#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# ******************************************************************************
#
#  Project:  GDAL
#  Purpose:  Command line raster calculator with numpy syntax
#  Author:   Chris Yesson, chris.yesson@ioz.ac.uk
#
# ******************************************************************************
#  Copyright (c) 2010, Chris Yesson <chris.yesson@ioz.ac.uk>
#  Copyright (c) 2010-2011, Even Rouault <even dot rouault at spatialys.com>
#  Copyright (c) 2016, Piers Titus van der Torren <pierstitus@gmail.com>
#  Copyright (c) 2020, Idan Miara <idan@miara.com>
#
#  Permission is hereby granted, free of charge, to any person obtaining a
#  copy of this software and associated documentation files (the "Software"),
#  to deal in the Software without restriction, including without limitation
#  the rights to use, copy, modify, merge, publish, distribute, sublicense,
#  and/or sell copies of the Software, and to permit persons to whom the
#  Software is furnished to do so, subject to the following conditions:
#
#  The above copyright notice and this permission notice shall be included
#  in all copies or substantial portions of the Software.
#
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
#  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
#  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
#  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
#  DEALINGS IN THE SOFTWARE.
# ******************************************************************************

import argparse
import glob
import os
import os.path
import string
import sys
import textwrap
from numbers import Number
from typing import Dict, Optional, Sequence, Tuple, Union

import numpy

from osgeo import gdal, gdal_array
from osgeo_utils.auxiliary import extent_util
from osgeo_utils.auxiliary.base import MaybeSequence, PathLikeOrStr, is_path_like
from osgeo_utils.auxiliary.color_table import ColorTableLike, get_color_table
from osgeo_utils.auxiliary.extent_util import GT, Extent
from osgeo_utils.auxiliary.gdal_argparse import GDALArgumentParser, GDALScript
from osgeo_utils.auxiliary.rectangle import GeoRectangle
from osgeo_utils.auxiliary.util import GetOutputDriverFor, open_ds

GDALDataType = int

# create alphabetic list (lowercase + uppercase) for storing input layers
AlphaList = list(string.ascii_letters)

# set up some default nodatavalues for each datatype
DefaultNDVLookup = {
    gdal.GDT_Byte: 255,
    gdal.GDT_UInt16: 65535,
    gdal.GDT_Int16: -32768,
    gdal.GDT_UInt32: 4294967293,
    gdal.GDT_Int32: -2147483647,
    gdal.GDT_UInt64: None,
    gdal.GDT_Int64: None,
    gdal.GDT_Float32: 3.402823466e38,
    gdal.GDT_Float64: 1.7976931348623158e308,
    gdal.GDT_CInt16: None,
    gdal.GDT_CInt32: None,
    gdal.GDT_CFloat32: None,
    gdal.GDT_CFloat64: None,
}

# tuple of available output datatypes names
GDALDataTypeNames = tuple(gdal.GetDataTypeName(dt) for dt in DefaultNDVLookup.keys())

""" Perform raster calculations with numpy syntax.
Use any basic arithmetic supported by numpy arrays such as +-* along with logical
operators such as >. Note that all files must have the same dimensions, but no projection checking is performed.

Keyword arguments:
    [A-Z]: input files
    [A_band - Z_band]: band to use for respective input file

Examples:
add two files together:
    Calc("A+B", A="input1.tif", B="input2.tif", outfile="result.tif")

average of two layers:
    Calc(calc="(A+B)/2", A="input1.tif", B="input2.tif", outfile="result.tif")

set values of zero and below to null:
    Calc(calc="A*(A>0)", A="input.tif", A_band=2, outfile="result.tif", NoDataValue=0)

work with two bands:
    Calc(["(A+B)/2", "A*(A>0)"], A="input.tif", A_band=1, B="input.tif", B_band=2, outfile="result.tif", NoDataValue=0)

sum all files with hidden noDataValue
    Calc(calc="sum(a,axis=0)", a=['0.tif','1.tif','2.tif'], outfile="sum.tif", hideNoData=True)
"""


