wot.py

import fcp
from mercurial import util
from config import Config
import xml.etree.ElementTree as ET
from defusedxml.ElementTree import fromstring
import smtplib
import atexit
from keys import USK
import yaml
from email.mime.text import MIMEText
import imaplib
from wot_id import Local_WoT_ID, WoT_ID

# TODO: Instead of fcpport and fcphost, functions should accept a node

# synchronize with __init__.py
FREEMAIL_SMTP_PORT = 4025
FREEMAIL_IMAP_PORT = 4143
VCS_TOKEN = "[vcs]"
# "infocalypse" is lower case in case it is used somewhere mixed case can
# cause problems like a filesystem path. Used for machine-readable VCS name.
VCS_NAME = "infocalypse"


def send_pull_request(ui, repo, from_identity, to_identity, to_repo_name, mailhost=None, smtpport=None):
    """
    Prompt for a pull request message, and send a pull request from
    from_identity to to_identity for the repository to_repo_name.

    :type to_identity: WoT_ID
    :type from_identity: Local_WoT_ID
    """
    from_address = require_freemail(from_identity)
    to_address = require_freemail(to_identity)

    cfg = Config.from_ui(ui)
    password = cfg.get_freemail_password(from_identity)

    to_repo = find_repo(ui, to_identity, to_repo_name)

    # TODO: Will there always be a request URI set in the config? What about
    # a path? The repo could be missing a request URI, if that URI is
    # set manually. We could check whether the default path is a
    # freenet path. We cannot be sure whether the request uri will
    # always be the uri we want to send the pull-request to, though:
    # It might be an URI we used to get some changes which we now want
    # to send back to the maintainer of the canonical repo.
    from_uri = cfg.get_request_uri(repo.root)
    # repo_context = repo['tip']
    # from_branch = repo_context.branch()

    # Use double-quoted scalars so that Unicode can be included. (Nicknames.)
    footer = yaml.dump({'request': 'pull',
                        'vcs': VCS_NAME,
                        'source': "freenet://" + from_uri, # + '#' + from_branch, # TODO: pulling from branch currently not supported with a freenet:// uri
                        'target': to_repo}, default_style='"',
                       explicit_start=True, explicit_end=True,
                       allow_unicode=True)

    # TODO: Break config sanity check and sending apart so that further
    # things can check config, prompt for whatever, then send.

    source_text = ui.edit("""

HG: Enter pull request message here. Lines beginning with 'HG:' are removed.
HG: The first line has "{0}" added before it in transit and is the subject.
HG: The second line is ignored.
HG: Subsequent lines are the body of the message.
""".format(VCS_TOKEN), str(from_identity))
    # TODO: Save message and load later in case sending fails.

    source_lines = source_text.splitlines()

    source_lines = [line for line in source_lines if not line.startswith('HG:')]

    if not ''.join(source_lines).strip():
        raise util.Abort("Empty pull request message.")

    # Body is third line and after.
    msg = MIMEText('\n'.join(source_lines[2:]) + footer)
    msg['Subject'] = VCS_TOKEN + ' ' + source_lines[0]
    msg['To'] = to_address
    msg['From'] = from_address

    host = mailhost or cfg.defaults['HOST']
    port = smtpport or FREEMAIL_SMTP_PORT
    smtp = smtplib.SMTP(host, port)
    smtp.login(from_address, password)
    # TODO: Catch exceptions and give nice error messages.
    smtp.sendmail(from_address, to_address, msg.as_string())

    ui.status("Pull request sent.\n")


def check_notifications(ui, local_identity, mailhost=None, imapport=None):
    """
    Check Freemail for local_identity and print information on any VCS
    messages received.

    :type local_identity: Local_WoT_ID
    """
    address = require_freemail(local_identity)

    # Log in and open inbox.
    cfg = Config.from_ui(ui)
    host = mailhost or cfg.defaults['HOST']
    port = imapport or FREEMAIL_IMAP_PORT
    imap = imaplib.IMAP4(host, port)
    imap.login(address, cfg.get_freemail_password(local_identity))
    imap.select()

    # Parenthesis to work around erroneous quotes:
    # http://bugs.python.org/issue917120
    reply_type, message_numbers = imap.search(None, '(SUBJECT %s)' % VCS_TOKEN)

    # imaplib returns numbers in a singleton string separated by whitespace.
    message_numbers = message_numbers[0].split()

    if not message_numbers:
        # TODO: Is aborting appropriate here? Should this be ui.status and
        # return?
        raise util.Abort("No notifications found.")

