sidebar: Create a Section Group

This group manages a list of sections so only one is active at a time.
Additionally, it adjusts the animation property of each section to match
the direction the header moves when activated.

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

emmental/sidebar/section.py

@@ -97,3 +97,54 @@ class Section(header.Header):
     @GObject.Signal(arg_types=(db.playlist.Playlist,))
     def playlist_selected(self, playlist: db.playlist.Playlist):
         """Signal that the selected playlist has changed."""
+
+
+class Group(GObject.GObject):
+    """A group of sections."""
+
+    sql = GObject.Property(type=db.Connection)
+    current = GObject.Property(type=Section)
+    selected_section = GObject.Property(type=Section)
+    selected_playlist = GObject.Property(type=db.playlist.Playlist)
+
+    def __init__(self, sql: db.Connection):
+        """Initialize a Section Group."""
+        super().__init__(sql=sql)
+        self._sections = []
+
+    def __on_active(self, section: Section, param: GObject.ParamSpec) -> None:
+        if section.active:
+            new = self._sections.index(section)
+            prev = len(self._sections)
+
+            if self.current and self.current is not section:
+                prev = self._sections.index(self.current)
+                self.current.active = False
+
+            self.current = section
+            if new < prev:
+                section.animation = Gtk.RevealerTransitionType.SLIDE_DOWN
+            else:
+                section.animation = Gtk.RevealerTransitionType.SLIDE_UP
+
+            if section is self.selected_section:
+                section.select_playlist(self.selected_playlist)
+
+    def __playlist_activated(self, section: Section,
+                             playlist: db.playlist.Playlist) -> None:
+        self.sql.set_active_playlist(playlist)
+
+    def __playlist_selected(self, section: Section,
+                            playlist: db.playlist.Playlist) -> None:
+        if self.selected_section and self.selected_section is not section:
+            self.selected_section.clear_selection()
+
+        self.selected_section = section
+        self.selected_playlist = playlist
+
+    def add(self, section: Section) -> None:
+        """Add a section to the group."""
+        self._sections.append(section)
+        section.connect("notify::active", self.__on_active)
+        section.connect("playlist-activated", self.__playlist_activated)
+        section.connect("playlist-selected", self.__playlist_selected)

tests/sidebar/test_section.py

@@ -4,6 +4,7 @@ import emmental.db
 import emmental.sidebar.section
 import tests.util
 import unittest.mock
+from gi.repository import GObject
 from gi.repository import GLib
 from gi.repository import Gtk
 
@@ -141,3 +142,94 @@ class TestSection(tests.util.TestCase):
         playlist = self.table.create("Test Playlist")
         self.section._listview.emit("activate", 0)
         playlist_activated.assert_called_with(self.section, playlist)
+
+
+class TestGroup(tests.util.TestCase):
+    """Test our sidebar section group."""
+
+    def setUp(self):
+        """Set up common variables."""
+        super().setUp()
+        self.group = emmental.sidebar.section.Group(self.sql)
+        self.row_type = emmental.sidebar.row.TreeRow
+        self.section1 = emmental.sidebar.section.Section(self.sql.playlists,
+                                                         self.row_type)
+        self.section2 = emmental.sidebar.section.Section(self.sql.genres,
+                                                         self.row_type)
+        self.section1.do_get_subtitle = unittest.mock.Mock(return_value="")
+        self.section2.do_get_subtitle = unittest.mock.Mock(return_value="")
+
+    def test_init(self):
+        """Test that the Group is set up properly."""
+        self.assertIsInstance(self.group, GObject.GObject)
+        self.assertListEqual(self.group._sections, [])
+        self.assertEqual(self.group.sql, self.sql)
+
+    def test_add(self):
+        """Test adding sections to the Group."""
+        self.group.add(self.section1)
+        self.assertListEqual(self.group._sections, [self.section1])
+        self.group.add(self.section2)
+        self.assertListEqual(self.group._sections,
+                             [self.section1, self.section2])
+
+    def test_current(self):
+        """Test the current section property."""
+        self.group.add(self.section1)
+        self.group.add(self.section2)
+        self.assertIsNone(self.group.current)
+
+        self.section1.active = True
+        self.assertEqual(self.group.current, self.section1)
+
+        self.section2.active = True
+        self.assertEqual(self.group.current, self.section2)
+        self.assertFalse(self.section1.active)
+
+    def test_animation(self):
+        """Test setting the section animation style."""
+        self.group.add(self.section1)
+        self.group.add(self.section2)
+
+        self.section1.active = True
+        self.assertEqual(self.section1.animation,
+                         Gtk.RevealerTransitionType.SLIDE_DOWN)
+
+        self.section2.active = True
+        self.assertEqual(self.section2.animation,
+                         Gtk.RevealerTransitionType.SLIDE_UP)
+
+    def test_playlist_activated(self):
+        """Test responding to the section playlist-activated signal."""
+        self.group.add(self.section1)
+        self.group.add(self.section2)
+        self.assertIsNone(self.sql.active_playlist)
+
+        playlist = self.sql.playlists.create("Test Playlist")
+        self.section1.emit("playlist-activated", playlist)
+        self.assertEqual(self.sql.active_playlist, playlist)
+
+        genre = self.sql.genres.create("Test Genre")
+        self.section2.emit("playlist-activated", genre)
+        self.assertEqual(self.sql.active_playlist, genre)
+
+    def test_selections(self):
+        """Test the selected section & playlist properties."""
+        self.group.add(self.section1)
+        self.group.add(self.section2)
+
+        self.assertIsNone(self.group.selected_section)
+        self.assertIsNone(self.group.selected_playlist)
+
+        genre = self.sql.genres.create("Test Genre")
+        self.section2.emit("playlist-selected", genre)
+        self.assertEqual(self.group.selected_section, self.section2)
+        self.assertEqual(self.group.selected_playlist, genre)
+
+        self.section2.active = True
+        treerow = self.section2._selection.get_selected_item()
+        self.assertEqual(treerow.get_item(), genre)
+
+        playlist = self.sql.playlists.create("Test Playlist")
+        self.section1.emit("playlist-selected", playlist)
+        self.assertIsNone(self.section2._selection.get_selected_item())