#!/usr/bin/python
#
# Copyright (C) 2010, Nokia <jean-luc.lamadon@nokia.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
#
from gi.repository import Gio
from gi.repository import GLib
from gi.repository import GObject
import os
import sys
import subprocess
import time
import re

import configuration as cfg
import options

class NoMetadataException (Exception):
    pass

REASONABLE_TIMEOUT = 30

def log (message):
    if options.is_verbose ():
        print (message)

class Helper:
    """
    Abstract helper for Tracker processes. Launches the process manually
    and waits for it to appear on the session bus.

    The helper will fail if the process is already running. Use
    test-runner.sh to ensure the processes run inside a separate DBus
    session bus.

    The process is watched using a timed GLib main loop source. If the process
    exits with an error code, the test will abort the next time the main loop
    is entered (or straight away if currently running the main loop). Tests
    that block waiting for results in time.sleep() won't benefit from this, but
    it works for those that use await_resource_inserted()/deleted() and others.
    """

    BUS_NAME = None
    PROCESS_NAME = None

    def __init__ (self):
        self.process = None
        self.available = False

        self.loop = GObject.MainLoop ()
        self.install_glib_excepthook(self.loop)

        self.bus = Gio.bus_get_sync(Gio.BusType.SESSION, None)

    def install_glib_excepthook(self, loop):
        """
        Handler to abort test if an exception occurs inside the GLib main loop.
        """
        old_hook = sys.excepthook
        def new_hook(etype, evalue, etb):
            old_hook(etype, evalue, etb)
            GLib.MainLoop.quit(loop)
            sys.exit()
        sys.excepthook = new_hook

    def _start_process (self):
        path = getattr (self,
                        "PROCESS_PATH",
                        os.path.join (cfg.EXEC_PREFIX, self.PROCESS_NAME))
        flags = getattr (self,
                         "FLAGS",
                         [])

        kws = {}

        if not options.is_verbose ():
            FNULL = open ('/dev/null', 'w')
            kws = { 'stdout': FNULL, 'stderr': FNULL }

        command = [path] + flags
        log ("Starting %s" % ' '.join(command))
        return subprocess.Popen ([path] + flags, **kws)

    def _bus_name_appeared(self, name, owner, data):
        log ("[%s] appeared in the bus as %s" % (self.PROCESS_NAME, owner))
        self.available = True
        self.loop.quit()

    def _bus_name_vanished(self, name, data):
        log ("[%s] disappeared from the bus" % self.PROCESS_NAME)
        self.available = False
        self.loop.quit()

    def _process_watch_cb (self):
        if self.process_watch_timeout == 0:
            # The GLib seems to call the timeout after we've removed it
            # sometimes, which causes errors unless we detect it.
            return False

        status = self.process.poll ()

        if status is None:
            return True    # continue
        elif status == 0 and not self.abort_if_process_exits_with_status_0:
            return True    # continue
        else:
            self.process_watch_timeout = 0
            raise Exception("%s exited with status: %i" % (self.PROCESS_NAME, status))

    def _timeout_on_idle_cb (self):
        log ("[%s] Timeout waiting... asumming idle." % self.PROCESS_NAME)
        self.loop.quit ()
        self.timeout_id = None
        return False

    def start (self):
        """
        Start an instance of process and wait for it to appear on the bus.
        """
        if self.process is not None:
            raise RuntimeError(
                "%s process already started" % self.PROCESS_NAME)

        self._bus_name_watch_id = Gio.bus_watch_name_on_connection(
            self.bus, self.BUS_NAME, Gio.BusNameWatcherFlags.NONE,
            self._bus_name_appeared, self._bus_name_vanished)
        self.loop.run()

        if options.is_manual_start():
            print ("Start %s manually" % self.PROCESS_NAME)
        else:
            if self.available:
                # It's running, but we didn't start it...
                raise Exception ("Unable to start test instance of %s: "
                                 "already running " % self.PROCESS_NAME)

            self.process = self._start_process ()
            log ('[%s] Started process %i' % (self.PROCESS_NAME, self.process.pid))
            self.process_watch_timeout = GLib.timeout_add (200, self._process_watch_cb)

        self.abort_if_process_exits_with_status_0 = True

        # Run the loop until the bus name appears, or the process dies.
        self.loop.run ()

        self.abort_if_process_exits_with_status_0 = False

    def stop (self):
        if self.process is None:
            # Seems that it didn't even start...
            return

        start = time.time()
        if self.process.poll() == None:
            GLib.source_remove(self.process_watch_timeout)
            self.process_watch_timeout = 0

            self.process.terminate()

            while self.process.poll() == None:
                time.sleep(0.1)

                if time.time() > (start + REASONABLE_TIMEOUT):
                    log ("[%s] Failed to terminate, sending kill!" % self.PROCESS_NAME)
                    self.process.kill()
                    self.process.wait()

        log ("[%s] stopped." % self.PROCESS_NAME)

