odinsea-elixir/lib/odinsea/channel/client.ex

defmodule Odinsea.Channel.Client do
  @moduledoc """
  Client connection handler for game channel servers.
  Manages the game session state.
  """

  use GenServer, restart: :temporary

  require Logger

  alias Odinsea.Net.Packet.In
  alias Odinsea.Net.Opcodes
  alias Odinsea.Channel.Handler

  defstruct [:socket, :ip, :channel_id, :state, :character_id]

  def start_link({socket, channel_id}) do
    GenServer.start_link(__MODULE__, {socket, channel_id})
  end

  @impl true
  def init({socket, channel_id}) do
    {:ok, {ip, _port}} = :inet.peername(socket)
    ip_string = format_ip(ip)

    Logger.info("Channel #{channel_id} client connected from #{ip_string}")

    state = %__MODULE__{
      socket: socket,
      ip: ip_string,
      channel_id: channel_id,
      state: :connected,
      character_id: nil
    }

    send(self(), :receive)
    {:ok, state}
  end

  @impl true
  def handle_info(:receive, %{socket: socket} = state) do
    case :gen_tcp.recv(socket, 0, 30_000) do
      {:ok, data} ->
        new_state = handle_packet(data, state)
        send(self(), :receive)
        {:noreply, new_state}

      {:error, :closed} ->
        Logger.info("Channel #{state.channel_id} client disconnected: #{state.ip}")
        {:stop, :normal, state}

      {:error, reason} ->
        Logger.warning("Channel client error: #{inspect(reason)}")
        {:stop, :normal, state}
    end
  end

  @impl true
  def terminate(_reason, state) do
    if state.socket do
      :gen_tcp.close(state.socket)
    end

    :ok
  end

  defp handle_packet(data, state) do
    packet = In.new(data)

    case In.decode_short(packet) do
      {opcode, packet} ->
        Logger.debug("Channel #{state.channel_id} packet: opcode=0x#{Integer.to_string(opcode, 16)}")
        dispatch_packet(opcode, packet, state)

      :error ->
        Logger.warning("Failed to read packet opcode")
        state
    end
  end

  defp dispatch_packet(opcode, packet, state) do
    # Define opcodes for matching
    cp_general_chat = Opcodes.cp_general_chat()
    cp_party_chat = Opcodes.cp_party_chat()
    cp_whisper = Opcodes.cp_whisper()
    cp_move_player = Opcodes.cp_move_player()
    cp_change_map = Opcodes.cp_change_map()
    cp_change_keymap = Opcodes.cp_change_keymap()
    cp_skill_macro = Opcodes.cp_skill_macro()
    cp_close_range_attack = Opcodes.cp_close_range_attack()
    cp_ranged_attack = Opcodes.cp_ranged_attack()
    cp_magic_attack = Opcodes.cp_magic_attack()
    cp_take_damage = Opcodes.cp_take_damage()

    case opcode do
      # Chat handlers
      ^cp_general_chat ->
        case Handler.Chat.handle_general_chat(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      ^cp_party_chat ->
        case Handler.Chat.handle_party_chat(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      ^cp_whisper ->
        case Handler.Chat.handle_whisper(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      # Player movement and actions
      ^cp_move_player ->
        case Handler.Player.handle_move_player(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      ^cp_change_map ->
        case Handler.Player.handle_change_map(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      ^cp_change_keymap ->
        case Handler.Player.handle_change_keymap(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      ^cp_skill_macro ->
        case Handler.Player.handle_change_skill_macro(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      # Combat handlers (stubs for now)
      ^cp_close_range_attack ->
        case Handler.Player.handle_close_range_attack(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      ^cp_ranged_attack ->
        case Handler.Player.handle_ranged_attack(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      ^cp_magic_attack ->
        case Handler.Player.handle_magic_attack(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      ^cp_take_damage ->
        case Handler.Player.handle_take_damage(packet, state) do
          {:ok, new_state} -> new_state
          _ -> state
        end

      _ ->
        Logger.debug("Unhandled channel opcode: 0x#{Integer.to_string(opcode, 16)}")
        state
    end
  end

  defp format_ip({a, b, c, d}) do
    "#{a}.#{b}.#{c}.#{d}"
  end

  defp format_ip({a, b, c, d, e, f, g, h}) do
    "#{a}:#{b}:#{c}:#{d}:#{e}:#{f}:#{g}:#{h}"
  end
end