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

# Mitter, a 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 urllib
import urllib2
import logging
import datetime
import base64
import htmlentitydefs
import re
import warnings

from httplib import BadStatusLine
from socket import error as socketError

from networkbase import NetworkBase, NetworkData, auth_options, \
        NetworkDNSError, NetworkBadStatusLineError, NetworkLowLevelError, \
        NetworkInvalidResponseError, NetworkPermissionDeniedError, \
        MessageTooLongWarning

try:
    # Python 2.6/3.0 JSON parser
    import json
except ImportError:
    # Fallback to SimpleJSON
    import simplejson as json

# logging
_log = logging.getLogger('mitterlib.network.Twitter')

# the month names come directly from the site, so we are not affected by
# locale settings.
_month_names = [None, 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug',
        'Sep', 'Oct', 'Nov', 'Dec']


def _unhtml(text):
    """Convert text coming in HTML encoded to UTF-8 representations."""
    new_text = []
    copy_pos = 0
    _log.debug('Original text: %s', text)
    for code in re.finditer(r'&(\w+);', text):
        new_text.append(text[copy_pos:code.start()])
        entity = text[code.start()+1:code.end()-1]
        if entity in htmlentitydefs.name2codepoint:
            new_text.append(unichr(
                    htmlentitydefs.name2codepoint[entity]))
        else:
            new_text.append(code.group().decode('utf8'))
        copy_pos = code.end()

    new_text.append(text[copy_pos:])

    _log.debug('New text: %s', new_text)
    result = u''.join(new_text)
    _log.debug('Result: %s', result)
    return result


def _htmlize(text):
    """Convert accented characters to their HTML entities."""
    new = []
    # XXX: This is not very effective, but Twitter only accepts 140 chars,
    # so it won't be a big pain.
    for char in text:
        if ord(char) in htmlentitydefs.codepoint2name:
            new.append('&%s;' % (htmlentitydefs.codepoint2name[ord(char)]))
        else:
            new.append(char)
    return ''.join(new)


def _to_datetime(server_str):
    """Convert a date send by the server to a datetime object.
    Ex:
        from this:
            Tue Mar 13 00:12:41 +0000 2007
            to datetime.
    """
    date_info = server_str.split(' ')
    month = _month_names.index(date_info[1])
    day = int(date_info[2])
    year = int(date_info[5])

    time_info = date_info[3].split(':')
    hour = int(time_info[0])
    minute = int(time_info[1])
    second = int(time_info[2])

    return datetime.datetime(year, month, day, hour, minute, second)


def _make_datetime(response):
    """Converts dates on responses to datetime objects."""
    result = []
    for tweet in response:
        result.append(TwitterNetworkData(tweet))

    return result


class TwitterNetworkData(NetworkData):
    """A simple wrapper around NetworkData, to make things easier to convert
    twitter data into a NetworkData object."""

    def __init__(self, data):
        """Class initialization. Receives a dictionary with a single tweet."""
        NetworkData.__init__(self)

        self.id = data['id']
        self.name = data['user']['name']
        self.username = data['user']['screen_name']
        self.avatar = data['user']['profile_image_url']
        self.message_time = _to_datetime(data['created_at'])

        if 'in_reply_to_status_id' in data and data['in_reply_to_status_id']:
            self.parent = int(data['in_reply_to_status_id'])

        # Twitter encodes a lot of HTML entities, which are not good when
        # you want to *display* then (e.g., "<" returns to us as "&lt;").
        # So we convert this here.
        self.message = _unhtml(data['text'])

        return


class Connection(NetworkBase):
    """Base class to talk to twitter."""

