Make flying a toggle state

fly with no args toggles flying on/off. Movement commands (fly east,
etc) only work while airborne. "You aren't flying." if you try to
move without toggling on first. Player.flying field tracks the state.

src/mudlib/commands/fly.py

@@ -22,15 +22,40 @@ CLOUD_COLOR = BOLD + BRIGHT_WHITE
 
 
 async def cmd_fly(player: Player, args: str) -> None:
-    """Fly through the air, moving 5 tiles in a direction.
+    """Toggle flying or move while airborne.
 
-    Args:
+    fly        - toggle flying on/off
-        player: The player executing the command
+    fly <dir>  - move 5 tiles in a direction (must be flying)
-        args: Direction to fly (e.g. "east", "nw")
     """
     direction = args.strip().lower()
+
+    # no args = toggle flying state
     if not direction:
-        player.writer.write("Fly which direction?\r\n")
+        if player.flying:
+            player.flying = False
+            player.writer.write("You land.\r\n")
+            await player.writer.drain()
+            await send_nearby_message(
+                player,
+                player.x,
+                player.y,
+                f"{player.name} lands.\r\n",
+            )
+        else:
+            player.flying = True
+            player.writer.write("You fly into the air!\r\n")
+            await player.writer.drain()
+            await send_nearby_message(
+                player,
+                player.x,
+                player.y,
+                f"{player.name} lifts into the air!\r\n",
+            )
+        return
+
+    # direction given but not flying
+    if not player.flying:
+        player.writer.write("You aren't flying.\r\n")
         await player.writer.drain()
         return
 
@@ -43,15 +68,6 @@ async def cmd_fly(player: Player, args: str) -> None:
     dx, dy = delta
     start_x, start_y = player.x, player.y
 
-    # tell the player
-    player.writer.write("You fly into the air!\r\n")
-    await player.writer.drain()
-
-    # tell nearby players at departure
-    await send_nearby_message(
-        player, player.x, player.y, f"{player.name} lifts into the air!\r\n"
-    )
-
     # lay cloud trail at starting position and each intermediate step
     for step in range(FLY_DISTANCE):
         trail_x, trail_y = world.wrap(start_x + dx * step, start_y + dy * step)
@@ -64,11 +80,6 @@ async def cmd_fly(player: Player, args: str) -> None:
     player.x = dest_x
     player.y = dest_y
 
-    # tell nearby players at arrival
-    await send_nearby_message(
-        player, player.x, player.y, f"{player.name} lands from the sky!\r\n"
-    )
-
     # auto-look at new position
     from mudlib.commands.look import cmd_look
 

src/mudlib/player.py

@@ -13,6 +13,7 @@ class Player:
     y: int
     writer: Any  # telnetlib3 TelnetWriter for sending output
     reader: Any  # telnetlib3 TelnetReader for reading input
+    flying: bool = False
 
 
 # Global registry of connected players

tests/test_fly.py

@@ -52,13 +52,107 @@ def clean_state(mock_world):
     active_effects.clear()
 
