defmodule Odinsea.Channel.Handler.Duey do
  @moduledoc """
  Handles Duey (parcel delivery) system operations.

  Ported from: src/handling/channel/handler/DueyHandler.java

  Duey allows players to:
  - Send items and mesos to other players
  - Receive packages from other players
  - Remove/delete packages

  ## Status Codes
  - 19 = Successful
  - 18 = One-of-a-kind item already in receiver's delivery
  - 17 = Character unable to receive parcel
  - 15 = Same account
  - 14 = Name does not exist
  - 16 = Not enough space
  - 12 = Not enough mesos

  ## Main Handlers
  - handle_duey_operation/2 - All Duey operations (send, receive, remove)
  """

  require Logger

  alias Odinsea.Net.Packet.In
  alias Odinsea.Game.Character
  alias Odinsea.Channel.Packets

  # ============================================================================
  # Duey Operations
  # ============================================================================

  @doc """
  Handles all Duey operations (CP_DUEY_ACTION / 0x48).

  Operations:
  - 1: Start Duey (load packages)
  - 3: Send item/mesos
  - 5: Receive package
  - 6: Remove package
  - 8: Close Duey

  Note: The original Java handler is mostly commented out.
  This is a stub implementation for future development.

  Reference: DueyHandler.DueyOperation()
  """
  def handle_duey_operation(packet, client_pid) do
    case Character.get_state_by_client(client_pid) do
      {:ok, character_id, char_state} ->
        # Check conversation state (should be 2 for Duey)
        # For now, allow without strict check since this is a stub
        
        operation = In.decode_byte(packet)
        handle_duey_op(operation, packet, client_pid, character_id, char_state)

      {:error, reason} ->
        Logger.warn("Failed to handle Duey operation: #{inspect(reason)}")
    end
  end

  # ============================================================================
  # Individual Operations
  # ============================================================================

  # Operation 1: Start Duey - Load packages
  defp handle_duey_op(1, packet, client_pid, character_id, _char_state) do
    # AS13Digit = packet.decodeString()  # 13 digit AS code (unused)
    
    # TODO: Load packages from database
    # packages = load_items(character_id)
    
    # TODO: Send package list to client
    # packet = Packets.send_duey(10, packages)
    # send(client_pid, {:send_packet, packet})
    
    Logger.debug("Duey start: character #{character_id}")
    :ok
  end

  # Operation 3: Send item/mesos
  defp handle_duey_op(3, packet, client_pid, character_id, char_state) do
    inventory_id = In.decode_byte(packet)
    item_pos = In.decode_short(packet)
    amount = In.decode_short(packet)
    mesos = In.decode_int(packet)
    recipient = In.decode_string(packet)
    quick_delivery = In.decode_byte(packet) > 0
    
    # Calculate cost
    # tax = GameConstants.getTaxAmount(mesos)
    # final_cost = mesos + tax + (if quick_delivery, do: 0, else: 5000)
    
    # TODO: Validate recipient exists
    # TODO: Validate recipient is not same account
    # TODO: Validate sender has enough mesos
    # TODO: Validate item exists if sending item
    # TODO: Check receiver has space
    # TODO: Add to database
    # TODO: Send success/failure packet
    
    Logger.debug("Duey send: #{mesos} mesos (quick=#{quick_delivery}) to #{recipient}, item inv=#{inventory_id}, pos=#{item_pos}, amount=#{amount}, character #{character_id}")
    
    # Send failure for now (not implemented)
    send(client_pid, {:send_packet, duey_error(17)})
    :ok
  end

  # Operation 5: Receive package
  defp handle_duey_op(5, packet, client_pid, character_id, _char_state) do
    package_id = In.decode_int(packet)
    
    # TODO: Load package from database
    # package = load_single_item(package_id, character_id)
    
    # TODO: Validate package exists
    # TODO: Check inventory space
    # TODO: Add item/mesos to character
    # TODO: Remove from database
    # TODO: Send remove packet
    
    Logger.debug("Duey receive: package #{package_id}, character #{character_id}")
    
    # Send failure for now
    send(client_pid, {:send_packet, duey_error(17)})
    :ok
  end

  # Operation 6: Remove package
  defp handle_duey_op(6, packet, client_pid, character_id, _char_state) do
    package_id = In.decode_int(packet)
    
    # TODO: Remove from database
    # remove_item_from_db(package_id, character_id)
    
    # TODO: Send remove confirmation
    # packet = Packets.remove_item_from_duey(true, package_id)
    # send(client_pid, {:send_packet, packet})
    
    Logger.debug("Duey remove: package #{package_id}, character #{character_id}")
    :ok
  end

  # Operation 8: Close Duey
  defp handle_duey_op(8, _packet, client_pid, character_id, _char_state) do
    # TODO: Set conversation state to 0
    Logger.debug("Duey close: character #{character_id}")
    :ok
  end

  # Unknown operation
  defp handle_duey_op(operation, _packet, _client_pid, character_id, _char_state) do
    Logger.warning("Unknown Duey operation #{operation} from character #{character_id}")
    :ok
  end

  # ============================================================================
  # Database Operations (Stubs)
  # ============================================================================

  @doc """
  Loads all packages for a character.
  """
  def load_items(character_id) do
    # TODO: Query dueypackages table
    # SELECT * FROM dueypackages WHERE RecieverId = ?
    []
  end

  @doc """
  Loads a single package by ID.
  """
  def load_single_item(package_id, character_id) do
    # TODO: Query dueypackages table
    # SELECT * FROM dueypackages WHERE PackageId = ? and RecieverId = ?
    nil
  end

  @doc """
  Adds mesos to database.
  """
  def add_meso_to_db(mesos, sender_name, recipient_id, is_online) do
    # TODO: INSERT INTO dueypackages (RecieverId, SenderName, Mesos, TimeStamp, Checked, Type)
    # VALUES (?, ?, ?, ?, ?, 3)
    false
  end

  @doc """
  Adds item to database.
  """
  def add_item_to_db(item, quantity, mesos, sender_name, recipient_id, is_online) do
    # TODO: INSERT INTO dueypackages with item data
    # Use ItemLoader.DUEY.saveItems for item serialization
    false
  end

  @doc """
  Removes item from database.
  """
  def remove_item_from_db(package_id, character_id) do
    # TODO: DELETE FROM dueypackages WHERE PackageId = ? and RecieverId = ?
    :ok
  end

  @doc """
  Marks messages as received (updates Checked flag).
  """
  def receive_msg(character_id) do
    # TODO: UPDATE dueypackages SET Checked = 0 WHERE RecieverId = ?
    :ok
  end

  # ============================================================================
  # Helper Functions
  # ============================================================================

  defp duey_error(code) do
    # TODO: Implement proper Duey error packet
    # Packets.send_duey(code, nil)
    <<>>
  end
end