#!/usr/bin/env python

"""
 (c) 2015 - Copyright Red Hat Inc

 Authors:
   Pierre-Yves Chibon <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 datetime
import logging
import os
import urlparse

import trollius
import trollius_redis

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
import pagure.lib
from pagure.exceptions import PagureEvException

SERVER = None

def get_obj_from_path(path):
    """ Return the Ticket or Request object based on the path provided.
    """
    username = None
    try:
        if path.startswith('/fork'):
            username, repo, obj, objid = path.split('/')[2:6]
        else:
            repo, obj, objid = path.split('/')[1:4]
    except:
        raise PagureEvException("Invalid URL: %s" % path)

    repo = pagure.lib.get_project(pagure.SESSION, repo, user=username)

    if repo is None:
        raise PagureEvException("Project '%s' not found" % repo)

    output = None
    if obj == 'issue':
        if not repo.settings.get('issue_tracker', True):
            raise PagureEvException("No issue tracker found for this project")

        output = pagure.lib.search_issues(
            pagure.SESSION, repo, issueid=objid)

        if output is None or output.project != repo:
            raise PagureEvException("Issue '%s' not found" % objid)

        if output.private:
            # TODO: find a way to do auth
            raise PagureEvException(
                "This issue is private and you are not allowed to view it")
    elif obj == 'pull-request':
        if not repo.settings.get('pull_requests', True):
            raise PagureEvException(
                "No pull-request tracker found for this project")

        output = pagure.lib.search_pull_requests(
            pagure.SESSION, project_id=repo.id, requestid=objid)

        if output is None or output.project != repo:
            raise PagureEvException("Pull-Request '%s' not found" % objid)

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

    return output


@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())

    connection = yield trollius.From(trollius_redis.Connection.create(
        host=pagure.APP.config['REDIS_HOST'],
        port=pagure.APP.config['REDIS_PORT'],
        db=pagure.APP.config['REDIS_DB']))

    try:

        # Create subscriber.
        subscriber = yield trollius.From(connection.start_subscribe())

        # Subscribe to channel.
        yield trollius.From(subscriber.subscribe(['pagure.%s' % obj.uid]))

        # Inside a while loop, wait for incoming events.
        while True:
            reply = yield trollius.From(subscriber.next_published())
            #print(u'Received: ', repr(reply.value), u'on channel', reply.channel)
            log.info(reply)
            log.info("Sending %s", reply.value)
            client_writer.write(('data: %s\n\n' % reply.value).encode())
            yield trollius.From(client_writer.drain())

    except trollius.ConnectionResetError as err:
        log.exception("ERROR: ConnectionResetError in handle_client")
    except Exception as err:
        log.exception("ERROR: Exception in handle_client")
    finally:
        # Wathever happens, close the connection.
        connection.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)
        pass
    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 as err:
        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()