import sys
from threading import Thread
from time import sleep

from PyQt5 import QtCore, QtWidgets
from PyQt5.QtCore import pyqtSlot
from PyQt5.QtWidgets import QApplication, QMainWindow, QVBoxLayout, QLabel


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(445, 333)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.verticalLayout_2 = QtWidgets.QVBoxLayout(self.centralwidget)
        self.verticalLayout_2.setObjectName("verticalLayout_2")
        self.verticalLayout = QtWidgets.QVBoxLayout()
        self.verticalLayout.setObjectName("verticalLayout")
        self.scrollArea = QtWidgets.QScrollArea(self.centralwidget)
        self.scrollArea.setWidgetResizable(False)
        self.scrollArea.setAlignment(QtCore.Qt.AlignLeading | QtCore.Qt.AlignLeft | QtCore.Qt.AlignTop)
        self.scrollArea.setObjectName("scrollArea")
        self.scrollAreaWidgetContents = QtWidgets.QWidget()
        self.scrollAreaWidgetContents.setGeometry(QtCore.QRect(0, 0, 423, 256))
        self.scrollAreaWidgetContents.setObjectName("scrollAreaWidgetContents")
        self.scrollArea.setWidget(self.scrollAreaWidgetContents)
        self.verticalLayout.addWidget(self.scrollArea)
        self.verticalLayout_2.addLayout(self.verticalLayout)
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setObjectName("pushButton")
        self.verticalLayout_2.addWidget(self.pushButton)
        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setObjectName("lineEdit")
        self.verticalLayout_2.addWidget(self.lineEdit)
        MainWindow.setCentralWidget(self.centralwidget)

        self.retranslateUi(MainWindow)
        self.pushButton.clicked.connect(MainWindow.start_thread)
        self.lineEdit.returnPressed.connect(MainWindow.send_message)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "Test"))
        self.pushButton.setText(_translate("MainWindow", "start thread"))


class Test(QMainWindow, Ui_MainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setupUi(self)
        layout = QVBoxLayout()
        layout.addStretch(1)
        self.scrollAreaWidgetContents.setLayout(layout)

    @pyqtSlot()
    def start_thread(self):
        start(self.incoming_message, err_callback)

    @pyqtSlot()
    def send_message(self):
        self.write_message(self.lineEdit.text(), "lightblue")
        self.lineEdit.setText("")

    def write_message(self, message, color):
        print(f"received {message}")
        label = QLabel(self.scrollAreaWidgetContents)
        label.setText(message)
        label.setStyleSheet(f"background-color:{color}")
        self.scrollAreaWidgetContents.layout().addWidget(label)

    def incoming_message(self, message):
        print(f"passed {message}")
        self.write_message(message, "khaki")


def start(msg_callback, error_callback):
    Thread(target=listen, args=(msg_callback, error_callback), daemon=True).start()


def listen(msg_callback, error_callback):
    while True:
        try:
            sleep(5.0)
            print("Ping !")
            msg_callback("Ping !")
        except:
            error_callback("error")


def err_callback(message):
    print(message)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    test = Test()
    test.show()
    app.exec_()