from PySide2 import QtCore, QtWidgets
import numpy as np

class HorizontalHeader(QtWidgets.QHeaderView):
    def __init__(self, values, parent=None):
        super(HorizontalHeader, self).__init__(QtCore.Qt.Horizontal, parent)
        self.setSectionsMovable(True)
        self.comboboxes = []
        self.sectionResized.connect(self.handleSectionResized)
        self.sectionMoved.connect(self.handleSectionMoved)

    def showEvent(self, event):
        for i in range(2, self.count()):
            if i < len(self.comboboxes):
                combo = self.comboboxes[i]
                combo.clear()
                combo.addItems(["A", "B", 'L', 'T', 'V'])
            else:
                combo = QtWidgets.QComboBox(self)
                combo.addItems(["A", "B", 'L', 'T', 'V'])
                self.comboboxes.append(combo)

            combo.setGeometry(self.sectionViewportPosition(i), 0, self.sectionSize(i)-4, self.height())
            combo.show()

        if len(self.comboboxes) > self.count():
            for i in range(self.count(), len(self.comboboxes)):
                self.comboboxes[i].deleteLater()

        super(HorizontalHeader, self).showEvent(event)

    def handleSectionResized(self, i):
        for i in range(self.count()):
            j = self.visualIndex(i)
            logical = self.logicalIndex(j)
            self.comboboxes[i].setGeometry(self.sectionViewportPosition(logical), 0, self.sectionSize(logical)-4, self.height())

    def handleSectionMoved(self, i, oldVisualIndex, newVisualIndex):
        for i in range(min(oldVisualIndex, newVisualIndex), self.count()):
            logical = self.logicalIndex(i)
            self.comboboxes[i].setGeometry(self.ectionViewportPosition(logical), 0, self.sectionSize(logical) - 5, height())

    def fixComboPositions(self):
        for i in range(self.count()):
            self.comboboxes[i].setGeometry(self.sectionViewportPosition(i), 0, self.sectionSize(i) - 5, self.height())

class TableWidget(QtWidgets.QTableWidget):
    def __init__(self, columns, *args, **kwargs):
        super(TableWidget, self).__init__(*args, **kwargs)
        header = HorizontalHeader(self)


        self.setRowCount(100)
        self.setHorizontalHeader(header)
        # self.setRowCount(rows)
        self.setColumnCount(columns)
        self.setHorizontalHeaderLabels(['Loadcase', 'Step'])
        self.columns = columns
        self.createTable()

    def createTable(self):
        start = 0

        for loadcase in range(10):
            steps = np.random.randint(1, 5)
            end = start + steps

            print(loadcase, steps, start, end)

            for row in range(start, end):
                item = QtWidgets.QTableWidgetItem(str(loadcase + 1))
                item.setFlags(QtCore.Qt.ItemIsUserCheckable |
                              QtCore.Qt.ItemIsEnabled)
                item.setCheckState(QtCore.Qt.Unchecked)
                self.setItem(row, 0, item)
            step = 0

            for row in range(start, end):
                step += 1
                item = QtWidgets.QTableWidgetItem(str(step))
                self.setItem(row, 1, item)

            start = end

        self.data = np.random.rand(end, self.columns-2)

        for i, row_values in enumerate(self.data):
            for j, value in enumerate(row_values):
                self.setItem(i, j+2, QtWidgets.QTableWidgetItem(str(round(value,4))))

        self.itemClicked.connect(self.handleItemClicked)

        self._list = []

    def handleItemClicked(self, item):
        if item.checkState() == QtCore.Qt.Checked:
            if item.row() not in self._list:
                self._list.append(item.row())
            print(self._list)
        else:
            if item.row() in self._list:
                self._list.remove(item.row())
            print(self._list)

    def headerItemClicked(self, logicalIndex):
        column = self.currentItem().column()
        selectedName = self.horizontalHeaderItem(column)
        print(selectedName.text())


    def scrollContentsBy(self, dx, dy):
        super(TableWidget, self).scrollContentsBy(dx, dy)
        if dx != 0:
            self.horizontalHeader().fixComboPositions()


class App(QtWidgets.QWidget):
    def __init__(self):
        super(App,self).__init__()
        self.createTable()
        layout = QtWidgets.QVBoxLayout(self)
        layout.addWidget(self.table)
        self.showMaximized()

    def createTable(self):
        self.table = TableWidget(16)

if __name__ == '__main__':
    import sys

    app = QtWidgets.QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec_())