#
# (C) Copyright 2005- ECMWF.
#
# This software is licensed under the terms of the Apache Licence Version 2.0
# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
#
# In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
# virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
#

# Description: How to use an iterator on lat/lon/values and query the bitmap
#              for missing values
#              (rather than compare each value with the missingValue key)
#
from __future__ import print_function

import sys
import traceback

from eccodes import *

VERBOSE = 1  # verbose error reporting


def example(INPUT):
    f = open(INPUT, "rb")

    while 1:
        gid = codes_grib_new_from_file(f)
        if gid is None:
            break

        iterid = codes_grib_iterator_new(gid, 0)

        bitmapPresent = codes_get(gid, "bitmapPresent")
        if bitmapPresent:
            # Get the bitmap array which contains 0s and 1s
            bitmap = codes_get_array(gid, "bitmap", int)
            # Do some sanity checking
            assert len(bitmap) == codes_get_size(gid, "values")
            assert len(bitmap) == codes_get(gid, "numberOfDataPoints")

        i = 0
        while 1:
            result = codes_grib_iterator_next(iterid)
            if not result:
                break

            [lat, lon, value] = result

            sys.stdout.write("- %d - lat=%.6e lon=%.6e value=" % (i, lat, lon))

            # Consult bitmap to see if the i'th value is missing
            if bitmapPresent and bitmap[i] == 0:
                print("missing")
            else:
                print("%.6f" % value)

            i += 1

        codes_grib_iterator_delete(iterid)
        codes_release(gid)

    f.close()


def main():
    try:
        example(sys.argv[1])
    except CodesInternalError as err:
        if VERBOSE:
            traceback.print_exc(file=sys.stderr)
        else:
            sys.stderr.write(err.msg + "\n")

        return 1


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