def Calc(
    calc: MaybeSequence[str],
    outfile: Optional[PathLikeOrStr] = None,
    NoDataValue: Optional[Number] = None,
    type: Optional[Union[GDALDataType, str]] = None,
    format: Optional[str] = None,
    creation_options: Optional[Sequence[str]] = None,
    allBands: str = "",
    overwrite: bool = False,
    hideNoData: bool = False,
    projectionCheck: bool = False,
    color_table: Optional[ColorTableLike] = None,
    extent: Optional[Extent] = None,
    projwin: Optional[Union[Tuple, GeoRectangle]] = None,
    user_namespace: Optional[Dict] = None,
    debug: bool = False,
    quiet: bool = False,
    **input_files,
):

    if debug:
        print(f"gdal_calc.py starting calculation {calc}")

    if outfile and os.path.isfile(outfile) and not overwrite:
        if type or format or creation_options or hideNoData or extent or projwin:
            raise Exception(
                "One or several options implying file creation have been provided but Output file exists, must use --overwrite option!"
            )

    # Single calc value compatibility
    if isinstance(calc, (list, tuple)):
        calc = calc
    else:
        calc = [calc]
    calc = [c.strip('"') for c in calc]

    creation_options = creation_options or []

    # set up global namespace for eval with all functions of gdal_array, numpy
    global_namespace = {
        key: getattr(module, key)
        for module in [gdal_array, numpy]
        for key in dir(module)
        if not key.startswith("__")
    }

    if user_namespace:
        global_namespace.update(user_namespace)

    if not calc:
        raise Exception("No calculation provided.")
    elif not outfile and format.upper() != "MEM":
        raise Exception("No output file provided.")

    if format is None:
        format = GetOutputDriverFor(outfile)

    if isinstance(extent, GeoRectangle):
        pass
    elif projwin:
        if isinstance(projwin, GeoRectangle):
            extent = projwin
        else:
            extent = GeoRectangle.from_lurd(*projwin)
    elif not extent:
        extent = Extent.IGNORE
    else:
        extent = extent_util.parse_extent(extent)

    compatible_gt_eps = 0.000001
    gt_diff_support = {
        GT.INCOMPATIBLE_OFFSET: extent != Extent.FAIL,
        GT.INCOMPATIBLE_PIXEL_SIZE: False,
        GT.INCOMPATIBLE_ROTATION: False,
        GT.NON_ZERO_ROTATION: False,
    }
    gt_diff_error = {
        GT.INCOMPATIBLE_OFFSET: "different offset",
        GT.INCOMPATIBLE_PIXEL_SIZE: "different pixel size",
        GT.INCOMPATIBLE_ROTATION: "different rotation",
        GT.NON_ZERO_ROTATION: "non zero rotation",
    }

    ################################################################
    # fetch details of input layers
    ################################################################

    # set up some lists to store data for each band
    myFileNames = []  # input filenames
    myFiles = []  # input DataSets
    myBands = []  # input bands
    myAlphaList = []  # input alpha letter that represents each input file
    myDataType = []  # string representation of the datatype of each input file
    myDataTypeNum = []  # datatype of each input file
    myNDV = []  # nodatavalue for each input file
    DimensionsCheck = None  # dimensions of the output
    Dimensions = []  # Dimensions of input files
    ProjectionCheck = None  # projection of the output
    GeoTransformCheck = None  # GeoTransform of the output
    GeoTransforms = []  # GeoTransform of each input file
    GeoTransformDiffer = False  # True if we have inputs with different GeoTransforms
    myTempFileNames = []  # vrt filename from each input file
    myAlphaFileLists = []  # list of the Alphas which holds a list of inputs

