package laba4_2;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.Scanner;

//accbaaaaabcabcbabacbacba
//accbbacbacba

public class Main {
    public static void main(String[] args) {
        System.out.println("This program changes string to specific rules");
        boolean isConsole = getConsole();
        String line = isConsole ? input() : inputFile();
        line = change(line);
        System.out.printf("Changed string:\n%s\n", line);
        if(!isConsole)
            saveToFile(line);
    }

    static Scanner scanner = new Scanner(System.in);

    static boolean getConsole() {
        String line;
        while(true) {
            System.out.println("Do you want to input from console? (y/n):");
            line = scanner.nextLine();
            line.toLowerCase();
            if(line.equals("y")) return true;
            if(line.equals("n")) return false;
        }
    }

    static String input() {
        String line;
        do {
            System.out.println("Input string that contains only ABC's:");
            line = scanner.nextLine();
            line.toLowerCase();
        } while(!checkInput(line));
        return line;
    }

    static String inputFile() {
        String line;
        boolean incorrect;
        do {
            incorrect = false;
            System.out.println("Input file's location:");
            line = scanner.nextLine();
            try (BufferedReader br = new BufferedReader(new FileReader(new File(line)))) {
                line = br.readLine();
                line.toLowerCase();
                incorrect = !checkInput(line);
            } catch (Exception e) {
                incorrect = true;
                System.out.println("Cannot open the file");
            }
        } while (incorrect);
        return line;
    }

    static boolean checkInput(String line) {
        for(char c : line.toCharArray()) {
            if(c != 'a' && c != 'b' && c != 'c') {
                System.out.println("String should contain only ABC's");
                return false;
            }
        }
        return true;
    }

    static String change(String line) {
        line = deletePattern(line, "aaaa", 0, 4, "");
        line = deletePattern(line, "baba", 0, 2, "");
        line = deletePattern(line, "abc", 0, 3, "");
        return line;
    }

    static String deletePattern(String line, String pattern, int i, int amount, String output) {
        String _output = output;
        if(i == line.length())
            return _output;
        if(line.charAt(i) == pattern.charAt(0) && isExact(line, pattern, i+1, 1))
            i += amount - 1;
        else
            _output += line.charAt(i);
        return deletePattern(line, pattern, i + 1, amount, _output);
    }

    static boolean isExact(String line, String pattern, int i1, int i2) {
        if(i1 == line.length() && i2 != pattern.length())
            return false;
        if(i2 == pattern.length())
            return true;
        if(line.charAt(i1) == pattern.charAt(i2))
            return isExact(line, pattern, i1+1, i2+1);
        return false;
    }

    static void saveToFile(String line) {
        System.out.println("Input location of a file:");
        String location;
        location = scanner.nextLine();
        try(BufferedWriter bw = new BufferedWriter(new FileWriter(new File(location), false))) {
            bw.append(line);
            System.out.println("File is saved");
        } catch (Exception e) {
            System.out.println("Cannot open the file");
        }
    }
}