# -*- coding: utf-8 -*-
#
# mercurial_keyring: save passwords in password database
#
# Copyright 2009 Marcin Kasperski <Marcin.Kasperski@mekk.waw.pl>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
#
# See README.txt for more details.

from mercurial import hg, repo, util
from mercurial.i18n import _
try:
    from mercurial.url import passwordmgr
except:
    from mercurial.httprepo import passwordmgr
from mercurial.httprepo import httprepository
from mercurial import mail

import keyring
from urlparse import urlparse
import urllib2
import smtplib, socket
import os

KEYRING_SERVICE = "Mercurial"

############################################################

def monkeypatch_method(cls):
    def decorator(func):
        setattr(cls, func.__name__, func)
        return func
    return decorator

############################################################

class PasswordStore(object):
    """
    Helper object handling keyring usage (password save&restore,
    the way passwords are keyed in the keyring).
    """
    def __init__(self):
        self.cache = dict()
    def get_http_password(self, url, username):
        return keyring.get_password(KEYRING_SERVICE,
                                    self._format_http_key(url, username))
    def set_http_password(self, url, username, password):
        keyring.set_password(KEYRING_SERVICE,
                             self._format_http_key(url, username),
                             password)
    def clear_http_password(self, url, username):
        self.set_http_password(url, username, "")
    def _format_http_key(self, url, username):
        return "%s@@%s" % (username, url)
    def get_smtp_password(self, machine, port, username):
        return keyring.get_password(
            KEYRING_SERVICE,
            self._format_smtp_key(machine, port, username))
    def set_smtp_password(self, machine, port, username, password):
        keyring.set_password(
            KEYRING_SERVICE,
            self._format_smtp_key(machine, port, username),
            password)
    def clear_smtp_password(self, machine, port, username):
        self.set_smtp_password(url, username, "")
    def _format_smtp_key(self, machine, port, username):
        return "%s@@%s:%s" % (username, machine, str(port))

password_store = PasswordStore()

############################################################

class HTTPPasswordHandler(object):
    """
    Actual implementation of password handling (user prompting,
    configuration file searching, keyring save&restore).

    Object of this class is bound as passwordmgr attribute.
    """
    def __init__(self):
        self.pwd_cache = {}
        self.last_reply = None
        
    def find_auth(self, pwmgr, realm, authuri):
        """
        Actual implementation of find_user_password - different
        ways of obtaining the username and password.
        """
        ui = pwmgr.ui

        # If we are called again just after identical previous
        # request, then the previously returned auth must have been
        # wrong. So we note this to force password prompt (and avoid
        # reusing bad password indifinitely).
        after_bad_auth = (self.last_reply \
                          and (self.last_reply['realm'] == realm) \
                          and (self.last_reply['authuri'] == authuri))
           
        # Strip arguments to get actual remote repository url.
        base_url = self.canonical_url(authuri)

        # Extracting possible username (or password)
        # stored directly in repository url
        user, pwd = urllib2.HTTPPasswordMgrWithDefaultRealm.find_user_password(
            pwmgr, realm, authuri)
        if user and pwd:
            self._debug_reply(ui, _("Auth data found in repository URL"), 
                              base_url, user, pwd)
            self.last_reply = dict(realm=realm,authuri=authuri,user=user)
            return user, pwd

        # Loading .hg/hgrc [auth] section contents. If prefix is given, 
        # it will be used as a key to lookup password in the keyring.
        auth_user, pwd, prefix_url = self.load_hgrc_auth(ui, base_url)
        if prefix_url:
            keyring_url = prefix_url
        else:
            keyring_url = base_url
        ui.debug("keyring URL: %s\n" % keyring_url)

        # Checking the memory cache (there may be many http calls per command)
        cache_key = (realm, keyring_url)
        if not after_bad_auth:
            cached_auth = self.pwd_cache.get(cache_key)
            if cached_auth:
                user, pwd = cached_auth
                self._debug_reply(ui, _("Cached auth data found"), 
                                  base_url, user, pwd)
                self.last_reply = dict(realm=realm,authuri=authuri,user=user)
                return user, pwd

        if auth_user:
            if user and (user != auth_user):
                raise util.Abort(_('mercurial_keyring: username for %s specified both in repository path (%s) and in .hg/hgrc/[auth] (%s). Please, leave only one of those' % (base_url, user, auth_user)))
            user = auth_user
            if pwd:
                self.pwd_cache[cache_key] = user, pwd
                self._debug_reply(ui, _("Auth data set in .hg/hgrc"), 
                                  base_url, user, pwd)
                self.last_reply = dict(realm=realm,authuri=authuri,user=user)
                return user, pwd
            else:
                ui.debug(_("Username found in .hg/hgrc: %s\n" % user))

