#!/bin/python3

#required modules

import json
import subprocess

#defining user / key location variables

ssh_key = "/key/location"
ssh_user= "theguy"

#dictionary defining servers, their ip and ssh port

servers = {
    "server1": {
        "ip": "1.2.3.4",
        "port": 1
    },
    "server2": {
        "ip": "5.6.7.8",
        "port": 2
    },
    "fakelol": {
        "ip": "200.200.200.200",
        "port": 22222
    },
}

#load previous state of servers, to avoid constant alert spam
try:
    with open("/var/www/porygon/status.json") as f:
        #creating a previous status dictionary
        previous_status = json.load(f)
except FileNotFoundError:
    pass

#creating the current status dictionary
status = {}

for server, info in servers.items():
    ip = info["ip"]
    port = info["port"]
    result = subprocess.run(
        ["ping", "-c", "2", "-W", "1", ip],
        stdout=subprocess.DEVNULL,
        stderr=subprocess.DEVNULL
    )

#if the ping returns successful the online status is true, else false
    if result.returncode == 0:
        status[server] = True
    else:
        status[server] = False

#if the server is now offline, and its last state was online send an email alert
    if status[server] == False:
        if previous_status.get(server) == True:
            message = f"""To: person@example.com
Subject: {server} is offline

{server} at {ip} looks to be offline and is no longer responding to pings.
"""

            subprocess.run(
                ["msmtp", "123@hehehe.net"],
                input=message,
                text=True
        )

#if the server is online run the stats collector python script over ssh
#copy back the stats.json it generates back via scp to the relevant dir for apache to host
    if status[server] == True:
        try:
            subprocess.run(
                [
                    "ssh",
                    "-o", "StrictHostKeyChecking=accept-new",
                    "-i", ssh_key,
                    "-p", str(port),
                    f"{ssh_user}@{ip}",
                    f"/home/{ssh_user}/collector.py"
                ],
                timeout=5
            )
            subprocess.run(
                [
                    "scp",
                    "-o", "StrictHostKeyChecking=accept-new",
                    "-i", ssh_key,
                    "-P", str(port),
                    f"{ssh_user}@{ip}:/tmp/stats.json",
                    f"/var/www/porygon/{server}/stats.json"
                ],
                timeout=5
            )
        except subprocess.TimeoutExpired:
            print(f"{server} ssh connection timed out")

#if the server is now online, but it was last offline send an email saying the alert has been cleared
        if previous_status.get(server) == False:
            message = f"""To: fakest@email.com
Subject: {server} is back online

{server} at {ip} looks to be back online and is now responding to pings once more.
"""

            subprocess.run(
                ["msmtp", "real@this.time"],
                input=message,
                text=True
        )

#dump the online/offline status from the status dictionary
with open("/var/www/porygon/status.json", "w") as f:
    json.dump(status, f, indent=4)