from PyQt5.QtWidgets import QTextEdit, QWidget, QSplitter, QVBoxLayout, QApplication
from PyQt5.Qt import Qt
from abc import abstractmethod
from typing import List
import sys


class MemoryNode:
    @abstractmethod
    def get_from_memory(self) -> str:
        raise NotImplementedError("get_from_memory")

    @abstractmethod
    def set_to_memory(self, content: str):
        raise NotImplementedError("set_to_memmory")


class MemorySkin:
    @abstractmethod
    def load_from_mem(self) -> None:
        raise NotImplementedError("load_from_mem")

    @abstractmethod
    def save_to_mem(self):
        raise NotImplementedError("save_to_mem")


class RelateReferView(QWidget, MemorySkin):
    def __init__(self, prev_frefs: MemoryNode, curr_frefs: MemoryNode, parent):
        """
        构建引用关系视图

        :param prev_frefs: 上游节点
        :param curr_frefs: 当前引用节点
        """
        QWidget.__init__(self, parent)
        self.prev_fragment = prev_frefs
        self.curr_fragment = curr_frefs
        layout = QVBoxLayout(self)
        layout.setContentsMargins(0, 0, 0, 0)

        splitter_container = QSplitter(Qt.Orientation.Vertical, self)
        layout.addWidget(splitter_container)

        self.immut_view: QTextEdit = QTextEdit(self)
        self.immut_view.setReadOnly(True)
        self.mut_refers: QTextEdit = QTextEdit(self)
        splitter_container.addWidget(self.immut_view)
        splitter_container.addWidget(self.mut_refers)

        pass

    def load_from_mem(self):
        """
        载入内存内容到视图
        """
        self.immut_view.setText(self.prev_fragment.get_from_memory())
        self.mut_refers.setText(self.curr_fragment.get_from_memory())
        pass

    def save_to_mem(self):
        """
        保存视图内容到内存
        """
        self.prev_fragment.set_to_memory(self.immut_view.toPlainText())
        self.curr_fragment.set_to_memory(self.mut_refers.toPlainText())
        pass


class EmptyNode(MemoryNode):
    def get_from_memory(self) -> str:
        return "站位视图内容"

    def set_to_memory(self, content: str):
        pass


if __name__ == "__main__":
    app = QApplication(sys.argv)
    view = RelateReferView(EmptyNode(), EmptyNode(), None)
    view.show()
    app.exec()