        # Loading password from keyring. 
        # Only if username is known (so we know the key) and we are
        # not after failure (so we don't reuse the bad password).
        if user and not after_bad_auth:
            pwd = password_store.get_http_password(keyring_url, user)
            if pwd:
                self.pwd_cache[cache_key] = user, pwd
                self._debug_reply(ui, _("Keyring password found"), 
                                  base_url, user, pwd)
                self.last_reply = dict(realm=realm,authuri=authuri,user=user)
                return user, pwd
        
        # Is the username permanently set?
        fixed_user = (user and True or False)

        # Last resort: interactive prompt
        if not ui.interactive():
            raise util.Abort(_('mercurial_keyring: http authorization required but program used in non-interactive mode'))

        if not fixed_user:
            ui.status(_("Username not specified in .hg/hgrc. Keyring will not be used.\n"))
            
        ui.write(_("http authorization required\n"))
        ui.status(_("realm: %s\n") % realm)
        if fixed_user:
            ui.write(_("user: %s (fixed in .hg/hgrc)\n" % user))
        else:
            user = ui.prompt(_("user:"), default=None)
        pwd = ui.getpass(_("password: "))

        if fixed_user:
            # Saving password to the keyring.
            # It is done only if username is permanently set.
            # Otherwise we won't be able to find the password so it
            # does not make much sense to preserve it
            ui.debug("Saving password for %s to keyring\n" % user)
            password_store.set_http_password(keyring_url, user, pwd)

        # Saving password to the memory cache
        self.pwd_cache[cache_key] = user, pwd

        self._debug_reply(ui, _("Manually entered password"), 
                          base_url, user, pwd)
        self.last_reply = dict(realm=realm,authuri=authuri,user=user)
        return user, pwd

    def load_hgrc_auth(self, ui, base_url):
        """
        Loading [auth] section contents from local .hgrc

        Returns (username, password, prefix) tuple (every
        element can be None)
        """
        # Theoretically 3 lines below should do:
        
        #auth_token = self.readauthtoken(base_url)
        #if auth_token:
        #   user, pwd = auth.get('username'), auth.get('password')
        
        # Unfortunately they do not work, readauthtoken always return
        # None. Why? Because ui (self.ui of passwordmgr) describes the
        # *remote* repository, so does *not* contain any option from
        # local .hg/hgrc.

        # TODO: mercurial 1.4.2 is claimed to resolve this problem
        # (thanks to: http://hg.xavamedia.nl/mercurial/crew/rev/fb45c1e4396f) 
        # so since this version workaround implemented below should
        # not be necessary. As it will take some time until people
        # migrate to >= 1.4.2, it would be best to implement
        # workaround conditionally.
        
        # Workaround: we recreate the repository object
        repo_root = ui.config("bundle", "mainreporoot")

        from mercurial.ui import ui as _ui
        local_ui = _ui(ui)
        if repo_root:
            local_ui.readconfig(os.path.join(repo_root, ".hg", "hgrc"))
        local_passwordmgr = passwordmgr(local_ui)
        auth_token = local_passwordmgr.readauthtoken(base_url)
        if auth_token:
            username = auth_token.get('username')
            password = auth_token.get('password')
            prefix = auth_token.get('prefix')
            shortest_url = self.shortest_url(base_url, prefix)
            return username, password, shortest_url

        return None, None, None

    def shortest_url(self, base_url, prefix):
        if not prefix or prefix == '*':
            return base_url
        scheme, hostpath = base_url.split('://', 1)
        p = prefix.split('://', 1)
        if len(p) > 1:
            prefix_host_path = p[1]
        else:
            prefix_host_path = prefix
        shortest_url = scheme + '://' + prefix_host_path
        return shortest_url

    def canonical_url(self, authuri):
        """
        Strips query params from url. Used to convert urls like
        https://repo.machine.com/repos/apps/module?pairs=0000000000000000000000000000000000000000-0000000000000000000000000000000000000000&cmd=between
        to
        https://repo.machine.com/repos/apps/module
        """
        parsed_url = urlparse(authuri)
        return "%s://%s%s" % (parsed_url.scheme, parsed_url.netloc,
                              parsed_url.path)

    def _debug_reply(self, ui, msg, url, user, pwd):
        ui.debug("%s. Url: %s, user: %s, passwd: %s\n" % (
            msg, url, user, pwd and '*' * len(pwd) or 'not set'))

