From 1d4a4142405fb6fa7b0f8815fbdf71b00e96c6ab Mon Sep 17 00:00:00 2001
From: Tim Bentley <tim.bentley@gmail.com>
Date: Sat, 20 Oct 2018 15:41:32 +0100
Subject: [PATCH] more state stuff

---
 openlp/core/app.py                            |   2 +
 openlp/core/lib/plugin.py                     |   6 +-
 openlp/core/loader.py                         |   3 +-
 openlp/core/state.py                          |  60 +++++++-
 openlp/core/ui/mainwindow.py                  |   1 -
 openlp/core/ui/media/mediacontroller.py       |  30 ++--
 .../core/ui/media/vendor/mediainfoWrapper.py  | 128 ------------------
 openlp/core/ui/media/vlcplayer.py             |   2 +-
 openlp/core/ui/slidecontroller.py             |  83 ++++++------
 openlp/plugins/alerts/alertsplugin.py         |   3 +
 openlp/plugins/bibles/bibleplugin.py          |   4 +-
 openlp/plugins/custom/customplugin.py         |   3 +
 openlp/plugins/images/imageplugin.py          |   3 +
 openlp/plugins/media/mediaplugin.py           |   3 +
 .../presentations/presentationplugin.py       |   3 +
 openlp/plugins/songs/lib/mediaitem.py         |   2 +-
 openlp/plugins/songs/songsplugin.py           |   3 +
 openlp/plugins/songusage/songusageplugin.py   |   3 +
 scripts/check_dependencies.py                 |   3 +-
 tests/functional/openlp_core/test_state.py    |  40 +++++-
 .../ui/media/test_mediacontroller.py          |  21 +++
 .../openlp_core/ui/media/__init__.py          |  21 ---
 .../openlp_core/ui/media/vendor/__init__.py   |  21 ---
 .../ui/media/vendor/test_mediainfoWrapper.py  |  48 -------
 24 files changed, 210 insertions(+), 286 deletions(-)
 delete mode 100644 openlp/core/ui/media/vendor/mediainfoWrapper.py
 delete mode 100644 tests/interfaces/openlp_core/ui/media/__init__.py
 delete mode 100644 tests/interfaces/openlp_core/ui/media/vendor/__init__.py
 delete mode 100644 tests/interfaces/openlp_core/ui/media/vendor/test_mediainfoWrapper.py

diff --git a/openlp/core/app.py b/openlp/core/app.py
index 66a821e09..b1077f1b0 100644
--- a/openlp/core/app.py
+++ b/openlp/core/app.py
@@ -35,6 +35,7 @@ from traceback import format_exception
 
 from PyQt5 import QtCore, QtWidgets
 
+from openlp.core.state import State
 from openlp.core.common import is_macosx, is_win
 from openlp.core.common.applocation import AppLocation
 from openlp.core.loader import loader
@@ -118,6 +119,7 @@ class OpenLP(QtWidgets.QApplication):
         self.main_window = MainWindow()
         Registry().execute('bootstrap_initialise')
         Registry().execute('bootstrap_post_set_up')
+        State().flush_preconditions()
         Registry().initialise = False
         self.main_window.show()
         if can_show_splash:
diff --git a/openlp/core/lib/plugin.py b/openlp/core/lib/plugin.py
index acb874119..c47ea5ced 100644
--- a/openlp/core/lib/plugin.py
+++ b/openlp/core/lib/plugin.py
@@ -24,11 +24,9 @@ Provide the generic plugin functionality for OpenLP plugins.
 """
 import logging
 
-from PyQt5 import QtCore
-
 from openlp.core.common.i18n import UiStrings
 from openlp.core.common.mixins import RegistryProperties
-from openlp.core.common.registry import Registry
+from openlp.core.common.registry import Registry, RegistryBase
 from openlp.core.common.settings import Settings
 from openlp.core.version import get_version
 
@@ -60,7 +58,7 @@ class StringContent(object):
     VisibleName = 'visible_name'
 
 
-class Plugin(QtCore.QObject, RegistryProperties):
+class Plugin(RegistryBase, RegistryProperties):
     """
     Base class for openlp plugins to inherit from.
 
diff --git a/openlp/core/loader.py b/openlp/core/loader.py
index 098e81dae..80c002172 100644
--- a/openlp/core/loader.py
+++ b/openlp/core/loader.py
@@ -25,6 +25,7 @@ The :mod:`~openlp.core.commmon.loader` module provides a bootstrap for the commo
 
 from openlp.core.state import State
 from openlp.core.ui.media import MediaController
+from openlp.core.lib.pluginmanager import PluginManager
 
 
 def loader():
@@ -34,5 +35,5 @@ def loader():
     :return: None
     """
     State().load_settings()
-
     MediaController()
+    PluginManager()
diff --git a/openlp/core/state.py b/openlp/core/state.py
index 934490d0a..cfcfd952e 100644
--- a/openlp/core/state.py
+++ b/openlp/core/state.py
@@ -28,13 +28,27 @@ logging and a plugin framework are contained within the openlp.core module.
 """
 import logging
 
