#!/usr/bin/env python

"""

 (c) 2015-2017 - Copyright Red Hat Inc

 Authors:

   Pierre-Yves Chibon <pingou@pingoured.fr></pingou@pingoured.fr>

Streaming server for pagure's eventsource feature

This server takes messages sent to redis and publish them at the specified

endpoint

To test, run this script and in another terminal

nc localhost 8080

  HELLO

  GET /test/issue/26?foo=bar HTTP/1.1

"""

import logging

import os

import urlparse

import redis

import trollius

log = logging.getLogger(__name__)

if 'PAGURE_CONFIG' not in os.environ \

        and os.path.exists('/etc/pagure/pagure.cfg'):

    print 'Using configuration file `/etc/pagure/pagure.cfg`'

    os.environ['PAGURE_CONFIG'] = '/etc/pagure/pagure.cfg'

import pagure  # noqa: E402

import pagure.lib  # noqa: E402

from pagure.exceptions import PagureEvException  # noqa: E402

SERVER = None

POOL = redis.ConnectionPool(

    host=pagure.APP.config['REDIS_HOST'],

    port=pagure.APP.config['REDIS_PORT'],

    db=pagure.APP.config['REDIS_DB'])

def _get_issue(repo, objid):

    """Get a Ticket (issue) instance for a given repo (Project) and

    objid (issue number).

    """

    issue = None

    if not repo.settings.get('issue_tracker', True):

        raise PagureEvException("No issue tracker found for this project")

    issue = pagure.lib.search_issues(

        pagure.SESSION, repo, issueid=objid)

    if issue is None or issue.project != repo:

        raise PagureEvException("Issue '%s' not found" % objid)

    if issue.private:

        # TODO: find a way to do auth

        raise PagureEvException(

            "This issue is private and you are not allowed to view it")

    return issue

def _get_pull_request(repo, objid):

    """Get a PullRequest instance for a given repo (Project) and objid

    (request number).

    """

    if not repo.settings.get('pull_requests', True):

        raise PagureEvException(

            "No pull-request tracker found for this project")

    request = pagure.lib.search_pull_requests(

        pagure.SESSION, project_id=repo.id, requestid=objid)

    if request is None or request.project != repo:

        raise PagureEvException("Pull-Request '%s' not found" % objid)

    return request

# Dict representing known object types that we handle requests for,

# and the bound functions for getting an object instance from the

# parsed path data. Has to come after the functions it binds

OBJECTS = {

    'issue': _get_issue,

    'pull-request': _get_pull_request

}

def _parse_path(path):

    """Get the repo name, object type, object ID, and (if present)

    username and/or namespace from a URL path component. Will only

    handle the known object types from the OBJECTS dict. Assumes:

    * Project name comes immediately before object type

    * Object ID comes immediately after object type

    * If a fork, path starts with /fork/(username)

    * Namespace, if present, comes after fork username (if present) or at start

    * No other components come before the project name

    * None of the parsed items can contain a /

    """

    username = None

    namespace = None

    # path always starts with / so split and throw away first item

    items = path.split('/')[1:]

    # find the *last* match for any object type

    try:

        objtype = [item for item in items if item in OBJECTS][-1]

    except IndexError:

        raise PagureEvException(

            "No known object type found in path: %s" % path)

    try:

        # objid is the item after objtype, we need all items up to it

        items = items[:items.index(objtype) + 2]

        # now strip the repo, objtype and objid off the end

        (repo, objtype, objid) = items[-3:]

        items = items[:-3]

    except (IndexError, ValueError):

        raise PagureEvException(

            "No project or object ID found in path: %s" % path)

    # now check for a fork

    if items and items[0] == 'fork':

        try:

            # get the username and strip it and 'fork'

            username = items[1]

            items = items[2:]

        except IndexError:

            raise PagureEvException(

                "Path starts with /fork but no user found! Path: %s" % path)

    # if we still have an item left, it must be the namespace

    if items:

        namespace = items.pop(0)

    # if we have any items left at this point, we've no idea

    if items:

        raise PagureEvException(

            "More path components than expected! Path: %s" % path)

    return username, namespace, repo, objtype, objid

def get_obj_from_path(path):

    """ Return the Ticket or Request object based on the path provided.

