"""
***************************************************************************
    raster.py
    ---------------------
    Date                 : February 2013
    Copyright            : (C) 2013 by Victor Olaya  and Alexander Bruy
    Email                : volayaf at gmail dot com
***************************************************************************
*                                                                         *
*   This program is free software; you can redistribute it and/or modify  *
*   it under the terms of the GNU General Public License as published by  *
*   the Free Software Foundation; either version 2 of the License, or     *
*   (at your option) any later version.                                   *
*                                                                         *
***************************************************************************
"""

__author__ = "Victor Olaya  and Alexander Bruy"
__date__ = "February 2013"
__copyright__ = "(C) 2013, Victor Olaya  and Alexander Bruy"

import struct

from osgeo import gdal

from qgis.core import QgsProcessingException

gdal.UseExceptions()


def scanraster(layer, feedback, band_number=1):
    filename = str(layer.source())
    dataset = gdal.Open(filename, gdal.GA_ReadOnly)
    band = dataset.GetRasterBand(band_number)
    nodata = band.GetNoDataValue()
    bandtype = gdal.GetDataTypeName(band.DataType)
    for y in range(band.YSize):
        feedback.setProgress(y / float(band.YSize) * 100)
        scanline = band.ReadRaster(0, y, band.XSize, 1, band.XSize, 1, band.DataType)
        if bandtype == "Byte":
            values = struct.unpack("B" * band.XSize, scanline)
        elif bandtype == "Int16":
            values = struct.unpack("h" * band.XSize, scanline)
        elif bandtype == "UInt16":
            values = struct.unpack("H" * band.XSize, scanline)
        elif bandtype == "Int32":
            values = struct.unpack("i" * band.XSize, scanline)
        elif bandtype == "UInt32":
            values = struct.unpack("I" * band.XSize, scanline)
        elif bandtype == "Float32":
            values = struct.unpack("f" * band.XSize, scanline)
        elif bandtype == "Float64":
            values = struct.unpack("d" * band.XSize, scanline)
        else:
            raise QgsProcessingException("Raster format not supported")
        for value in values:
            if value == nodata:
                value = None
            yield value


def mapToPixel(mX, mY, geoTransform):
    (pX, pY) = gdal.ApplyGeoTransform(gdal.InvGeoTransform(geoTransform), mX, mY)
    return (int(pX), int(pY))


def pixelToMap(pX, pY, geoTransform):
    return gdal.ApplyGeoTransform(geoTransform, pX + 0.5, pY + 0.5)