Initial approach to eliminating inaccessible regions resulting from OW Layout Shuffle

OverworldShuffle.py

@@ -280,6 +280,12 @@ def link_overworld(world, player):
         trimmed_groups = remove_reserved(world, trimmed_groups, connected_edges, player)
         groups = reorganize_groups(world, trimmed_groups, player)
         
+        tries = 10
+        valid_layout = False
+        connected_edge_cache = connected_edges.copy()
+        while not valid_layout and tries > 0:
+            connected_edges = connected_edge_cache.copy()
+
             if world.mode[player] == 'standard':
                 random.shuffle(groups[2:]) # keep first 2 groups (Standard) first
             else:
@@ -321,7 +327,11 @@ def link_overworld(world, player):
                             logging.getLogger('').warning("Edge '%s' could not find a valid connection" % back_set[0])
             assert len(connected_edges) == len(default_connections) * 2, connected_edges
             
-    # TODO: Reshuffle some areas if impossible to reach, exception if non-dungeon ER enabled or if area is LW with no portal and flute shuffle is enabled
+            world.owsectors[player] = build_sectors(world, player)
+            valid_layout = validate_layout(world, player)
+
+            tries -= 1
+        assert valid_layout, 'Could not find a valid OW layout'
 
     # flute shuffle
     def connect_flutes(flute_destinations):
@@ -914,6 +924,20 @@ def build_accessible_region_list(world, start_region, player, build_copy_world=F
 
     return explored_regions
 
+def validate_layout(world, player):
+    sectors = [[r for l in s for r in l] for s in world.owsectors[player]]
+    for sector in sectors:
+        entrances_present = False
+        for region_name in sector:
+            region = world.get_region(region_name, player)
+            if any(x.spot_type == 'Entrance' for x in region.exits):
+                entrances_present = True
+                break
+        if not entrances_present and not all(r in isolated_regions for r in sector):
+            return False
+
+    return True
+    
 test_connections = [
                     #('Links House ES', 'Octoballoon WS'),
                     #('Links House NE', 'Lost Woods Pass SW')
@@ -1670,6 +1694,11 @@ default_connections = [#('Lost Woods NW', 'Master Sword Meadow SC'),
                         ('East Dark Death Mountain EN', 'Turtle Rock WN')
                         ]
 
+isolated_regions = [
+    'Death Mountain Floating Island',
+    'Mimic Cave Ledge'
+]
+
 flute_data = {
     #Slot    LW Region                         DW Region                            OWID   VRAM    BG Y    BG X   Link Y  Link X   Cam Y   Cam X   Unk1    Unk2   IconY   IconX    AltY    AltX
     0x09: (['Lost Woods East Area',           'Skull Woods Forest'],                0x00, 0x1042, 0x022e, 0x0202, 0x0290, 0x0288, 0x029b, 0x028f, 0xfff2, 0x000e, 0x0290, 0x0288, 0x0290, 0x0290),