############################################################

@monkeypatch_method(passwordmgr)
def find_user_password(self, realm, authuri):
    """
    keyring-based implementation of username/password query
    for HTTP(S) connections

    Passwords are saved in gnome keyring, OSX/Chain or other platform
    specific storage and keyed by the repository url
    """
    # Extend object attributes
    if not hasattr(self, '_pwd_handler'):
        self._pwd_handler = HTTPPasswordHandler()

    return self._pwd_handler.find_auth(self, realm, authuri)

############################################################

def try_smtp_login(ui, smtp_obj, username, password):
    """
    Attempts smtp login on smtp_obj (smtplib.SMTP) using username and
    password. 

    Returns:
    - True if login succeeded
    - False if login failed due to the wrong credentials

    Throws Abort exception if login failed for any other reason.

    Immediately returns False if password is empty
    """
    if not password:
        return False
    try:
        ui.note(_('(authenticating to mail server as %s)\n') %
                 (username))
        smtp_obj.login(username, password)
        return True
    except smtplib.SMTPException, inst:
        if inst.smtp_code == 535:
            ui.status(_("SMTP login failed: %s\n\n") % inst.smtp_error)
            return False
        else:
            raise util.Abort(inst)

def keyring_supported_smtp(ui, username):
    """
    keyring-integrated replacement for mercurial.mail._smtp
    Used only when configuration file contains username, but
    does not contain the password.

    Most of the routine below is copied as-is from
    mercurial.mail._smtp. The only changed part is
    marked with #>>>>> and #<<<<< markers
    """
    local_hostname = ui.config('smtp', 'local_hostname')
    s = smtplib.SMTP(local_hostname=local_hostname)
    mailhost = ui.config('smtp', 'host')
    if not mailhost:
        raise util.Abort(_('no [smtp]host in hgrc - cannot send mail'))
    mailport = int(ui.config('smtp', 'port', 25))
    ui.note(_('sending mail: smtp host %s, port %s\n') %
            (mailhost, mailport))
    s.connect(host=mailhost, port=mailport)
    if ui.configbool('smtp', 'tls'):
        if not hasattr(socket, 'ssl'):
            raise util.Abort(_("can't use TLS: Python SSL support "
                               "not installed"))
        ui.note(_('(using tls)\n'))
        s.ehlo()
        s.starttls()
        s.ehlo()
        
    #>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
    stored = password = password_store.get_smtp_password(
        mailhost, mailport, username)
    # No need to check whether password was found as try_smtp_login
    # just returns False if it is absent.
    while not try_smtp_login(ui, s, username, password):
        password = ui.getpass(_("Password for %s on %s:%d: ") % (username, mailhost, mailport))

    if stored != password:
        password_store.set_smtp_password(
            mailhost, mailport, username, password)
    #<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

    def send(sender, recipients, msg):
        try:
            return s.sendmail(sender, recipients, msg)
        except smtplib.SMTPRecipientsRefused, inst:
            recipients = [r[1] for r in inst.recipients.values()]
            raise util.Abort('\n' + '\n'.join(recipients))
        except smtplib.SMTPException, inst:
            raise util.Abort(inst)

    return send

############################################################

orig_smtp = mail._smtp

@monkeypatch_method(mail)
def _smtp(ui):
    """
    build an smtp connection and return a function to send email

    This is the monkeypatched version of _smtp(ui) function from
    mercurial/mail.py. It calls the original unless username
    without password is given in the configuration.
    """
    username = ui.config('smtp', 'username')
    password = ui.config('smtp', 'password')

    if username and not password:
        return keyring_supported_smtp(ui, username)
    else:
        return orig_smtp(ui)