        # Run the loop until the bus name appears, or the process dies.
        self.loop.run ()
        Gio.bus_unwatch_name(self._bus_name_watch_id)

        self.process = None

    def kill (self):
        if options.is_manual_start():
            log ("kill(): ignoring, because process was started manually.")
            return

        self.process.kill ()

        # Name owner changed callback should take us out from this loop
        self.loop.run ()
        Gio.bus_unwatch_name(self._bus_name_watch_id)

        self.process = None

        log ("[%s] killed." % self.PROCESS_NAME)


class StoreHelper (Helper):
    """
    Wrapper for the Store API

    Every method tries to reconnect once if there is a dbus exception
    (some tests kill the daemon and make the connection useless)
    """

    PROCESS_NAME = "tracker-store"
    BUS_NAME = cfg.TRACKER_BUSNAME

    graph_updated_handler_id = 0

    def start (self):
        Helper.start (self)

        self.resources = Gio.DBusProxy.new_sync(
            self.bus, Gio.DBusProxyFlags.DO_NOT_AUTO_START, None,
            cfg.TRACKER_BUSNAME, cfg.TRACKER_OBJ_PATH, cfg.RESOURCES_IFACE)

        self.backup_iface = Gio.DBusProxy.new_sync(
            self.bus, Gio.DBusProxyFlags.DO_NOT_AUTO_START, None,
            cfg.TRACKER_BUSNAME, cfg.TRACKER_BACKUP_OBJ_PATH, cfg.BACKUP_IFACE)

        self.stats_iface = Gio.DBusProxy.new_sync(
            self.bus, Gio.DBusProxyFlags.DO_NOT_AUTO_START, None,
            cfg.TRACKER_BUSNAME, cfg.TRACKER_STATS_OBJ_PATH, cfg.STATS_IFACE)

        self.status_iface = Gio.DBusProxy.new_sync(
            self.bus, Gio.DBusProxyFlags.DO_NOT_AUTO_START, None,
            cfg.TRACKER_BUSNAME, cfg.TRACKER_STATUS_OBJ_PATH, cfg.STATUS_IFACE)

        log ("[%s] booting..." % self.PROCESS_NAME)
        self.status_iface.Wait ()
        log ("[%s] ready." % self.PROCESS_NAME)

        self.reset_graph_updates_tracking ()

        def signal_handler(proxy, sender_name, signal_name, parameters):
            if signal_name == 'GraphUpdated':
                self._graph_updated_cb(*parameters.unpack())

        self.graph_updated_handler_id = self.resources.connect(
            'g-signal', signal_handler)

    def stop (self):
        Helper.stop (self)

        if self.graph_updated_handler_id != 0:
            self.resources.disconnect(self.graph_updated_handler_id)

    # A system to follow GraphUpdated and make sure all changes are tracked.
    # This code saves every change notification received, and exposes methods
    # to await insertion or deletion of a certain resource which first check
    # the list of events already received and wait for more if the event has
    # not yet happened.

    def reset_graph_updates_tracking (self):
        self.inserts_list = []
        self.deletes_list = []
        self.inserts_match_function = None
        self.deletes_match_function = None
        self.graph_updated_timed_out = False

    def _graph_updated_timeout_cb (self):
        # Don't fail here, exceptions don't get propagated correctly
        # from the GMainLoop
        self.graph_updated_timed_out = True
        self.loop.quit ()

    def _graph_updated_cb (self, class_name, deletes_list, inserts_list):
        """
        Process notifications from tracker-store on resource changes.
        """
        exit_loop = False

        if inserts_list is not None:
            if self.inserts_match_function is not None:
                # The match function will remove matched entries from the list
                (exit_loop, inserts_list) = self.inserts_match_function (inserts_list)
            self.inserts_list += inserts_list

        if deletes_list is not None:
            if self.deletes_match_function is not None:
                (exit_loop, deletes_list) = self.deletes_match_function (deletes_list)
            self.deletes_list += deletes_list

        if exit_loop:
            GLib.source_remove(self.graph_updated_timeout_id)
            self.graph_updated_timeout_id = 0
            self.loop.quit ()

    def _enable_await_timeout (self):
        self.graph_updated_timeout_id = GLib.timeout_add_seconds (REASONABLE_TIMEOUT,
                                                                  self._graph_updated_timeout_cb)

