import argparse
import json
import requests


def main():
    parser = argparse.ArgumentParser(description='RESTful Client')

    main_args = parser.add_mutually_exclusive_group(required=True)
    main_args.add_argument('-g', '--get', action='store_true', help='Print JSON response from URL with GET request')
    main_args.add_argument('-p', '--post', action='store_true', help='Send data to URL with POST request.')

    required = parser.add_argument_group('required arguments')
    required.add_argument('-u', '--url', metavar='URL', type=str, help='Source URL', required=True)

    parser.add_argument('-n', '--names', action='store_true', help='Print names from JSON response')
    parser.add_argument('-d', '--data', type=str, help='JSON data')

    args = parser.parse_args()

    if args.get:
        data = get(args.url)
        if args.names:
            names = get_names(data)
            print(*names, sep='\n')
        else:
            print(data)
    elif args.post:
        post(args.url, args.data)


def get(url):
    try:
        response = requests.get(url)

        if response.ok:
            try:
                return json.loads(response.content)
            except json.decoder.JSONDecodeError:
                print('Response is not in JSON!')
        else:
            print('STATUS CODE: ' + response.status_code)

    except requests.RequestException as e:
        print(e)


def post(url, data):
    try:
        data = json.dumps(data)
        data = json.loads(data)
        data = eval(data)

        names = get_names(get(url))

        exists = False
        for name in names:
            if name == data['name']:
                exists = True
                break

        if not exists:
            r = requests.post(url, data=json.dumps(data))
            print(r)
        else:
            print('User is already exists.')
    except json.JSONDecodeError as e:
        print('Input parameter is not in JSON format.')


def get_names(data):
    names = []
    for key in data:
        names.append(key['name'])

    return names


if __name__ == '__main__':
    main()