#!/usr/bin/env python3
#
# Author: Bekaert David
# Year: 2017

import os 
import sys
import argparse
from osgeo import gdal

import isce
import isceobj


# command line parsing of input file
def cmdLineParse():
    '''
    Command line parser.
    '''
    parser = argparse.ArgumentParser(description='Generate ISCE xml from gdal products')
    parser.add_argument('-i','--input', dest='fname', type=str, required=True, help='Input filename (GDAL supported)')
    return parser.parse_args()


def gdal2isce_xml(fname):
    """
    Generate ISCE xml file from gdal supported file

    Example: import isce
             from applications.gdal2isce_xml import gdal2isce_xml
             xml_file = gdal2isce_xml(fname+'.vrt')
    """

    # open the GDAL file and get typical data informationi
    GDAL2ISCE_DATATYPE = {
       1 : 'BYTE',
       2 : 'uint16',
       3 : 'SHORT',
       4 : 'uint32',
       5 : 'INT',
       6 : 'FLOAT',
       7 : 'DOUBLE',
       10: 'CFLOAT',
       11: 'complex128',
    }
#    GDAL2NUMPY_DATATYPE = {
#       1 : np.uint8,
#       2 : np.uint16,
#       3 : np.int16,
#       4 : np.uint32,
#       5 : np.int32,
#       6 : np.float32,
#       7 : np.float64,
#       10: np.complex64,
#       11: np.complex128,
#     }

    # check if the input file is a vrt
    fbase, fext = os.path.splitext(fname)
    print(fext)
    if fext == ".vrt":
        outname = fbase
    else:
        outname = fname
    print(outname)

    # open the GDAL file and get typical ds information
    ds =  gdal.Open(fname, gdal.GA_ReadOnly)
    width = ds.RasterXSize
    length = ds.RasterYSize
    bands = ds.RasterCount
    print("width:       " + "\t" + str(width))
    print("length:      " + "\t" + str(length))
    print("num of bands:" + "\t" + str(bands))

    # getting the datatype information
    raster = ds.GetRasterBand(1)
    dataTypeGdal = raster.DataType

    # user look-up dictionary from gdal to isce format
    dataType= GDAL2ISCE_DATATYPE[dataTypeGdal]
    print("dataType: " + "\t" + str(dataType))

    # transformation contains gridcorners (lines/pixels or lonlat and the spacing 1/-1 or deltalon/deltalat)
    transform = ds.GetGeoTransform()
    # if a complex data type, then create complex image
    # if a real data type, then create a regular image

    img = isceobj.createImage()
    img.setFilename(os.path.abspath(outname))
    img.setWidth(width)
    img.setLength(length)
    img.setAccessMode('READ')
    img.bands = bands
    img.dataType = dataType

    # interleave
    md = ds.GetMetadata('IMAGE_STRUCTURE')
    sch = md.get('INTERLEAVE', None)
    if sch == 'LINE':
        img.scheme = 'BIL'
    elif sch == 'PIXEL':
        img.scheme = 'BIP'
    elif sch == 'BAND':
        img.scheme = 'BSQ'
    else:
        print('Unrecognized interleaving scheme, {}'.format(sch))
        if bands < 2:
            print('Assuming default, BIP')
            img.scheme = 'BIP'
        else:
            print('Assuming default, BSQ')
            img.scheme = 'BSQ'

    img.firstLongitude = transform[0]
    img.firstLatitude = transform[3] 
    img.deltaLatitude = transform[5] 
    img.deltaLongitude = transform[1]

    xml_file = outname + ".xml"
    img.dump(xml_file)

    return xml_file


# main script
if __name__ == '__main__':
    '''
    Main driver.
    '''
 
    # Parse command line
    inps = cmdLineParse()

    # check if the input file exist
    if not os.path.isfile(inps.fname):
        raise Exception('Input file is not found ....')

    gdal2isce_xml(inps.fname)