# (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.

#
# Python implementation: bufr_keys_iterator
#
# Description: Example on how to use keys_iterator functions and the
#              codes_bufr_keys_iterator structure to get all the available
#              keys in a BUFR message.


from __future__ import print_function
import traceback
import sys

from eccodes import *

VERBOSE = 1  # verbose error reporting


def example(INPUT):
    # open bufr file
    f = open(INPUT, 'rb')

    cnt = 0

    # loop for the messages in the file
    while 1:
        # get handle for message
        bufr = codes_bufr_new_from_file(f)
        if bufr is None:
            break

        print("message: %s" % cnt)

        # we need to instruct ecCodes to expand all the descriptors
        # i.e. unpack the data values
        codes_set(bufr, 'unpack', 1)

        # get BUFR key iterator
        iterid = codes_bufr_keys_iterator_new(bufr)

        # loop over the keys
        while codes_bufr_keys_iterator_next(iterid):
            # print key name
            keyname = codes_bufr_keys_iterator_get_name(iterid)
            print("  %s" % keyname)

        # delete the key iterator
        codes_bufr_keys_iterator_delete(iterid)

        cnt += 1

        # delete handle
        codes_release(bufr)

    # close the file
    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())