# TODO
#  1. Verify that commands successfully did what they are
#     supposed to do by querying state of VM using QMP.
#  2. Implement Monitoring of VM.


# For QEMU Monitor Protocol Commands Information, See
# https://qemu.weilnetz.de/doc/qemu-doc.html#pcsys_005fmonitor

import json
import shutil
import os
import subprocess
import argparse
import qmp

from etcd3_wrapper import Etcd3Wrapper
from decouple import config


def get_vm_start_cmd(owner_dir, vm_uuid):
    vm_sock_flags = f"-qmp unix:{owner_dir}/.vm/{vm_uuid}-sock,server,nowait"
    vm_start_command_flags = (
        f"-boot c -net nic -net user -m 256 {vm_sock_flags} -daemonize"
    )
    vm_start_command = f"""qemu-system-x86_64 {owner_dir}/.vm/{vm_uuid}.raw {vm_start_command_flags}"""
    return vm_start_command


def get_qemu_mon(sock_file):
    m = qmp.QEMUMonitorProtocol(sock_file)
    try:
        m.connect()
    except FileNotFoundError as _:
        return None
    return m


def main(hostname):
    client = Etcd3Wrapper()

    events = client.watch_prefix("/v1/vm/")

    # events = client.get_prefix("/v1/vm/")
    for e in events:
        e.value = json.loads(e.value)
        e_hostname = e.value["hostname"]
        e_status = e.value["status"]
        vm_uuid = e.key.split("/")[-1]
        owner_dir = f"/var/www/{e.value['owner']}"

        # If it is not for me then skip it
        if e_hostname != hostname:
            continue
        print(e_status, e)

        if e_status == "SCHEDULED_DEPLOY":
            image = client.get(
                f"/v1/image/{e.value['image_uuid']}", value_in_json=True
            )
            if image:
                image_uuid = e.value["image_uuid"]
                print(image)
                print("Creating New VM...")

                os.makedirs(f"{owner_dir}/.vm", exist_ok=True)

                if not os.path.isfile(f"{owner_dir}/.vm/{vm_uuid}.raw"):
                    shutil.copy(
                        f"/var/vm/{image_uuid}.raw",
                        f"{owner_dir}/.vm/{vm_uuid}.raw",
                    )

                e.value["status"] = "REQUESTED_START"
            client.put(e.key, json.dumps(e.value))

        elif e_status == "REQUESTED_SUSPEND":
            m = get_qemu_mon(f"{owner_dir}/.vm/{vm_uuid}-sock")

            if m:
                print("Suspending")
                m.command("stop")
                m.close()
                e.value["status"] = "SUSPENDED"
                client.put(e.key, json.dumps(e.value))
            else:
                print("VM Not Running")

        elif e_status == "REQUESTED_RESUME":
            m = get_qemu_mon(f"{owner_dir}/.vm/{vm_uuid}-sock")
            if m:
                print("Resuming")

                m.command("cont")
                m.close()

                e.value["status"] = "RESUMED"
                client.put(e.key, json.dumps(e.value))
            else:
                print("VM Not Running")

        elif e_status == "REQUESTED_START":
            m = get_qemu_mon(f"{owner_dir}/.vm/{vm_uuid}-sock")
            if m:
                m.close()
                print("VM already running")
                e.value["status"] = "RUNNING"
                client.put(e.key, e.value, value_in_json=True)
            else:
                print("Starting VM")
                subprocess.run(
                    get_vm_start_cmd(owner_dir, vm_uuid).split(" ")
                )
                e.value["status"] = "RUNNING"
                client.put(e.key, e.value, value_in_json=True)
        else:
            continue


argparser = argparse.ArgumentParser()
argparser.add_argument("hostname", help="Name of this host. e.g /v1/host/1")
args = argparser.parse_args()

main(args.hostname)