    # loop through input files - checking dimensions
    for alphas, filenames in input_files.items():
        if isinstance(filenames, (list, tuple)):
            # alpha is a list of files
            myAlphaFileLists.append(alphas)
        elif is_path_like(filenames) or isinstance(filenames, gdal.Dataset):
            # alpha is a single filename or a Dataset
            filenames = [filenames]
            alphas = [alphas]
        else:
            # I guess this alphas should be in the global_namespace,
            # It would have been better to pass it as user_namespace, but I'll accept it anyway
            global_namespace[alphas] = filenames
            continue
        for alpha, filename in zip(alphas * len(filenames), filenames):
            if not alpha.endswith("_band"):
                # check if we have asked for a specific band...
                alpha_band = f"{alpha}_band"
                if alpha_band in input_files:
                    myBand = input_files[alpha_band]
                else:
                    myBand = 1

                myF_is_ds = not is_path_like(filename)
                if myF_is_ds:
                    myFile = filename
                    filename = None
                else:
                    myFile = open_ds(filename)
                if not myFile:
                    raise IOError(f"No such file or directory: '{filename}'")

                myFileNames.append(filename)
                myFiles.append(myFile)
                myBands.append(myBand)
                myAlphaList.append(alpha)
                dt = myFile.GetRasterBand(myBand).DataType
                myDataType.append(gdal.GetDataTypeName(dt))
                myDataTypeNum.append(dt)
                myNDV.append(
                    None
                    if hideNoData
                    else myFile.GetRasterBand(myBand).GetNoDataValue()
                )

                # check that the dimensions of each layer are the same
                myFileDimensions = [myFile.RasterXSize, myFile.RasterYSize]
                if DimensionsCheck:
                    if DimensionsCheck != myFileDimensions:
                        GeoTransformDiffer = True
                        if extent in [Extent.IGNORE, Extent.FAIL]:
                            raise Exception(
                                f"Error! Dimensions of file {filename} ({myFileDimensions[0]:d}, "
                                f"{myFileDimensions[1]:d}) are different from other files "
                                f"({DimensionsCheck[0]:d}, {DimensionsCheck[1]:d}).  Cannot proceed"
                            )
                else:
                    DimensionsCheck = myFileDimensions

                # check that the Projection of each layer are the same
                myProjection = myFile.GetProjection()
                if ProjectionCheck:
                    if projectionCheck and ProjectionCheck != myProjection:
                        raise Exception(
                            f"Error! Projection of file {filename} {myProjection} "
                            f"are different from other files {ProjectionCheck}.  Cannot proceed"
                        )
                else:
                    ProjectionCheck = myProjection

                # check that the GeoTransforms of each layer are the same
                myFileGeoTransform = myFile.GetGeoTransform(can_return_null=True)
                if extent == Extent.IGNORE:
                    GeoTransformCheck = myFileGeoTransform
                else:
                    Dimensions.append(myFileDimensions)
                    GeoTransforms.append(myFileGeoTransform)
                    if not GeoTransformCheck:
                        GeoTransformCheck = myFileGeoTransform
                    else:
                        my_gt_diff = extent_util.gt_diff(
                            GeoTransformCheck,
                            myFileGeoTransform,
                            eps=compatible_gt_eps,
                            diff_support=gt_diff_support,
                        )
                        if my_gt_diff not in [GT.SAME, GT.ALMOST_SAME]:
                            GeoTransformDiffer = True
                            if my_gt_diff != GT.COMPATIBLE_DIFF:
                                raise Exception(
                                    f"Error! GeoTransform of file {filename} {myFileGeoTransform} is incompatible "
                                    f"({gt_diff_error[my_gt_diff]}), first file GeoTransform is {GeoTransformCheck}. "
                                    f"Cannot proceed"
                                )
                if debug:
                    print(
                        f"file {alpha}: {filename}, dimensions: "
                        f"{DimensionsCheck[0]}, {DimensionsCheck[1]}, type: {myDataType[-1]}"
                    )

