#!/usr/bin/python3

import argparse
import flask
import subprocess
import os
from functools import wraps

HOST = "icinga.atlantishq.de"
SIGNAL_USER_FILE = "signal_targets.txt"
app = flask.Flask("Signal Notification Gateway")

def dbReadSignalUserFile():
    users = []
    with open(SIGNAL_USER_FILE, "r") as f:
        for line in f:
            user = line.strip()
            if user:
                users.append(user)
    return users

def login_required(f):
    @wraps(f)
    def decorated_function(*args, **kwargs):
        auth = flask.request.authorization
        if not auth or not auth.password == app.config["PASSWORD"]:
            return (flask.jsonify({ 'message' : 'Authentication required' }), 401)
        return f(*args, **kwargs)
    return decorated_function

def signalSend(user, msg):

    if user not in dbReadSignalUserFile():
        print("{} not in Userfiler, refusing to send".format(user), file=sys.stderr)
        return

    signalCliBin = "signal-cli"
    if app.config["SIGNAL_CLI_BIN"]:
        signalCliBin = app.config["SIGNAL_CLI_BIN"]

    cmd = [signalCliBin, "send", "-m", msg, user]
    subprocess.Popen(cmd)

def sendMessageToAllClients(msg):
    for number in dbReadSignalUserFile():
        signalSend(number, msg)

@app.route('/send-to-clients', methods=["POST"])
@login_required
def sendToNumbers():

    jsonDict = flask.request.json
    if jsonDict.get("number"):
        print("Request received to send to {} only".format(number))
        signalSend(jsonDict["number"], flask.request.json["message"])
    else:
        for number in flask.request.json["numbers"]:
            signalSend(number, flask.request.json["message"])

    return ("","204")

@app.route('/send-all', methods=["POST"])
@login_required
def sendToAll():
    sendMessageToAllClients(flask.request.json["message"])
    return ("","204")

@app.route('/send-all-icinga', methods=["POST"])
@login_required
def sendToAllIcinga():
    args = flask.request.json

    for key in args.keys():
        if type(args[key]) == str:
            print(key)

    # build message #
    serviceName = args["service_name"]
    if args["service_display_name"]:
        serviceName = args["service_display_name"]

    message = "{service} {state}\n{host}\n{output}".format(service=serviceName,
                                                                state=args["service_state"],
                                                                host=args["service_host"],
                                                                output=args["service_output"])
    sendMessageToAllClients(message)
    return ("","204")

@app.route('/smart-send', methods=["POST"])
@login_required
def smart_send_to_clients():
    '''Send to clients based on querying the LDAP
        requests MAY include:
            - list of usernames under key "users"
            - list of groups    under key "groups"
            - neither of the above to automatically target the configured administrators group"
        retuest MUST include:
            - message as STRING in field "msg"
            OR
            - supported struct of type "ICINGA|ZABBIX|GENERIC" (see docs) in field "data"
    '''

    instructions = flask.request.json

    users = instructions.get("users")
    groups = instructions.get("groups")
    message = instructions.get("msg")

    struct = instructions.get("data")
    if struct:
        try:
            message = messagetools.load_struct(struct)
        except messagetools.UnsupporedStruct() as e:
            return (408, e.response())


    persons = ldaptools.select_targets(users, groups, app.config["LDAP_ARGS"])
    signal.bulk_dispatch(persons, message)
    return (200, "OK")

@app.before_first_request
def init():
    app.config["PASSWORD"] = os.environ["SIGNAL_API_PASS"]
    app.config["SIGNAL_CLI_BIN"] = os.environ["SIGNAL_CLI_BIN"]

if __name__ == "__main__":

    parser = argparse.ArgumentParser(description='Simple Telegram Notification Interface',
                        formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    parser.add_argument('--interface', default="localhost", help='Interface on which to listen')
    parser.add_argument('--port', default="5000", help='Port on which to listen')
    parser.add_argument("--signal-cli-bin", default=None, type=str,
                            help="Path to signal-cli binary if no in $PATH")


    parser.add_argument('--ldap-server')
    parser.add_argument('--ldap-base-dn')
    parser.add_argument('--ldap-manager-dn')
    parser.add_argument('--ldap-manager-password')

    args = parser.parse_args()

    # define ldap args #
    ldap_args = {
        "LDAP_SERVER" : args.ldap_server,
        "LDAP_BIND_DN" : args.manager_dn,
        "LDAP_BIND_PW" : args.manager_password,
        "LDAP_BASE_DN" : args.ldap_base_dn,
    }
    
    if not any([value is None for value in ldap_args.values()]):
        app.config["LDAP_ARGS"] = ldap_args
    else:
        app.config["LDAP_ARGS"] = None

    app.config["SIGNAL_CLI_BIN"] = os.path.expanduser(args.signal_cli_bin)
    app.config["PASSWORD"] = os.environ["SIGNAL_API_PASS"]

    app.run(host=args.interface, port=args.port)