+from openlp.core.common.mixins import LogMixin
 from openlp.core.lib.plugin import PluginStatus
 
 
 log = logging.getLogger()
 
 
-class State(object):
+class StateModule(LogMixin):
+    def __init__(self):
+        """
+        """
+        super(StateModule, self).__init__()
+        self.name = None
+        self.order = 0
+        self.status = PluginStatus.Inactive
+        self.pass_preconditions = True
+        self.requires = None
+        self.required_by = None
+
+
+class State(LogMixin):
 
     __instance__ = None
 
@@ -44,7 +58,6 @@ class State(object):
         """
         if not cls.__instance__:
             cls.__instance__ = object.__new__(cls)
-            cls.modules = {}
         return cls.__instance__
 
     def load_settings(self):
@@ -53,12 +66,47 @@ class State(object):
     def save_settings(self):
         pass
 
-    def add_service(self, name, order, status, dependance=None):
+    def add_service(self, name, order, status=PluginStatus.Active, requires=None):
+        """
+        Add a module to the array and lod dependancies.  There will only be one item per module
+        :param name: Module name
+        :param order: Order fo display
+        :param status: The active status
+        :param requires: Module name this requires
+        :return:
+        """
         if name not in self.modules:
-            self.modules[name] = {'order': order, 'status': status, 'depemdancy': dependance}
+            state = StateModule()
+            state.name = name
+            state.order = order
+            state.status = status
+            state.requires = requires
+            state.required_by = []
+            self.modules[name] = state
+            if requires and requires in self.modules:
+                if requires not in self.modules[requires].required_by:
+                    self.modules[requires].required_by.append(name)
 
-    def is_service_active(self, name):
-        return self.modules[name]['status'] == PluginStatus.Active
+    def update_pre_conditions(self, name, status):
+        """
+        Updates the preconditions state of a module
+        :param name: Module name
+        :param status: Module new status
+        :return:
+        """
+        self.modules[name].pass_preconditions = status
+
+    def flush_preconditions(self):
+        """
+        Now all modules are loaded lets update all the preconditions.
+        :return:
+        """
+        for mods in self.modules:
+            for req in self.modules[mods].required_by:
+                self.modules[mods].pass_preconditions = self.modules[req].pass_preconditions
+
+    def is_module_active(self, name):
+        return self.modules[name].status == PluginStatus.Active
 
     def check_active_dependency(self, name):
         pass
diff --git a/openlp/core/ui/mainwindow.py b/openlp/core/ui/mainwindow.py
index 592f48a04..41eee40db 100644
--- a/openlp/core/ui/mainwindow.py
+++ b/openlp/core/ui/mainwindow.py
@@ -506,7 +506,6 @@ class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow, LogMixin, RegistryPropert
         self.formatting_tag_form = FormattingTagForm(self)
         self.shortcut_form = ShortcutListForm(self)
         # Set up the path with plugins
-        PluginManager(self)
         ImageManager()
         Renderer()
         # Set up the interface
diff --git a/openlp/core/ui/media/mediacontroller.py b/openlp/core/ui/media/mediacontroller.py
index 7afabe3cb..ad75e143a 100644
--- a/openlp/core/ui/media/mediacontroller.py
+++ b/openlp/core/ui/media/mediacontroller.py
@@ -25,13 +25,20 @@ related to playing media, such as sliders.
 """
 import datetime
 import logging
-import os
+
+try:
+    import pymediainfo
+    pymediainfo_available = True
+except ImportError:
+    pymediainfo_available = False
+
+from subprocess import check_output
 
 from PyQt5 import QtCore, QtWidgets
 
+from openlp.core.state import State
 from openlp.core.api.http import register_endpoint
-from openlp.core.common import extension_loader
-from openlp.core.common.i18n import UiStrings, translate
+from openlp.core.common.i18n import translate
 from openlp.core.common.mixins import LogMixin, RegistryProperties
 from openlp.core.common.registry import Registry, RegistryBase
 from openlp.core.common.settings import Settings
@@ -41,9 +48,7 @@ from openlp.core.ui import DisplayControllerType
 from openlp.core.ui.icons import UiIcons
 from openlp.core.ui.media import MediaState, MediaInfo, MediaType, parse_optical_path
 from openlp.core.ui.media.endpoint import media_endpoint
-from openlp.core.ui.media.mediaplayer import MediaPlayer
-from openlp.core.ui.media.vlcplayer import VlcPlayer
-from openlp.core.ui.media.vendor.mediainfoWrapper import MediaInfoWrapper
+from openlp.core.ui.media.vlcplayer import VlcPlayer, get_vlc
 from openlp.core.widgets.toolbar import OpenLPToolbar
 
 log = logging.getLogger(__name__)
@@ -62,7 +67,6 @@ class MediaSlider(QtWidgets.QSlider):
         super(MediaSlider, self).__init__(direction)
         self.manager = manager
         self.controller = controller
-        self.no_matching_player = translate('MediaPlugin.MediaItem', 'File %s not supported using player %s')
 
     def mouseMoveEvent(self, event):
         """
@@ -193,6 +197,9 @@ class MediaController(RegistryBase, LogMixin, RegistryProperties):
         # self.register_players()
         self.setup()
         self.media_players = VlcPlayer(self)
+        State().add_service("mediacontroller", 0)
+        if get_vlc() and pymediainfo_available:
+            State().update_pre_conditions("mediacontroller", True)
         self._generate_extensions_lists()
         return True
 
