# -*- coding: utf-8 -*-
'''
Functions which implement running reactor jobs
'''


# Import python libs
from __future__ import absolute_import, print_function, unicode_literals
import fnmatch
import glob
import logging

# Import salt libs
import salt.client
import salt.runner
import salt.state
import salt.utils.args
import salt.utils.cache
import salt.utils.data
import salt.utils.event
import salt.utils.files
import salt.utils.process
import salt.utils.yaml
import salt.wheel
import salt.defaults.exitcodes

# Import 3rd-party libs
from salt.ext import six

log = logging.getLogger(__name__)

REACTOR_INTERNAL_KEYWORDS = frozenset([
    '__id__',
    '__sls__',
    'name',
    'order',
    'fun',
    'state',
])


class Reactor(salt.utils.process.SignalHandlingProcess, salt.state.Compiler):
    '''
    Read in the reactor configuration variable and compare it to events
    processed on the master.
    The reactor has the capability to execute pre-programmed executions
    as reactions to events
    '''
    aliases = {
        'cmd': 'local',
    }

    def __init__(self, opts, **kwargs):
        super(Reactor, self).__init__(**kwargs)
        local_minion_opts = opts.copy()
        local_minion_opts['file_client'] = 'local'
        self.minion = salt.minion.MasterMinion(local_minion_opts)
        salt.state.Compiler.__init__(self, opts, self.minion.rend)

    # We need __setstate__ and __getstate__ to avoid pickling errors since
    # 'self.rend' (from salt.state.Compiler) contains a function reference
    # which is not picklable.
    # These methods are only used when pickling so will not be used on
    # non-Windows platforms.
    def __setstate__(self, state):
        Reactor.__init__(
            self, state['opts'],
            log_queue=state['log_queue'],
            log_queue_level=state['log_queue_level']
        )

    def __getstate__(self):
        return {
            'opts': self.opts,
            'log_queue': self.log_queue,
            'log_queue_level': self.log_queue_level
        }

    def render_reaction(self, glob_ref, tag, data):
        '''
        Execute the render system against a single reaction file and return
        the data structure
        '''
        react = {}

        if glob_ref.startswith('salt://'):
            glob_ref = self.minion.functions['cp.cache_file'](glob_ref) or ''
        globbed_ref = glob.glob(glob_ref)
        if not globbed_ref:
            log.error('Can not render SLS %s for tag %s. File missing or not found.', glob_ref, tag)
        for fn_ in globbed_ref:
            try:
                res = self.render_template(
                    fn_,
                    tag=tag,
                    data=data)

                # for #20841, inject the sls name here since verify_high()
                # assumes it exists in case there are any errors
                for name in res:
                    res[name]['__sls__'] = fn_

                react.update(res)
            except Exception:  # pylint: disable=broad-except
                log.exception('Failed to render "%s": ', fn_)
        return react

    def list_reactors(self, tag):
        '''
        Take in the tag from an event and return a list of the reactors to
        process
        '''
        log.debug('Gathering reactors for tag %s', tag)
        reactors = []
        if isinstance(self.opts['reactor'], six.string_types):
            try:
                with salt.utils.files.fopen(self.opts['reactor']) as fp_:
                    react_map = salt.utils.yaml.safe_load(fp_)
            except (OSError, IOError):
                log.error('Failed to read reactor map: "%s"', self.opts['reactor'])
            except Exception:  # pylint: disable=broad-except
                log.error('Failed to parse YAML in reactor map: "%s"', self.opts['reactor'])
        else:
            react_map = self.opts['reactor']
        for ropt in react_map:
            if not isinstance(ropt, dict):
                continue
            if len(ropt) != 1:
                continue
            key = next(six.iterkeys(ropt))
            val = ropt[key]
            if fnmatch.fnmatch(tag, key):
                if isinstance(val, six.string_types):
                    reactors.append(val)
                elif isinstance(val, list):
                    reactors.extend(val)
        return reactors

    def list_all(self):
        '''
        Return a list of the reactors
        '''
        if isinstance(self.minion.opts['reactor'], six.string_types):
            log.debug('Reading reactors from yaml %s', self.opts['reactor'])
            try:
                with salt.utils.files.fopen(self.opts['reactor']) as fp_:
                    react_map = salt.utils.yaml.safe_load(fp_)
            except (OSError, IOError):
                log.error('Failed to read reactor map: "%s"', self.opts['reactor'])
            except Exception:  # pylint: disable=broad-except
                log.error(
                    'Failed to parse YAML in reactor map: "%s"',
                    self.opts['reactor']
                )
        else:
            log.debug('Not reading reactors from yaml')
            react_map = self.minion.opts['reactor']
        return react_map

    def add_reactor(self, tag, reaction):
        '''
        Add a reactor
        '''
        reactors = self.list_all()
        for reactor in reactors:
            _tag = next(six.iterkeys(reactor))
            if _tag == tag:
                return {'status': False, 'comment': 'Reactor already exists.'}

        self.minion.opts['reactor'].append({tag: reaction})
        return {'status': True, 'comment': 'Reactor added.'}