    NAMESPACE = 'Twitter'
    SHORTCUT = 'tw'     # TODO: find a way to move this to the config file

    def is_setup(self):
        """Return True or False if the network is setup/enabled."""
        if (self._options[self.NAMESPACE]['username'] and
                self._options[self.NAMESPACE]['password']):
            # Consider the network enabled if there is an username and
            # password
            return True
        else:
            return False

    def __init__(self, options):
        self._options = options

    @property
    def server(self):
        if self._options[self.NAMESPACE]['https']:
            return self._options[self.NAMESPACE]['secure_server_url']
        else:
            return self._options[self.NAMESPACE]['server_url']

    def _common_headers(self):
        """Returns a string with the normal headers we should add on every
        request"""

        auth = base64.b64encode('%s:%s' % (
            self._options[self.NAMESPACE]['username'],
            self._options[self.NAMESPACE]['password']))

        headers = {
                'Authorization': 'Basic %s' % (auth),
                'User-Agent': self._user_agent}
        return headers

    def _request(self, resource, headers=None, body=None):
        """Send a request to the Twitter server. Once finished, call the
        function at callback."""

        url = '%s%s' % (self.server, resource)
        _log.debug('Request %s' % (url))

        request = urllib2.Request(url=url)
        request_headers = self._common_headers()
        if headers:
            request_headers.update(headers)

        for key in request_headers:
            _log.debug('Header: %s=%s' % (key, request_headers[key]))
            request.add_header(key, request_headers[key])

        if body:
            _log.debug('Body: %s' % (body))
            request.add_data(body)

        try:
            _log.debug('Starting request of %s' % (url))
            response = urllib2.urlopen(request)
            data = response.read()
        except urllib2.HTTPError, exc:
            _log.debug('HTTPError: %d' % (exc.code))
            _log.debug('HTTPError: response body:\n%s' % exc.read())
            # To me, I got a lot of 502 for "replies". It shows the
            # "Something is technically wrong" most of the time in the real
            # pages.
            if exc.code == 403:
                # Permission denied.
                raise NetworkPermissionDeniedError
            raise NetworkInvalidResponseError
        except urllib2.URLError, exc:
            _log.error('URL error: %s' % exc.reason)
            raise NetworkDNSError
        except BadStatusLine:
            _log.error('Bad status line (Twitter is going bananas)')
            raise NetworkBadStatusLineError
        except socketError:   # That's the worst exception ever.
            _log.error('Socket connection error')
            raise NetworkLowLevelError
        # TODO: Permission denied?

        # Introduced in Twitter in 2009.03.27
        response_headers = response.info()
        if 'X-RateLimit-Remaining' in response_headers:
            self._rate_limit = int(response_headers['X-RateLimit-Remaining'])
            _log.debug('Remaning hits: %d', self._rate_limit)
        elif 'x-ratelimit-remaining' in response_headers:
            self._rate_limit = int(response_headers['x-ratelimit-remaining'])
            _log.debug('Remaning hits: %d', self._rate_limit)
        else:
            self._rate_limit = None

        _log.debug('Request completed')
        _log.debug('info(%s): %s', type(response.info()), response.info())

        return json.loads(data)

    #
    # New network style methods
    #
    
    AUTH = [
                {'name': 'username',
                 'flags': ['-u', '--username'],
                 'prompt': 'Username',
                 'help': 'Your twitter username',
                 'type': 'str'},
                {'name': 'password',
                 'flags': ['-p', '--password'],
                 'prompt': 'Password',
                 'help': 'Your twitter password',
                 'type': 'passwd'}]

    @classmethod
    def options(self, options):
        """Add options related to Twitter."""
        options.add_group(self.NAMESPACE, 'Twitter network')
        options.add_option('-s', '--no-https',
                group=self.NAMESPACE,
                option='https',
                default=True,   # Secure connections by default
                help='Disable HTTPS (secure) connection with Twitter.',
                action='store_false')
        options.add_option(
                group=self.NAMESPACE,
                option='last_tweet',
                default=0,
                is_cmd_option=False)
        options.add_option(
                group=self.NAMESPACE,
                option='last_reply',
                default=0,
                is_cmd_option=False)
        options.add_option(
                group=self.NAMESPACE,
                option='server_url',
                default='http://twitter.com',
                is_cmd_option=False)
        options.add_option(
                group=self.NAMESPACE,
                option='secure_server_url',
                default='https://twitter.com',
                is_cmd_option=False)
        auth_options(self.NAMESPACE, options, self.AUTH)
        return