@@ -460,7 +467,14 @@ class MediaController(RegistryBase, LogMixin, RegistryProperties):
         media_info = MediaInfo()
         media_info.volume = 0
         media_info.file_info = QtCore.QFileInfo(service_item.get_frame_path())
-        media_data = MediaInfoWrapper.parse(service_item.get_frame_path())
+        filename = service_item.get_frame_path()
+        if pymediainfo.MediaInfo.can_parse():
+            media_data = pymediainfo.MediaInfo.parse(filename)
+        else:
+            xml = check_output(['mediainfo', '-f', '--Output=XML', '--Inform=OLDXML', filename])
+            if not xml.startswith(b'<?xml'):
+                xml = check_output(['mediainfo', '-f', '--Output=XML', filename])
+            media_data = pymediainfo.MediaInfo(xml)
         # duration returns in milli seconds
         service_item.set_media_length(media_data.tracks[0].duration)
         return True
diff --git a/openlp/core/ui/media/vendor/mediainfoWrapper.py b/openlp/core/ui/media/vendor/mediainfoWrapper.py
deleted file mode 100644
index d28fe1395..000000000
--- a/openlp/core/ui/media/vendor/mediainfoWrapper.py
+++ /dev/null
@@ -1,128 +0,0 @@
-# -*- coding: utf-8 -*-
-# vim: autoindent shiftwidth=4 expandtab textwidth=120 tabstop=4 softtabstop=4
-
-###############################################################################
-# OpenLP - Open Source Lyrics Projection                                      #
-# --------------------------------------------------------------------------- #
-# Copyright (c) 2008-2018 OpenLP Developers                                   #
-# --------------------------------------------------------------------------- #
-# 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; version 2 of the License.                              #
-#                                                                             #
-# 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., 59  #
-# Temple Place, Suite 330, Boston, MA 02111-1307 USA                          #
-###############################################################################
-"""
-The :mod:`~openlp.core.ui.media.mediainfo` module contains code to run mediainfo on a media file and obtain
-information related to the rwquested media.
-"""
-import json
-import os
-from subprocess import check_output
-
-from bs4 import BeautifulSoup, NavigableString
-
-ENV_DICT = os.environ
-
-
-class Track(object):
-
-    def __getattribute__(self, name):
-        try:
-            return object.__getattribute__(self, name)
-        except:
-            pass
-        return None
-
-    def __init__(self, xml_dom_fragment):
-        self.xml_dom_fragment = xml_dom_fragment
-        self.track_type = xml_dom_fragment.attrs['type']
-        for el in self.xml_dom_fragment.children:
-            if not isinstance(el, NavigableString):
-                node_name = el.name.lower().strip().strip('_')
-                if node_name == 'id':
-                    node_name = 'track_id'
-                node_value = el.string
-                other_node_name = "other_%s" % node_name
-                if getattr(self, node_name) is None:
-                    setattr(self, node_name, node_value)
-                else:
-                    if getattr(self, other_node_name) is None:
-                        setattr(self, other_node_name, [node_value, ])
-                    else:
-                        getattr(self, other_node_name).append(node_value)
-
-        for o in [d for d in self.__dict__.keys() if d.startswith('other_')]:
-            try:
-                primary = o.replace('other_', '')
-                setattr(self, primary, int(getattr(self, primary)))
-            except:
-                for v in getattr(self, o):
-                    try:
-                        current = getattr(self, primary)
-                        setattr(self, primary, int(v))
-                        getattr(self, o).append(current)
-                        break
-                    except:
-                        pass
-
-    def __repr__(self):
-        return "<Track track_id='{0}', track_type='{1}'>".format(self.track_id, self.track_type)
-
-    def to_data(self):
-        data = {}
-        for k, v in self.__dict__.items():
-            if k != 'xml_dom_fragment':
-                data[k] = v
-        return data
-
-
-class MediaInfoWrapper(object):
-
-    def __init__(self, xml):
-        self.xml_dom = xml
-        xml_types = (str,)     # no unicode type in python3
-        if isinstance(xml, xml_types):
-            self.xml_dom = MediaInfoWrapper.parse_xml_data_into_dom(xml)
-
-    @staticmethod
-    def parse_xml_data_into_dom(xml_data):
-        return BeautifulSoup(xml_data, "xml")
-
-    @staticmethod
-    def parse(filename, environment=ENV_DICT):
-        xml = check_output(['mediainfo', '-f', '--Output=XML', '--Inform=OLDXML', filename])
-        if not xml.startswith(b'<?xml'):
-            xml = check_output(['mediainfo', '-f', '--Output=XML', filename])
-        xml_dom = MediaInfoWrapper.parse_xml_data_into_dom(xml)
-        return MediaInfoWrapper(xml_dom)
-
-    def _populate_tracks(self):
-        if self.xml_dom is None:
-            return
-        for xml_track in self.xml_dom.Mediainfo.File.find_all("track"):
-            self._tracks.append(Track(xml_track))
-
-    @property
-    def tracks(self):
-        if not hasattr(self, "_tracks"):
-            self._tracks = []
-        if len(self._tracks) == 0:
-            self._populate_tracks()
-        return self._tracks
-
-    def to_data(self):
-        data = {'tracks': []}
-        for track in self.tracks:
-            data['tracks'].append(track.to_data())
-        return data
-
-    def to_json(self):
-        return json.dumps(self.to_data())
diff --git a/openlp/core/ui/media/vlcplayer.py b/openlp/core/ui/media/vlcplayer.py
index 13888e28d..1ebff5f9f 100644
--- a/openlp/core/ui/media/vlcplayer.py
+++ b/openlp/core/ui/media/vlcplayer.py
@@ -81,7 +81,7 @@ def get_vlc():
             # Newer versions of VLC on OS X need this. See https://forum.videolan.org/viewtopic.php?t=124521
             os.environ['VLC_PLUGIN_PATH'] = '/Applications/VLC.app/Contents/MacOS/plugins'
         # On Windows when frozen in PyInstaller, we need to blank SetDllDirectoryW to allow loading of the VLC dll.
-        # This is due to limitations (by desgin) in PyInstaller. SetDllDirectoryW original value is restored once
+        # This is due to limitations (by design) in PyInstaller. SetDllDirectoryW original value is restored once
         # VLC has been imported.
         if is_win():
             buffer_size = 1024
diff --git a/openlp/core/ui/slidecontroller.py b/openlp/core/ui/slidecontroller.py
index 12c3abdab..1cb8489c0 100644
--- a/openlp/core/ui/slidecontroller.py
+++ b/openlp/core/ui/slidecontroller.py
@@ -339,31 +339,31 @@ class SlideController(DisplayController, LogMixin, RegistryProperties):
             self.toolbar.add_toolbar_widget(self.song_menu)
             # Stuff for items with background audio.
             # FIXME: object name should be changed. But this requires that we migrate the shortcut.
-            self.audio_pause_item = self.toolbar.add_toolbar_action(
-                'audioPauseItem',