    def delete_reactor(self, tag):
        '''
        Delete a reactor
        '''
        reactors = self.list_all()
        for reactor in reactors:
            _tag = next(six.iterkeys(reactor))
            if _tag == tag:
                self.minion.opts['reactor'].remove(reactor)
                return {'status': True, 'comment': 'Reactor deleted.'}

        return {'status': False, 'comment': 'Reactor does not exists.'}

    def resolve_aliases(self, chunks):
        '''
        Preserve backward compatibility by rewriting the 'state' key in the low
        chunks if it is using a legacy type.
        '''
        for idx, _ in enumerate(chunks):
            new_state = self.aliases.get(chunks[idx]['state'])
            if new_state is not None:
                chunks[idx]['state'] = new_state

    def reactions(self, tag, data, reactors):
        '''
        Render a list of reactor files and returns a reaction struct
        '''
        log.debug('Compiling reactions for tag %s', tag)
        high = {}
        chunks = []
        try:
            for fn_ in reactors:
                high.update(self.render_reaction(fn_, tag, data))
            if high:
                errors = self.verify_high(high)
                if errors:
                    log.error(
                        'Unable to render reactions for event %s due to '
                        'errors (%s) in one or more of the sls files (%s)',
                        tag, errors, reactors
                    )
                    return []  # We'll return nothing since there was an error
                chunks = self.order_chunks(self.compile_high_data(high))
        except Exception as exc:  # pylint: disable=broad-except
            log.exception('Exception encountered while compiling reactions')

        self.resolve_aliases(chunks)
        return chunks

    def call_reactions(self, chunks):
        '''
        Execute the reaction state
        '''
        for chunk in chunks:
            self.wrap.run(chunk)

    def run(self):
        '''
        Enter into the server loop
        '''
        salt.utils.process.appendproctitle(self.__class__.__name__)

        # instantiate some classes inside our new process
        with salt.utils.event.get_event(
                self.opts['__role'],
                self.opts['sock_dir'],
                self.opts['transport'],
                opts=self.opts,
                listen=True) as event:
            self.wrap = ReactWrap(self.opts)

            for data in event.iter_events(full=True):
                # skip all events fired by ourselves
                if data['data'].get('user') == self.wrap.event_user:
                    continue
                if data['tag'].endswith('salt/reactors/manage/add'):
                    _data = data['data']
                    res = self.add_reactor(_data['event'], _data['reactors'])
                    event.fire_event({'reactors': self.list_all(),
                                           'result': res},
                                          'salt/reactors/manage/add-complete')
                elif data['tag'].endswith('salt/reactors/manage/delete'):
                    _data = data['data']
                    res = self.delete_reactor(_data['event'])
                    event.fire_event({'reactors': self.list_all(),
                                           'result': res},
                                          'salt/reactors/manage/delete-complete')
                elif data['tag'].endswith('salt/reactors/manage/list'):
                    event.fire_event({'reactors': self.list_all()},
                                          'salt/reactors/manage/list-results')
                else:
                    reactors = self.list_reactors(data['tag'])
                    if not reactors:
                        continue
                    chunks = self.reactions(data['tag'], data['data'], reactors)
                    if chunks:
                        try:
                            self.call_reactions(chunks)
                        except SystemExit:
                            log.warning('Exit ignored by reactor')


class ReactWrap(object):
    '''
    Wrapper that executes low data for the Reactor System
    '''
    # class-wide cache of clients
    client_cache = None
    event_user = 'Reactor'

    reaction_class = {
        'local': salt.client.LocalClient,
        'runner': salt.runner.RunnerClient,
        'wheel': salt.wheel.Wheel,
        'caller': salt.client.Caller,
    }

    def __init__(self, opts):
        self.opts = opts
        if ReactWrap.client_cache is None:
            ReactWrap.client_cache = salt.utils.cache.CacheDict(opts['reactor_refresh_interval'])

        self.pool = salt.utils.process.ThreadPool(
            self.opts['reactor_worker_threads'],  # number of workers for runner/wheel
            queue_size=self.opts['reactor_worker_hwm']  # queue size for those workers
        )

    def populate_client_cache(self, low):
        '''
        Populate the client cache with an instance of the specified type
        '''
        reaction_type = low['state']
        if reaction_type not in self.client_cache:
            log.debug('Reactor is populating %s client cache', reaction_type)
            if reaction_type in ('runner', 'wheel'):
                # Reaction types that run locally on the master want the full
                # opts passed.
                self.client_cache[reaction_type] = \
                    self.reaction_class[reaction_type](self.opts)
                # The len() function will cause the module functions to load if
                # they aren't already loaded. We want to load them so that the
                # spawned threads don't need to load them. Loading in the
                # spawned threads creates race conditions such as sometimes not
                # finding the required function because another thread is in
                # the middle of loading the functions.
                len(self.client_cache[reaction_type].functions)
            else:
                # Reactions which use remote pubs only need the conf file when
                # instantiating a client instance.
                self.client_cache[reaction_type] = \
                    self.reaction_class[reaction_type](self.opts['conf_file'])