    # process allBands option
    allBandsIndex = None
    allBandsCount = 1
    if allBands:
        if len(calc) > 1:
            raise Exception("Error! --allBands implies a single --calc")
        try:
            allBandsIndex = myAlphaList.index(allBands)
        except ValueError:
            raise Exception(
                f"Error! allBands option was given but Band {allBands} not found.  Cannot proceed"
            )
        allBandsCount = myFiles[allBandsIndex].RasterCount
        if allBandsCount <= 1:
            allBandsIndex = None
    else:
        allBandsCount = len(calc)

    if extent not in [Extent.IGNORE, Extent.FAIL] and (
        GeoTransformDiffer or isinstance(extent, GeoRectangle)
    ):
        # mixing different GeoTransforms/Extents
        (
            GeoTransformCheck,
            DimensionsCheck,
            ExtentCheck,
        ) = extent_util.calc_geotransform_and_dimensions(
            GeoTransforms, Dimensions, extent
        )
        if GeoTransformCheck is None:
            raise Exception("Error! The requested extent is empty. Cannot proceed")
        for i in range(len(myFileNames)):
            temp_vrt_filename, temp_vrt_ds = extent_util.make_temp_vrt(
                myFiles[i], ExtentCheck
            )
            myTempFileNames.append(temp_vrt_filename)
            myFiles[i] = None  # close original ds
            myFiles[i] = temp_vrt_ds  # replace original ds with vrt_ds

            # update the new precise dimensions and gt from the new ds
            GeoTransformCheck = temp_vrt_ds.GetGeoTransform()
            DimensionsCheck = [temp_vrt_ds.RasterXSize, temp_vrt_ds.RasterYSize]
        temp_vrt_ds = None

    ################################################################
    # set up output file
    ################################################################

    # open output file exists
    if outfile and os.path.isfile(outfile) and not overwrite:
        if allBandsIndex is not None:
            raise Exception(
                "Error! allBands option was given but Output file exists, must use --overwrite option!"
            )
        if len(calc) > 1:
            raise Exception(
                "Error! multiple calc options were given but Output file exists, must use --overwrite option!"
            )
        if debug:
            print(f"Output file {outfile} exists - filling in results into file")

        myOut = open_ds(outfile, access_mode=gdal.OF_UPDATE | gdal.OF_RASTER)
        if myOut is None:
            error = "but cannot be opened for update"
        elif [myOut.RasterXSize, myOut.RasterYSize] != DimensionsCheck:
            error = "but is the wrong size"
        elif ProjectionCheck and ProjectionCheck != myOut.GetProjection():
            error = "but is the wrong projection"
        elif GeoTransformCheck and GeoTransformCheck != myOut.GetGeoTransform(
            can_return_null=True
        ):
            error = "but is the wrong geotransform"
        else:
            error = None
        if error:
            raise Exception(
                f"Error! Output exists, {error}.  Use the --overwrite option "
                f"to automatically overwrite the existing file"
            )

        myOutB = myOut.GetRasterBand(1)
        myOutNDV = myOutB.GetNoDataValue()
        myOutType = myOutB.DataType

    else:
        if outfile:
            # remove existing file and regenerate
            if os.path.isfile(outfile):
                os.remove(outfile)
            # create a new file
            if debug:
                print(f"Generating output file {outfile}")
        else:
            outfile = ""

        # find data type to use
        if not type:
            # use the largest type of the input files
            if hasattr(gdal, "DataTypeUnion"):
                myOutType = myDataTypeNum[0]
                for dt in myDataTypeNum:
                    myOutType = gdal.DataTypeUnion(myOutType, dt)
            else:
                # GDAL < 3.5: not super reliable as it depends on the values of the GDALDataType enumeration ...
                myOutType = max(myDataTypeNum)
        else:
            myOutType = type
            if isinstance(myOutType, str):
                myOutType = gdal.GetDataTypeByName(myOutType)

        # create file
        myOutDrv = gdal.GetDriverByName(format)
        myOut = myOutDrv.Create(
            os.fspath(outfile),
            DimensionsCheck[0],
            DimensionsCheck[1],
            allBandsCount,
            myOutType,
            creation_options,
        )
        if myOut is None:
            raise Exception(f"Error! Could not create output file {outfile}")

