Start repo, claude & kimi still vibing tho

lib/odinsea/game/movement.ex

@@ -0,0 +1,146 @@
+defmodule Odinsea.Game.Movement do
+  @moduledoc """
+  Movement parsing and validation for players, mobs, pets, summons, and dragons.
+  Ported from Java MovementParse.java.
+
+  Movement types (kind):
+  - 1: Player
+  - 2: Mob
+  - 3: Pet
+  - 4: Summon
+  - 5: Dragon
+
+  This is a SIMPLIFIED implementation for now. The full Java version has complex
+  parsing for different movement command types. We'll expand this as needed.
+  """
+
+  require Logger
+  alias Odinsea.Net.Packet.In
+  alias Odinsea.Game.Character.Position
+
+  @doc """
+  Parses movement data from a packet.
+  Returns {:ok, movements} or {:error, reason}.
+
+  For now, this returns a simplified structure. The full implementation
+  would parse all movement fragment types.
+  """
+  def parse_movement(packet, _kind) do
+    num_commands = In.decode_byte(packet)
+
+    # For now, just skip through the movement data and extract final position
+    # TODO: Implement full movement parsing with all command types
+    case extract_final_position(packet, num_commands) do
+      {:ok, position} ->
+        {:ok, %{num_commands: num_commands, final_position: position}}
+
+      :error ->
+        {:error, :invalid_movement}
+    end
+  end
+
+  @doc """
+  Updates an entity's position from movement data.
+  """
+  def update_position(_movements, character_id) do
+    # TODO: Implement position update logic
+    # For now, just return ok
+    Logger.debug("Update position for character #{character_id}")
+    :ok
+  end
+
+  # ============================================================================
+  # Private Functions
+  # ============================================================================
+
+  # Extract the final position from movement data
+  # This is a TEMPORARY simplification - we just read through the movement
+  # commands and try to extract the last absolute position
+  defp extract_final_position(packet, num_commands) do
+    try do
+      final_pos = parse_commands(packet, num_commands, nil)
+      {:ok, final_pos || %{x: 0, y: 0, stance: 0, foothold: 0}}
+    rescue
+      _ ->
+        :error
+    end
+  end
+
+  defp parse_commands(_packet, 0, last_position) do
+    last_position
+  end
+
+  defp parse_commands(packet, remaining, last_position) do
+    command = In.decode_byte(packet)
+
+    new_position =
+      case command do
+        # Absolute movement commands - extract position
+        cmd when cmd in [0, 37, 38, 39, 40, 41, 42] ->
+          x = In.decode_short(packet)
+          y = In.decode_short(packet)
+          _xwobble = In.decode_short(packet)
+          _ywobble = In.decode_short(packet)
+          _unk = In.decode_short(packet)
+          _xoffset = In.decode_short(packet)
+          _yoffset = In.decode_short(packet)
+          stance = In.decode_byte(packet)
+          _duration = In.decode_short(packet)
+          %{x: x, y: y, stance: stance, foothold: 0}
+
+        # Relative movement - skip for now
+        cmd when cmd in [1, 2, 33, 34, 36] ->
+          _xmod = In.decode_short(packet)
+          _ymod = In.decode_short(packet)
+          _stance = In.decode_byte(packet)
+          _duration = In.decode_short(packet)
+          last_position
+
+        # Teleport movement
+        cmd when cmd in [3, 4, 8, 100, 101] ->
+          x = In.decode_short(packet)
+          y = In.decode_short(packet)
+          _xwobble = In.decode_short(packet)
+          _ywobble = In.decode_short(packet)
+          stance = In.decode_byte(packet)
+          %{x: x, y: y, stance: stance, foothold: 0}
+
+        # Chair movement
+        cmd when cmd in [9, 12] ->
+          x = In.decode_short(packet)
+          y = In.decode_short(packet)
+          _unk = In.decode_short(packet)
+          stance = In.decode_byte(packet)
+          _duration = In.decode_short(packet)
+          %{x: x, y: y, stance: stance, foothold: 0}
+
+        # Aran combat step
+        cmd when cmd in [21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 35] ->
+          _stance = In.decode_byte(packet)
+          _unk = In.decode_short(packet)
+          last_position
+
+        # Jump down
+        cmd when cmd in [13, 14] ->
+          # Simplified - just skip the data
+          x = In.decode_short(packet)
+          y = In.decode_short(packet)
+          _xwobble = In.decode_short(packet)
+          _ywobble = In.decode_short(packet)
+          _unk = In.decode_short(packet)
+          _fh = In.decode_short(packet)
+          _xoffset = In.decode_short(packet)
+          _yoffset = In.decode_short(packet)
+          stance = In.decode_byte(packet)
+          _duration = In.decode_short(packet)
+          %{x: x, y: y, stance: stance, foothold: 0}
+
+        # Unknown/unhandled - log and skip
+        _ ->
+          Logger.warning("Unhandled movement command: #{command}")
+          last_position
+      end
+
+    parse_commands(packet, remaining - 1, new_position || last_position)
+  end
+end