    # fetch() expects strings for both. Individual message numbers are
    # separated by commas. It seems desirable to peek because it's not yet
    # apparent that this is a [vcs] message with YAML.
    # Parenthesis to prevent quotes: http://bugs.python.org/issue917120
    status, subjects = imap.fetch(','.join(message_numbers),
                                  r'(body[header.fields Subject])')

    # Expecting 2 list items from imaplib for each message, for example:
    # ('5 (body[HEADER.FIELDS Subject] {47}', 'Subject: [vcs]  ...\r\n\r\n'),
    # ')',

    # Exclude closing parens, which are of length one.
    subjects = filter(lambda x: len(x) == 2, subjects)

    subjects = [x[1] for x in subjects]

    # Match message numbers with subjects; remove prefix and trim whitespace.
    subjects = dict((message_number, subject[len('Subject: '):].rstrip()) for
                    message_number, subject in zip(message_numbers, subjects))

    for message_number, subject in subjects.iteritems():
        status, fetched = imap.fetch(str(message_number),
                                     r'(body[text] '
                                     r'body[header.fields From)')

        # Expecting 3 list items, as with the subject fetch above.
        body = fetched[0][1]
        from_address = fetched[1][1][len('From: '):].rstrip()

        read_message_yaml(ui, from_address, subject, body)


def read_message_yaml(ui, from_address, subject, body):
    """
    Print information about the given message.
    """
    # Get consistent line endings.
    body = '\n'.join(body.splitlines())
    yaml_start = body.rfind('---\n')
    # The .join() does not add a trailing newline, and the end token might be
    # the last line.
    end_token = '...'
    yaml_end = body.rfind(end_token)

    cfg = Config.from_ui(ui)

    if not yaml_end == -1:
        # Better to point to the end of the end token, but don't confuse
        # failure.
        yaml_end += len(end_token)

    if yaml_start == -1 or yaml_end == -1:
        ui.status("Notification '%s' does not have a request.\n" % subject)
        return

    def require(field, request):
        if field not in request:
            ui.status("Notification '%s' has a properly formatted request "
                      "that does not include necessary information. ('%s')\n"
                      % (subject, field))
            return False
        return True

    try:
        request = yaml.safe_load(body[yaml_start:yaml_end])

        if not require('vcs', request) or not require('request', request):
            return
    except yaml.YAMLError, e:
        ui.status("Notification '%s' has a request but it is not properly"
                  " formatted. Details:\n%s\n" % (subject, e))
        return

    if request['vcs'] != VCS_NAME:
        ui.status("Notification '%s' is for '%s', not Infocalypse.\n"
                  % (subject, request['vcs']))
        return

    if request['request'] == 'pull':
        ui.status("Found pull request from '%s':\n" % from_address)
        separator = ('-' * len(subject)) + '\n'

        ui.status(separator)
        ui.status(subject[subject.find(VCS_TOKEN) + len(VCS_TOKEN):] + '\n')

        ui.status(separator)
        ui.status(body[:yaml_start] + '\n')
        ui.status(separator)

        ui.status("To accept this request, pull from: %s\n" %
                  (request['source'], ))
        # FIXME: request['target'] can be more up to date than the local listing? Maybe only when sending to myself.
        ui.status("               To your repository: %s\n" %
                  (cfg.get_repo_dir(request['target'])))
        ui.status("hg -R %s pull '%s'\n" % (request['source'], cfg.get_repo_dir(request['target'])))
        return

    ui.status("Notification '%s' has an unrecognized request of type '%s'"
              % (subject, request['request']))


def require_freemail(wot_identity):
    """
    Return the given identity's Freemail address.
    Abort with an error message if the given identity does not have a
    Freemail address / context.

    :type wot_identity: WoT_ID
    """
    if not wot_identity.freemail_address:
        raise util.Abort("{0} is not using Freemail.\n".format(wot_identity))

    return wot_identity.freemail_address


def update_repo_listing(ui, for_identity, fcphost=None, fcpport=None):
    """
    Insert list of repositories published by the given identity.

    :type for_identity: Local_WoT_ID
    """
    # TODO: Somehow store the edition, perhaps in ~/.infocalypse. WoT
    # properties are apparently not appropriate.

    cfg = Config.from_ui(ui)

    # TODO: WoT property containing repo list edition. Used when requesting.
    # Version number to support possible format changes.
    root = ET.Element('vcs', {'version': '0'})

    ui.status("Updating repo listing for '%s'\n" % for_identity)

    for request_uri in build_repo_list(ui, for_identity):
        repo = ET.SubElement(root, 'repository', {
            'vcs': VCS_NAME,
        })
        repo.text = request_uri