-                icon=UiIcons().pause, text=translate('OpenLP.SlideController', 'Pause Audio'),
-                tooltip=translate('OpenLP.SlideController', 'Pause audio.'),
-                checked=False, visible=False, category=self.category, context=QtCore.Qt.WindowShortcut,
-                can_shortcuts=True, triggers=self.set_audio_pause_clicked)
-            self.audio_menu = QtWidgets.QMenu(translate('OpenLP.SlideController', 'Background Audio'), self.toolbar)
-            self.audio_pause_item.setMenu(self.audio_menu)
-            self.audio_pause_item.setParent(self.toolbar)
-            self.toolbar.widgetForAction(self.audio_pause_item).setPopupMode(QtWidgets.QToolButton.MenuButtonPopup)
-            self.next_track_item = create_action(self, 'nextTrackItem', text=UiStrings().NextTrack,
-                                                 icon=UiIcons().arrow_right,
-                                                 tooltip=translate('OpenLP.SlideController',
-                                                                   'Go to next audio track.'),
-                                                 category=self.category,
-                                                 can_shortcuts=True,
-                                                 triggers=self.on_next_track_clicked)
-            self.audio_menu.addAction(self.next_track_item)
-            self.track_menu = self.audio_menu.addMenu(translate('OpenLP.SlideController', 'Tracks'))
-            self.audio_time_label = QtWidgets.QLabel(' 00:00 ', self.toolbar)
-            self.audio_time_label.setAlignment(QtCore.Qt.AlignCenter | QtCore.Qt.AlignHCenter)
-            self.audio_time_label.setStyleSheet(AUDIO_TIME_LABEL_STYLESHEET)
-            self.audio_time_label.setObjectName('audio_time_label')
-            self.toolbar.add_toolbar_widget(self.audio_time_label)
-            self.toolbar.set_widget_visible(AUDIO_LIST, False)
+            # self.audio_pause_item = self.toolbar.add_toolbar_action(
+            #     'audioPauseItem',
+            #     icon=UiIcons().pause, text=translate('OpenLP.SlideController', 'Pause Audio'),
+            #     tooltip=translate('OpenLP.SlideController', 'Pause audio.'),
+            #     checked=False, visible=False, category=self.category, context=QtCore.Qt.WindowShortcut,
+            #     can_shortcuts=True, triggers=self.set_audio_pause_clicked)
+            # self.audio_menu = QtWidgets.QMenu(translate('OpenLP.SlideController', 'Background Audio'), self.toolbar)
+            # self.audio_pause_item.setMenu(self.audio_menu)
+            # self.audio_pause_item.setParent(self.toolbar)
+            # self.toolbar.widgetForAction(self.audio_pause_item).setPopupMode(QtWidgets.QToolButton.MenuButtonPopup)
+            # self.next_track_item = create_action(self, 'nextTrackItem', text=UiStrings().NextTrack,
+            #                                      icon=UiIcons().arrow_right,
+            #                                      tooltip=translate('OpenLP.SlideController',
+            #                                                        'Go to next audio track.'),
+            #                                      category=self.category,
+            #                                      can_shortcuts=True,
+            #                                      triggers=self.on_next_track_clicked)
+            # self.audio_menu.addAction(self.next_track_item)
+            # self.track_menu = self.audio_menu.addMenu(translate('OpenLP.SlideController', 'Tracks'))
+            # self.audio_time_label = QtWidgets.QLabel(' 00:00 ', self.toolbar)
+            # self.audio_time_label.setAlignment(QtCore.Qt.AlignCenter | QtCore.Qt.AlignHCenter)
+            # self.audio_time_label.setStyleSheet(AUDIO_TIME_LABEL_STYLESHEET)
+            # self.audio_time_label.setObjectName('audio_time_label')
+            # self.toolbar.add_toolbar_widget(self.audio_time_label)
+            # self.toolbar.set_widget_visible(AUDIO_LIST, False)
             self.toolbar.set_widget_visible('song_menu', False)
         # Screen preview area
         self.preview_frame = QtWidgets.QFrame(self.splitter)
@@ -874,24 +874,25 @@ class SlideController(DisplayController, LogMixin, RegistryProperties):
             if self.display.audio_player:
                 self.display.audio_player.reset()
                 self.set_audio_items_visibility(False)
-                self.audio_pause_item.setChecked(False)
+                # self.audio_pause_item.setChecked(False)
                 # If the current item has background audio
                 if self.service_item.is_capable(ItemCapabilities.HasBackgroundAudio):
-                    self.log_debug('Starting to play...')
-                    self.display.audio_player.add_to_playlist(self.service_item.background_audio)
-                    self.track_menu.clear()
-                    for counter in range(len(self.service_item.background_audio)):
-                        action = self.track_menu.addAction(
-                            os.path.basename(str(self.service_item.background_audio[counter])))
-                        action.setData(counter)
-                        action.triggered.connect(self.on_track_triggered)
-                    self.display.audio_player.repeat = \
-                        Settings().value(self.main_window.general_settings_section + '/audio repeat list')
-                    if Settings().value(self.main_window.general_settings_section + '/audio start paused'):
-                        self.audio_pause_item.setChecked(True)
-                        self.display.audio_player.pause()
-                    else:
-                        self.display.audio_player.play()
+                    self.on_media_start(service_item)
+                    #self.log_debug('Starting to play...')
+                    #self.display.audio_player.add_to_playlist(self.service_item.background_audio)
+                    #self.track_menu.clear()
+                    #for counter in range(len(self.service_item.background_audio)):
+                    #    action = self.track_menu.addAction(
+                    #        os.path.basename(str(self.service_item.background_audio[counter])))
+                    #    action.setData(counter)
+                    #    action.triggered.connect(self.on_track_triggered)
+                    #self.display.audio_player.repeat = \
+                    #    Settings().value(self.main_window.general_settings_section + '/audio repeat list')
+                    #if Settings().value(self.main_window.general_settings_section + '/audio start paused'):
+                    #    self.audio_pause_item.setChecked(True)
+                    #    self.display.audio_player.pause()
+                    #else:
+                    #    self.display.audio_player.play()
                     self.set_audio_items_visibility(True)
         row = 0
         width = self.main_window.control_splitter.sizes()[self.split]
diff --git a/openlp/plugins/alerts/alertsplugin.py b/openlp/plugins/alerts/alertsplugin.py
index f65be76be..9f8ee0085 100644
--- a/openlp/plugins/alerts/alertsplugin.py
+++ b/openlp/plugins/alerts/alertsplugin.py
@@ -24,6 +24,7 @@ import logging
 
