Main.java

import java.util.ArrayList; // Import the ArrayList class for dynamically resizable lists
import java.util.Scanner; // Import the Scanner class for user input
import java.io.File; // Import the File class for file handling
import java.io.FileWriter; // Import the FileWriter class for file writing
import java.io.IOException;  // Import the IOException class to handle input/output errors

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class Main {
  static Scanner inputScanner = new Scanner(System.in); // module for user input
  
  static ArrayList<String> tasks = new ArrayList<String>();
  static ArrayList<Boolean> done = new ArrayList<Boolean>();
  static ArrayList<Boolean> important = new ArrayList<Boolean>();
  static ArrayList<String> lists = new ArrayList<String>();
  static String input;
  static String[] splitInput;
  static String currentFilename = "todo";

  // Color constants
  static final String RESET = "\u001B[0m";
  static final String RED = "\u001B[31m";
  static final String GREEN = "\u001B[32m";
  static final String YELLOW = "\u001B[33m";
  static final String BLUE = "\u001B[34m";
  static final String MAGENTA = "\u001B[35m";
  static final String CYAN = "\u001B[36m";
  static final String WHITE = "\u001B[37m";
  static final String BOLD = "\u001B[1m";
  static final String CROSSED_OUT = "\u001B[9m";
  static final String CLS = "\033[H\033[2J";

  // LEVEL 0

  public static void main(String[] args) {
    splashScreen();
    decodeCommandLineArguments(args);
    lists = convertStringToStringArrayList(loadData("_lists"));
    loadList(currentFilename);
    while (true) {
      AsciiUi();
      input = inputScanner.nextLine(); // Get user imput
      processInput(input);
      saveList(currentFilename);
    }
  }

  // LEVEL 1

  static void splashScreen() {
    System.out.print(CLS);
    System.out.println("###################\n#                 #\n#  MY TO-DO LIST  #\n#                 #\n###################\n"); // stylized title 
    System.out.println("Momie_et_Masque first Java project !\nType /help to get help.");
    try {
      Thread.sleep(3000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
  }
  
  static void decodeCommandLineArguments(String[] args) {
    if (args.length > 0) {
      currentFilename = args[0];
    }
  }

  static void AsciiUi() {
    System.out.print(CLS);
    System.out.println("###################\n#                 #\n#  MY TO-DO LIST  #\n#                 #\n###################\n"); // stylized title 
    System.out.println("List : " + currentFilename);
    for (int i = 0; i < tasks.size(); i++) {
      System.out.print(i + 1 + " ");
      if (done.get(i)) {
        System.out.print("[X] " + CROSSED_OUT);
      } else {
        System.out.print("[ ] " + BOLD);
      }
      if (important.get(i)) {
        System.out.print(RED);
      }
      System.out.println(tasks.get(i) + RESET);
    }
    System.out.print("\n >  ");
  }

  // LEVEL 2

  static void processInput(String input) {
    if (input.startsWith("/")){
      try {
        processInputCommand(input);
      } catch (Exception e) {
        appendTask(input);
      }
    } else {
      appendTask(input);
    }
  }

  // LEVEL 3

  static void processInputCommand(String input) {
    splitInput = input.split(" ");
    switch (splitInput[0]) {
      case "/add":
        appendTask(lastArg(1));
        break;
      case "/insert":
        insertTask(splitInput[1], lastArg(2));
        break;
      case "/del":
        deleteTask(splitInput[1]);
        break;
      case "/edit":
        editTask(splitInput[1], lastArg(2));
        break;
      case "/done":
        doneTask(splitInput[1]);
        break;
      case "/!":
        importantTask(splitInput[1]);
        break;
      case "/clear":
        clearTasks();
        break;
        case "/save":
        saveList(lastArg(1).replace("_", "-"));
        break;
      case "/load":
        loadList(lastArg(1).replace("_", "-"));
        break;
      case "/help":
        printHelp();
        break;
      case "/lists":
        printLists();
        break;
      case "/exit":
        exitProgram();
        break;
      default:
        appendTask(input);
    }
  }

  // LEVEL 4

  // get the last user command argument, which may contain spaces, from its index
  static String lastArg(int index) {
    int startIndex = 0;
    for (int i = 0; i < index; i++) {
      startIndex += splitInput[i].length() + 1;
    }
    return input.substring(startIndex);
  }

