#!/usr/bin/env python3
import argparse
import json
import logging
import signal
import time
from threading import Thread
from typing import Union

import dbus
import dbus.service

from session import Session
from trigger import TriggerServerThread

logging.basicConfig(format="%(asctime)s %(levelname)s: %(message)s", level=logging.INFO)

ONE_TIME_SERVICE = False
ALLOW_ONLY_ONE_SESSION = True


class RWAService(dbus.service.Object):
    def __init__(self, loop, mockup_mode: bool = False):
        self.loop = loop
        self.mockup_mode = mockup_mode

        self.bus = dbus.SessionBus()
        name = dbus.service.BusName("org.ArcticaProject.RWA", bus=self.bus)

        self.trigger_service = TriggerServerThread(self._trigger)
        self.trigger_service.start()

        self.update_service_running = False
        self.sessions = {}
        super().__init__(name, "/RWA")

        logging.info("DBus service has been started.")

    @dbus.service.method("org.ArcticaProject.RWA", out_signature="s")
    def start(self):
        """Start a new remote session."""
        if ALLOW_ONLY_ONE_SESSION and len(self.sessions.values()) > 0:
            logging.warning(
                "There is already one session running and the service is configured to allow only one "
                "session, so this session won't be started."
            )
            return json.dumps({"status": "error"})

        # Start session
        session = Session(self.trigger_service.port, mockup_mode)

        # Add session to sessions list
        self.sessions[session.pid] = session

        # Start session update service
        self._ensure_update_service()

        return_json = session.client_meta
        return_json["status"] = "success"

        logging.info(f"New session #{session.pid} was started with meta {return_json}.")

        return json.dumps(return_json)

    @dbus.service.method("org.ArcticaProject.RWA", in_signature="i", out_signature="s")
    def status(self, pid: int) -> str:
        """Get status information about a service."""
        return self._get_status(pid)

    @dbus.service.method("org.ArcticaProject.RWA", in_signature="i", out_signature="s")
    def refresh_status(self, pid: int) -> str:
        """Get status information about a service and refresh status before."""
        self._update_session(pid)
        return self._get_status(pid)

    @dbus.service.method("org.ArcticaProject.RWA", in_signature="i", out_signature="s")
    def stop(self, pid: int):
        """Stop a remote session."""
        try:
            session = self.sessions[pid]
        except KeyError:
            return json.dumps({"pid": pid, "status": "stopped"}, sort_keys=True)
        session.stop()
        return json.dumps({"id": pid, "status": "stopped"}, sort_keys=True)

    def _get_status(self, pid: int) -> str:
        try:
            session = self.sessions[pid]
        except KeyError:
            return json.dumps({"id": pid, "status": "dead"}, sort_keys=True)
        return json.dumps(session.status)

    def _ensure_update_service(self):
        """Start session update thread if it isn't already running."""
        if not self.update_service_running:
            self.update_thread = Thread(target=self._update_sessions)
            self.update_thread.start()

    def _update_session(self, pid: int):
        """Update the status of a session."""
        logging.info(f"Update status for session #{pid} …")

        try:
            session = self.sessions[pid]
        except KeyError:
            logging.warning("  Session is dead.")
            return

        # Check if VNC process is still running
        running = session.vnc_process_running
        if running:
            logging.info("  Session is running.")
        elif session.status_text == "stopped" and session.pid in self.sessions:
            logging.warning("  Session is dead.")

            del self.sessions[session.pid]
        else:
            logging.warning("  VNC was stopped, so session is dead.")

            session.stop()
            del self.sessions[session.pid]

    def _update_sessions(self):
        """Go through all running sessions and update their status using ``_update_session``."""
        logging.info("Started update service for sessions.")
        while len(self.sessions.values()) > 0:
            for session in list(self.sessions.values()):
                self._update_session(session.pid)

            time.sleep(2)

        self.update_service_running = False
        logging.info("Stopped update service for sessions.")
        if ONE_TIME_SERVICE:
            self._stop_all()

    def _trigger(self, token: str) -> bool:
        """Trigger a specific session via trigger token."""
        logging.info(f"Triggered with token {token}")

        for session in self.sessions.values():
            if token == session.trigger_token:
                logging.info(f"Session #{session.pid} matches the token.")
                session.trigger()
                return True

        logging.warning("  No matching session found for this token.")
        return False

    def _stop_all(self):
        """Stop all sessions and this daemon."""
        logging.info("Stop all sessions and exit service.")
        for session in list(self.sessions.values()):
            session.stop()
            del self.sessions[session.pid]
        self.trigger_service.shutdown()
        self.loop.quit()


def str2bool(v: Union[str, bool, int]) -> bool:
    """Return true or false if the given string can be interpreted as a boolean otherwise raise an exception."""
    if isinstance(v, bool):
        return v
    if v.lower() in ("yes", "true", "t", "y", "1", 1):
        return True
    elif v.lower() in ("no", "false", "f", "n", "0", 0):
        return False
    else:
        raise argparse.ArgumentTypeError("Boolean value expected.")


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="DBus session service for " + "ArcticaProject's " + "Remote Web App"
    )
    parser.add_argument(
        "-m",
        "--mockup-mode",
        type=str2bool,
        nargs="?",
        const=True,
        default=False,
        help="Activate mockup mode. Act like the session "
        + "service but don't do changes or call other "
        + "parts of RWA.",
    )

    args = parser.parse_args()
    mockup_mode = args.mockup_mode

    if mockup_mode:
        logging.warning(
            "All API responses are faked and should NOT BE USED IN PRODUCTION!"
        )

    import dbus.mainloop.glib
    from gi.repository import GLib

    dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)

    loop = GLib.MainLoop()
    object = RWAService(loop, mockup_mode)

    def signal_handler(sig, frame):
        logging.info("Service was terminated.")
        object._stop_all()

    signal.signal(signal.SIGINT, signal_handler)

    loop.run()