#
# Copyright 2009, Martin Owens.
#
# 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/>
#
"""
Fake launchpad web browser for logging on and oauthorising and submitting
Things not available via the offical launchpad API.

Hopefully this can be removed when launchpad intergrates better.
"""

import os
import re
import logging
import urllib
import httplib2

from htmllib import HTMLParser
from formatter import NullFormatter
from socket import gethostname

from GroundControl.base import LAUNCHPAD_XDG, __stage__
from GroundControl.sshkeys import generate_key, generate_key_file

CACHE_DIR = LAUNCHPAD_XDG.get_cache_dir('website')
NORMAL_ROOT = 'https://launchpad.net/'

USER_REX = re.compile('href="\/~(?P<user>.*?)" ' +
    'class="sprite person">(?P<name>.*?)<\/a>')
SSH_REX  = re.compile('input type="hidden" name="key" ' +
    'value="(?P<id>\d*?)".*?<dd style="overflow: auto;">(?P<key>.*?)<',
    re.MULTILINE|re.DOTALL)
# This is for logging http requests for debug
REQLOG = """Request: %s / %s\nHeaders: '%s'\nBody: '%s'\n
Response: '%s'\nContent: '%s'"""

class NotLogedInError(KeyError):
    """What happens when your not logged in."""
    pass

class NoUsernameError(ValueError):
    """What happens when we don't have a valid username."""
    pass

class LoginFailedError(ValueError):
    """What happens when the web login fails."""
    pass

class KeyExistsError(ValueError):
    """What happens when there already is a launchpad ssh key uploaded."""
    pass

class GenerateError(ValueError):
    """A problem involving the generation of ssh keys."""
    pass

class PublicMissingError(ValueError):
    """The public half of an SSH key is missing from the local computer."""
    pass


class LaunchpadWeb(object):
    """Fake Launchpad Web Browser"""
    login_file = os.path.join(CACHE_DIR, "auth_login")
    session_file = os.path.join(CACHE_DIR, "session_login")

    def __init__(self, root=NORMAL_ROOT):
        self.address = root
        self.session = None
        self.user = None
        self.name = None
        self.get_session()
        self.sessions = {}
        self.http = httplib2.Http()

    def logoff(self):
        """Remove the session cookies and email file, reset object"""
        logging.debug("Removing Session File")
        os.unlink(self.session_file)
        self.previous_url = None
        self.name      = None
        self.user      = None
        self.session   = None
        self.sessions  = {}

    def set_session(self, session_key, write=True):
        """Set the session cookie to something interesting"""
        logging.debug("Setting session to '%s' (%s)" % (
            session_key, str(write)))
        self.session = session_key
        if write:
            logging.debug("Writing session to file '%s'" % (
                self.session_file))
            fhl = open(self.session_file, "w")
            fhl.write(self.session)
            fhl.close()

    def get_session(self, file=None):
        """Get the session cookie from a file"""
        if not file:
            file = self.session_file
        if os.path.exists(file):
            fhl = open(file, "r")
            logging.debug("Loading session from '%s'" % file)
            self.set_session(fhl.read(), write=False)
            fhl.close()

    def store_metadata(self, content):
        """Makes use of standard data about a logged in user"""
        rex = USER_REX.search(content)
        if rex:
            dict = rex.groupdict()
            self.user = dict['user']
            self.name = dict['name']
        else:
            logging.warn(_("Unable to generate data from content."))
            self.user = None
            self.name = None

    def loggedin(self):
        """Return true if the current state is logged in launchpad"""
        try:
            self.store_metadata(self.request(""))
        except NotLogedInError:
            return False
        return True

    def request_url(self, url):
        """Return a valid URL"""
        if '://' not in url:
            url = self.address + url
        return url

    def request(self, url, method='GET', data=None, user_required=True):
        """Make a launchpad request"""
        url = self.request_url(url)

        body = None
        headers = {}

        if self.session:
            headers['Cookie'] = self.session
            logging.debug("Feeding in cookie '%s'" % self.session)
        else:
            logging.debug("No cookie to feed in")

        http = httplib2.Http()
        if method == 'POST' and data:
            body = urllib.urlencode(data)
            headers['Content-type'] = 'application/x-www-form-urlencoded'
            headers['Referer'] = self.previous_url
            http.follow_redirects = False
        elif method == 'POST':
            method = 'GET'

        headers['User-Agent'] = 'Mozilla/5.0'

        response, content = http.request( url, method,
            headers=headers, body=body )
        self.previous_url = url

        # We're going to save the transaction
        if __stage__ in ['DEV', 'DEBUG']:
            import tempfile
            fhl = tempfile.NamedTemporaryFile(delete=False)
            fhl.write(REQLOG % (url, method, str(headers), body,
                str(response), str(content)))
            logging.debug("Request logged to '%s'" % fhl.name)
            fhl.close()
        else:
            logging.debug("Requesting '%s' via %s headers: '%s'"
                % (url, method, str(headers)) )

        # Save session cookies here, this doesn't check to see
        # if it's the right cookie, so possible future errors.
        if response.has_key('set-cookie'):
            logging.debug("Got cookie response")
            self.set_session(response['set-cookie'])

        if user_required and (content.find('+login') > 0
            or content.find('form name="login"') > 0):
            raise NotLogedInError("Launchpad web isn't logged in anymore.")
        elif user_required:
            logging.debug("User found - you are logged in")
        else:
            logging.debug("User wasn't required to be logged in")
        return content

    # EXTRA FUNCTIONS
    def user_request(self, url, method='GET', data=None):
        """Make a user specific request"""
        if not self.user:
            self.loggedin()
        return self.request("~%s/%s" % (self.user, url), method, data)

    def ssh_keys(self):
        """Return a list of stored ssh public keys.