    def run(self, low):
        '''
        Execute a reaction by invoking the proper wrapper func
        '''
        self.populate_client_cache(low)
        try:
            l_fun = getattr(self, low['state'])
        except AttributeError:
            log.error(
                'ReactWrap is missing a wrapper function for \'%s\'',
                low['state']
            )

        try:
            wrap_call = salt.utils.args.format_call(l_fun, low)
            args = wrap_call.get('args', ())
            kwargs = wrap_call.get('kwargs', {})
            # TODO: Setting user doesn't seem to work for actual remote pubs
            if low['state'] in ('runner', 'wheel'):
                # Update called function's low data with event user to
                # segregate events fired by reactor and avoid reaction loops
                kwargs['__user__'] = self.event_user
                # Replace ``state`` kwarg which comes from high data compiler.
                # It breaks some runner functions and seems unnecessary.
                kwargs['__state__'] = kwargs.pop('state')
                # NOTE: if any additional keys are added here, they will also
                # need to be added to filter_kwargs()

            if 'args' in kwargs:
                # New configuration
                reactor_args = kwargs.pop('args')
                for item in ('arg', 'kwarg'):
                    if item in low:
                        log.warning(
                            'Reactor \'%s\' is ignoring \'%s\' param %s due to '
                            'presence of \'args\' param. Check the Reactor System '
                            'documentation for the correct argument format.',
                            low['__id__'], item, low[item]
                        )
                if low['state'] == 'caller' \
                        and isinstance(reactor_args, list) \
                        and not salt.utils.data.is_dictlist(reactor_args):
                    # Legacy 'caller' reactors were already using the 'args'
                    # param, but only supported a list of positional arguments.
                    # If low['args'] is a list but is *not* a dictlist, then
                    # this is actually using the legacy configuration. So, put
                    # the reactor args into kwarg['arg'] so that the wrapper
                    # interprets them as positional args.
                    kwargs['arg'] = reactor_args
                    kwargs['kwarg'] = {}
                else:
                    kwargs['arg'] = ()
                    kwargs['kwarg'] = reactor_args
                if not isinstance(kwargs['kwarg'], dict):
                    kwargs['kwarg'] = salt.utils.data.repack_dictlist(kwargs['kwarg'])
                    if not kwargs['kwarg']:
                        log.error(
                            'Reactor \'%s\' failed to execute %s \'%s\': '
                            'Incorrect argument format, check the Reactor System '
                            'documentation for the correct format.',
                            low['__id__'], low['state'], low['fun']
                        )
                        return
            else:
                # Legacy configuration
                react_call = {}
                if low['state'] in ('runner', 'wheel'):
                    if 'arg' not in kwargs or 'kwarg' not in kwargs:
                        # Runner/wheel execute on the master, so we can use
                        # format_call to get the functions args/kwargs
                        react_fun = self.client_cache[low['state']].functions.get(low['fun'])
                        if react_fun is None:
                            log.error(
                                'Reactor \'%s\' failed to execute %s \'%s\': '
                                'function not available',
                                low['__id__'], low['state'], low['fun']
                            )
                            return

                        react_call = salt.utils.args.format_call(
                            react_fun,
                            low,
                            expected_extra_kws=REACTOR_INTERNAL_KEYWORDS
                        )

                if 'arg' not in kwargs:
                    kwargs['arg'] = react_call.get('args', ())
                if 'kwarg' not in kwargs:
                    kwargs['kwarg'] = react_call.get('kwargs', {})

            # Execute the wrapper with the proper args/kwargs. kwargs['arg']
            # and kwargs['kwarg'] contain the positional and keyword arguments
            # that will be passed to the client interface to execute the
            # desired runner/wheel/remote-exec/etc. function.
            l_fun(*args, **kwargs)
        except SystemExit:
            log.warning(
                'Reactor \'%s\' attempted to exit. Ignored.', low['__id__']
            )
        except Exception:  # pylint: disable=broad-except
            log.error(
                'Reactor \'%s\' failed to execute %s \'%s\'',
                low['__id__'], low['state'], low['fun'], exc_info=True
            )

    def runner(self, fun, **kwargs):
        '''
        Wrap RunnerClient for executing :ref:`runner modules <all-salt.runners>`
        '''
        self.pool.fire_async(self.client_cache['runner'].low, args=(fun, kwargs))

    def wheel(self, fun, **kwargs):
        '''
        Wrap Wheel to enable executing :ref:`wheel modules <all-salt.wheel>`
        '''
        self.pool.fire_async(self.client_cache['wheel'].low, args=(fun, kwargs))

    def local(self, fun, tgt, **kwargs):
        '''
        Wrap LocalClient for running :ref:`execution modules <all-salt.modules>`
        '''
        self.client_cache['local'].cmd_async(tgt, fun, **kwargs)

    def caller(self, fun, **kwargs):
        '''
        Wrap LocalCaller to execute remote exec functions locally on the Minion
        '''
        self.client_cache['caller'].cmd(fun, *kwargs['arg'], **kwargs['kwarg'])
