'''
Author: Brian Oliver II
Instagram: bolo_ne3
License:
    MIT License

    Copyright (c) 2016 Brian Oliver II

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE.
'''

"""
Uses the ssh-keygen and ssh-copy-id commands found on Mac and Linux systems.
Mac Users will need to install ssh-copy-id before attempting to use this script.
If you do not have Homebrew installed, please visit https://github.com/beautifulcode/ssh-copy-id-for-OSX for the install.
If you do have Homebrew installed, run the command brew install ssh-copy-id in Terminal.

"""
import os
import sys
import subprocess
import argparse

# Constants
CUR_USER = os.getlogin()
PLATFORM = sys.platform

if PLATFORM == "darwin":
    PRIV_SSH_DIR = "/Users/%s/.ssh" % (CUR_USER)
elif PLATFORM == "linux":
    PRIV_SSH_DIR = "/home/%s/.ssh" % (CUR_USER)


def key_present():
    """Checks to see if there is an RSA already present. Returns a bool."""
    if "id_rsa" in os.listdir(PRIV_SSH_DIR):
        return True
    else:
        return False


def show(msg):
    """Local print() function."""
    print(msg)


def gen_key():
    """Generate a SSH Key."""
    os.chdir(PRIV_SSH_DIR)
    if key_present():
        show("A key is already present.")
    else:
        # Genarate private key
        subprocess.call('ssh-keygen', shell=True)


def push_key(user, host, port=22):
    """Push a SSH Key to a remote server."""
    os.chdir(PRIV_SSH_DIR)
    if key_present():
        if PLATFORM != "linux":
            if "ssh-copy-id" in os.listdir("/usr/local/bin"):
                show("SSH key found. Pushing key to remote server")
                command = "ssh-copy-id -p %s %s@%s" % (port, user, host)
                subprocess.call(command, shell=True)
            else:
                show(
                    "ssh-copy-id required for Mac Users. Use --help for more information.")
    else:
        show("A SSH key is required. Run script again with action set as GenKey")


def main():
    """Start of script."""
    parser = argparse.ArgumentParser(
        description="Uses the ssh-keygen and ssh-copy-id commands found on Mac and Linux systems. Mac Users will need to install ssh-copy-id before attempting to use this script. If you do not have Homebrew installed, please visit https://github.com/beautifulcode/ssh-copy-id-for-OSX for the install. If you do have Homebrew installed, run the command brew install ssh-copy-id in Terminal.")
    parser.add_argument("action", choices=[
                        "GenKey", "PushKey"], help="Action to be preformed")
    parser.add_argument("-u", "--user", help="SSH username")
    parser.add_argument("-s", "--host", help="IP or FQDN of server")
    parser.add_argument("-p", "--port", help="SSH port number")
    args = parser.parse_args()
    if (args.action == "GenKey"):
        gen_key()
    elif (args.action == "PushKey"):
        if args.user and args.host:
            if args.port:
                push_key(args.user, args.host, args.port)
            else:
                push_key(args.user, args.host)
        else:
            show("-u and -s are required for action PushKey. Use -h for Help.")

if __name__ == "__main__":
    main()