  static void appendTask(String task) {
    tasks.add(task);
    done.add(false);
    important.add(false);
  }
  static void insertTask(String indexStr, String task) {
    int index = Integer.parseInt(indexStr) - 1;
    tasks.add(index, task);
    done.add(index, false);
    important.add(index, false);
  }
  static void editTask(String indexStr, String newTask) {
    int index = Integer.parseInt(indexStr);
    tasks.set(index - 1, newTask);
  }
  static void deleteTask(String indexStr) {
    int index = Integer.parseInt(indexStr);
    tasks.remove(index - 1);
    done.remove(index - 1);
    important.remove(index - 1);
  }
  static void doneTask(String indexStr) {
    int index = Integer.parseInt(indexStr) - 1;
    if (done.get(index)) {
      done.set(index, false);
    } else {
      done.set(index, true);
    }
  }
  static void importantTask(String indexStr) {
    int index = Integer.parseInt(indexStr) - 1;
    if (important.get(index)) {
      important.set(index, false);
    } else {
      important.set(index, true);
    }
  }
  static void clearTasks() {
    tasks.clear();
    done.clear();
    important.clear();
  }

  static void saveList(String filename) {
    currentFilename = filename;
    String tasksString = convertStringArrayListToString(tasks);
    saveData(currentFilename, tasksString);
    saveData(currentFilename + "_done", convertBooleanArrayListToString(done));
    saveData(currentFilename + "_important", convertBooleanArrayListToString(important));
    if (!lists.contains(currentFilename)) {
      lists.add(currentFilename);
      saveData("_lists", convertStringArrayListToString(lists));
    }
    if (tasksString == "") {
      lists.remove(lists.indexOf(currentFilename));
      saveData("_lists", convertStringArrayListToString(lists));
    }
  }

  static void loadList(String filename) {
    currentFilename = filename;
    tasks = convertStringToStringArrayList(loadData(currentFilename));
    done = convertStringToBooleanArrayList(loadData(currentFilename + "_done"));
    important = convertStringToBooleanArrayList(loadData(currentFilename + "_important"));
  }

  static void printHelp() {
    System.out.println("\nHELP :\nYou can type a new task to add it to the list, or type a command :");
    System.out.println("/add <task> - Add a new task");
    System.out.println("/insert <index> <task> - Insert a new task at a given index");
    System.out.println("/del <index> - Delete a task at a given index");
    System.out.println("/edit <index> <task> - Edit a task at a given index");
    System.out.println("/done <index> - Mark a task as done");
    System.out.println("/! <index> - Mark a task as important");
    System.out.println("/clear - Clear all tasks");
    System.out.println("/save <filename> - Save the current list to a file");
    System.out.println("/load <filename> - Load a list from a file");
    System.out.println("/help - Print this help");
    System.out.println("/lists - Print existing to-do lists names");
    System.out.println("/exit - Exit the program");
    System.out.println("\nPress enter to close this help");
    inputScanner.nextLine();
  }

  static void printLists() {
    System.out.println("\nTO-DO LISTS :\n");
    for (String list : lists) {
      System.out.println(list);
    }
    System.out.println("\nPress enter to close this listing");
    inputScanner.nextLine();
  }

  static void exitProgram() {
    System.out.print(CLS);
    System.exit(0);
  }
  
  // LEVEL 5
  
  static void saveData(String filename, String data) {
    try {
      File dataFile = new File(filename + ".txt");
      if (data == "") {
        dataFile.delete();
      } else {
        dataFile.createNewFile();
        FileWriter myWriter = new FileWriter(filename + ".txt");
        myWriter.write(data);
        myWriter.close();
      }
    } catch (IOException e) {}
  }

  static String loadData(String filename) {
    String content = "";
    try {
      Path path = Paths.get(filename + ".txt");
        content = Files.readString(path);
    } catch (IOException e) {}
    return content;
  }

  static ArrayList<String> convertStringToStringArrayList(String input) {
    String[] lines = input.split("\n");
    ArrayList<String> list = new ArrayList<>();
    if (lines.length > 1 || lines[0] != "") {
      for (String line : lines) {
        list.add(line);
      }
    }
    return list;
  }

  static ArrayList<Boolean> convertStringToBooleanArrayList(String input) {
    String[] lines = input.split("\n");
    ArrayList<Boolean> list = new ArrayList<>();
    if (lines.length > 1 || lines[0] != "") {
      for (String line : lines) {
        list.add(Boolean.parseBoolean(line));
      }
    }
    return list;
  }

  static String convertStringArrayListToString(ArrayList<String> list) {
    StringBuilder sb = new StringBuilder();
    for (String item : list) {
      sb.append(item).append("\n");
    }
    // Remove the last line break if needed
    if (!list.isEmpty()) {
      sb.setLength(sb.length() - 1);
    }
    return sb.toString();
  }
  
  static String convertBooleanArrayListToString(ArrayList<Boolean> list) {
    StringBuilder sb = new StringBuilder();
    for (Boolean item : list) {
      sb.append(item).append("\n");
    }
    // Remove the last line break if needed
    if (!list.isEmpty()) {
      sb.setLength(sb.length() - 1);
    }
    return sb.toString();
  }
}