#!/usr/bin/env python3

r"""
This program will get the system serial number from an OBMC machine and print it to stdout.
"""

import sys
import os
import requests

save_path_0 = sys.path[0]
del sys.path[0]

from gen_arg import *
from gen_print import *
from gen_valid import *

# Restore sys.path[0].
sys.path.insert(0, save_path_0)

logging.captureWarnings(True)

parser = argparse.ArgumentParser(
    usage='%(prog)s [OPTIONS]',
    description="%(prog)s will get the system serial number from an OBMC"
    + " machine and print it to stdout as follows:\n\n"
    + "mch_ser_num:<ser num>",
    formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    prefix_chars='-+')

parser.add_argument(
    '--openbmc_username',
    default="root",
    help='The username for communicating with the OpenBMC machine.')

parser.add_argument(
    '--openbmc_password',
    default="0penBmc",
    help='The password for communicating with the OpenBMC machine.')

parser.add_argument(
    'openbmc_host',
    help='The host name or IP address of the OpenBMC machine.')

# Populate stock_list with options we want.
stock_list = [("test_mode", 0), ("quiet", 1)]


def exit_function(signal_number=0,
                  frame=None):
    r"""
    Execute whenever the program ends normally or with the signals that we catch (i.e. TERM, INT).
    """

    dprint_executing()
    dprint_var(signal_number)

    qprint_pgm_footer()


def signal_handler(signal_number,
                   frame):
    r"""
    Handle signals.  Without a function to catch a SIGTERM or SIGINT, our program would terminate immediately
    with return code 143 and without calling our exit_function.
    """

    # Our convention is to set up exit_function with atexit.register() so there is no need to explicitly
    # call exit_function from here.

    dprint_executing()

    # Calling exit prevents us from returning to the code that was running when we received the signal.
    exit(0)


def validate_parms():
    r"""
    Validate program parameters, etc.  Return True or False (i.e. pass/fail) accordingly.
    """

    gen_post_validation(exit_function, signal_handler)

    return True


def create_http_prefix(host):
    r"""
    Create and return an http prefix string.

    Description of argument(s):
    host                            The host being communicated with via the curl command.
    """

    return "https://" + host + "/"


def main():

    if not gen_get_options(parser, stock_list):
        return False

    if not validate_parms():
        return False

    qprint_pgm_header()

    session = requests.Session()

    http_prefix = create_http_prefix(openbmc_host)

    command = http_prefix + 'login'
    qprint_issuing(command)
    resp = session.post(command,
                        json={'data': [openbmc_username, openbmc_password]},
                        verify=False)
    if resp.json()['status'] != 'ok':
        json = resp.json()
        print_error_report("http request failed:\n" + sprint_var(command))
        raise Exception("Login failed.\n")

    command = http_prefix + "xyz/openbmc_project/inventory/system"
    qprint_issuing(command)
    resp = session.get(command, verify=False)
    json = resp.json()
    if json['status'] != 'ok':
        print_error_report("http request failed:\n" + sprint_var(command))
        raise Exception("http request failed.\n")

    try:
        mch_ser_num = json['data']['SerialNumber']
    except KeyError:
        print_error_report("Failed to find 'SerialNumber' key in the"
                           + " following data:\n" + sprint_var(json))
        return False
    print_var(mch_ser_num, 0, 0, 0)

    return True


# Main

if not main():
    exit(1)