import java.io.*;
import java.util.*;
import javax.swing.JOptionPane;
public class MCQ
{
    public static ArrayList<ArrayList<String>> topics;
    public static ArrayList<ArrayList<String>> questions;


    public static void main (String[] args) throws IOException
    {
        boolean readFile;
        readFile = readFilesIntoArrayLists();
        if(!readFile)
            System.out.println("One or more files do not exist");
        else
        {
            quizImplementation();
        }
    }

    public static boolean readFilesIntoArrayLists() throws IOException
    {
        String filename1 = "topics.txt";
        String filename2 = "questions.txt";

        File topicFile = new File(filename1);
        File questionFile = new File(filename2);
        String fileElements[];

        topics = new ArrayList<ArrayList<String>>();
        topics.add(new ArrayList<String>());
        topics.add(new ArrayList<String>());

        questions = new ArrayList<ArrayList<String>>();
        questions.add(new ArrayList<String>());
        questions.add(new ArrayList<String>());
        questions.add(new ArrayList<String>());
        questions.add(new ArrayList<String>());
        questions.add(new ArrayList<String>());
        questions.add(new ArrayList<String>());
        questions.add(new ArrayList<String>());
        questions.add(new ArrayList<String>());
        questions.add(new ArrayList<String>());

        if(topicFile.exists() && questionFile.exists())
        {
            Scanner in = new Scanner(topicFile);
            while(in.hasNext())
            {
                fileElements = (in.nextLine()).split(",");
                topics.get(0).add(fileElements[0]);
                topics.get(1).add(fileElements[1]);
            }
            in.close();
            in = new Scanner(questionFile);
            while(in.hasNext())
            {
                fileElements = (in.nextLine()).split(",");
                questions.get(0).add(fileElements[0]);
                questions.get(1).add(fileElements[1]);
                questions.get(2).add(fileElements[2]);
                questions.get(3).add(fileElements[3]);
                questions.get(4).add(fileElements[4]);
                questions.get(5).add(fileElements[5]);
                questions.get(6).add(fileElements[6]);
                questions.get(7).add(fileElements[7]);
                questions.get(8).add(fileElements[8]);
            }
            in.close();
            return true;
        }else
            return false;

    }

    /*
        John Long - 12132306
        This method dynamically gets the topic selection from the user
        and returns this as a String
    */

    public static String getTopicOption()
    {
        String topicOptionNums = "";
        String topicOptionText = "";
        String topicOptions = "";
        String selection = "";
        int topicNumListSize = topics.get(0).size();                                               // **
        int topicTextListSize = topics.get(1).size();                                              // **

        // get topic numbers and question text from topics file
        for(int i=0; i<topicNumListSize && i<topicTextListSize; i++)
        {
            topicOptionNums = topics.get(0).get(i);                                                 // **
            topicOptionText = topics.get(1).get(i);                                                 // **
            topicOptions += topicOptionNums + " " + topicOptionText + "n";
        }

        String menuMessage = "Select which topics test you would like to take";
        String errorMessage =  "Invalid menu selection.nnValid options are 0 to " + topicNumListSize + " inclusive.";
           errorMessage += "nSelect OK to retry or cancel to exit.";
        String errorHeader = "Error in user input";
        boolean validInput = false;
        String menuChoicePattern = "[1-4]{1}"; // **need to modify to dynamically perform**

        while (!(validInput))
        {
            selection = JOptionPane.showInputDialog(null, topicOptions, menuMessage, 3);
            if (selection == null || selection.matches(menuChoicePattern))
            validInput = true;
            else
            JOptionPane.showMessageDialog(null, errorMessage, errorHeader, 2);
        }

        return selection;
    }

    /*
        John Long - 12132306
        This method runs the quiz for the user
    */
    public static void quizImplementation()
    {
        int selection = Integer.parseInt(getTopicOption());
        String fileElements[];
        String qOptions = "";
        String question = "";
        String topicHeader = "";
        String msg1 = "Enter the number of the chosen answer.";


        for(int i=0; i<questions.get(0).size(); i++)
        {
            if(Integer.parseInt(questions.get(i).get(0)) == selection)
            {
                topicHeader += topics.get(selection).get(0);
                qOptions = questions.get(2).get(i) + "n";
                qOptions += "1. " + questions.get(3).get(i) + "n";
                qOptions += "2. " + questions.get(4).get(i) + "n";
                qOptions += "3. " + questions.get(5).get(i) + "n";
                qOptions += "4. " + questions.get(6).get(i) + "n";
            }
            question = JOptionPane.showInputDialog(null,qOptions,topicHeader,3);
        }
    }
}