# TODO: Use Unix File Socket for VNC instead of TCP

# QEMU Manual
# https://qemu.weilnetz.de/doc/qemu-doc.html

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

import json
import argparse
import qmp
import logging
import os
import subprocess
import atexit
import signal

from etcd3_wrapper import Etcd3Wrapper
from dataclasses import dataclass
from typing import Union
from functools import wraps
from decouple import config
from datetime import datetime

running_vms = []
vnc_port_pool = list(range(5900, 6000))
client = Etcd3Wrapper()


@dataclass
class VM:
    key: str
    vm: qmp.QEMUMachine


logging.basicConfig(
    level=logging.DEBUG,
    filename="log.txt",
    filemode="a",
    format="%(asctime)s: %(levelname)s - %(message)s",
    datefmt="%d-%b-%y %H:%M:%S",
)


def goodbye(host):
    host.value["status"] = "DEAD"
    host.value["last_heartbeat"] = datetime.utcnow().isoformat()
    client.put(host.key, json.dumps(host.value))
    logging.info(f"Host {host.key} dead! at {host.value['last_heartbeat']}")
    os.kill(os.getpid(), signal.SIGKILL)


def need_running_vm(func):
    @wraps(func)
    def wrapper(e):
        vm = get_vm(running_vms, e.key)
        if vm:
            try:
                status = vm.vm.command("query-status")
                logging.debug(f"VM Status Check - {status}")
            except OSError:
                logging.info(f"{func.__name__} failed - VM {e.key} - Unknown Error")

            return func(e)
        else:
            logging.info(f"{func.__name__} failed because VM {e.key} is not running")
            return
    return wrapper


def create_vm(vm_uuid, e):
    image = client.get(
        f"/v1/image/{e.value['image_uuid']}", value_in_json=True
    )
    if image:
        logging.debug(image)
        image_uuid = e.value["image_uuid"]

        logging.info("Creating New VM...")
        _command_to_create = f"rbd clone images/{image_uuid}@protected uservms/{vm_uuid}"
        subprocess.call(_command_to_create.split(" "))

        # DELETEME: Delete when CEPH integeration is complete

        # 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))


def start_vm(vm_path, e):
    # FIXME: Assume for the moment that the image exists
    #        Use librados to list files that exists in
    #        uservms pool then checkwhether the e.key.split("/").pop()
    #        exists in rbd_ls(uservms_pool)

    # if not os.path.isfile(vm_path):
    #     logging.info(f"Image file of vm {e.key} does not exists")
    #     logging.info(f"Setting vm {e.key} status to DELETED")
    #     e.value["status"] = "DELETED"
    #     client.put(e.key, json.dumps(e.value))
    #     return

    _vm = get_vm(running_vms, e.key)
    if _vm:
        logging.info(f"{e.key} already running")
        e.value["status"] = "RUNNING"
        client.put(e.key, json.dumps(e.value))
        return

    # FIXME: There should be better vnc port allocation scheme
    vm = qmp.QEMUMachine(
        "/usr/bin/qemu-system-x86_64",
        test_dir="vm_socklog",
        args=[
            vm_path,
            "-boot", "c",  # First Boot Hard drive
            "-m", "1024",  # RAM limit
            # Ever growing port number
            "-vnc", f":{vnc_port_pool.pop(0)}",  # Allow VNC
        ],
    )
    try:
        logging.info(f"Starting {e.key}")
        vm.launch()
        if vm.is_running():
            running_vms.append(VM(e.key, vm))
            e.value["status"] = "RUNNING"
            client.put(e.key, e.value, value_in_json=True)
        else:
            e.value["status"] = "KILLED"
            client.put(e.key, e.value, value_in_json=True)
            return
    except (qmp.QEMUMachineError, TypeError):
        logging.info()
        logging.exception(f"Machine Error Occurred on {e.key}")
        e.value["status"] = "KILLED"
        client.put(e.key, e.value, value_in_json=True)
    else:
        logging.info(f"Started Successfully {e.key}")


@need_running_vm
def suspend_vm(e):
    vm = get_vm(running_vms, e.key)
    vm.vm.command("stop")
    if vm.vm.command("query-status")["status"] == "paused":
        e.value["status"] = "SUSPENDED"
        client.put(e.key, json.dumps(e.value))
        logging.info(f"Successfully suspended VM {e.key}")
    else:
        logging.info(f"Suspending VM {e.key} failed")