        # set output geo info based on first input layer
        if not GeoTransformCheck:
            GeoTransformCheck = myFiles[0].GetGeoTransform(can_return_null=True)
        if GeoTransformCheck:
            myOut.SetGeoTransform(GeoTransformCheck)

        if not ProjectionCheck:
            ProjectionCheck = myFiles[0].GetProjection()
        if ProjectionCheck:
            myOut.SetProjection(ProjectionCheck)

        if NoDataValue is None:
            myOutNDV = DefaultNDVLookup[
                myOutType
            ]  # use the default noDataValue for this datatype
        elif isinstance(NoDataValue, str) and NoDataValue.lower() == "none":
            myOutNDV = None  # not to set any noDataValue
        else:
            myOutNDV = NoDataValue  # use the given noDataValue

        for i in range(1, allBandsCount + 1):
            myOutB = myOut.GetRasterBand(i)
            if myOutNDV is not None:
                myOutB.SetNoDataValue(myOutNDV)
            if color_table:
                # set color table and color interpretation
                if is_path_like(color_table):
                    color_table = get_color_table(color_table)
                myOutB.SetRasterColorTable(color_table)
                myOutB.SetRasterColorInterpretation(gdal.GCI_PaletteIndex)

            myOutB = None  # write to band

        if hideNoData:
            myOutNDV = None

    myOutTypeName = gdal.GetDataTypeName(myOutType)
    if debug:
        print(
            f"output file: {outfile}, dimensions: {myOut.RasterXSize}, {myOut.RasterYSize}, type: {myOutTypeName}"
        )

    ################################################################
    # find block size to chop grids into bite-sized chunks
    ################################################################

    # use the block size of the first layer to read efficiently
    myBlockSize = myFiles[0].GetRasterBand(myBands[0]).GetBlockSize()
    # find total x and y blocks to be read
    nXBlocks = (int)((DimensionsCheck[0] + myBlockSize[0] - 1) / myBlockSize[0])
    nYBlocks = (int)((DimensionsCheck[1] + myBlockSize[1] - 1) / myBlockSize[1])
    myBufSize = myBlockSize[0] * myBlockSize[1]

    if debug:
        print(f"using blocksize {myBlockSize[0]} x {myBlockSize[1]}")

    # variables for displaying progress
    ProgressCt = -1
    ProgressMk = -1
    ProgressEnd = nXBlocks * nYBlocks * allBandsCount

    ################################################################
    # start looping through each band in allBandsCount
    ################################################################

    for bandNo in range(1, allBandsCount + 1):

        ################################################################
        # start looping through blocks of data
        ################################################################

        # store these numbers in variables that may change later
        nXValid = myBlockSize[0]
        nYValid = myBlockSize[1]

        count_file_per_alpha = {}
        largest_datatype_per_alpha = {}
        for i, Alpha in enumerate(myAlphaList):
            if Alpha in myAlphaFileLists:
                # populate lettered arrays with values
                if allBandsIndex is not None and allBandsIndex == i:
                    myBandNo = bandNo
                else:
                    myBandNo = myBands[i]
                band = myFiles[i].GetRasterBand(myBandNo)
                if Alpha not in count_file_per_alpha:
                    count_file_per_alpha[Alpha] = 1
                    largest_datatype_per_alpha[Alpha] = band.DataType
                else:
                    count_file_per_alpha[Alpha] += 1
                    if hasattr(gdal, "DataTypeUnion"):
                        largest_datatype_per_alpha[Alpha] = gdal.DataTypeUnion(
                            largest_datatype_per_alpha[Alpha], band.DataType
                        )

        # loop through X-lines
        for X in range(0, nXBlocks):

            # in case the blocks don't fit perfectly
            # change the block size of the final piece
            if X == nXBlocks - 1:
                nXValid = DimensionsCheck[0] - X * myBlockSize[0]

