#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Mitter, a simple client for Twitter
# Copyright (C) 2007, 2008  The Mitter Contributors
#
# 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 3 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, see <http://www.gnu.org/licenses/>.

import logging
import os.path
import urllib2

from mitterlib.network.networkbase import NetworkData
from mitterlib import module_search

_log = logging.getLogger('mitterlib.network.Networks')

# List of files that are not networks
SKIPPABLES = ('__init__.py', 'networkbase.py')

#--------------------------------------------------------------------
# Helper functions
#--------------------------------------------------------------------

def _import_name(module):
    """Based on the name of the module, return the proper "import"
    statement."""
    (name, _) = os.path.splitext(module)
    return 'mitterlib.network.%s' % (name)


#--------------------------------------------------------------------
# Exceptions
#--------------------------------------------------------------------

class NetworksError(Exception):
    """Basic Networks exception."""
    pass


class NetworksNoSuchNetworkError(NetworksError):
    """The request network does not exists."""

    def __init__(self, network):
        self._network = network

    def __str__(self):
        return 'Unknown network %s' % (self._network)
    pass


class NetworksNoNetworkSetupError(NetworksError):
    """There are no networks set up."""
    pass


class NetworksErrorLoadingNetwork(NetworksError):
    """Error loadig one of the networks."""

    def __init__(self, network, exception):
        self._network = network
        self._exception = str(exception)

    def __str__(self):
        return "Couldn't load %s (%s)" % (self._network, self._exception)


class Networks(object):
    """Network transparency layer: Keeps a list of available networks and send
    requests to all those who have been setup."""

    def __init__(self, options):
        self._networks = {}
        self._options = options
        self._operations = 0
        self._proxy_handler = None
        self.options()

    @property
    def networks(self):
        if self._networks:
            return self._networks

        for module_name in module_search(__file__, SKIPPABLES):
            import_name = _import_name(module_name)
            module = __import__(import_name, fromlist=[import_name])
            connection = module.Connection(self._options)
            self._networks[connection.SHORTCUT] = connection

        return self._networks

    def user(self, network=None):
        """Return a :class:`NetworkUser` representation for the logged user in
        the requested network. If no network is selected, will return the
        first found."""
        shortcut = self._targets(network).next()    # need this due yield
        return self.networks[shortcut].user

    def _targets(self, shortcut=None):
        """Select a network based on the shortcut. If the shortcut is None,
        returns all available network shortcuts."""
        if shortcut:
            if not shortcut in self.networks:
                raise NetworksNoSuchNetworkError(shortcut)
            else:
                targets = [shortcut]
        else:
            targets = self.networks

        setup = False
        for target in targets:
            if self.networks[target].is_setup:
                setup = True
                yield target

        if not setup:
            raise NetworksNoNetworkSetupError
        return

    def _save(self):
        """Check the number of operations and, if it above the minimum value,
        save the config file."""
        max_count = self._options['NetworkManager']['save_count']
        _log.debug('Operations %d, max %d', self._operations, max_count)
        if self._operations > max_count:
            self._options.save()
            self._operations = 0
            _log.debug('Config file saved')
        return

    def _proxy(self):
        """Check and install the proxy."""
        if not self._options['NetworkManager']['proxy']:
            return

        if self._proxy_handler:
            return

        proxy = self._options['NetworkManager']['proxy']
        if not '://' in proxy:
            proxy = 'http://' + proxy

        _log.debug('Installing proxy ' + proxy)
        self._proxy_handler = urllib2.ProxyHandler({
            'http': proxy,
            'https': proxy})
        opener = urllib2.build_opener(self._proxy_handler)
        urllib2.install_opener(opener)
        return

    def settings(self):
        """Return a dictionary with the options that the interfaces need to
        setup."""
        result = []
        for shortcut in self.networks:
            settings = {
                'shortcut': shortcut,
                'name': self.networks[shortcut].NAMESPACE,
                'options': self.networks[shortcut].AUTH,
            }
            result.append(settings)
        return result

    def options(self):
        """Add the options for all networks and the network manager options
        itself."""
        # Remember that, in case you add or remove any options here, you
        # should also update the CHEAT-CODES file.
        for shortcut in self.networks:
            conn = self.networks[shortcut]
            conn.options(self._options)

