MarkdownParse.java

//https://howtodoinjava.com/java/io/java-read-file-to-string-examples/

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;

public class MarkdownParse {

    public static ArrayList<String> getLinks(String markdown) {
        ArrayList<String> toReturn = new ArrayList<>();
        // find the next [, then find the ], then find the (, then read link upto next )
        int currentIndex = 0;
        while(currentIndex < markdown.length()) {
            int openBracket = markdown.indexOf("[", currentIndex); 
            if (openBracket == -1) {
                break;
            }

            //Checks if there is an "!" that denotes an image link before the open bracket and ends the loop if there is.
            
            if (openBracket != 0) {
                if (markdown.substring(openBracket - 1, openBracket).equals("!")) {
                    currentIndex = openBracket + 1;
                    continue;
                }
            }
            
            int closeBracket = markdown.indexOf("]", openBracket);
            if (closeBracket == -1) {
                break;
            }
            int openParen = markdown.indexOf("(", closeBracket);
           
            if (openParen == -1 || openParen != closeBracket + 1) {
                break;
            }
            
            int closeParen = markdown.indexOf(")", openParen);

            
            if (closeParen == -1) {
                break;
            }
            
            toReturn.add(markdown.substring(openParen + 1, closeParen));

            currentIndex = closeParen + 1;
        }
        //41, 67

        return toReturn;
    }


    public static void main(String[] args) throws IOException {
        Path fileName = Path.of(args[0]);
        String content = Files.readString(fileName);
        ArrayList<String> links = getLinks(content);
	    System.out.println(links);
    }
}