 
-# --- direction parsing ---
+# --- toggle ---
+
+
+@pytest.mark.asyncio
+async def test_fly_toggles_on(player, mock_writer):
+    """fly with no args sets flying=True."""
+    players[player.name] = player
+    assert not player.flying
+
+    await fly.cmd_fly(player, "")
+
+    assert player.flying
+    calls = [str(c) for c in mock_writer.write.call_args_list]
+    assert any("fly" in c.lower() and "air" in c.lower() for c in calls)
+
+
+@pytest.mark.asyncio
+async def test_fly_toggles_off(player, mock_writer):
+    """fly again sets flying=False."""
+    players[player.name] = player
+    player.flying = True
+
+    await fly.cmd_fly(player, "")
+
+    assert not player.flying
+    calls = [str(c) for c in mock_writer.write.call_args_list]
+    assert any("land" in c.lower() for c in calls)
+
+
+@pytest.mark.asyncio
+async def test_fly_toggle_on_notifies_nearby(player):
+    """Others see liftoff message."""
+    players[player.name] = player
+
+    other_writer = MagicMock()
+    other_writer.write = MagicMock()
+    other_writer.drain = AsyncMock()
+    other = Player(
+        name="bystander",
+        x=52,
+        y=50,
+        reader=MagicMock(),
+        writer=other_writer,
+    )
+    players[other.name] = other
+
+    await fly.cmd_fly(player, "")
+
+    calls = [str(c) for c in other_writer.write.call_args_list]
+    assert any("shmup" in c.lower() and "lifts" in c.lower() for c in calls)
+
+
+@pytest.mark.asyncio
+async def test_fly_toggle_off_notifies_nearby(player):
+    """Others see landing message."""
+    players[player.name] = player
+    player.flying = True
+
+    other_writer = MagicMock()
+    other_writer.write = MagicMock()
+    other_writer.drain = AsyncMock()
+    other = Player(
+        name="bystander",
+        x=52,
+        y=50,
+        reader=MagicMock(),
+        writer=other_writer,
+    )
+    players[other.name] = other
+
+    await fly.cmd_fly(player, "")
+
+    calls = [str(c) for c in other_writer.write.call_args_list]
+    assert any("shmup" in c.lower() and "lands" in c.lower() for c in calls)
+
+
+# --- must be flying to move ---
+
+
+@pytest.mark.asyncio
+async def test_fly_direction_without_flying_errors(player, mock_writer):
+    """fly east when not flying gives an error."""
+    players[player.name] = player
+    assert not player.flying
+
+    await fly.cmd_fly(player, "east")
+
+    calls = [str(c) for c in mock_writer.write.call_args_list]
+    assert any("aren't flying" in c.lower() for c in calls)
+    assert player.x == 50
+    assert player.y == 50
+
+
+# --- movement while flying ---
 
 
 @pytest.mark.asyncio
 async def test_fly_east_moves_5_tiles(player):
     """fly east should move player 5 tiles east."""
     players[player.name] = player
+    player.flying = True
     await fly.cmd_fly(player, "east")
 
     assert player.x == 55
@@ -68,6 +162,7 @@ async def test_fly_east_moves_5_tiles(player):
 @pytest.mark.asyncio
 async def test_fly_north_moves_5_tiles(player):
     players[player.name] = player
+    player.flying = True
     await fly.cmd_fly(player, "north")
 
     assert player.x == 50
@@ -77,6 +172,7 @@ async def test_fly_north_moves_5_tiles(player):
 @pytest.mark.asyncio
 async def test_fly_northwest_moves_5_diagonal(player):
     players[player.name] = player
+    player.flying = True
     await fly.cmd_fly(player, "nw")
 
     assert player.x == 45
@@ -88,10 +184,10 @@ async def test_fly_wraps_around_world(player):
     """Flying near an edge should wrap toroidally."""
     player.x = 98
     player.y = 50
+    player.flying = True
     players[player.name] = player
     await fly.cmd_fly(player, "east")
 
-    # 98 + 5 = 103, wraps to 3
     assert player.x == 3
     assert player.y == 50
 
@@ -103,10 +199,9 @@ async def test_fly_wraps_around_world(player):
 async def test_fly_creates_cloud_trail(player):
     """Flying should leave ~ effects along the path."""
     players[player.name] = player
+    player.flying = True
     await fly.cmd_fly(player, "east")
 