    def await_resource_inserted (self, rdf_class, url = None, title = None, required_property = None):
        """
        Block until a resource matching the parameters becomes available
        """
        assert (self.inserts_match_function == None)

        self.matched_resource_urn = None
        self.matched_resource_id = None

        log ("Await new %s (%i existing inserts)" % (rdf_class, len (self.inserts_list)))

        if required_property is not None:
            required_property_id = self.get_resource_id_by_uri(required_property)
            log ("Required property %s id %i" % (required_property, required_property_id))

        def find_resource_insertion (inserts_list):
            matched_creation = (self.matched_resource_id is not None)
            matched_required_property = False
            remaining_events = []

            # FIXME: this could be done in an easier way: build one query that filters
            # based on every subject id in inserts_list, and returns the id of the one
            # that matched :)
            for insert in inserts_list:
                id = insert[1]

                if not matched_creation:
                    where = "  ?urn a %s " % rdf_class

                    if url is not None:
                        where += "; nie:url \"%s\"" % url

                    if title is not None:
                        where += "; nie:title \"%s\"" % title

                    query = "SELECT ?urn WHERE { %s FILTER (tracker:id(?urn) = %s)}" % (where, insert[1])
                    result_set = self.query (query)

                    if len (result_set) > 0:
                        matched_creation = True
                        self.matched_resource_urn = result_set[0][0]
                        self.matched_resource_id = insert[1]
                        log ("Matched creation of resource %s (%i)" %
                             (self.matched_resource_urn,
                              self.matched_resource_id))
                        if required_property is not None:
                            log ("Waiting for property %s (%i) to be set" %
                                 (required_property, required_property_id))

                if required_property is not None and matched_creation and not matched_required_property:
                    if id == self.matched_resource_id and insert[2] == required_property_id:
                        matched_required_property = True
                        log ("Matched %s %s" % (self.matched_resource_urn, required_property))

                if not matched_creation or id != self.matched_resource_id:
                    remaining_events += [insert]

            matched = matched_creation if required_property is None else matched_required_property
            return matched, remaining_events

        def match_cb (inserts_list):
            matched, remaining_events = find_resource_insertion (inserts_list)
            exit_loop = matched
            return exit_loop, remaining_events

        # Check the list of previously received events for matches
        (existing_match, self.inserts_list) = find_resource_insertion (self.inserts_list)

        if not existing_match:
            self._enable_await_timeout ()
            self.inserts_match_function = match_cb
            # Run the event loop until the correct notification arrives
            self.loop.run ()
            self.inserts_match_function = None

        if self.graph_updated_timed_out:
            raise Exception ("Timeout waiting for resource: class %s, URL %s, title %s" % (rdf_class, url, title))

        return (self.matched_resource_id, self.matched_resource_urn)

    def await_resource_deleted (self, id, fail_message = None):
        """
        Block until we are notified of a resources deletion
        """
        assert (self.deletes_match_function == None)

        def find_resource_deletion (deletes_list):
            log ("find_resource_deletion: looking for %i in %s" % (id, deletes_list))

            matched = False
            remaining_events = []

            for delete in deletes_list:
                if delete[1] == id:
                    matched = True
                else:
                    remaining_events += [delete]

            return matched, remaining_events

        def match_cb (deletes_list):
            matched, remaining_events = find_resource_deletion(deletes_list)
            exit_loop = matched
            return exit_loop, remaining_events

        log ("Await deletion of %i (%i existing)" % (id, len (self.deletes_list)))

        (existing_match, self.deletes_list) = find_resource_deletion (self.deletes_list)

        if not existing_match:
            self._enable_await_timeout ()
            self.deletes_match_function = match_cb
            # Run the event loop until the correct notification arrives
            self.loop.run ()
            self.deletes_match_function = None

        if self.graph_updated_timed_out:
            if fail_message is not None:
                raise Exception (fail_message)
            else:
                raise Exception ("Resource %i has not been deleted." % id)

        return

    def await_property_changed (self, subject_id, property_uri):
        """
        Block until a property of a resource is updated or inserted.
        """
        assert (self.inserts_match_function == None)

        property_id = self.get_resource_id_by_uri(property_uri)

        def find_property_change (inserts_list):
            matched = False
            remaining_events = []

            for insert in inserts_list:
                if insert[1] == subject_id and insert[2] == property_id:
                    log("Matched property change: %s" % str(insert))
                    matched = True
                else:
                    remaining_events += [insert]

            return matched, remaining_events

        def match_cb (inserts_list):
            matched, remaining_events = find_property_change (inserts_list)
            exit_loop = matched
            return exit_loop, remaining_events