 from PyQt5 import QtGui
 
+from openlp.core.state import State
 from openlp.core.api.http import register_endpoint
 from openlp.core.common.actions import ActionList
 from openlp.core.common.i18n import UiStrings, translate
@@ -146,6 +147,8 @@ class AlertsPlugin(Plugin):
         self.alert_form = AlertForm(self)
         register_endpoint(alerts_endpoint)
         register_endpoint(api_alerts_endpoint)
+        State().add_service(self.name, self.weight)
+        State().update_pre_conditions(self.name, self.check_pre_conditions())
 
     def add_tools_menu_item(self, tools_menu):
         """
diff --git a/openlp/plugins/bibles/bibleplugin.py b/openlp/plugins/bibles/bibleplugin.py
index 1b507e97f..303e537aa 100644
--- a/openlp/plugins/bibles/bibleplugin.py
+++ b/openlp/plugins/bibles/bibleplugin.py
@@ -22,11 +22,11 @@
 
 import logging
 
+from openlp.core.state import State
 from openlp.core.api.http import register_endpoint
 from openlp.core.common.actions import ActionList
 from openlp.core.common.i18n import UiStrings, translate
 from openlp.core.ui.icons import UiIcons
-from openlp.core.lib import build_icon
 from openlp.core.lib.plugin import Plugin, StringContent
 from openlp.core.lib.ui import create_action
 from openlp.plugins.bibles.endpoint import api_bibles_endpoint, bibles_endpoint
@@ -81,6 +81,8 @@ class BiblePlugin(Plugin):
         self.manager = BibleManager(self)
         register_endpoint(bibles_endpoint)
         register_endpoint(api_bibles_endpoint)
+        State().add_service(self.name, self.weight)
+        State().update_pre_conditions(self.name, self.check_pre_conditions())
 
     def initialise(self):
         """
diff --git a/openlp/plugins/custom/customplugin.py b/openlp/plugins/custom/customplugin.py
index 194553bfd..299286cb4 100644
--- a/openlp/plugins/custom/customplugin.py
+++ b/openlp/plugins/custom/customplugin.py
@@ -26,6 +26,7 @@ for the Custom Slides plugin.
 
