# Copyright 2011-2012 Canonical Ltd.
#
# This file is part of u1db.
#
# u1db is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License version 3
# as published by the Free Software Foundation.
#
# u1db 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 u1db.  If not, see <http://www.gnu.org/licenses/>.
"""
Test infrastructure for U1DB
"""

import copy
import shutil
import socket
import tempfile
import threading
import json
import sys

from six import StringIO
from wsgiref import simple_server

import testscenarios
from twisted.trial import unittest
from twisted.web.server import Site
from twisted.web.wsgi import WSGIResource
from twisted.internet import reactor

from leap.soledad.common.l2db import errors
from leap.soledad.common.l2db import Document
from leap.soledad.common.l2db.backends import inmemory
from leap.soledad.common.l2db.backends import sqlite_backend
from leap.soledad.common.l2db.remote import server_state
from leap.soledad.common.l2db.remote import http_app
from leap.soledad.common.l2db.remote import http_target

if sys.version_info[0] < 3:
    from pysqlcipher import dbapi2
else:
    from pysqlcipher3 import dbapi2


class TestCase(unittest.TestCase):

    def createTempDir(self, prefix='u1db-tmp-'):
        """Create a temporary directory to do some work in.

        This directory will be scheduled for cleanup when the test ends.
        """
        tempdir = tempfile.mkdtemp(prefix=prefix)
        self.addCleanup(shutil.rmtree, tempdir)
        return tempdir

    def make_document(self, doc_id, doc_rev, content, has_conflicts=False):
        return self.make_document_for_test(
            self, doc_id, doc_rev, content, has_conflicts)

    def make_document_for_test(self, test, doc_id, doc_rev, content,
                               has_conflicts):
        return make_document_for_test(
            test, doc_id, doc_rev, content, has_conflicts)

    def assertGetDoc(self, db, doc_id, doc_rev, content, has_conflicts):
        """Assert that the document in the database looks correct."""
        exp_doc = self.make_document(doc_id, doc_rev, content,
                                     has_conflicts=has_conflicts)
        self.assertEqual(exp_doc, db.get_doc(doc_id))

    def assertGetDocIncludeDeleted(self, db, doc_id, doc_rev, content,
                                   has_conflicts):
        """Assert that the document in the database looks correct."""
        exp_doc = self.make_document(doc_id, doc_rev, content,
                                     has_conflicts=has_conflicts)
        self.assertEqual(exp_doc, db.get_doc(doc_id, include_deleted=True))

    def assertGetDocConflicts(self, db, doc_id, conflicts):
        """Assert what conflicts are stored for a given doc_id.

        :param conflicts: A list of (doc_rev, content) pairs.
            The first item must match the first item returned from the
            database, however the rest can be returned in any order.
        """
        if conflicts:
            conflicts = [(rev,
                          (json.loads(cont) if isinstance(cont, basestring)
                           else cont)) for (rev, cont) in conflicts]
            conflicts = conflicts[:1] + sorted(conflicts[1:])
        actual = db.get_doc_conflicts(doc_id)
        if actual:
            actual = [
                (doc.rev, (json.loads(doc.get_json())
                           if doc.get_json() is not None else None))
                for doc in actual]
            actual = actual[:1] + sorted(actual[1:])
        self.assertEqual(conflicts, actual)


def multiply_scenarios(a_scenarios, b_scenarios):
    """Create the cross-product of scenarios."""

    all_scenarios = []
    for a_name, a_attrs in a_scenarios:
        for b_name, b_attrs in b_scenarios:
            name = '%s,%s' % (a_name, b_name)
            attrs = dict(a_attrs)
            attrs.update(b_attrs)
            all_scenarios.append((name, attrs))
    return all_scenarios


simple_doc = '{"key": "value"}'
nested_doc = '{"key": "value", "sub": {"doc": "underneath"}}'


def make_memory_database_for_test(test, replica_uid):
    return inmemory.InMemoryDatabase(replica_uid)


def copy_memory_database_for_test(test, db):
    # DO NOT COPY OR REUSE THIS CODE OUTSIDE TESTS: COPYING U1DB DATABASES IS
    # THE WRONG THING TO DO, THE ONLY REASON WE DO SO HERE IS TO TEST THAT WE
    # CORRECTLY DETECT IT HAPPENING SO THAT WE CAN RAISE ERRORS RATHER THAN
    # CORRUPT USER DATA. USE SYNC INSTEAD, OR WE WILL SEND NINJA TO YOUR
    # HOUSE.
    new_db = inmemory.InMemoryDatabase(db._replica_uid)
    new_db._transaction_log = db._transaction_log[:]
    new_db._docs = copy.deepcopy(db._docs)
    new_db._conflicts = copy.deepcopy(db._conflicts)
    new_db._indexes = copy.deepcopy(db._indexes)
    new_db._factory = db._factory
    return new_db