        # Check the list of previously received events for matches
        (existing_match, self.inserts_list) = find_property_change (self.inserts_list)

        if not existing_match:
            self._enable_await_timeout ()
            self.inserts_match_function = match_cb
            # Run the event loop until the correct notification arrives
            self.loop.run ()
            self.inserts_match_function = None

        if self.graph_updated_timed_out:
            raise Exception ("Timeout waiting for property change, subject %i "
                             "property %s" % (subject_id, property_uri))

    def query (self, query, timeout=5000, **kwargs):
        return self.resources.SparqlQuery ('(s)', query, timeout=timeout, **kwargs)

    def update (self, update_sparql, timeout=5000, **kwargs):
        return self.resources.SparqlUpdate ('(s)', update_sparql, timeout=timeout, **kwargs)

    def batch_update (self, update_sparql, **kwargs):
        return self.resources.BatchSparqlUpdate ('(s)', update_sparql, **kwargs)

    def batch_commit (self, **kwargs):
        return self.resources.BatchCommit (**kwargs)

    def backup (self, backup_file, **kwargs):
        return self.backup_iface.Save ('(s)', backup_file, **kwargs)

    def restore (self, backup_file, **kwargs):
        return self.backup_iface.Restore ('(s)', backup_file, **kwargs)

    def get_stats (self, **kwargs):
        return self.stats_iface.Get(**kwargs)

    def get_tracker_iface (self):
        return self.resources

    def count_instances (self, ontology_class):
        QUERY = """
        SELECT COUNT(?u) WHERE {
            ?u a %s .
        }
        """
        result = self.resources.SparqlQuery ('(s)', QUERY % (ontology_class))

        if (len (result) == 1):
            return int (result [0][0])
        else:
            return -1

    def get_resource_id_by_uri(self, uri):
        """
        Get the internal ID for a given resource, identified by URI.
        """
        result = self.query(
            'SELECT tracker:id(%s) WHERE { }' % uri)
        if len(result) == 1:
            return int (result [0][0])
        elif len(result) == 0:
            raise Exception ("No entry for resource %s" % uri)
        else:
            raise Exception ("Multiple entries for resource %s" % uri)

    # FIXME: rename to get_resource_id_by_nepomuk_url !!
    def get_resource_id(self, url):
        """
        Get the internal ID for a given resource, identified by URL.
        """
        result = self.query(
            'SELECT tracker:id(?r) WHERE { ?r nie:url "%s" }' % url)
        if len(result) == 1:
            return int (result [0][0])
        elif len(result) == 0:
            raise Exception ("No entry for resource %s" % url)
        else:
            raise Exception ("Multiple entries for resource %s" % url)

    def ask (self, ask_query):
        assert ask_query.strip ().startswith ("ASK")
        result = self.query (ask_query)
        assert len (result) == 1
        if result[0][0] == "true":
            return True
        elif result[0][0] == "false":
            return False
        else:
            raise Exception ("Something fishy is going on")


class MinerFsHelper (Helper):

    PROCESS_NAME = 'tracker-miner-fs'
    PROCESS_PATH = os.path.join (cfg.EXEC_PREFIX, "tracker-miner-fs")
    BUS_NAME = cfg.MINERFS_BUSNAME

    FLAGS = ['--initial-sleep=0']

    def start (self):
        Helper.start (self)

        self.miner_fs = Gio.DBusProxy.new_sync(
            self.bus, Gio.DBusProxyFlags.DO_NOT_AUTO_START, None,
            cfg.MINERFS_BUSNAME, cfg.MINERFS_OBJ_PATH, cfg.MINER_IFACE)
        self.index = Gio.DBusProxy.new_sync(
            self.bus, Gio.DBusProxyFlags.DO_NOT_AUTO_START, None,
            cfg.MINERFS_BUSNAME, cfg.MINERFS_INDEX_OBJ_PATH, cfg.MINER_INDEX_IFACE)

    def stop (self):
        Helper.stop (self)

    def index_file (self, uri):
        return self.index.IndexFile('(s)', uri)


class ExtractorHelper (Helper):

    PROCESS_NAME = 'tracker-extract'
    BUS_NAME = cfg.TRACKER_EXTRACT_BUSNAME


class WritebackHelper (Helper):

    PROCESS_NAME = 'tracker-writeback'
    PROCESS_PATH = os.path.join (cfg.EXEC_PREFIX, 'tracker-writeback')
    BUS_NAME = cfg.WRITEBACK_BUSNAME