    def _timeline(self, config_var, url):
        """Request one of the lists of tweets."""
        last_id = int(self._options[self.NAMESPACE][config_var])
        _log.debug('%s: %d', config_var, last_id)

        params = {}

        if last_id > 0:
            params['since_id'] = last_id

        page = 1
        result = []
        response = [0]  # So we stay in the loop.
        high_id = 0

        while response: # Not the cleanest code
            if page > 1:
                params['page'] = page

            final_url = '?'.join([url, urllib.urlencode(params)])
            response = self._request(final_url)

            _log.debug('Page %d, %d results', page, len(response))

            if response:
                # extract the highest id in the respone and save it so we can
                # use it when requesting data again (using the since_id
                # parameter)

                top_tweet_id = response[0]['id']
                _log.debug('Top tweet: %d; Highest seen tweet: %d',
                    top_tweet_id, high_id)

                if top_tweet_id > high_id:
                    high_id = top_tweet_id

                result.extend(_make_datetime(response))
                page += 1   # Request the next page

            if last_id == 0:
                # do not try to download everything if we don't have a
                # previous list (or we'll blow the available requests in one
                # short)
                break

        # only update the "last seen id" if everything goes alright
        if high_id > int(self._options[self.NAMESPACE][config_var]):
            _log.debug('Last tweet updated: %d', high_id)
            self._options[self.NAMESPACE][config_var] = high_id

        return result

    def messages(self):
        """Return a list of NetworkData objects for the main "timeline"."""
        return self._timeline('last_tweet', '/statuses/friends_timeline.json')

    def message(self, message_id):
        """Retrieves the information of one message."""
        response = self._request('/statuses/show/%d.json' % (message_id))
        return TwitterNetworkData(response)

    def replies(self):
        """Return a list of NetworkData objects for the replies for the user
        messages."""
        return self._timeline('last_reply', '/statuses/replies.json')

    def available_requests(self):
        """Return the current user rate limit."""
        if self._rate_limit:
            return self._rate_limit

        data = self._request('/account/rate_limit_status.json')
        _log.debug('Requests: %s', data)
        return int(data['remaining_hits'])


    def update(self, status, reply_to=None):
        """Update the user status."""
        if len(status) > 140:
            warnings.warn('Message too long', MessageTooLongWarning)

        # In Python 2.5, urllib.urlencode calls str(), which removes the
        # unicodeness of the "status". So we need to convert those peski
        # accents to HTML entities, so everything falls into ASCII.

        body = {
            'status': _htmlize(status),
            'source': 'mitter'}

        if reply_to:
            if isinstance(reply_to, NetworkData):
                body['in_reply_to_status_id'] = reply_to.id

                # This is to protect the user from himself. You don't *need*
                # to start a reply with a @<username>, but it looks really
                # confusing in the Twiter website. So if the line doesn't
                # start with the username of the original user, we add it
                # for the user.

                if not status.startswith('@' + reply_to.username):
                    body['status'] = '@' + reply_to.username + ' ' + \
                            status
            else:
                body['in_reply_to_status_id'] = reply_to

        _log.debug('Body: %s', body)
        body = urllib.urlencode(body)
        _log.debug('Message to twitter: %s' % (body))

        data = self._request('/statuses/update.json', body=body)
        # TODO: Check if twitter sends an error message when the message is
        #       too large.
        return TwitterNetworkData(data)

    def delete_message(self, message):
        """Delete a message."""
        if isinstance(message, NetworkData):
            message = message.id    # We don't need anything else for Twitter

        # make a body, so _request makes it a post.
        body = urllib.urlencode({'id': message})
        resource = '/statuses/destroy/%s.json' % (message)
        response = self._request(resource, body=body)
        _log.debug('Delete response: %s', response)
        return response