##########################################################################
#
# pgAdmin 4 - PostgreSQL Tools
#
# Copyright (C) 2013 - 2024, The pgAdmin Development Team
# This software is released under the PostgreSQL Licence
#
#########################################################################

"""Server heartbeat manager."""


import threading
import datetime
import config
from flask import session, current_app
from flask_babel import gettext


def log_server_heartbeat(data):
    """Log Server Heartbeat."""
    from config import PG_DEFAULT_DRIVER
    from pgadmin.utils.driver import get_driver
    manager = get_driver(PG_DEFAULT_DRIVER).connection_manager(int(data['sid'])
                                                               )

    _server_heartbeat = getattr(current_app, '_pgadmin_server_heartbeat', {})

    if session.sid not in _server_heartbeat:
        _server_heartbeat[session.sid] = {}

    if not manager:
        stop_server_heartbeat(data)
        return False, gettext("Manager not found. Stopped Heartbeat logging.")
    else:
        _server_heartbeat[session.sid][data['sid']] = {
            'timestamp': datetime.datetime.now(),
            'conn': manager.connections
        }
        current_app.logger.debug(
            "Heartbeat logged for the session id##server id: {0}##{1}".format(
                session.sid, data['sid']))

        setattr(current_app, '_pgadmin_server_heartbeat', _server_heartbeat)
        return True, gettext("Heartbeat logged successfully.")


def stop_server_heartbeat(data):
    """Stop logging server heartbeat."""
    _server_heartbeat = getattr(current_app, '_pgadmin_server_heartbeat', {})

    if session.sid in _server_heartbeat and \
            data['sid'] in _server_heartbeat[session.sid]:
        _server_heartbeat[session.sid].pop(data['sid'])

        current_app.logger.debug(
            "Heartbeat logging stopped for the session"
            " id##server id: {0}##{1}".format(session.sid, data['sid']))

        setattr(current_app, '_pgadmin_server_heartbeat', _server_heartbeat)

    return True, gettext("Stopped Heartbeat logging.")


def get_server_heartbeat(server_id):
    _server_heartbeat = getattr(current_app, '_pgadmin_server_heartbeat', {})

    if session.sid in _server_heartbeat and server_id in _server_heartbeat[
            session.sid]:
        return _server_heartbeat[session.sid][server_id]
    else:
        return None


class ServerHeartbeatTimer():
    def __init__(self, sec, _app):
        def func_wrapper():
            self.t = threading.Timer(sec, func_wrapper)
            self.t.start()
            self.release_server_heartbeat()
        self.t = threading.Timer(sec, func_wrapper)
        self.t.daemon = True
        self.t.start()
        self._app = _app

    def release_server_heartbeat(self):
        with self._app.app_context():
            _server_heartbeat = getattr(self._app,
                                        '_pgadmin_server_heartbeat', {})
            if len(_server_heartbeat) > 0:
                for sess_id in list(_server_heartbeat):
                    for sid in list(_server_heartbeat[sess_id]):
                        last_heartbeat_time = _server_heartbeat[sess_id][sid][
                            'timestamp']
                        current_time = datetime.datetime.now()
                        diff = current_time - last_heartbeat_time

                        # Wait for 4 times then the timeout
                        if diff.total_seconds() > (
                                config.SERVER_HEARTBEAT_TIMEOUT * 4):
                            self._release_connections(
                                _server_heartbeat[sess_id][sid]['conn'],
                                sess_id, sid)
                            _server_heartbeat[sess_id].pop(sid)
                            if len(_server_heartbeat[sess_id]) == 0:
                                _server_heartbeat.pop(sess_id)
                setattr(self._app, '_pgadmin_server_heartbeat',
                        _server_heartbeat)

    @staticmethod
    def _release_connections(server_conn, sess_id, sid):
        for d in server_conn:
            try:
                # Release the connection only if it is connected
                if server_conn[d].wasConnected:
                    server_conn[d]._release()
                    # Reconnect on the reload
                    server_conn[d].wasConnected = True
                    current_app.logger.debug(
                        "Heartbeat not received. Released "
                        "connection for the session "
                        "id##server id: {0}##{1}".format(
                            sess_id, sid))
            except Exception as e:
                current_app.logger.exception(e)

    def cancel(self):
        self.t.cancel()


def init_app(app):
    setattr(app, '_pgadmin_server_heartbeat', {})
    ServerHeartbeatTimer(sec=config.SERVER_HEARTBEAT_TIMEOUT,
                         _app=app)