    # TODO: Nonstandard IP and port from cfg
    node = fcp.FCPNode(**get_fcpopts(fcphost=fcphost,
                                     fcpport=fcpport))
    atexit.register(node.shutdown)

    insert_uri = for_identity.insert_uri.clone()

    insert_uri.name = 'vcs'
    insert_uri.edition = cfg.get_repo_list_edition(for_identity)

    ui.status("Inserting with URI:\n{0}\n".format(insert_uri))
    uri = node.put(uri=str(insert_uri), mimetype='application/xml',
                   data=ET.tostring(root), priority=1)

    if uri is None:
        ui.warn("Failed to update repository listing.")
    else:
        ui.status("Updated repository listing:\n{0}\n".format(uri))
        cfg.set_repo_list_edition(for_identity, USK(uri).edition)
        Config.to_file(cfg)


def build_repo_list(ui, for_identity):
    """
    Return a list of request URIs to repos for the given local identity.

    :type for_identity: Local_WoT_ID
    :param ui: to provide feedback
    :param for_identity: local WoT identity to list repos for.
    """
    config = Config.from_ui(ui)

    repos = []

    # Add request URIs associated with the given identity.
    for request_uri in config.request_usks.itervalues():
        if config.get_wot_identity(request_uri) == for_identity.identity_id:
            repos.append(request_uri)

    return repos


def find_repo(ui, identity, repo_name):
    """
    Return a request URI for a repo of the given name published by an
    identity matching the given identifier.
    Raise util.Abort if unable to read repo listing or a repo by that name
    does not exist.

    :type identity: WoT_ID
    """
    listing = read_repo_listing(ui, identity)

    if repo_name not in listing:
        raise util.Abort("{0} does not publish a repo named '{1}'\n"
                         .format(identity, repo_name))
    r = listing[repo_name]
    ui.status("Using repository {}\n".format(r))

    return r


def read_repo_listing(ui, identity, fcphost=None, fcpport=None):
    """
    Read a repo listing for a given identity.
    Return a dictionary of repository request URIs keyed by name.

    :type identity: WoT_ID
    
    TODO: get host and port from config
    """
    cfg = Config.from_ui(ui)
    uri = identity.request_uri.clone()
    uri.name = 'vcs'
    uri.edition = cfg.get_repo_list_edition(identity)

    # TODO: Set and read vcs edition property.
    ui.status("Fetching.\n")
    mime_type, repo_xml, msg = fetch_edition(uri, fcphost=fcphost, fcpport=fcpport)
    ui.status("Fetched {0}.\n".format(uri))

    cfg.set_repo_list_edition(identity, uri.edition)
    Config.to_file(cfg)

    repositories = {}
    ambiguous = []
    root = fromstring(repo_xml)
    for repository in root.iterfind('repository'):
        if repository.get('vcs') == VCS_NAME:
            uri = USK(repository.text)
            name = uri.get_repo_name()
            if name not in repositories:
                repositories[name] = uri
            else:
                existing = repositories[name]
                if uri.key == existing.key and uri.name == existing.name:
                    # Different edition of same key and complete name.
                    # Use the latest edition.
                    if uri.edition > existing.edition:
                        repositories[name] = uri
                else:
                    # Different key or complete name. Later remove and give
                    # warning.
                    ambiguous.append(name)

    for name in ambiguous:
        # Same repo name but different key or exact name.
        ui.warn("\"{0}\" refers ambiguously to multiple paths. Ignoring.\n"
                .format(name))
        del repositories[name]

    # TODO: Would it make sense to mention those for which multiple editions
    # are specified? It has no practical impact from this perspective,
    # and these problems should be pointed out (or prevented) for local repo
    # lists.

    for name in repositories.iterkeys():
        ui.status("Found repository \"{0}\".\n".format(name))

    # Convert values from USKs to strings - USKs are not expected elsewhere.
    for key in repositories.keys():
        repositories[key] = str(repositories[key])

    return repositories


def fetch_edition(uri, fcphost=None, fcpport=None):
    """
    Fetch a USK uri, following redirects. Change the uri edition to the one
    fetched.
    :type uri: USK
    """
    node = fcp.FCPNode(**get_fcpopts(fcphost=fcphost,
                                     fcpport=fcpport))
    atexit.register(node.shutdown)
    # Following a redirect automatically does not provide the edition used,
    # so manually following redirects is required.
    # TODO: Is there ever legitimately more than one redirect?
    try:
        return node.get(str(uri), priority=1)
    except fcp.FCPGetFailed, e:
        # Error code 27 is permanent redirect: there's a newer edition of
        # the USK.
        # https://wiki.freenetproject.org/FCPv2/GetFailed#Fetch_Error_Codes
        if not e.info['Code'] == 27:
            raise

        uri.edition = USK(e.info['RedirectURI']).edition

        return node.get(str(uri), priority=1)


def get_fcpopts(fcphost=None, fcpport=None):
    """
    Get the minimal FCP opts.

