package com.mattrixwv.adventOfCode24.days;


import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.mattrixwv.Stopwatch;


public class Problem5 extends Problem{
	private static final String inputFileName = "days/Problem5.txt";


	public Problem5(){
		super();
		description = "Find the non-corrupted multiplication instructions that are allowed to run.";
		result = "Unresolved";
	}

	public String runSolution(){
		Stopwatch timer = new Stopwatch();
		timer.start();

		int sum = 0;
		StringBuilder fileInput = new StringBuilder();


		//Read the file
		try(Scanner scanner = new Scanner(this.getClass().getClassLoader().getResourceAsStream(inputFileName))){
			while(scanner.hasNext()){
				fileInput.append(scanner.next());
			}
		}

		//Pull out the valid references from the file
		Pattern functionPattern = Pattern.compile("mul\\(\\d{1,3},\\d{1,3}\\)");
		Matcher functionMatcher = functionPattern.matcher(fileInput.toString());
		List<String> functions = new ArrayList<>();
		while(functionMatcher.find()){
			functions.add(functionMatcher.group());
		}
		StringBuilder functionString = new StringBuilder();
		functions.forEach(func -> functionString.append(func));

		//Perform the required multiplication
		Pattern digitPattern = Pattern.compile("\\d{1,3}");
		Matcher digitMatcher = digitPattern.matcher(functionString.toString());
		while(digitMatcher.find()){
			int num1 = Integer.parseInt(digitMatcher.group());
			digitMatcher.find();
			int num2 = Integer.parseInt(digitMatcher.group());
			sum += (num1 * num2);
		}


		//Save the results
		timer.stop();
		result = "The sum of the non-corrupted multiplication instructions is " + sum + ".\nIt took " + timer.toString() + " to run the algorithm.";
		return result;
	}
}

/*
Find the non-corrupted multiplication instructions that are allowed to run
The sum of the non-corrupted multiplication instructions is 168539636.
It took 13.816 milliseconds to run the algorithm.
*/