-    # trail at positions 50,51,52,53,54 (start through second-to-last)
-    # player ends at 55
     assert len(active_effects) == 5
     trail_positions = [(e.x, e.y) for e in active_effects]
     for i in range(5):
@@ -116,6 +211,7 @@ async def test_fly_creates_cloud_trail(player):
 @pytest.mark.asyncio
 async def test_cloud_trail_chars_are_tilde(player):
     players[player.name] = player
+    player.flying = True
     await fly.cmd_fly(player, "east")
 
     for e in active_effects:
@@ -126,6 +222,7 @@ async def test_cloud_trail_chars_are_tilde(player):
 async def test_cloud_trail_has_ttl(player):
     """Cloud effects should expire after roughly 2 seconds."""
     players[player.name] = player
+    player.flying = True
 
     before = time.monotonic()
     await fly.cmd_fly(player, "east")
@@ -139,65 +236,35 @@ async def test_cloud_trail_has_ttl(player):
 async def test_fly_diagonal_trail(player):
     """Diagonal flight should leave trail at each intermediate step."""
     players[player.name] = player
+    player.flying = True
     await fly.cmd_fly(player, "se")
 
-    # southeast: dx=1, dy=1, 5 steps
-    # trail at (50,50), (51,51), (52,52), (53,53), (54,54)
-    # player ends at (55, 55)
     assert len(active_effects) == 5
     trail_positions = [(e.x, e.y) for e in active_effects]
     for i in range(5):
         assert (50 + i, 50 + i) in trail_positions
 
 
-# --- messages ---
+# --- no movement without flying leaves no trail ---
 
 
 @pytest.mark.asyncio
-async def test_fly_sends_self_message(player, mock_writer):
+async def test_no_trail_when_not_flying(player):
-    """Player should see 'You fly into the air'."""
+    """Trying to fly a direction while grounded creates no effects."""
     players[player.name] = player
     await fly.cmd_fly(player, "east")
 
-    calls = [str(c) for c in mock_writer.write.call_args_list]
+    assert len(active_effects) == 0
-    assert any("fly" in c.lower() and "air" in c.lower() for c in calls)
 
 
-@pytest.mark.asyncio
+# --- error cases ---
-async def test_fly_sends_nearby_message(player):
-    """Other players should see '{name} lifts into the air'."""
-    players[player.name] = player
-
-    other_writer = MagicMock()
-    other_writer.write = MagicMock()
-    other_writer.drain = AsyncMock()
-    other = Player(
-        name="bystander", x=52, y=50, reader=MagicMock(), writer=other_writer
-    )
-    players[other.name] = other
-
-    await fly.cmd_fly(player, "east")
-
-    calls = [str(c) for c in other_writer.write.call_args_list]
-    assert any("shmup" in c.lower() and "lifts" in c.lower() for c in calls)
-
-
-@pytest.mark.asyncio
-async def test_fly_no_direction_gives_error(player, mock_writer):
-    """fly with no args should tell the player to specify a direction."""
-    players[player.name] = player
-    await fly.cmd_fly(player, "")
-
-    calls = [str(c) for c in mock_writer.write.call_args_list]
-    assert any("direction" in c.lower() for c in calls)
-    assert player.x == 50
-    assert player.y == 50
 
 
 @pytest.mark.asyncio
 async def test_fly_bad_direction_gives_error(player, mock_writer):
     """fly with an invalid direction should give feedback."""
     players[player.name] = player
+    player.flying = True
     await fly.cmd_fly(player, "sideways")
 
     calls = [str(c) for c in mock_writer.write.call_args_list]
@@ -210,7 +277,17 @@ async def test_fly_bad_direction_gives_error(player, mock_writer):
 async def test_fly_triggers_look(player, mock_world):
     """Flying should auto-look at the destination."""
     players[player.name] = player
+    player.flying = True
     await fly.cmd_fly(player, "east")
 
-    # get_viewport is called by look, which fly triggers
     assert mock_world.get_viewport.called
+
+
+@pytest.mark.asyncio
+async def test_stays_flying_after_move(player):
+    """Moving while flying doesn't turn off flying."""
+    players[player.name] = player
+    player.flying = True
+    await fly.cmd_fly(player, "east")
+
+    assert player.flying