 import logging
 
+from openlp.core.state import State
 from openlp.core.api.http import register_endpoint
 from openlp.core.common.i18n import translate
 from openlp.core.ui.icons import UiIcons
@@ -68,6 +69,8 @@ class CustomPlugin(Plugin):
         self.icon = build_icon(self.icon_path)
         register_endpoint(custom_endpoint)
         register_endpoint(api_custom_endpoint)
+        State().add_service(self.name, self.weight)
+        State().update_pre_conditions(self.name, self.check_pre_conditions())
 
     @staticmethod
     def about():
diff --git a/openlp/plugins/images/imageplugin.py b/openlp/plugins/images/imageplugin.py
index cb6f91741..adac1fb8e 100644
--- a/openlp/plugins/images/imageplugin.py
+++ b/openlp/plugins/images/imageplugin.py
@@ -24,6 +24,7 @@ import logging
 
 from PyQt5 import QtGui
 
+from openlp.core.state import State
 from openlp.core.api.http import register_endpoint
 from openlp.core.common.i18n import translate
 from openlp.core.ui.icons import UiIcons
@@ -59,6 +60,8 @@ class ImagePlugin(Plugin):
         self.icon = build_icon(self.icon_path)
         register_endpoint(images_endpoint)
         register_endpoint(api_images_endpoint)
+        State().add_service(self.name, self.weight)
+        State().update_pre_conditions(self.name, self.check_pre_conditions())
 
     @staticmethod
     def about():
diff --git a/openlp/plugins/media/mediaplugin.py b/openlp/plugins/media/mediaplugin.py
index 17d2ec82c..c06f2d833 100644
--- a/openlp/plugins/media/mediaplugin.py
+++ b/openlp/plugins/media/mediaplugin.py
@@ -27,6 +27,7 @@ import re
 
 from PyQt5 import QtCore
 
+from openlp.core.state import State
 from openlp.core.api.http import register_endpoint
 from openlp.core.common import check_binary_exists
 from openlp.core.common.applocation import AppLocation
@@ -64,6 +65,8 @@ class MediaPlugin(Plugin):
         self.dnd_id = 'Media'
         register_endpoint(media_endpoint)
         register_endpoint(api_media_endpoint)
+        State().add_service(self.name, self.weight, requires='mediacontroller')
+        State().update_pre_conditions(self.name, self.check_pre_conditions())
 
     def initialise(self):
         """
diff --git a/openlp/plugins/presentations/presentationplugin.py b/openlp/plugins/presentations/presentationplugin.py
index c64df5cde..268151262 100644
--- a/openlp/plugins/presentations/presentationplugin.py
+++ b/openlp/plugins/presentations/presentationplugin.py
@@ -28,6 +28,7 @@ import os
 
 from PyQt5 import QtCore
 
+from openlp.core.state import State
 from openlp.core.api.http import register_endpoint
 from openlp.core.common import extension_loader
 from openlp.core.common.i18n import translate
@@ -74,6 +75,8 @@ class PresentationPlugin(Plugin):
         self.icon = build_icon(self.icon_path)
         register_endpoint(presentations_endpoint)
         register_endpoint(api_presentations_endpoint)
+        State().add_service(self.name, self.weight)
+        State().update_pre_conditions(self.name, self.check_pre_conditions())
 
     def create_settings_tab(self, parent):
         """
diff --git a/openlp/plugins/songs/lib/mediaitem.py b/openlp/plugins/songs/lib/mediaitem.py
index 51f4d0407..d3e134a55 100644
--- a/openlp/plugins/songs/lib/mediaitem.py
+++ b/openlp/plugins/songs/lib/mediaitem.py
@@ -634,7 +634,7 @@ class SongMediaItem(MediaManagerItem):
         if song.media_files:
             service_item.add_capability(ItemCapabilities.HasBackgroundAudio)
             service_item.background_audio = [m.file_path for m in song.media_files]
-            item.metadata.append('<em>{label}:</em> {media}'.
+            service_item.metadata.append('<em>{label}:</em> {media}'.
                                  format(label=translate('SongsPlugin.MediaItem', 'Media'),
                                         media=service_item.background_audio))
         return True
diff --git a/openlp/plugins/songs/songsplugin.py b/openlp/plugins/songs/songsplugin.py
index e810dab3e..356b96f02 100644
--- a/openlp/plugins/songs/songsplugin.py
+++ b/openlp/plugins/songs/songsplugin.py
@@ -31,6 +31,7 @@ from tempfile import gettempdir
 
