# -*- coding: utf-8 -*-
"""
qtnumpy
-------

Module implementing some utilities between Qt and NumPy

License/copyright: MIT License © Pierre Raybaut 2020.
"""

import os
import shiboken2
import ctypes
import numpy as np

from PySide2 import QtWidgets as QW
from PySide2 import QtGui as QG
from PySide2 import QtCore as QC

from PySide2 import __version__
import time

def array2d_to_qpolygonf(xdata, ydata):
    """
    Utility function to convert two 1D-NumPy arrays representing curve data 
    (X-axis, Y-axis data) into a single polyline (QtGui.PolygonF object). 
    This feature is compatible with PyQt4, PyQt5 and PySide2 (requires QtPy).
    
    License/copyright: MIT License © Pierre Raybaut 2020.
    
    :param numpy.ndarray xdata: 1D-NumPy array (numpy.float64)
    :param numpy.ndarray ydata: 1D-NumPy array (numpy.float64)
    :return: Polyline
    :rtype: QtGui.QPolygonF
    """
    dtype = np.float
    if not (xdata.size == ydata.size == xdata.shape[0] == ydata.shape[0]
            and xdata.dtype == ydata.dtype == dtype):
        raise ValueError("Arguments must be 1D, float64 NumPy arrays with same size")
    size = xdata.size
    polyline = QG.QPolygonF(size)
    address = shiboken2.getCppPointer(polyline.data())[0]
    buffer = (ctypes.c_double * 2 * size).from_address(address)
    memory = np.frombuffer(buffer, dtype)
    memory[: (size - 1) * 2 + 1 : 2] = xdata
    memory[1 : (size - 1) * 2 + 2 : 2] = ydata
    return polyline    


class TestWidget(QW.QWidget):
    def __init__(self, polyline=None):
        super(TestWidget, self).__init__()
        self.polyline = polyline
        
    def paintEvent(self, event):
        painter = QG.QPainter(self)
        painter.setPen(QC.Qt.red)
        if self.polyline is not None:            
            print(self.polyline.size(), 'lines')
            qtlib = "PySide2 v%s" % __version__
            t0 = time.time()
            painter.drawPolyline(self.polyline)
            print("dt[%s] = %d ms" % (qtlib, ((time.time()-t0)*1e3)))


if __name__ == '__main__':
    app = QW.QApplication.instance()
    print(QC.QLibraryInfo.build())
    if app is None:
        app = QW.QApplication([])
    xdata = np.linspace(0, 800, 1000000)
    ydata = np.cos(xdata/100.)**2*300
    polyline = array2d_to_qpolygonf(xdata, ydata)
    # for index, point in enumerate(polyline):
    #     assert point.x() == xdata[index] and point.y() == ydata[index]
        # print("%s <==> NumPy(%s, %s)" % (point, xdata[index], ydata[index]))
    widget = TestWidget(polyline)
    widget.show()
    app.exec_()