            # find X offset
            myX = X * myBlockSize[0]

            # reset buffer size for start of Y loop
            nYValid = myBlockSize[1]
            myBufSize = nXValid * nYValid

            # loop through Y lines
            for Y in range(0, nYBlocks):
                ProgressCt += 1
                if 10 * ProgressCt / ProgressEnd % 10 != ProgressMk and not quiet:
                    ProgressMk = 10 * ProgressCt / ProgressEnd % 10
                    print("%d.." % (10 * ProgressMk), end=" ")

                # change the block size of the final piece
                if Y == nYBlocks - 1:
                    nYValid = DimensionsCheck[1] - Y * myBlockSize[1]
                    myBufSize = nXValid * nYValid

                # find Y offset
                myY = Y * myBlockSize[1]

                # create empty buffer to mark where nodata occurs
                myNDVs = None

                # make local namespace for calculation
                local_namespace = {}

                # Create destination numpy arrays for each alpha
                numpy_arrays = {}
                counter_per_alpha = {}
                for Alpha in count_file_per_alpha:
                    dtype = gdal_array.GDALTypeCodeToNumericTypeCode(
                        largest_datatype_per_alpha[Alpha]
                    )
                    if count_file_per_alpha[Alpha] == 1:
                        numpy_arrays[Alpha] = numpy.empty(
                            (nYValid, nXValid), dtype=dtype
                        )
                    else:
                        numpy_arrays[Alpha] = numpy.empty(
                            (count_file_per_alpha[Alpha], nYValid, nXValid), dtype=dtype
                        )
                    counter_per_alpha[Alpha] = 0

                # fetch data for each input layer
                for i, Alpha in enumerate(myAlphaList):

                    # populate lettered arrays with values
                    if allBandsIndex is not None and allBandsIndex == i:
                        myBandNo = bandNo
                    else:
                        myBandNo = myBands[i]

                    if Alpha in myAlphaFileLists:
                        if count_file_per_alpha[Alpha] == 1:
                            buf_obj = numpy_arrays[Alpha]
                        else:
                            buf_obj = numpy_arrays[Alpha][counter_per_alpha[Alpha]]
                        myval = gdal_array.BandReadAsArray(
                            myFiles[i].GetRasterBand(myBandNo),
                            xoff=myX,
                            yoff=myY,
                            win_xsize=nXValid,
                            win_ysize=nYValid,
                            buf_obj=buf_obj,
                        )
                        counter_per_alpha[Alpha] += 1
                    else:
                        myval = gdal_array.BandReadAsArray(
                            myFiles[i].GetRasterBand(myBandNo),
                            xoff=myX,
                            yoff=myY,
                            win_xsize=nXValid,
                            win_ysize=nYValid,
                        )
                    if myval is None:
                        raise Exception(
                            f"Input block reading failed from filename {filename[i]}"
                        )

                    # fill in nodata values
                    if myNDV[i] is not None:
                        # myNDVs is a boolean buffer.
                        # a cell equals to 1 if there is NDV in any of the corresponding cells in input raster bands.
                        if myNDVs is None:
                            # this is the first band that has NDV set. we initializes myNDVs to a zero buffer
                            # as we didn't see any NDV value yet.
                            myNDVs = numpy.zeros(myBufSize)
                            myNDVs.shape = (nYValid, nXValid)
                        myNDVs = 1 * numpy.logical_or(myNDVs == 1, myval == myNDV[i])

                    # add an array of values for this block to the eval namespace
                    if Alpha not in myAlphaFileLists:
                        local_namespace[Alpha] = myval
                    myval = None

                for lst in myAlphaFileLists:
                    local_namespace[lst] = numpy_arrays[lst]

                # try the calculation on the array blocks
                this_calc = calc[bandNo - 1 if len(calc) > 1 else 0]
                try:
                    myResult = eval(this_calc, global_namespace, local_namespace)
                except Exception:
                    print(f"evaluation of calculation {this_calc} failed")
                    raise

                # Propagate nodata values (set nodata cells to zero
                # then add nodata value to these cells).
                if myNDVs is not None and myOutNDV is not None:
                    myResult = ((1 * (myNDVs == 0)) * myResult) + (myOutNDV * myNDVs)
                elif not isinstance(myResult, numpy.ndarray):
                    myResult = numpy.ones((nYValid, nXValid)) * myResult

