messenger

import sys
from sys import argv
from typing import Self

from PySide6.QtWidgets import (
    QApplication,
    QComboBox,
    QLabel,
    QLineEdit,
    QVBoxLayout,
    QWidget,
)


class MainWindow(QWidget):
    def __init__(self: Self) -> None:
        super().__init__()

        self.messages = {
            "chat_1": [],
            "chat_2": [],
            "chat_3": [],
        }

        self.chat_selection = QComboBox()
        self.chat_selection.addItems(tuple(self.messages.keys()))
        self.chat_selection.currentTextChanged.connect(self.select_chat)

        self.messages_layout = QVBoxLayout()

        self.message_input = QLineEdit()
        self.message_input.returnPressed.connect(self.send_message)

        layout = QVBoxLayout()
        layout.addWidget(self.chat_selection)
        layout.addLayout(self.messages_layout)
        layout.addWidget(self.message_input)
        self.setLayout(layout)

    def select_chat(self: Self) -> None:
        chat_name = self.chat_selection.currentText()

        for i in reversed(range(self.messages_layout.count())):
            widget = self.messages_layout.itemAt(i).widget()
            self.messages_layout.removeWidget(widget)
            widget.deleteLater()

        for message in self.messages[chat_name]:
            self.messages_layout.addWidget(QLabel(message))

    def send_message(self: Self) -> None:
        message = self.message_input.text()
        if message == "":
            return
        self.message_input.clear()

        chat_name = self.chat_selection.currentText()
        self.messages[chat_name].append(message)
        self.messages_layout.addWidget(QLabel(message))


def main() -> int:
    application = QApplication(argv)
    main_window = MainWindow()
    main_window.show()
    return application.exec()


if __name__ == "__main__":
    sys.exit(main())