defmodule Odinsea.Game.Storage do
  @moduledoc """
  Manages personal storage (bank) for characters.
  Ported from src/server/MapleStorage.java

  TODO: Full implementation requires:
  - Database persistence
  - Inventory system integration
  - Item serialization
  - Slot management
  - Meso storage
  """

  use GenServer
  require Logger

  @default_slots 4
  @max_slots 48
  @storage_fee 100

  defstruct [
    :character_id,
    :account_id,
    :slots,
    :meso,
    items: %{}
  ]

  # Client API

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

  @doc """
  Load storage for a character.
  """
  def load_storage(account_id) do
    # TODO: Load from database
    {:ok, %__MODULE__{account_id: account_id, slots: @default_slots, meso: 0, items: %{}}}
  end

  @doc """
  Send storage to client.
  """
  def send_storage(client_pid, storage) do
    # TODO: Send OPEN_STORAGE packet
    Logger.debug("Sending storage to client #{inspect(client_pid)} (STUB)")
    :ok
  end

  @doc """
  Take out an item from storage.
  """
  def take_out_item(storage, slot) do
    # TODO: Full implementation:
    # 1. Validate slot
    # 2. Get item from storage
    # 3. Check inventory space
    # 4. Remove from storage
    # 5. Add to inventory
    # 6. Send update packet

    Logger.debug("Storage take out: slot=#{slot} (STUB)")
    {:ok, storage}
  end

  @doc """
  Store an item in storage.
  """
  def store_item(storage, item, slot) do
    # TODO: Full implementation:
    # 1. Check storage is not full
    # 2. Validate item (not pet, not trade-restricted)
    # 3. Charge storage fee (100 mesos)
    # 4. Remove karma flags if applicable
    # 5. Remove from inventory
    # 6. Add to storage
    # 7. Send update packet

    Logger.debug("Storage store: item=#{inspect(item)}, slot=#{slot} (STUB)")
    {:ok, storage}
  end

  @doc """
  Arrange/sort storage items.
  """
  def arrange(storage) do
    # TODO: Sort items by type/ID
    Logger.debug("Storage arrange (STUB)")
    {:ok, storage}
  end

  @doc """
  Deposit or withdraw mesos.
  """
  def transfer_meso(storage, amount) do
    # TODO: Full implementation:
    # 1. Validate amount (positive = withdraw, negative = deposit)
    # 2. Check character has mesos (if depositing)
    # 3. Check storage has mesos (if withdrawing)
    # 4. Handle overflow protection
    # 5. Transfer mesos
    # 6. Send update packet

    Logger.debug("Storage meso transfer: #{amount} (STUB)")
    {:ok, storage}
  end

  @doc """
  Close storage.
  """
  def close(storage) do
    # TODO: Save to database
    Logger.debug("Storage close (STUB)")
    :ok
  end

  @doc """
  Check if storage is full.
  """
  def full?(storage) do
    map_size(storage.items) >= storage.slots
  end

  @doc """
  Get next available slot.
  """
  def next_slot(storage) do
    Enum.find(1..storage.slots, fn slot -> !Map.has_key?(storage.items, slot) end)
  end

  @doc """
  Find item by ID in storage.
  """
  def find_by_id(storage, item_id) do
    Enum.find(storage.items, fn {_slot, item} -> item.item_id == item_id end)
  end

  # GenServer callbacks

  @impl true
  def init(opts) do
    account_id = Keyword.fetch!(opts, :account_id)

    state = %__MODULE__{
      account_id: account_id,
      slots: @default_slots,
      meso: 0,
      items: %{}
    }

    {:ok, state}
  end

  @impl true
  def handle_call({:add_item, slot, item}, _from, state) do
    if slot <= state.slots and !Map.has_key?(state.items, slot) do
      new_items = Map.put(state.items, slot, item)
      {:reply, :ok, %{state | items: new_items}}
    else
      {:reply, {:error, :invalid_slot}, state}
    end
  end

  @impl true
  def handle_call({:remove_item, slot}, _from, state) do
    case Map.pop(state.items, slot) do
      {nil, _} -> {:reply, {:error, :no_item}, state}
      {item, new_items} -> {:reply, {:ok, item}, %{state | items: new_items}}
    end
  end

  @impl true
  def handle_call({:set_meso, meso}, _from, state) do
    {:reply, :ok, %{state | meso: meso}}
  end

  @impl true
  def handle_call(:get_meso, _from, state) do
    {:reply, state.meso, state}
  end
end