TaskTracker.java

import java.time.LocalDateTime;
import java.util.Iterator;
import java.util.List;

public class TaskTracker {
	public static void main(String[] args) {
		TaskStorage.createFile();

		if (args.length == 0) {
			System.out.println("No command provided.");
			return;
		}

		String command = args[0];
		List<Task> tasks = TaskStorage.loadTasks();

		switch (command) {
			case "add":
				handleAdd(args, tasks);
				break;
			case "list":
				if (args.length == 2) {
					handleListPrint(args, tasks);
				} else {
					handleList(tasks);
				}
				break;
			case "delete":
				handleDelete(args, tasks);
				break;
			case "update":
				handleUpdate(args, tasks);
				break;
			case "mark-done":
				handleStatus(args, tasks, "done");
				break;
			case "mark-in-progress":
				handleStatus(args, tasks, "in-progress");
				break;
			default:
				System.out.println("Unknown command: " + command);
		}

		TaskStorage.saveTasks(tasks);
	}

	public static void handleAdd(String[] args, List<Task> tasks) {
		if (args.length < 2) {
			System.out.println("Please enter a description.");
			return;
		}

		// build the description
		StringBuilder sb = new StringBuilder();
		for (int i = 1; i < args.length; i++) {
			sb.append(args[i]);
			if (i < args.length - 1) sb.append(" ");
		}

		String description = sb.toString();

		// generate ID
		int maxId = 0;
		for (Task t : tasks) {
			if (t.getID() > maxId) maxId = t.getID();
		}
		int newId = maxId + 1;

		Task newTask = new Task(description);
		newTask.setId(newId);
		tasks.add(newTask);

		System.out.println("Task was successfully added with the ID: " + newId);
	}

	public static void handleList(List<Task> tasks) {
		if (tasks.isEmpty()) {
			System.out.println("No tasks were found.");
			return;
		}

		for (Task task : tasks) {
			System.out.println(task.toString());
			System.out.println();
		}
	}

	public static void handleDelete(String[] args, List<Task> tasks) {
		if (args.length < 2) {
			System.out.println("Please enter an ID.");
			return;
		}

		int id;
		try {
			id = Integer.parseInt(args[1]);
		} catch (NumberFormatException e) {
			System.out.println("Invalid ID. Please enter a number.");
			return;
		}

		Iterator<Task> iterator = tasks.iterator();
		while (iterator.hasNext()) {
			Task task = iterator.next();
			if (task.getID() == id) {
				iterator.remove();
				System.out.println("Task deleted successfully with the ID: " + id);
				return;
			}
		}

		System.out.println("Task with ID " + id + " not found.");
	}

	public static void handleUpdate(String[] args, List<Task> tasks) {
		if (args.length < 2) {
			System.out.println("Please enter an ID.");
			return;
		}

		if (args.length < 3) {
			System.out.println("Please enter a description.");
			return;
		}

		int id;
		try {
			id = Integer.parseInt(args[1]);
		} catch (NumberFormatException e) {
			System.out.println("Invalid ID. Please enter a number.");
			return;
		}

		for (Task task : tasks) {
			if (task.getID() == id) {
				task.setDescription(args[2]);
				task.setUpdatedAt(LocalDateTime.now());
				System.out.println("Task updated successfully.");
				return;
			}
		}

		System.out.println("Task with ID " + id + " not found.");
	}

	public static void handleStatus(String[] args, List<Task> tasks, String status) {
		if (args.length < 2) {
			System.out.println("Please enter an ID.");
			return;
		}

		int id;
		try {
			id = Integer.parseInt(args[1]);
		} catch (NumberFormatException e) {
			System.out.println("Invalid ID. Please enter a number.");
			return;
		}

		for (Task task : tasks) {
			if (task.getID() == id) {
				task.setStatus(status);
				task.setUpdatedAt(LocalDateTime.now());
				System.out.println("Task updated successfully.");
				return;
			}
		}

		System.out.println("Task with ID " + id + " not found.");
	}

	public static void handleListPrint(String[] args, List<Task> tasks) {
		if (args.length < 2) {
			System.out.println("Please enter status.");
			return;
		}

		boolean found = false;
		for (Task task : tasks) {
			if (task.getStatus().equals(args[1])) {
				System.out.println(task.toString());
				System.out.println();
				found = true;
			}
		}

		if (!found) {
			System.out.println("No task with the status " + args[1] + " found.");
		}
	}
}