# copyright 2003-2010 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
"""this module contains base classes and utilities for integration with running
http server
"""
__docformat__ = "restructuredtext en"

import random
import threading
import socket
import httplib
from urlparse import urlparse

from twisted.internet import reactor, error

from cubicweb.etwist.server import run
from cubicweb.devtools.testlib import CubicWebTC
from cubicweb.devtools import ApptestConfiguration


def get_available_port(ports_scan):
    """return the first available port from the given ports range

    Try to connect port by looking for refused connection (111) or transport
    endpoint already connected (106) errors

    Raise a RuntimeError if no port can be found

    :type ports_range: list
    :param ports_range: range of ports to test
    :rtype: int

    .. see:: :func:`test.test_support.bind_port`
    """
    ports_scan = list(ports_scan)
    random.shuffle(ports_scan)  # lower the chance of race condition
    for port in ports_scan:
        try:
            s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            sock = s.connect(("localhost", port))
        except socket.error as err:
            if err.args[0] in (111, 106):
                return port
        finally:
            s.close()
    raise RuntimeError('get_available_port([ports_range]) cannot find an available port')


class CubicWebServerConfig(ApptestConfiguration):
    """basic configuration class for configuring test server

    Class attributes:

    * `ports_range`: list giving range of http ports to test (range(7000, 8000)
      by default). The first port found as available in `ports_range` will be
      used to launch the test web server.

    """
    ports_range = range(7000, 8000)

    def default_base_url(self):
        port = self['port'] or get_available_port(self.ports_range)
        self.global_set_option('port', port) # force rewrite here
        return 'http://127.0.0.1:%d/' % self['port']

    def pyro_enabled(self):
        return False


class CubicWebServerTC(CubicWebTC):
    """Class for running test web server. See :class:`CubicWebServerConfig`.

    Class attributes:
    * `anonymous_allowed`: flag telling if anonymous browsing should be allowed
    """
    configcls = CubicWebServerConfig
    # anonymous is logged by default in cubicweb test cases
    anonymous_allowed = True

    def start_server(self):
        # use a semaphore to avoid starting test while the http server isn't
        # fully initilialized
        semaphore = threading.Semaphore(0)
        def safe_run(*args, **kwargs):
            try:
                run(*args, **kwargs)
            finally:
                semaphore.release()

        reactor.addSystemEventTrigger('after', 'startup', semaphore.release)
        t = threading.Thread(target=safe_run, name='cubicweb_test_web_server',
                             args=(self.config, self.vreg, True))
        self.web_thread = t
        t.start()
        semaphore.acquire()
        if not self.web_thread.isAlive():
            # XXX race condition with actual thread death
            raise RuntimeError('Could not start the web server')
        #pre init utils connection
        parseurl = urlparse(self.config['base-url'])
        assert parseurl.port == self.config['port'], (self.config['base-url'], self.config['port'])
        self._web_test_cnx = httplib.HTTPConnection(parseurl.hostname,
                                                    parseurl.port)
        self._ident_cookie = None

    def stop_server(self, timeout=15):
        """Stop the webserver, waiting for the thread to return"""
        if self._web_test_cnx is None:
            self.web_logout()
            self._web_test_cnx.close()
        try:
            reactor.stop()
            self.web_thread.join(timeout)
            assert not self.web_thread.isAlive()

        finally:
            reactor.__init__()

    def web_login(self, user=None, passwd=None):
        """Log the current http session for the provided credential

        If no user is provided, admin connection are used.
        """
        if user is None:
            user  = self.admlogin
            passwd = self.admpassword
        if passwd is None:
            passwd = user
        self.login(user)
        response = self.web_get("login?__login=%s&__password=%s" %
                                (user, passwd))
        assert response.status == httplib.SEE_OTHER, response.status
        self._ident_cookie = response.getheader('Set-Cookie')
        assert self._ident_cookie
        return True

    def web_logout(self, user='admin', pwd=None):
        """Log out current http user"""
        if self._ident_cookie is not None:
            response = self.web_get('logout')
        self._ident_cookie = None

    def web_request(self, path='', method='GET', body=None, headers=None):
        """Return an httplib.HTTPResponse object for the specified path

        Use available credential if available.
        """
        if headers is None:
            headers = {}
        if self._ident_cookie is not None:
            assert 'Cookie' not in headers
            headers['Cookie'] = self._ident_cookie
        self._web_test_cnx.request(method, '/' + path, headers=headers, body=body)
        response = self._web_test_cnx.getresponse()
        response.body = response.read() # to chain request
        response.read = lambda : response.body
        return response

    def web_get(self, path='', body=None, headers=None):
        return self.web_request(path=path, body=body, headers=headers)

    def setUp(self):
        super(CubicWebServerTC, self).setUp()
        self.start_server()

    def tearDown(self):
        try:
            self.stop_server()
        except error.ReactorNotRunning as err:
            # Server could be launched manually
            print err
        super(CubicWebServerTC, self).tearDown()

    @classmethod
    def init_config(cls, config):
        config.set_anonymous_allowed(cls.anonymous_allowed)
        super(CubicWebServerTC, cls).init_config(config)