    """

    (username, namespace, reponame, objtype, objid) = _parse_path(path)

    repo = pagure.get_authorized_project(

            pagure.SESSION, reponame, user=username, namespace=namespace)

    if repo is None:

        raise PagureEvException("Project '%s' not found" % reponame)

    # find the appropriate object getter function from OBJECTS

    try:

        getfunc = OBJECTS[objtype]

    except KeyError:

        raise PagureEvException("Invalid object provided: '%s'" % objtype)

    return getfunc(repo, objid)

@trollius.coroutine

def handle_client(client_reader, client_writer):

    data = None

    while True:

        # give client a chance to respond, timeout after 10 seconds

        line = yield trollius.From(trollius.wait_for(

            client_reader.readline(),

            timeout=10.0))

        if not line.decode().strip():

            break

        line = line.decode().rstrip()

        if data is None:

            data = line

    if data is None:

        log.warning("Expected ticket uid, received None")

        return

    data = data.decode().rstrip().split()

    log.info("Received %s", data)

    if not data:

        log.warning("No URL provided: %s" % data)

        return

    if '/' not in data[1]:

        log.warning("Invalid URL provided: %s" % data[1])

        return

    url = urlparse.urlsplit(data[1])

    try:

        obj = get_obj_from_path(url.path)

    except PagureEvException as err:

        log.warning(err.message)

        return

    origin = pagure.APP.config.get('APP_URL')

    if origin.endswith('/'):

        origin = origin[:-1]

    client_writer.write((

        "HTTP/1.0 200 OK\n"

        "Content-Type: text/event-stream\n"

        "Cache: nocache\n"

        "Connection: keep-alive\n"

        "Access-Control-Allow-Origin: %s\n\n" % origin

    ).encode())

    conn = redis.Redis(connection_pool=POOL)

    subscriber = conn.pubsub(ignore_subscribe_messages=True)

    try:

        subscriber.subscribe('pagure.%s' % obj.uid)

        # Inside a while loop, wait for incoming events.

        oncall = 0

        while True:

            msg = subscriber.get_message()

            if msg is None:

                # Send a ping to see if the client is still alive

                if oncall >= 5:

                    # Only send a ping once every 5 seconds

                    client_writer.write(('event: ping\n\n').encode())

                    oncall = 0

                oncall += 1

                yield trollius.From(client_writer.drain())

                yield trollius.From(trollius.sleep(1))

            else:

                log.info("Sending %s", msg['data'])

                client_writer.write(('data: %s\n\n' % msg['data']).encode())

                yield trollius.From(client_writer.drain())

    except OSError:

        log.info("Client closed connection")

    except trollius.ConnectionResetError as err:

        log.exception("ERROR: ConnectionResetError in handle_client")

    except Exception as err:

        log.exception("ERROR: Exception in handle_client")

        log.info(type(err))

    finally:

        # Wathever happens, close the connection.

        log.info("Client left. Goodbye!")

        subscriber.close()

        client_writer.close()

@trollius.coroutine

def stats(client_reader, client_writer):

    try:

        log.info('Clients: %s', SERVER.active_count)

        client_writer.write((

            "HTTP/1.0 200 OK\n"

            "Cache: nocache\n\n"

        ).encode())

        client_writer.write(('data: %s\n\n' % SERVER.active_count).encode())

        yield trollius.From(client_writer.drain())

    except trollius.ConnectionResetError as err:

        log.info(err)

    finally:

        client_writer.close()

    return

def main():

    global SERVER

    try:

        loop = trollius.get_event_loop()

        coro = trollius.start_server(

            handle_client,

            host=None,

            port=pagure.APP.config['EVENTSOURCE_PORT'],

            loop=loop)

        SERVER = loop.run_until_complete(coro)

        log.info(

            'Serving server at {}'.format(SERVER.sockets[0].getsockname()))

        if pagure.APP.config.get('EV_STATS_PORT'):

            stats_coro = trollius.start_server(

                stats,

                host=None,

                port=pagure.APP.config.get('EV_STATS_PORT'),

                loop=loop)

            stats_server = loop.run_until_complete(stats_coro)

            log.info('Serving stats  at {}'.format(

                stats_server.sockets[0].getsockname()))

        loop.run_forever()

    except KeyboardInterrupt:

        pass

    except trollius.ConnectionResetError as err:

        log.exception("ERROR: ConnectionResetError in main")

    except Exception:

        log.exception("ERROR: Exception in main")

    finally:

        # Close the server

        SERVER.close()

        if pagure.APP.config.get('EV_STATS_PORT'):

            stats_server.close()

        log.info("End Connection")

        loop.run_until_complete(SERVER.wait_closed())

        loop.close()

        log.info("End")

if __name__ == '__main__':

    log = logging.getLogger("")

    formatter = logging.Formatter(

        "%(asctime)s %(levelname)s [%(module)s:%(lineno)d] %(message)s")

    # setup console logging

    log.setLevel(logging.DEBUG)

    ch = logging.StreamHandler()

    ch.setLevel(logging.DEBUG)

    aslog = logging.getLogger("asyncio")

    aslog.setLevel(logging.DEBUG)

    ch.setFormatter(formatter)

    log.addHandler(ch)

    main()