package com.company.parsing;

import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class RecursiveParsing {

    public static final Map<Integer, Integer> map = new HashMap<>();
    public static final Set<Integer> keySet = new HashSet<>();
    public static String temp = "";
    public static final String TEXT = "# Sport\n" +
            "common text  \n" +
            "## Tennis \n" +
            "### Table\n" +
            "### Ping Pong \n" +
            "commontext  \n" +
            "# Dance";

    public static void main(String[] args) throws IOException {
        List<String> lines = Arrays.stream(TEXT.split("\n")).collect(Collectors.toList());
        StringBuilder header = new StringBuilder();
        StringBuilder body = new StringBuilder();
        lines.stream().filter(s -> s.startsWith("#")).forEach(s -> header.append(getValue(s)));
        map.clear();
        keySet.clear();
        lines.forEach(s -> body.append(getValue(s)));
        System.out.println(header);
        System.out.println(body);
        Scanner sc = new Scanner(System.in);
    }

    private static String diff(String s) {
        OptionalInt first = IntStream.range(0, s.length()).filter(i -> s.charAt(i) != ' ').findFirst();
        if (first.isPresent()) {
            return " ".repeat(Math.max(0, first.getAsInt()) - 1);
        }
        throw new NullPointerException();
    }

    public static String getValue(String sharp) {
        if (sharp.startsWith("#")) {
            temp = sharp.replace("#", " ");
            return merge(sharp, 0);
        } else {
            return "\n" + diff(temp) + sharp;
        }
    }

    private static String merge(String sharp, int section) {
        if (sharp.startsWith("#")) {
            return merge(sharp.substring(1), section + 1);
        } else {
            setupKeySet(section);
            return "\n" + " ".repeat(Math.max(0, section) - 1) + sharp + " " + getIndex(section);
        }
    }

    private static String getIndex(int section) {
        String value = "";
        if (section > 1) {
            value = getIndex(section - 1) + ".";
        }
        return value + Optional.ofNullable(map.get(section))
                .orElseThrow(() -> new UnsupportedOperationException("Нарушена вложенность разделов"));
    }

    private static void setupKeySet(int section) {
        map.merge(section, 1, Integer::sum);
        if (keySet.contains(section)) {
            keySet.forEach(key -> {
                if (key > section) map.remove(key);
            });
        } else {
            keySet.add(section);
        }
    }
}