"""
实例：
汤宝宝有一张TODO表，记录着自己想干的事情。
"""

from abc import ABC, abstractmethod


# 任务结构体 - 迭代器元素
class Todo:
    content: str
    done: bool

    def __init__(self, content: str, done: bool = False):
        self.content = content
        self.done = done


# 集合接口
class Collection(ABC):
    @abstractmethod
    def CreateIterator(self) -> "Iterator":
        pass


# 具体集合 - 汤宝宝的TODO表
class TodoList(Collection):
    todos: list[Todo]

    def __init__(self, todos: list[Todo]):
        self.todos = todos

    def CreateIterator(self) -> "Iterator":
        return TodoListIterator(self)


# 迭代器接口
class Iterator(ABC):
    @abstractmethod
    def First(self) -> Todo:
        pass

    @abstractmethod
    def Next(self) -> Todo | None:
        pass

    @abstractmethod
    def isDone(self) -> bool:
        pass

    @abstractmethod
    def CurrentItem(self) -> int:
        pass


# 具体迭代器 - 汤宝宝的TODO表迭代器
class TodoListIterator(Iterator):
    def __init__(self, todo_list: "TodoList"):
        self._todo_list = todo_list
        self._current = 0

    def First(self) -> Todo:
        self._current = 0
        return self._todo_list.todos[self._current]

    def Next(self) -> Todo | None:
        self._current += 1
        if not self.isDone():
            return self._todo_list.todos[self._current]
        return None

    def isDone(self) -> bool:
        return self._current >= len(self._todo_list.todos)

    def CurrentItem(self) -> int:
        if self.isDone():
            return len(self._todo_list.todos)
        return self._current + 1


if __name__ == "__main__":
    print("============= 迭代器模式 =============")

    # 创建TODO表并添加任务
    todo_list = TodoList(
        todos=[
            Todo("学习Go语言", True),
            Todo("完成设计模式作业", False),
            Todo("锻炼身体", False),
        ]
    )

    # 创建迭代器
    iterator = todo_list.CreateIterator()

    # 使用迭代器遍历TODO表
    item = iterator.First()
    while not iterator.isDone():
        done = "已完成" if item and item.done else "未完成"
        print(
            f"当前第 {iterator.CurrentItem()} 项任务内容: {item.content if item else ''} 是否完成: {done}"
        )
        item = iterator.Next()

    print("\n=========== 迭代器模式结束 ===========")