defmodule Odinsea.Shop.Client do
  @moduledoc """
  Client connection handler for the cash shop server.
  """

  use GenServer, restart: :temporary

  require Logger

  alias Odinsea.Net.Packet.In

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

  def start_link(socket) do
    GenServer.start_link(__MODULE__, socket)
  end

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

    Logger.info("Cash shop client connected from #{ip_string}")

    state = %__MODULE__{
      socket: socket,
      ip: ip_string,
      state: :connected,
      character_id: nil,
      account_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("Cash shop client disconnected: #{state.ip}")
        {:stop, :normal, state}

      {:error, reason} ->
        Logger.warning("Cash shop 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("Cash shop 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
    # TODO: Implement cash shop packet handlers
    state
  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