def make_sqlite_partial_expanded_for_test(test, replica_uid):
    db = sqlite_backend.SQLitePartialExpandDatabase(':memory:')
    db._set_replica_uid(replica_uid)
    return db


def copy_sqlite_partial_expanded_for_test(test, db):
    # DO NOT COPY OR REUSE THIS CODE OUTSIDE TESTS: COPYING U1DB DATABASES IS
    # THE WRONG THING TO DO, THE ONLY REASON WE DO SO HERE IS TO TEST THAT WE
    # CORRECTLY DETECT IT HAPPENING SO THAT WE CAN RAISE ERRORS RATHER THAN
    # CORRUPT USER DATA. USE SYNC INSTEAD, OR WE WILL SEND NINJA TO YOUR
    # HOUSE.
    new_db = sqlite_backend.SQLitePartialExpandDatabase(':memory:')
    tmpfile = StringIO()
    for line in db._db_handle.iterdump():
        if 'sqlite_sequence' not in line:  # work around bug in iterdump
            tmpfile.write('%s\n' % line)
    tmpfile.seek(0)
    new_db._db_handle = dbapi2.connect(':memory:')
    new_db._db_handle.cursor().executescript(tmpfile.read())
    new_db._db_handle.commit()
    new_db._set_replica_uid(db._replica_uid)
    new_db._factory = db._factory
    return new_db


def make_document_for_test(test, doc_id, rev, content, has_conflicts=False):
    return Document(doc_id, rev, content, has_conflicts=has_conflicts)


LOCAL_DATABASES_SCENARIOS = [
    ('mem', {'make_database_for_test': make_memory_database_for_test,
             'copy_database_for_test': copy_memory_database_for_test,
             'make_document_for_test': make_document_for_test}),
    ('sql', {'make_database_for_test':
             make_sqlite_partial_expanded_for_test,
             'copy_database_for_test':
             copy_sqlite_partial_expanded_for_test,
             'make_document_for_test': make_document_for_test}),
]


class DatabaseBaseTests(TestCase):

    # set to True assertTransactionLog
    # is happy with all trans ids = ''
    accept_fixed_trans_id = False

    scenarios = LOCAL_DATABASES_SCENARIOS

    def make_database_for_test(self, replica_uid):
        return make_memory_database_for_test(self, replica_uid)

    def create_database(self, *args):
        return self.make_database_for_test(self, *args)

    def copy_database(self, db):
        # DO NOT COPY OR REUSE THIS CODE OUTSIDE TESTS: COPYING U1DB DATABASES
        # IS THE WRONG THING TO DO, THE ONLY REASON WE DO SO HERE IS TO TEST
        # THAT WE CORRECTLY DETECT IT HAPPENING SO THAT WE CAN RAISE ERRORS
        # RATHER THAN CORRUPT USER DATA. USE SYNC INSTEAD, OR WE WILL SEND
        # NINJA TO YOUR HOUSE.
        return self.copy_database_for_test(self, db)

    def setUp(self):
        super(DatabaseBaseTests, self).setUp()
        self.db = self.create_database('test')

    def tearDown(self):
        if hasattr(self, 'db') and self.db is not None:
            self.db.close()
        super(DatabaseBaseTests, self).tearDown()

    def assertTransactionLog(self, doc_ids, db):
        """Assert that the given docs are in the transaction log."""
        log = db._get_transaction_log()
        just_ids = []
        seen_transactions = set()
        for doc_id, transaction_id in log:
            just_ids.append(doc_id)
            self.assertIsNot(None, transaction_id,
                             "Transaction id should not be None")
            if transaction_id == '' and self.accept_fixed_trans_id:
                continue
            self.assertNotEqual('', transaction_id,
                                "Transaction id should be a unique string")
            self.assertTrue(transaction_id.startswith('T-'))
            self.assertNotIn(transaction_id, seen_transactions)
            seen_transactions.add(transaction_id)
        self.assertEqual(doc_ids, just_ids)

    def getLastTransId(self, db):
        """Return the transaction id for the last database update."""
        return self.db._get_transaction_log()[-1][-1]


class ServerStateForTests(server_state.ServerState):

    """Used in the test suite, so we don't have to touch disk, etc."""

