"""Manage IPython.parallel clusters in the notebook.

Authors:

* Brian Granger
"""

#-----------------------------------------------------------------------------
#  Copyright (C) 2008-2011  The IPython Development Team
#
#  Distributed under the terms of the BSD License.  The full license is in
#  the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------

import os

from tornado import web
from zmq.eventloop import ioloop

from IPython.config.configurable import LoggingConfigurable
from IPython.config.loader import load_pyconfig_files
from IPython.utils.traitlets import Dict, Instance, CFloat
from IPython.parallel.apps.ipclusterapp import find_launcher_class
from IPython.core.profileapp import list_profiles_in
from IPython.core.profiledir import ProfileDir
from IPython.utils.path import get_ipython_dir
from IPython.utils.sysinfo import num_cpus


#-----------------------------------------------------------------------------
# Classes
#-----------------------------------------------------------------------------

class ClusterManager(LoggingConfigurable):

    profiles = Dict()

    delay = CFloat(1., config=True,
        help="delay (in s) between starting the controller and the engines")

    loop = Instance('zmq.eventloop.ioloop.IOLoop')
    def _loop_default(self):
        from zmq.eventloop.ioloop import IOLoop
        return IOLoop.instance()

    def load_cluster_config(self, profile_dir):
        config_files = ['ipcontroller_config.py', 'ipengine_config.py', 'ipcluster_config.py']
        config = load_pyconfig_files(config_files, profile_dir)
        return config

    def build_launchers(self, profile_dir):
        config = self.load_cluster_config(profile_dir)
        cont_clsname = config.IPClusterStart.get('controller_launcher_class','Local')
        cont_class = find_launcher_class(cont_clsname,'Controller')
        cl = cont_class(work_dir=u'.',config=config, profile_dir=profile_dir)

        engine_clsname = config.IPClusterEngines.get('engine_launcher_class','Local')
        engine_class = find_launcher_class(engine_clsname,'EngineSet')
        esl = engine_class(work_dir=u'.',config=config, profile_dir=profile_dir)
        n = config.IPClusterEngines.get('n', num_cpus())
        n = getattr(esl, 'engine_count', n)
        return cl, esl, n

    def get_profile_dir(self, name, path):
        p = ProfileDir.find_profile_dir_by_name(path,name=name)
        return p.location

    def update_profiles(self):
        """List all profiles in the ipython_dir and cwd.
        """
        for path in [get_ipython_dir(), os.getcwdu()]:
            for profile in list_profiles_in(path):
                pd = self.get_profile_dir(profile, path)
                if profile not in self.profiles:
                    self.log.debug("Overwriting profile %s" % profile)
                    self.profiles[profile] = {
                        'profile': profile,
                        'profile_dir': pd,
                        'status': 'stopped'
                    }

    def list_profiles(self):
        self.update_profiles()
        result = [self.profile_info(p) for p in self.profiles.keys()]
        return result

    def check_profile(self, profile):
        if profile not in self.profiles:
            raise web.HTTPError(404, u'profile not found')

    def profile_info(self, profile):
        self.check_profile(profile)
        result = {}
        data = self.profiles.get(profile)
        result['profile'] = profile
        result['profile_dir'] = data['profile_dir']
        result['status'] = data['status']
        if 'n' in data:
            result['n'] = data['n']
        return result

    def start_cluster(self, profile, n=None):
        """Start a cluster for a given profile."""
        self.check_profile(profile)
        data = self.profiles[profile]
        if data['status'] == 'running':
            raise web.HTTPError(409, u'cluster already running')
        cl, esl, default_n = self.build_launchers(data['profile_dir'])
        n = n if n is not None else default_n
        def clean_data():
            data.pop('controller_launcher',None)
            data.pop('engine_set_launcher',None)
            data.pop('n',None)
            data['status'] = 'stopped'
        def engines_stopped(r):
            self.log.debug('Engines stopped')
            if cl.running:
                cl.stop()
            clean_data()
        esl.on_stop(engines_stopped)
        def controller_stopped(r):
            self.log.debug('Controller stopped')
            if esl.running:
                esl.stop()
            clean_data()
        cl.on_stop(controller_stopped)

        dc = ioloop.DelayedCallback(lambda: cl.start(), 0, self.loop)
        dc.start()
        dc = ioloop.DelayedCallback(lambda: esl.start(n), 1000*self.delay, self.loop)
        dc.start()

        self.log.debug('Cluster started')
        data['controller_launcher'] = cl
        data['engine_set_launcher'] = esl
        data['n'] = n
        data['status'] = 'running'
        return self.profile_info(profile)

    def stop_cluster(self, profile):
        """Stop a cluster for a given profile."""
        self.check_profile(profile)
        data = self.profiles[profile]
        if data['status'] == 'stopped':
            raise web.HTTPError(409, u'cluster not running')
        data = self.profiles[profile]
        cl = data['controller_launcher']
        esl = data['engine_set_launcher']
        if cl.running:
            cl.stop()
        if esl.running:
            esl.stop()
        # Return a temp info dict, the real one is updated in the on_stop
        # logic above.
        result = {
            'profile': data['profile'],
            'profile_dir': data['profile_dir'],
            'status': 'stopped'
        }
        return result

    def stop_all_clusters(self):
        for p in self.profiles.keys():
            self.stop_cluster(profile)