 from PyQt5 import QtCore, QtWidgets
 
+from openlp.core.state import State
 from openlp.core.api.http import register_endpoint
 from openlp.core.common.actions import ActionList
 from openlp.core.common.i18n import UiStrings, translate
@@ -99,6 +100,8 @@ class SongsPlugin(Plugin):
         self.songselect_form = None
         register_endpoint(songs_endpoint)
         register_endpoint(api_songs_endpoint)
+        State().add_service(self.name, self.weight)
+        State().update_pre_conditions(self.name, self.check_pre_conditions())
 
     def check_pre_conditions(self):
         """
diff --git a/openlp/plugins/songusage/songusageplugin.py b/openlp/plugins/songusage/songusageplugin.py
index a0dcff54f..86227db73 100644
--- a/openlp/plugins/songusage/songusageplugin.py
+++ b/openlp/plugins/songusage/songusageplugin.py
@@ -25,6 +25,7 @@ from datetime import datetime
 
 from PyQt5 import QtCore, QtWidgets
 
+from openlp.core.state import State
 from openlp.core.common.actions import ActionList
 from openlp.core.common.i18n import translate
 from openlp.core.common.registry import Registry
@@ -66,6 +67,8 @@ class SongUsagePlugin(Plugin):
         self.weight = -4
         self.icon = UiIcons().song_usage
         self.song_usage_active = False
+        State().add_service(self.name, self.weight)
+        State().update_pre_conditions(self.name, self.check_pre_conditions())
 
     def check_pre_conditions(self):
         """
diff --git a/scripts/check_dependencies.py b/scripts/check_dependencies.py
index 242b28477..c8743ab8e 100755
--- a/scripts/check_dependencies.py
+++ b/scripts/check_dependencies.py
@@ -99,7 +99,8 @@ MODULES = [
     'six',
     'webob',
     'requests',
-    'qtawesome'
+    'qtawesome',
+    'pymediainfo'
 ]
 
 
diff --git a/tests/functional/openlp_core/test_state.py b/tests/functional/openlp_core/test_state.py
index fc5df9703..04925f9f4 100644
--- a/tests/functional/openlp_core/test_state.py
+++ b/tests/functional/openlp_core/test_state.py
@@ -72,9 +72,24 @@ class TestState(TestCase, TestMixin):
         # WHEN I add a new service twice
         State().add_service("test", 1, PluginStatus.Active)
         State().add_service("test1", 1, PluginStatus.Active, "test")
+        State().add_service("test1", 1, PluginStatus.Active, "test")
 
-        # THEN I have a single saved service
+        # THEN I have a single saved service and one dependancy
         assert len(State().modules) == 2
+        assert len(State().modules['test'].required_by) == 1
+
+    def test_add_service_multiple_depends(self):
+        # GIVEN a new state
+        State().load_settings()
+
+        # WHEN I add a new service twice
+        State().add_service("test", 1, PluginStatus.Active)
+        State().add_service("test1", 1, PluginStatus.Active, "test")
+        State().add_service("test2", 1, PluginStatus.Active, "test")
+
+        # THEN I have a 3 modules and 2 dependancies
+        assert len(State().modules) == 3
+        assert len(State().modules['test'].required_by) == 2
 
     def test_active_service(self):
         # GIVEN a new state
@@ -84,7 +99,7 @@ class TestState(TestCase, TestMixin):
         State().add_service("test", 1, PluginStatus.Active)
 
         # THEN I have a single saved service
-        assert State().is_service_active('test') is True
+        assert State().is_module_active('test') is True
 
     def test_inactive_service(self):
         # GIVEN a new state
@@ -94,4 +109,23 @@ class TestState(TestCase, TestMixin):
         State().add_service("test", 1, PluginStatus.Inactive)
 
         # THEN I have a single saved service
-        assert State().is_service_active('test') is False
+        assert State().is_module_active('test') is False
+
+    def test_basic_preconditions(self):
+        # GIVEN a new state
+        State().load_settings()
+
+        # WHEN I add a new services with dependancies and a failed pre condition
+        State().add_service("test", 1, PluginStatus.Inactive)
+        State().add_service("test2", 1, PluginStatus.Inactive)
+        State().add_service("test1", 1, PluginStatus.Inactive, 'test')
+        State().update_pre_conditions('test1', False)
+
+        # THEN correct the state when I flush the preconditions
+        assert State().modules['test'].pass_preconditions == True
+        assert State().modules['test2'].pass_preconditions == True
+        assert State().modules['test1'].pass_preconditions == False
+        State().flush_preconditions()
+        assert State().modules['test'].pass_preconditions == False
+        assert State().modules['test2'].pass_preconditions == True
+        assert State().modules['test1'].pass_preconditions == False
diff --git a/tests/functional/openlp_core/ui/media/test_mediacontroller.py b/tests/functional/openlp_core/ui/media/test_mediacontroller.py
index 8fb141c13..dca3417d2 100644
--- a/tests/functional/openlp_core/ui/media/test_mediacontroller.py
+++ b/tests/functional/openlp_core/ui/media/test_mediacontroller.py
@@ -30,6 +30,12 @@ from openlp.core.ui.media.mediacontroller import MediaController
 from openlp.core.ui.media.mediaplayer import MediaPlayer
 from tests.helpers.testmixin import TestMixin
 