    TODO: Retrieve defaults from setup.
    """
    fcpopts = {}
    if fcphost:
        fcpopts["host"] = fcphost
    if fcpport:
        fcpopts["port"] = fcpport
    return fcpopts

    
def resolve_pull_uri(ui, path, truster, repo=None, fcphost=None, fcpport=None):
        """
        Return a pull URI for the given path.
        Print an error message and abort on failure.

        TODO: Is it appropriate to outline possible errors?
        Possible failures are being unable to fetch a repo list for the given
        identity, which may be a fetch failure or being unable to find the
        identity, and not finding the requested repo in the list.

        :type truster: Local_WoT_ID
        :param ui: For feedback.
        :param path: path describing a repo. nick@key/reponame
        :param truster: identity whose trust list to use.
        :param repo: If given, add a path that points to the resolved URI.
        :return: pull URI
        """
        # Expecting <id stuff>/reponame
        wot_id, repo_name = path.split('/', 1)
        identity = WoT_ID(wot_id, truster,
                          fcpopts=get_fcpopts(fcphost=fcphost,
                                              fcpport=fcpport))

        # TODO: How to handle redundancy? Does Infocalypse automatically try
        # an R0 if an R1 fails?

        request_uri = find_repo(ui, identity, repo_name)

        if repo:
            # TODO: Writing paths in this way preserves comments,
            # but does not allow dealing intelligently with paths of the same
            # name. Also it's duplicated in the clone support.
            ui.status("Adding this repository as path '{0}'. To pull from the "
                      "same repository in the future use this path.\n"
                      .format(identity.nickname))
            with repo.opener("hgrc", "a", text=True) as f:
                f.write("""
[paths]
{0} = freenet:{1}
""".format(identity.nickname, request_uri))

        return request_uri


def resolve_push_uri(ui, path, resolve_edition=True, fcphost=None, fcpport=None):
    """
    Return a push URI for the given path.
    Raise util.Abort if unable to resolve identity or repository.

    :param resolve_edition: Defaults to True. If False, skips resolving the
                            repository, uses the edition number 0. and does
                            not modify the repository name. This is useful
                            for finding a push URI for a repository that does
                            not already exist.
    :param ui: For feedback.
    :param path: path describing a repo - nick@key/repo_name,
    where the identity is a local one. (Such that the insert URI is known.)
    """
    # Expecting <id stuff>/repo_name
    wot_id, repo_name = path.split('/', 1)
    local_id = Local_WoT_ID(wot_id,
                            fcpopts=get_fcpopts(fcphost=fcphost,
                                                fcpport=fcpport))

    if resolve_edition:
        # TODO: find_repo should make it clearer that it returns a request URI,
        # and return a USK.
        repo = find_repo(ui, local_id, repo_name)

        # Request URI
        repo_uri = USK(repo)

        # Maintains name, edition.
        repo_uri.key = local_id.insert_uri.key

        return str(repo_uri)
    else:
        repo_uri = local_id.insert_uri.clone()

        repo_uri.name = repo_name
        repo_uri.edition = 0

        return str(repo_uri)


def execute_setup_wot(ui_, local_id):
    """
    Set WoT-related defaults.

    :type local_id: Local_WoT_ID
    """
    cfg = Config.from_ui(ui_)

    ui_.status("Setting default truster to {0}.\n".format(local_id))

    cfg.defaults['DEFAULT_TRUSTER'] = local_id.identity_id
    Config.to_file(cfg)


def execute_setup_freemail(ui, local_id, mailhost=None, smtpport=None):
    """
    Prompt for, test, and set a Freemail password for the identity.

    :type local_id: Local_WoT_ID
    """
    address = require_freemail(local_id)

    password = ui.getpass()
    if password is None:
        raise util.Abort("Cannot prompt for a password in a non-interactive "
                         "context.\n")

    ui.status("Checking password for {0}.\n".format(local_id))

    cfg = Config.from_ui(ui)
    host = mailhost or cfg.defaults['HOST']
    port = smtpport or FREEMAIL_SMTP_PORT
    
    # Check that the password works.
    try:
        # TODO: Is this the correct way to get the configured host?
        smtp = smtplib.SMTP(host, port)
        smtp.login(address, password)
    except smtplib.SMTPAuthenticationError, e:
        raise util.Abort("Could not log in with the given password.\nGot '{0}'\n"
                         .format(e.smtp_error))
    except smtplib.SMTPConnectError, e:
        raise util.Abort("Could not connect to server.\nGot '{0}'\n"
                         .format(e.smtp_error))

    cfg.set_freemail_password(local_id, password)
    Config.to_file(cfg)
    ui.status("Password set.\n")