        Note that the keys on Launchpad may be multiple lines so they must be
        joined and have the newlines stripped.
        """
        keys = self.user_request("+sshkeys").split("\n\n")
        return [key.replace('\n', '') for key in keys]

    def ssh_keys_dict(self):
        """Returns a dictionary of ssh keys with lp db ids as keys"""
        content = self.user_request("+editsshkeys")
        result = {}
        for rex in SSH_REX.findall(content):
            result[rex[0]] = rex[1]
        return result

    def add_ssh_key(self, key):
        """Add an SSH key to your launchpad account."""
        return self.user_request("+editsshkeys",
            method="POST",
            data={ 'action': 'add_ssh', 'sshkey': key })

    def del_ssh_key(self, lkey):
        """Remove an SSH key from the lp account."""
        pres = self.ssh_keys_dict()
        for kid, okey in pres.iteritems():
            if okey in lkey:
                logging.debug("Removing Key %s '%s'" % (kid, okey[-20]))
                return self.user_request("+editsshkeys",
                    method="POST",
                    data={ 'action': 'remove_ssh', 'key': kid })
            logging.debug("Key %s doesn't match: '%s' in '%s'" % (
                kid, okey[-10:], lkey[-25:]))
        return None

    def gen_key_filename(self):
        """Return the filename that we use for our ssh key"""
        return generate_key_file('launchpad')

    def has_gen_key(self, filename=None):
        """Returns true if we already have our generated key"""
        if not filename:
            filename = self.gen_key_filename()
        return os.path.exists(filename)

    def gen_ssh_key(self, passwd):
        """Generate a new ssh key and upload to launchpad."""
        # This should make a specific key just for launchpad for no conflict.
        logging.debug("Generating new SSH Key for Launchpad.")
        filename = self.gen_key_filename()
        if self.has_gen_key(filename):
            raise KeyExistsError("Launchpad SSH Key already exists - won't regenerate.")

        # The comment will identify the ssh key as generated for launchpad.
        username = os.environ.get("USER")
        cmnt = "%s@launchpad.%s" % (username, str(gethostname()))
        logging.debug("Key doesn't exist, creating: %s" % cmnt)

        if not generate_key(filename, passwd, comment=cmnt):
            raise GenerateError("Could not generate Launchpad key.")
        return self.upload_key(filename)

    def upload_key(self, filename=None):
        """Uploads a key to the server spcified by filesname"""
        if not filename:
            filename = self.gen_key_filename()
        if not ".pub" in filename:
            filename += ".pub"
        if os.path.exists(filename):
            logging.debug("Uploading %s to Launchpad." % filename)
            fhl = open(filename, "r")
            self.add_ssh_key(fhl.readline())
            fhl.close()
            logging.debug("Finished - key re-uploaded...")
            return True
        raise PublicMissingError("Public bit of SSH key missing: %s" % filename)


METHODS = {
  'submit' : 'GET',
  'post'   : 'POST',
}

class Form(object):
    """Parse a simple form"""
    def __init__(self, action=None, method=None, **attrs):
        self.inputs = {}
        self.submit = {}
        self.action = action
        self.attrs  = attrs
        self.method = METHODS[method.lower()]

    def add_input(self, name=None, value=None, **attrs):
        """Add an input to the form object."""
        atype = attrs.pop('type')
        if atype == 'submit':
            self.submit[name] = value
        else:
            self.inputs[name] = value

    def submit_data(self, name):
        """Submit data via this form it's self."""
        result = self.inputs.copy()
        if not self.submit.has_key(name):
            logging.error("Can't find submit button: %s from (%s)" % (
                name, ','.join(self.submit.keys())))
        else:
            result[name] = self.submit[name]
        return result


class FormParser(HTMLParser):
    """Parse an HTML form and manage requests."""
    lpmode = None
    def __init__(self, *opts, **attrs):
        HTMLParser.__init__(self, NullFormatter(), *opts, **attrs)
        self.forms = []

    def get_form(self, name):
        """Return the first instance that matches"""
        for pform in self.forms:
            if pform.attrs.has_key('name'):
                if pform.attrs['name'] == name:
                    return pform
        logging.warn("Can't find form %s" % name)

    def proc_fucked_up_attrs(self, attrs):
        """Process wrong headed attributes."""
        result = {}
        for attr in attrs:
            result[attr[0]] = attr[1]
        return result

    def do_form(self, attrs):
        """Form element processing."""
        attr = self.proc_fucked_up_attrs(attrs)
        self.forms.append(Form(**attr))

    def do_input(self, attrs):
        """Input element processing."""
        attr = self.proc_fucked_up_attrs(attrs)
        self.forms[-1].add_input(**attr)