#!/usr/bin/env python3

import numpy as np 
import argparse
from osgeo import gdal
import isce
import isceobj
import os

def cmdLineParse():
    '''
    Parse command line.
    '''
    parser = argparse.ArgumentParser(description='Convert GeoTiff to ISCE file')
    parser.add_argument('-i','--input', dest='infile', type=str,
            required=True, help='Input GeoTiff file. If tar file  is also included, this will be output file extracted from the TAR archive.')
    parser.add_argument('-o','--output', dest='outfile', type=str,
            required=True, help='Output GeoTiff file')
    parser.add_argument('-t','--tar', dest='tarfile', type=str,
            default=None, help='Optional input tar archive. If provided, Band 8 is extracted to file name provided with input option.')

    return parser.parse_args()

def dumpTiff(infile, outfile):
    '''
    Read geotiff tags.
    '''
    ###Uses gdal bindings to read geotiff files
    data = {}
    ds = gdal.Open(infile)
    data['width'] = ds.RasterXSize
    data['length'] = ds.RasterYSize
    gt = ds.GetGeoTransform()

    data['minx'] = gt[0]
    data['miny'] = gt[3] + data['width'] * gt[4] + data['length']*gt[5]
    data['maxx'] = gt[0] + data['width'] * gt[1] + data['length']*gt[2]
    data['maxy'] = gt[3]
    data['deltax'] = gt[1]
    data['deltay'] = gt[5]
    data['reference'] = ds.GetProjectionRef()

    band = ds.GetRasterBand(1)
    inArr = band.ReadAsArray(0,0, data['width'], data['length'])
    inArr.astype(np.float32).tofile(outfile)

    return data

def extractBand8(intarfile, destfile):
    '''
    Extracts Band 8 of downloaded Tar file from EarthExplorer
    '''
    import tarfile
    import shutil

    fid = tarfile.open(intarfile)
    fileList = fid.getmembers()

    ###Find the band 8 file
    src = None
    for kk in fileList:
        if kk.name.endswith('B8.TIF'):
            src = kk

    if src is None:
        raise Exception('Band 8 TIF file not found in tar archive')

    print('Extracting: %s'%(src.name))

    ####Create source and target file Ids.
    srcid = fid.extractfile(src)
    destid = open(destfile,'wb')
    
    ##Copy content
    shutil.copyfileobj(srcid, destid)
    fid.close()
    destid.close()

    
if __name__ == '__main__':
    ####Parse cmd line

    inps = cmdLineParse()

    ####If input tar file is given
    if inps.tarfile is not None:
        extractBand8(inps.tarfile, inps.infile)

    print('Dumping image to file')
    meta = dumpTiff(inps.infile, inps.outfile)

#    print(meta)
    ####Create an ISCE XML header for the landsat image
    img = isceobj.createDemImage()
    img.setFilename(inps.outfile)
    img.setDataType('FLOAT')
    
    dictProp = {
                'REFERENCE' : meta['reference'],
                'Coordinate1': {
                                 'size': meta['width'],
                                 'startingValue' : meta['minx'],
                                 'delta': meta['deltax']
                               },
                'Coordinate2': {
                                  'size' : meta['length'],
                                  'startingValue' : meta['maxy'],
                                  'delta': meta['deltay']
                               },
                'FILE_NAME' : inps.outfile
              }
    img.init(dictProp)
    img.renderHdr()