#!/usr/bin/env python3

import sys
import requests
import hmac
import hashlib
import pathlib
import os
import json
import sys


def get_args():
    """ Get command line arguments """

    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument('command')
    parser.add_argument('-s', '--server', default="")
    parser.add_argument('-l', '--shortlink', default="")
    parser.add_argument('-r', '--redirect', default="")
    parser.add_argument('-a', '--alt-redirect', default="")
    parser.add_argument('-c', '--alt-condition', default="")
    parser.add_argument('--config', type=pathlib.Path, default=pathlib.Path(os.path.expanduser('~/.config/susmng/config.json')))
    parser.add_argument('-H', '--http', action='store_true')
    return parser.parse_args()


def main(args):
    """ Entry point for script """

    if args.command == "init":
        print(f"creating config file and quitting")

        if args.config.exists():
            print("config file exists... doing nothing")
            return

        with open(args.config, 'w+') as fp:
            json.dump({ 'secrets': { 'sus.example.com': 'secret' } }, fp, indent=2)

        return

    with open(args.config) as fp:
        config = json.load(fp)

    server = args.server
    if server == "":
        server = list(config['secrets'].keys())[0]

    secret = config['secrets'][server]

    formstring = args.command+":"+args.shortlink+":"+args.redirect+":"+args.alt_condition+":"+args.alt_redirect
    print(f"{formstring=}")

    r = requests.post(f"{'http' if args.http else 'https'}://{server}",
            data = {
                'Command': args.command,
                'Shortlink': args.shortlink,
                'Redirect': args.redirect,
                'AltCondition': args.alt_condition,
                'AltRedirect': args.alt_redirect,
                },
            headers = {
                'Signature': 'SUS-SIGNATURE-' + hmac.new(
                    secret.encode("UTF-8"),
                    formstring.encode("UTF-8"),
                    hashlib.sha256
                    ).hexdigest()
                }
            )
    print(r, file=sys.stderr)
    print(r.content.decode().strip())
    return 0


if __name__ == '__main__':
    try:
        sys.exit(main(get_args()))
    except KeyboardInterrupt:
        sys.exit(0)