#!/usr/bin/env python
#
# vim:ts=4:sw=4:expandtab
#
######################################################################

from __future__ import print_function
# from __future__ import with_statement

import argparse
import logging
import os
import sys
import yaml

import yaml_utilities
# from yaml_utilities import R13, B64, Vault

from yaml_utilities import version, get_parameter_path, get_section_path

_description = """This small utility extracts a yaml file from another
"""

_epilog = """
Example(s):
    %(script)s -h                             - To provide this help
    %(script)s -P users config.yml            - To return the value of name var
    %(script)s -S users -P groups config.yml  - Same with a section
    """ % {
        'script': os.path.basename(sys.argv[0]),
    }


def main():
    parser = argparse.ArgumentParser(
        description=_description,
        epilog=_epilog,
        formatter_class=argparse.RawTextHelpFormatter,
    )
    parser.add_argument(
        '-d', '--debug',
        action='store_true',
        default=False,
        help='Debug mode',
        required=False,
    )
    parser.add_argument(
        '-I', '--input-separator',
        default='/',
        help='Separator used in input parameters',
        required=False,
    )
    parser.add_argument(
        '-O', '--output-file',
        help='Output file',
        required=False,
    )
    parser.add_argument(
        '-P', '--parameter',
        help='Parameter to extract',
        required=False,
    )
    parser.add_argument(
        '-S', '--section',
        default='/',
        help='Section to extract',
        required=False,
    )
    parser.add_argument(
        '-v', '--version',
        action='store_true',
        default=False,
        help='Return version',
        required=False,
    )
    parser.add_argument(
        'yaml_files',
        help='YAML files to read',
        nargs='*',
    )
    args = parser.parse_args()
    debug = args.debug
    input_separator = args.input_separator
    output_file = args.output_file
    section = args.section
    parameter = args.parameter
    yaml_files = args.yaml_files
    data = dict()

    if debug > 0:
        logging.basicConfig(level=logging.DEBUG)
        logging.debug('debug=%s', args.debug)

    logging.debug('yaml_files=%s', yaml_files)
    logging.debug('parameter=%s', parameter)
    logging.debug('input_separator=%s', input_separator)
    logging.debug('output_file=%s', output_file)
    logging.debug('section=%s', section)

    if args.version is True:
        print(version)
        return

    n_yaml_files = len(yaml_files)
    if n_yaml_files > 1:
        logging.error('Only one YAML file please!')
        exit(2)
    elif n_yaml_files == 0:
        logging.debug('Reading from stdin!')
        input_str = sys.stdin.read()
        data = yaml.load(input_str)
    else:
        filename = yaml_files[0]
        try:
            with open(filename, 'r') as f:
                data = yaml.load(f)
        except IOError:
            logging.error("File '%s' not found!", filename)
            sys.exit(1)

    logging.debug('data=%s', data)

    section_path = get_section_path(section, input_separator)
    parameter_path = get_parameter_path(parameter, input_separator)

    keys = section_path + parameter_path

    ptr = data
    try:
        for key in keys:
            ptr = ptr[key]
    except KeyError:
        logging.error("Key '%s' not found!", key)
        sys.exit(1)

    kwargs = {
        'canonical': False,
        'default_flow_style': False,
        'explicit_start': True,
        'explicit_end': True,
        'width': 50,
        'indent': 4,
        'default_style': '',
    }

    dump = yaml.dump(ptr, **kwargs)

    if output_file is not None:
        with open(output_file, 'w') as f:
            print(dump, file=f)
    else:
        print(dump)

if __name__ == "__main__":
    main()