    def __init__(self):
        super(ServerStateForTests, self).__init__()
        self._dbs = {}

    def open_database(self, path):
        try:
            return self._dbs[path]
        except KeyError:
            raise errors.DatabaseDoesNotExist

    def check_database(self, path):
        # cares only about the possible exception
        self.open_database(path)

    def ensure_database(self, path):
        try:
            db = self.open_database(path)
        except errors.DatabaseDoesNotExist:
            db = self._create_database(path)
        return db, db._replica_uid

    def _copy_database(self, db):
        # DO NOT COPY OR REUSE THIS CODE OUTSIDE TESTS: COPYING U1DB DATABASES
        # IS THE WRONG THING TO DO, THE ONLY REASON WE DO SO HERE IS TO TEST
        # THAT WE CORRECTLY DETECT IT HAPPENING SO THAT WE CAN RAISE ERRORS
        # RATHER THAN CORRUPT USER DATA. USE SYNC INSTEAD, OR WE WILL SEND
        # NINJA TO YOUR HOUSE.
        new_db = copy_memory_database_for_test(None, db)
        path = db._replica_uid
        while path in self._dbs:
            path += 'copy'
        self._dbs[path] = new_db
        return new_db

    def _create_database(self, path):
        db = inmemory.InMemoryDatabase(path)
        self._dbs[path] = db
        return db

    def delete_database(self, path):
        del self._dbs[path]


class ResponderForTests(object):

    """Responder for tests."""
    _started = False
    sent_response = False
    status = None

    def start_response(self, status='success', **kwargs):
        self._started = True
        self.status = status
        self.kwargs = kwargs

    def send_response(self, status='success', **kwargs):
        self.start_response(status, **kwargs)
        self.finish_response()

    def finish_response(self):
        self.sent_response = True


class TestCaseWithServer(TestCase):

    @staticmethod
    def server_def():
        # hook point
        # should return (ServerClass, "shutdown method name", "url_scheme")
        class _RequestHandler(simple_server.WSGIRequestHandler):

            def log_request(*args):
                pass  # suppress

        def make_server(host_port, application):
            assert application, "forgot to override make_app(_with_state)?"
            srv = simple_server.WSGIServer(host_port, _RequestHandler)
            # patch the value in if it's None
            if getattr(application, 'base_url', 1) is None:
                application.base_url = "http://%s:%s" % srv.server_address
            srv.set_app(application)
            return srv

        return make_server, "shutdown", "http"

    @staticmethod
    def make_app_with_state(state):
        # hook point
        return None

    def make_app(self):
        # potential hook point
        self.request_state = ServerStateForTests()
        return self.make_app_with_state(self.request_state)

    def setUp(self):
        super(TestCaseWithServer, self).setUp()
        self.server = self.server_thread = self.port = None

    def tearDown(self):
        if self.server is not None:
            self.server.shutdown()
            self.server_thread.join()
            self.server.server_close()
        if self.port:
            self.port.stopListening()
        super(TestCaseWithServer, self).tearDown()

    @property
    def url_scheme(self):
        return 'http'

    def startTwistedServer(self):
        application = self.make_app()
        resource = WSGIResource(reactor, reactor.getThreadPool(), application)
        site = Site(resource)
        self.port = reactor.listenTCP(0, site, interface='127.0.0.1')
        host = self.port.getHost()
        self.server_address = (host.host, host.port)
        self.addCleanup(self.port.stopListening)

    def startServer(self):
        server_def = self.server_def()
        server_class, shutdown_meth, _ = server_def
        application = self.make_app()
        self.server = server_class(('127.0.0.1', 0), application)
        self.server_thread = threading.Thread(target=self.server.serve_forever,
                                              kwargs=dict(poll_interval=0.01))
        self.server_thread.start()
        self.addCleanup(self.server_thread.join)
        self.addCleanup(getattr(self.server, shutdown_meth))
        self.server_address = self.server.server_address

    def getURL(self, path=None):
        host, port = self.server_address
        if path is None:
            path = ''
        return '%s://%s:%s/%s' % (self.url_scheme, host, port, path)


def socket_pair():
    """Return a pair of TCP sockets connected to each other.

    Unlike socket.socketpair, this should work on Windows.
    """
    sock_pair = getattr(socket, 'socket_pair', None)
    if sock_pair:
        return sock_pair(socket.AF_INET, socket.SOCK_STREAM)
    listen_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    listen_sock.bind(('127.0.0.1', 0))
    listen_sock.listen(1)
    client_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    client_sock.connect(listen_sock.getsockname())
    server_sock, addr = listen_sock.accept()
    listen_sock.close()
    return server_sock, client_sock


def load_with_scenarios(loader, standard_tests, pattern):
    """Load the tests in a given module.

    This just applies testscenarios.generate_scenarios to all the tests that
    are present. We do it at load time rather than at run time, because it
    plays nicer with various tools.
    """
    suite = loader.suiteClass()
    suite.addTests(testscenarios.generate_scenarios(standard_tests))
    return suite


# from u1db.tests.test_remote_sync_target

def make_http_app(state):
    return http_app.HTTPApp(state)


def http_sync_target(test, path):
    return http_target.HTTPSyncTarget(test.getURL(path))