        # add Networks own options
        self._options.add_group('NetworkManager', 'Network Manager')
        self._options.add_option(
                '--timeout',
                group='NetworkManager',
                option='timeout',
                help='Timeout for requests in all networks.',
                type='int',
                metavar='SECONDS',
                default=120)
        self._options.add_option(
                '--proxy',
                group='NetworkManager',
                option='proxy',
                help='Proxy server (Note: This is not needed on Windows " \
                        "and OS X systems as Mitter will use the system " \
                        "value.)',
                metavar='SERVER',
                default='')
        self._options.add_option(
                group='NetworkManager',
                option='save_count',
                help='Number of network operations till the config file ' \
                        'is saved',
                type='int',
                metavar='OPERATIONS',
                default=5,
                is_cmd_option=False)
        return

    def name(self, shortcut):
        """Return the name of a network based on the shortcut."""
        try:
            name = self.networks[shortcut].NAMESPACE
        except KeyError:
            raise NetworksNoSuchNetworkError(shortcut)
        return name

    # This is basically a copy of all methods available in NetworkBase, with
    # the additional parameter "network" (to request data from just one
    # source)
    def messages(self, network=None):
        """Return a list of NetworkData objects for the main "timeline" (the
        default list presented to the user.)"""
        self._proxy()
        result = []
        for shortcut in self._targets(network):
            for message in self.networks[shortcut].messages():
                message.network = shortcut
                message.network_name = self.networks[shortcut].NAMESPACE
                result.append(message)
            self._operations += 1
            # don't check the operations count inside the loop; if Mitter
            # fails, all the last messages can still be retrieved ('cause the
            # config file wasn't saved yet.)
        self._save()
        return result

    def update(self, status, reply_to=None, network=None):
        """Update the user status. Must return the id for the new status."""
        self._proxy()
        if reply_to and isinstance(reply_to, NetworkData):
            # If you pass a NetworkData object, we get the proper network
            network = reply_to.network

        results = []
        for shortcut in self._targets(network):
            results.append(self.networks[shortcut].update(status, reply_to))
            self._operations += 1
        self._save()
        return results

    def repost(self, message):
        """Repost a message in the user's timeline. The network used is
        the same in the message."""
        assert(isinstance(message, NetworkData))
        self._proxy()
        self.networks[message.network].repost(message)
        self._operations += 1
        self._save()
        return

    def favouite(self, message):
        """Change the favorite status of the message. Returns the new
        favorite status."""
        assert(isinstance(message, NetworkData))
        self._proxy()
        self.networks[message.network].favorite(message)
        self._operations += 1
        self._save()

        # since the operation completed without a problem, we can toggle the
        # message as favorited already.
        message.favorite = not message.favorite
        return message.favorite

    def delete_message(self, message, network=None):
        """Delete an update. Message can be a :class:`NetworkData` object,
        in which case network is not necessary; otherwise a network must be
        provided. Always return the same message object"""
        if isinstance(message, NetworkData):
            network = message.network

        self._proxy()
        self.networks[network].delete_message(message)
        self._operations += 1
        self._save()
        return message

    def message(self, message_id, network):
        """Return a single NetworkData object for a specified message."""
        # TODO: This should probably be named parent() and receive a
        # NetworkData. Still returns a single NetworkData object.
        if not network in self.networks:
            raise NetworksNoSuchNetworkError(network)

        self._proxy()
        data = self.networks[network].message(message_id)
        data.network = network
        self._operations += 1
        self._save()
        return data

    def replies(self, network=None):
        """Return a list of NetworkData objects for the replies for the user
        messages."""
        result = []
        self._proxy()
        for shortcut in self._targets(network):
            for message in self.networks[shortcut].replies():
                message.network = shortcut
                result.append(message)
            self._operations += 1
        self._save()
        return result

    def available_requests(self, network=None):
        """Return a dictionary with the available requests the user can
        make to each network before getting capped."""
        result = {}
        for shortcut in self._targets(network):
            requests = self.networks[shortcut].available_requests()
            result[shortcut] = requests
        return result