#  -*- coding: utf-8 -*-
# *****************************************************************************
# NICOS, the Networked Instrument Control System of the MLZ
# Copyright (c) 2009-2018 by the NICOS contributors (see AUTHORS)
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# Module authors:
#   Markus Zolliker <markus.zolliker@psi.ch>
#
# *****************************************************************************
"""managing SECoP server and connections

SEC Node with added functionality for starting and stoping frappy servers
connected to a SEC node
"""

import os
from os.path import expanduser

from nicos import config, session
from nicos.core import Override, Param, Moveable, status
from nicos.devices.secop import SecNodeDevice
from nicos.utils.comparestrings import compare
from servicemanager import FrappyManager


def suggest(poi, allowed_keys):
    comp = {}
    for key in allowed_keys:
        comp[key] = compare(poi, key)
    comp = sorted(comp.items(), key=lambda t: t[1], reverse=True)
    return [m[0] for m in comp[:3] if m[1] > 2]


class FrappyNode(SecNodeDevice, Moveable):
    """SEC node device

    with ability to start / restart / stop the frappy server
    """

    parameter_overrides = {
        'target': Override(description='configuration for the frappy server or host:port',
                           type=str, default=''),
    }
    parameters = {
        'service': Param('frappy service name (main, stick or addons)', type=str, default=''),
    }

    _service_manager = FrappyManager()
    _cfgvalue = None

    def doStart(self, value):
        if value == 'None':
            value = None
        self.restart(value)

    def doStop(self):
        """never busy"""

    def doRead(self, maxage=0):
        if self._cfgvalue is None and self._cache:
            self._cfgvalue = self._cache.get(self, 'value')
        return self._cfgvalue

    @classmethod
    def config_dirs(cls, ins, service):
        sm = cls._service_manager
        sm.get_info()
        return sm.config_dirs(ins, service)

    @classmethod
    def available_cfg(cls, service):
        ins = config.instrument
        available_cfg = set()
        for d in cls.config_dirs(ins, service):
            try:
                available_cfg |= set(c[:-4] for c in os.listdir(expanduser(d)) if c.endswith('.cfg'))
            except FileNotFoundError:  # ignore missing directories
                pass
        return available_cfg

    def disable(self):
        seaconn = session.devices.get('seaconn')
        if seaconn and seaconn._attached_secnode:
            seaconn.communicate('frappy_remove %s' % self.service)
        self._set_status(*self._status)

    def _set_status(self, code, text):
        if self.uri == '':
            code, text = status.DISABLED, 'disabled'
        SecNodeDevice._set_status(self, code, text)

    def restart(self, cfg=None):
        """restart frappy server

        if value is not given: restart with the same config
        else restart with given config
        """
        was_cfg = self._cfgvalue and ':' not in self._cfgvalue
        if cfg is None:  # do restart anyway
            cfg = self._cfgvalue
        elif cfg == self._cfgvalue:  # probably called from doStart
            if cfg == '':
                self.disable()
            # do not restart in this case
            return
        is_cfg = cfg and ':' not in cfg
        ins = config.instrument
        info = self._service_manager.get_ins_info(ins)
        if is_cfg:
            available_cfg = self.available_cfg(self.service)
            failed = False
            for cfgitem in cfg.split(','):
                if cfgitem not in available_cfg:
                    failed = True
                    suggestions = suggest(cfgitem, available_cfg)
                    if suggestions:
                        session.log.error('%s unknown, did you mean: %s' % (cfgitem, ', '.join(suggestions)))
            if failed:
                raise ValueError('use "frappy_list()" to get a list of valid frappy configurations')
            uri = 'localhost:%d' % info[self.service]
        else:
            uri = cfg
        if uri != self.uri:
            self.uri = ''  # disconnect
            if was_cfg:
                self._service_manager.do_stop(ins, self.service)
        if uri:
            if is_cfg:
                self._service_manager.do_restart(ins, self.service, cfg, self.log)
            self.uri = uri  # connect
        else:
            self.disable()
        self._cfgvalue = cfg
        if self._cache:
            self._cache.put(self, 'value', cfg)
        self._setROParam('target', cfg)