                # write data block to the output file
                myOutB = myOut.GetRasterBand(bandNo)
                if gdal_array.BandWriteArray(myOutB, myResult, xoff=myX, yoff=myY) != 0:
                    raise Exception("Block writing failed")
                myOutB = None  # write to band

    # remove temp files
    for idx, tempFile in enumerate(myTempFileNames):
        myFiles[idx] = None
        os.remove(tempFile)

    gdal.ErrorReset()
    myOut.FlushCache()
    if gdal.GetLastErrorMsg() != "":
        raise Exception("Dataset writing failed")

    if not quiet:
        print("100 - Done")

    return myOut


def doit(opts):
    kwargs = vars(opts)
    if "outF" in kwargs:
        kwargs["outfile"] = kwargs.pop("outF")
    return Calc(**kwargs)


class GDALCalc(GDALScript):
    def __init__(self):
        super().__init__()
        self.title = "Raster calculator with numpy syntax"
        self.description = textwrap.dedent(
            """\
            Use any basic arithmetic supported by numpy arrays such as +, -, *, and
            along with logical operators such as >.
            Note that all files must have the same dimensions (unless extent option is used),
            but no projection checking is performed (unless projectionCheck option is used)."""
        )
        # add an explicit --help option because the standard -h/--help option is not valid as -h is an alpha option
        self.add_help = "--help"
        self.optfile_arg = "--optfile"

        self.add_example(
            "add two files together",
            '-A input1.tif -B input2.tif --outfile=result.tif --calc="A+B"',
        )
        self.add_example(
            "average of two files",
            '-A input.tif -B input2.tif --outfile=result.tif --calc="(A+B)/2"',
        )
        self.add_example(
            "average of many files",
            '-A input.tif input2.tif input3.tif ... inputN.tif --outfile=result.tif --calc="average(A,axis=0)"',
        )
        self.add_example(
            "average of many files (using wildcards)",
            '-A input*.tif --outfile=result.tif --calc="average(A,axis=0)"',
        )
        self.add_example(
            "set values of zero and below to null",
            '-A input.tif --outfile=result.tif --calc="A*(A>0)" --NoDataValue=0',
        )
        self.add_example(
            "using logical operator to keep a range of values from input",
            '-A input.tif --outfile=result.tif --calc="A*logical_and(A>100,A<150)"',
        )
        self.add_example(
            "work with multiple bands",
            "-A input.tif --A_band=1 -B input.tif --B_band=2 "
            '--outfile=result.tif --calc="(A+B)/2" --calc="A*logical_and(A>100,A<150)"',
        )

    @staticmethod
    def add_alpha_args(parser, is_help):
        if is_help:
            alpha_list = [
                "A"
            ]  # we don't want to make help with all the full alpha list, as it's too long...
        else:
            alpha_list = AlphaList
        for alpha in alpha_list:
            try:
                band = alpha + "_band"
                alpha_arg = "-" + alpha
                band_arg = "--" + band
                parser.add_argument(
                    alpha_arg,
                    action="extend",
                    nargs="*",
                    type=str,
                    help="input gdal raster file, you can use any letter [a-z, A-Z]",
                    metavar="filename",
                )
                parser.add_argument(
                    band_arg,
                    action="extend",
                    nargs="*",
                    type=int,
                    help=f"number of raster band for file {alpha} (default 1)",
                    metavar="n",
                )
            except argparse.ArgumentError:
                pass

    def get_parser(self, argv) -> GDALArgumentParser:
        parser = self.parser
        parser.add_argument(
            "--calc",
            dest="calc",
            type=str,
            required=True,
            nargs="*",
            action="extend",
            help="calculation in numpy syntax using +-/* or any numpy array functions (i.e. log10()). "
            "May appear multiple times to produce a multi-band file",
            metavar="expression",
        )

