;
        }

    }

    public double getResult() {
        return result;
    }

    public void setResult(double result) {
        this.result = result;
    }

}