package com.company;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Stack;

public class PolishExpression {

    private final static Map<String, Integer> relativePriorities = Map.of
            ("+", 1, "-", 1, "*", 3, "/", 3, "^", 6, "operand", 7, "(", 9, ")", 0);

    private final static Map<String, Integer> stackPriorities = Map.of
            ("+", 2, "-", 2, "*", 4, "/", 4, "^", 5, "operand", 8, "(", 0);

    private final String expression;

    private final int rank;

    private PolishExpression(String expression) {
        this.expression = expression;
        this.rank = countRank(expression);
    }

    public int getRank() {
        return rank;
    }

    @Override
    public String toString() {
        return expression;
    }

    public static PolishExpression getInstance(String expression) {
        System.out.println("SYMBOL        STACK          RESULT");
        List<String> symbols = getSymbols(expression);
        Stack<String> stack = new Stack<>();
        StringBuilder res = new StringBuilder();
        for (String symbol : symbols) {
            boolean deeper = true;
            int relativePriority = getPriority(symbol, relativePriorities);
            printState(symbol, stack, res.toString());
            if (!stack.isEmpty()) {
                while (deeper) {
                    String stackSymbol = stack.peek();
                    int stackPriority = getPriority(stackSymbol, stackPriorities);
                    if (stackSymbol.equals("(") && symbol.equals(")")) {
                        stack.pop();
                        break;
                    }
                    if (relativePriority > stackPriority) {
                        stack.push(symbol);
                        deeper = false;
                    } else {
                        res.append(stack.pop());
                        deeper = true;
                    }
                    if (stack.isEmpty()) {
                        stack.push(symbol);
                        deeper = false;
                    }
                }
            } else {
                stack.push(symbol);
            }
        }

        while (!stack.isEmpty()) {
            res.append(stack.pop());
        }
        return new PolishExpression(res.toString());
    }

    private static void printState(String symbol, Stack<String> stack, String res) {
        String stackStr = stack.toString().replaceAll("\\s|,|\\[|\\]", "");
        System.out.printf("%2s", symbol);
        System.out.printf("%15s", stackStr);
        System.out.printf("%20s", res);
        System.out.println();
    }

    private int countRank(String expression) {
        List<String> symbols = getSymbols(expression);
        int rank = 0;
        for (String symbol : symbols) {
            if (symbol.matches("^\\w$")) {
                rank += 1;
            } else {
                rank -= 1;
            }
        }
        return rank;
    }

    private static List<String> getSymbols(String expression) {
        List<String> symbols = new ArrayList<>();
        for (int i = 0; i < expression.length(); i++) {
            symbols.add(String.valueOf(expression.charAt(i)));
        }
        return symbols;
    }

    private static int getPriority(String symbol, Map<String, Integer> priorities) {
        if (symbol.matches("^\\w$")) {
            return priorities.get("operand");
        } else {
            return priorities.get(symbol);
        }
    }
}