        is_help = "--help" in argv
        self.add_alpha_args(parser, is_help)

        parser.add_argument(
            "--outfile",
            dest="outfile",
            required=True,
            metavar="filename",
            help="output file to generate or fill",
        )
        parser.add_argument(
            "--NoDataValue",
            dest="NoDataValue",
            type=float,
            metavar="value",
            help="output nodata value (default datatype specific value)",
        )
        parser.add_argument(
            "--hideNoData",
            dest="hideNoData",
            action="store_true",
            help="ignores the NoDataValues of the input rasters",
        )
        parser.add_argument(
            "--type",
            dest="type",
            type=str,
            metavar="datatype",
            choices=GDALDataTypeNames,
            help="output datatype",
        )
        parser.add_argument(
            "--format",
            dest="format",
            type=str,
            metavar="gdal_format",
            help="GDAL format for output file",
        )
        parser.add_argument(
            "--creation-option",
            "--co",
            dest="creation_options",
            default=[],
            action="append",
            metavar="option",
            help="Passes a creation option to the output format driver. Multiple "
            "options may be listed. See format specific documentation for legal "
            "creation options for each format.",
        )
        parser.add_argument(
            "--allBands",
            dest="allBands",
            type=str,
            default="",
            metavar="[a-z, A-Z]",
            help="process all bands of given raster [a-z, A-Z]",
        )
        parser.add_argument(
            "--overwrite",
            dest="overwrite",
            action="store_true",
            help="overwrite output file if it already exists",
        )
        parser.add_argument(
            "--debug",
            dest="debug",
            action="store_true",
            help="print debugging information",
        )
        parser.add_argument(
            "--quiet",
            dest="quiet",
            action="store_true",
            help="suppress progress messages",
        )

        parser.add_argument(
            "--color-table", type=str, dest="color_table", help="color table file name"
        )

        group = parser.add_mutually_exclusive_group()
        group.add_argument(
            "--extent",
            dest="extent",
            choices=[e.name.lower() for e in Extent],
            help="how to treat mixed geotransforms",
        )
        group.add_argument(
            "--projwin",
            dest="projwin",
            type=float,
            nargs=4,
            metavar=("ulx", "uly", "lrx", "lry"),
            help="extent corners given in georeferenced coordinates",
        )

        parser.add_argument(
            "--projectionCheck",
            dest="projectionCheck",
            action="store_true",
            help="check that all rasters share the same projection",
        )

        # parser.add_argument('--namespace', dest='user_namespace', action='extend', nargs='*', type=str)

        return parser

    def doit(self, **kwargs):
        return Calc(**kwargs)

    def augment_kwargs(self, kwargs) -> dict:
        # create the input_files dict from the alpha arguments ('-a' and '--a_band')
        input_files = {}
        input_bands = {}
        for alpha in AlphaList:
            if alpha in kwargs:
                alpha_val = kwargs[alpha]
                del kwargs[alpha]
                if alpha_val is not None:
                    dst_alpha_val = []
                    for val in alpha_val:
                        val = val.strip('"')
                        # If the shell didn't already expand wildcards
                        if ("?" in val or "*" in val) and not os.path.exists(val):
                            dst_alpha_val += glob.glob(val)
                        else:
                            dst_alpha_val.append(val)
                    if len(dst_alpha_val) == 0:
                        raise Exception(
                            "-A " + " ".join(alpha_val) + " did not expand to any file"
                        )
                    input_files[alpha] = (
                        dst_alpha_val if len(dst_alpha_val) > 1 else dst_alpha_val[0]
                    )
            band_key = alpha + "_band"
            if band_key in kwargs:
                band_val = kwargs[band_key]
                del kwargs[band_key]
                if band_val is not None:
                    input_bands[band_key] = (
                        band_val if len(band_val) > 1 else band_val[0]
                    )
        kwargs = {**kwargs, **input_files, **input_bands}
        # kwargs['input_files'] = input_files

        return kwargs


def main(argv=sys.argv):
    return GDALCalc().main(argv)


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