lib: Give Tags a random next() function

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

lib/tag.py

@@ -1,5 +1,6 @@
 # Copyright 2021 (c) Anna Schumaker.
 from . import publisher
+import random
 import threading
 
 class Tag:
@@ -8,6 +9,7 @@ class Tag:
         self.sort = sort.lower() if sort else str(name).lower()
         self.current = -1
         self.loop = False
+        self.random = False
         self.tracks = [ ]
         self.widgets = None
         self.lock = threading.Lock()
@@ -20,6 +22,7 @@ class Tag:
                      "sort"    : self.sort,
                      "current" : self.current,
                      "loop"    : self.loop,
+                     "random"  : self.random,
                      "tracks"  : [ t.trackid for t in self.tracks ] }
 
     def __len__(self):
@@ -38,11 +41,19 @@ class Tag:
             return 0
         return self.current + 1
 
+    def __random_track__(self):
+        i = 1
+        length = len(self.tracks)
+        if len(self.tracks) >= 3:
+            i = random.randint(1, length - 1)
+        return (self.current + i) % (1 if length == 0 else length)
+
     def __setstate__(self, state):
         self.name    = state["name"]
         self.sort    = state["sort"]
         self.current = state["current"]
         self.loop    = state["loop"]
+        self.random  = state["random"]
         self.tracks  = state["tracks"]
         self.widgets = None
         self.lock    = threading.Lock()
@@ -58,6 +69,7 @@ class Tag:
         self.TrackAdded.publish(self, track)
 
     def can_loop(self): return True
+    def can_random(self): return True
 
     def get_header(self):
         return self.sort[0].upper() if len(self.sort) > 0 else ""
@@ -72,7 +84,11 @@ class Tag:
 
     def next(self):
         with self.lock:
-            self.current = self.__next_track__()
+            if self.random == True:
+                self.current = self.__random_track__()
+            else:
+                self.current = self.__next_track__()
+
             if self.current < len(self.tracks):
                 return self.tracks[self.current]
             return None

lib/test_tag.py

@@ -1,6 +1,7 @@
 # Copyright 2021 (c) Anna Schumaker.
 from . import publisher
 from . import tag
+import random
 import threading
 import unittest
 
@@ -23,7 +24,9 @@ class TestTag(unittest.TestCase):
         self.assertEqual(t.current, -1)
         self.assertEqual(t.tracks, [ ])
         self.assertFalse(t.loop)
+        self.assertFalse(t.random)
         self.assertTrue( t.can_loop())
+        self.assertTrue( t.can_random())
         self.assertIsNone(t.widgets)
         self.assertIsInstance(t.lock, type(threading.Lock()))
         self.assertIsInstance(t.TrackAdded, publisher.Publisher)
@@ -63,12 +66,13 @@ class TestTag(unittest.TestCase):
 
         state = t.__getstate__()
         self.assertEqual(set(state.keys()),
-                set([ "name", "sort", "current", "loop", "tracks" ]))
+                set([ "name", "sort", "current", "loop", "random", "tracks" ]))
         self.assertEqual(state["name"], "test")
         self.assertEqual(state["sort"], "test")
         self.assertEqual(state["current"], -1)
         self.assertEqual(state["tracks"], [ 0, 1, 2, 3, 4 ])
         self.assertFalse(state["loop"])
+        self.assertFalse(state["random"])
 
         state["sort"] = "sort"
         state["current"] = 42
@@ -81,6 +85,7 @@ class TestTag(unittest.TestCase):
         self.assertEqual(t.tracks, [ 0, 1, 2, 3, 4 ])
         self.assertEqual(t.widgets, None)
         self.assertFalse(t.loop)
+        self.assertFalse(t.random)
         self.assertIsInstance(t.lock, type(threading.Lock()))
         self.assertIsInstance(t.TrackAdded, publisher.Publisher)
         self.assertIsInstance(t.TrackRemoved, publisher.Publisher)
@@ -134,6 +139,34 @@ class TestTag(unittest.TestCase):
         self.assertEqual(t.next(), 1)
         self.assertEqual(t.current, 0)
 
+    def test_tag_random_next(self):
+        t = tag.Tag("test")
+        t.tracks = [ 0, 1, 2, 3, 4, 5 ]
+        t.random = True
+
+        # Expected randint(): 5, 3, 2, 5, 5, 5
+        random.seed(20210318)
+        self.assertEqual(t.next(), 4) # -1 + 5
+        self.assertEqual(t.next(), 1) # (4 + 3) % 6 = 7 % 6
+        self.assertEqual(t.next(), 3) # 1 + 2
+        self.assertEqual(t.next(), 2) # (3 + 5) % 6 = 8 % 6
+        self.assertEqual(t.next(), 1) # (2 + 5) % 6 = 7 % 6
+        self.assertEqual(t.next(), 0) # (1 + 5) % 6 = 0
+
+        t.tracks = [ ]
+        self.assertIsNone(t.next())
+
+        t.tracks = [ 0 ]
+        self.assertEqual(t.next(), 0)
+        self.assertEqual(t.next(), 0)
+
+        t.tracks = [ 0, 1 ]
+        t.current = -1
+        self.assertEqual(t.next(), 0)
+        self.assertEqual(t.next(), 1)
+        self.assertEqual(t.next(), 0)
+        self.assertEqual(t.next(), 1)
+
 
 class TestSuperTag(unittest.TestCase):
     def test_super_tag(self):