+from tests.utils.constants import RESOURCE_PATH
+
+
+TEST_PATH = RESOURCE_PATH / 'media'
+TEST_MEDIA = [['avi_file.avi', 61495], ['mp3_file.mp3', 134426], ['mpg_file.mpg', 9404], ['mp4_file.mp4', 188336]]
+
 
 class TestMediaController(TestCase, TestMixin):
 
@@ -254,3 +260,18 @@ class TestMediaController(TestCase, TestMixin):
 
         # THEN: The underlying method is called
         mocked_media_seek.assert_called_with(1, 800)
+
+    def test_media_length(self):
+        """
+        Test the Media Info basic functionality
+        """
+        for test_data in TEST_MEDIA:
+            # GIVEN: a media file
+            full_path = str(TEST_PATH / test_data[0])
+            media_controller = MediaController()
+
+            # WHEN the media data is retrieved
+            results = media_controller.media_length(full_path)
+
+            # THEN you can determine the run time
+            assert results.tracks[0].duration == test_data[1], 'The correct duration is returned for ' + test_data[0]
diff --git a/tests/interfaces/openlp_core/ui/media/__init__.py b/tests/interfaces/openlp_core/ui/media/__init__.py
deleted file mode 100644
index 711ded4ae..000000000
--- a/tests/interfaces/openlp_core/ui/media/__init__.py
+++ /dev/null
@@ -1,21 +0,0 @@
-# -*- coding: utf-8 -*-
-# vim: autoindent shiftwidth=4 expandtab textwidth=120 tabstop=4 softtabstop=4
-
-###############################################################################
-# OpenLP - Open Source Lyrics Projection                                      #
-# --------------------------------------------------------------------------- #
-# Copyright (c) 2008-2018 OpenLP Developers                                   #
-# --------------------------------------------------------------------------- #
-# 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; version 2 of the License.                              #
-#                                                                             #
-# 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., 59  #
-# Temple Place, Suite 330, Boston, MA 02111-1307 USA                          #
-###############################################################################
diff --git a/tests/interfaces/openlp_core/ui/media/vendor/__init__.py b/tests/interfaces/openlp_core/ui/media/vendor/__init__.py
deleted file mode 100644
index 711ded4ae..000000000
--- a/tests/interfaces/openlp_core/ui/media/vendor/__init__.py
+++ /dev/null
@@ -1,21 +0,0 @@
-# -*- coding: utf-8 -*-
-# vim: autoindent shiftwidth=4 expandtab textwidth=120 tabstop=4 softtabstop=4
-
-###############################################################################
-# OpenLP - Open Source Lyrics Projection                                      #
-# --------------------------------------------------------------------------- #
-# Copyright (c) 2008-2018 OpenLP Developers                                   #
-# --------------------------------------------------------------------------- #
-# 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; version 2 of the License.                              #
-#                                                                             #
-# 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., 59  #
-# Temple Place, Suite 330, Boston, MA 02111-1307 USA                          #
-###############################################################################
diff --git a/tests/interfaces/openlp_core/ui/media/vendor/test_mediainfoWrapper.py b/tests/interfaces/openlp_core/ui/media/vendor/test_mediainfoWrapper.py
deleted file mode 100644
index 1d106e1d4..000000000
--- a/tests/interfaces/openlp_core/ui/media/vendor/test_mediainfoWrapper.py
+++ /dev/null
@@ -1,48 +0,0 @@
-# -*- coding: utf-8 -*-
-# vim: autoindent shiftwidth=4 expandtab textwidth=120 tabstop=4 softtabstop=4
-
-###############################################################################
-# OpenLP - Open Source Lyrics Projection                                      #
-# --------------------------------------------------------------------------- #
-# Copyright (c) 2008-2018 OpenLP Developers                                   #
-# --------------------------------------------------------------------------- #
-# 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; version 2 of the License.                              #
-#                                                                             #
-# 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., 59  #
-# Temple Place, Suite 330, Boston, MA 02111-1307 USA                          #
-###############################################################################
-"""
-Package to test the openlp.core.ui.media package.
-"""
-from unittest import TestCase
-
-from openlp.core.ui.media.vendor.mediainfoWrapper import MediaInfoWrapper
-from tests.utils.constants import RESOURCE_PATH
-
-TEST_PATH = RESOURCE_PATH / 'media'
-TEST_MEDIA = [['avi_file.avi', 61495], ['mp3_file.mp3', 134426], ['mpg_file.mpg', 9404], ['mp4_file.mp4', 188336]]
-
-
-class TestMediainfoWrapper(TestCase):
-
-    def test_media_length(self):
-        """
-        Test the Media Info basic functionality
-        """
-        for test_data in TEST_MEDIA:
-            # GIVEN: a media file
-            full_path = str(TEST_PATH / test_data[0])
-
-            # WHEN the media data is retrieved
-            results = MediaInfoWrapper.parse(full_path)
-
-            # THEN you can determine the run time
-            assert results.tracks[0].duration == test_data[1], 'The correct duration is returned for ' + test_data[0]