@need_running_vm
def resume_vm(e):
    vm = get_vm(running_vms, e.key)
    vm.vm.command("cont")
    if vm.vm.command("query-status")["status"] == "running":
        e.value["status"] = "RUNNING"
        client.put(e.key, json.dumps(e.value))
        logging.info(f"Successfully resumed VM {e.key}")
    else:
        logging.info(f"Resuming VM {e.key} failed")


@need_running_vm
def shutdown_vm(e):
    vm = get_vm(running_vms, e.key)
    vm.vm.shutdown()
    if not vm.vm.is_running():
        logging.info(f"VM {e.key} shutdown successfully")
        e.value["status"] = "STOPPED"
        client.put(e.key, json.dumps(e.value))
        running_vms.remove(vm)


def delete_vm(e):
    logging.info(f"Deleting VM {e.key}")
    shutdown_vm(e)
    vm = client.get(e.key, value_in_json=True)
    if vm:
        vm_id = e.key.split('/')[-1]
        vm_owner = e.value['owner']
        vm_path = f"{config('BASE_DIR')}/{vm_owner}/.vm/{vm_id}"

        if os.path.exists(vm_path):
            os.remove(vm_path)
        client.client.delete(e.key)
        logging.info(f"VM {vm.key} deleted")
    else:
        logging.info(f"Cannot delete key {e.key} because it doesn't exists")


def get_vm(vm_list: list, vm_key) -> Union[VM, None]:
    return next((vm for vm in vm_list if vm.key == vm_key), None)


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

    host = client.get(args.hostname, value_in_json=True)
    host.value["status"] = "ALIVE"
    host.value["last_heartbeat"] = datetime.utcnow().isoformat()

    atexit.register(goodbye, host=host)

    for events_iterator in [client.get_prefix("/v1/vm/"),
                            client.watch_prefix("/v1/vm/", timeout=10)]:
        for e in events_iterator:
            try:
                e.value = json.loads(e.value)
            except json.JSONDecodeError:
                logging.error(f"Invalid JSON {e.value}")
                continue

            e_status = e.value["status"]

            if e_status == "TIMEOUT":
                logging.info("Timeout")
                _vms = filter(lambda v: v.value["hostname"] == args.hostname, client.get_prefix("/v1/vm", value_in_json=True))
                alleged_running_vms = filter(lambda v: v.value["status"] == "RUNNING", _vms)
                should_be_running = filter(lambda v: v.value["status"] == "REQUESTED_START", _vms)
                for vm in alleged_running_vms:
                    _vm = get_vm(running_vms, vm.key)
                    if (_vm and not _vm.vm.is_running()) or _vm is None:
                        logging.debug(f"{_vm} {vm.key}")
                        logging.info(f"{vm.key} is not running but is said to be running")
                        logging.info(f"Updating {vm.key} status to KILLED")
                        vm.value["status"] = "KILLED"
                        client.put(vm.key, json.dumps(vm.value))

                for vm in should_be_running:
                    vm_path = f"rbd:uservms/{vm.key.split('/')[-1]}"
                    start_vm(vm_path, e)

                host.value["status"] = "ALIVE"
                host.value["last_heartbeat"] = datetime.utcnow().isoformat()
                client.put(host.key, json.dumps(host.value))
                logging.info(f"Updated last heartbeat time {host.value['last_heartbeat']}")
                continue

            e_hostname = e.value["hostname"]
            vm_uuid = e.key.split("/")[-1]

            # If it is not for me then skip it
            if e_hostname != args.hostname:
                continue

            logging.debug(f"EVENT: {e}")

            if e_status == "SCHEDULED_DEPLOY":
                create_vm(vm_uuid, e)

            elif e_status == "REQUESTED_SUSPEND":
                suspend_vm(e)

            elif e_status == "REQUESTED_RESUME":
                resume_vm(e)

            elif e_status == "REQUESTED_START":
                
                # DELETEME: Delete when CEPH integeration is complete
                # vm_path = f"{owner_dir}/.vm/{vm_uuid}.raw"

                vm_path = f"rbd:uservms/{vm_uuid}"
                start_vm(vm_path, e)

            elif e_status == "REQUESTED_SHUTDOWN":
                shutdown_vm(e)

            elif e_status == "DELETED":
                delete_vm(e)

            logging.info(f"Running VMs {running_vms}")


main()