package TodoListApp;
import java.util.Scanner;

// 主类
public class TodoListApp {
    private static final String ADD_TODO = "1";
    private static final String LIST_TODOS = "2";
    private static final String REMOVE_TODO = "3";
    private static final String MARK_AS_COMPLETED = "4";
    private static final String SAVE_TODOS = "5";
    private static final String EXIT = "6";

    private static final TodoListManager manager = new TodoListManager();
    private static final Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {
        boolean exit = false;
        while (!exit) {
            printMenu();
            String choice = scanner.nextLine();
            switch (choice) {
                case ADD_TODO:
                    addTodoUI();
                    break;
                case LIST_TODOS:
                    manager.listTodos();
                    break;
                case REMOVE_TODO:
                    removeTodoUI();
                    break;
                case MARK_AS_COMPLETED:
                    markAsCompletedUI();
                    break;
                case SAVE_TODOS:
                    manager.saveToFile("todos.dat");
                    break;
                case EXIT:
                    exit = true;
                    System.out.println("退出程序。");
                    break;
                default:
                    System.out.println("无效的选择，请重新输入。");
            }
        }
        scanner.close();
    }

    // 打印菜单
    private static void printMenu() {
        System.out.println("\n===== 简易待办事项管理器 =====");
        System.out.println("1. 添加待办事项");
        System.out.println("2. 查看所有待办事项");
        System.out.println("3. 删除待办事项");
        System.out.println("4. 标记待办为已完成");
        System.out.println("5. 保存待办事项（字节流）");
        System.out.println("6. 退出");
        System.out.print("请选择操作（1-6）：");
    }

    // 添加待办事项的用户界面
    private static void addTodoUI() {
        String description = getNonEmptyInput("请输入待办事项描述：");
        try {
            manager.addTodo(description);
        } catch (EmptyDescriptionException e) {
            System.out.println("自定义异常：" + e.getMessage());
        }
    }

    // 删除待办事项的用户界面
    private static void removeTodoUI() {
        System.out.print("请输入要删除的待办事项编号：");
        String input = scanner.nextLine().trim();
        try {
            int id = Integer.parseInt(input);
            manager.removeTodo(id);
        } catch (NumberFormatException e) {
            try {
                throw new InvalidIdException("请输入有效的ID编号。");
            } catch (InvalidIdException ex) {
                System.out.println("自定义异常：" + ex.getMessage());
                ;
            }
        } catch (TodoNotFoundException e) {
            System.out.println("自定义异常：" + e.getMessage());
        }
    }

    //用于对用户的输入进行提示和预处理的能用方法
    private static String getNonEmptyInput(String prompt) {
        System.out.println(prompt);
        String input = scanner.nextLine().trim();
        while (input.isEmpty()) {
            System.out.println("输入不能为空，请重新输入。");
            System.out.println(prompt);
            input = scanner.nextLine().trim();
        }
        return input;
    }

    private static void markAsCompletedUI() {
        String input = getNonEmptyInput("请输入要标记为已完成的待办事项编号：");
        try {
            int id = Integer.parseInt(input);
            manager.markAsCompleted(id);
        } catch (NumberFormatException e) {
            System.out.println("请输入有效的数字编号。");
        }
    }
}