#!/usr/bin/env python
#coding=utf8

import inspect
import logging
from sjrpc.utils import RpcHandler, pure
from tql import TqlQuery
from conf import CCConf

def listed(func):
    func.__listed__ = True
    return func

class CCHandler(RpcHandler):
    '''
    Base class for handlers of CloudControl server.

    :cvar role_name: the name of the role binded to the handler
    :type role_name: str or None is not applicable
    '''
    
    role_name = None

    def __init__(self, server):
        self._server = server

    def __getitem__(self, name):
        logging.debug('Called method %s.%s' % (self.__class__.__name__, name))
        return super(CCHandler, self).__getitem__(name)

    @pure
    def list_commands(self):
        cmd_list = []

        for attr in dir(self):
            attr = getattr(self, attr, None)
            if getattr(attr, '__listed__', False):
                cmd = {}
                cmd['name'] = attr.__name__
                cmd['description'] = inspect.cleandoc(inspect.getdoc(attr))
                cmd_list.append(cmd)

        return cmd_list

class HypervisorHandler(CCHandler):
    '''
    Handler binded to 'node' role.
    '''
    role_name = 'hypervisor'


class ClientHandler(CCHandler):
    '''
    Handler binded to 'cli' role.
    '''
    
    role_name = 'client'

    @pure
    @listed
    def list_vm(self):
        '''
        List all VMs on nodes.
        '''
        
        found_vm = []
        async_ids = set()
        # Send the asynchronous request to all nodes:
        for node in self._server.iterrole('node'):
            async_ids.add(node.async_call('list_vm'))

        # Wait for the response:
        responses = self._server.manager.wait(frozenset(async_ids), timeout=5)

        # Process the responses:
        for resp in responses:
            if resp['error'] is None:
                for vm in resp['return']:
                    found_vm.append(vm)

        return tuple(found_vm)

    @pure
    @listed
    def list(self, query):
        '''
        List all objects registered on this instance.
        '''

        logging.debug('Executed list function with query %s' % query)
        
        # Contains all the objects to be filted:
        objects = []

        # The query object:
        query = TqlQuery(query)

        # Get the hypervisors that match the query:
        hypervisors = list(self._server.iterrole('hypervisor'))
        if query.has_condition('hv'):
            hypervisors = query.filter(hypervisors, tag_name='hv',
                                       key=lambda o,n: o.get_tags([n]).get(n))
        logging.debug('Querying %d hypervisors: %s' % (len(hypervisors),
                                                       hypervisors))

        # Try to get vm for each matched hypervisor:
        async_calls = {}
        tags = tuple(query.tags)
        for hy in hypervisors:
            async_calls[hy.connection.async_call('list_vm', tags=tags)] = hy

        logging.debug('Waiting for the response of hypervisors...')
        responses = self._server.manager.wait(frozenset(async_calls), timeout=5)
        logging.debug('Responses received.')

        # Make the hypervisor object -> tags mapping:
        hv_tags = {}
        for hy in hypervisors:
            tags = hy.get_tags(tags=tuple(query.tags))
            hv_tags[hy] = tags
            objects.append(tags)

        for resp in responses:
            if resp['error'] is None:
                hy = async_calls[resp['id']]
                for vm in resp['return']:
                    vm_tags = hv_tags[hy].copy()
                    vm_tags.update(vm)
                    vm_tags['role'] = 'vm'
                    objects.append(vm_tags)
        # Filter the objects with the query, and return it:
        return query.filter(objects)


class AuthenticationError(Exception):
    pass


class WelcomeHandler(CCHandler):
    '''
    Default handler used on client connections of the server.

    :cvar ROLES: role name/handler mapping
    '''
    
    ROLES = {
        'client': ClientHandler,
        'hypervisor': HypervisorHandler,
    }

    @listed
    def authentify(self, connection, login, password):
        '''
        Authenticate the client.
        '''
        try:
            role = self._server.conf.authentify(login, password)
        except CCConf.UnknownAccount:
            raise AuthenticationError('Authentication failure (Unknown login)')

        if role is None:
            logging.info('New authentication from %s: failure' % login)
            raise AuthenticationError('Authentication failure')
        else:
            # If authentication is a success, ask tags to the server:
            self._server.register(login, role, connection)
            connection.set_handler(WelcomeHandler.ROLES.get(role)(self._server))
            logging.info('New authentication from %s: success' % login)
            
            return role