defmodule Odinsea.Channel.Handler.Summon do
  @moduledoc """
  Handles summon-related packets (puppet, dragon, summons).

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

  ## Main Handlers
  - handle_move_dragon/2 - Dragon movement
  - handle_move_summon/2 - Summon movement  
  - handle_damage_summon/2 - Summon taking damage
  - handle_summon_attack/2 - Summon attacking
  - handle_remove_summon/2 - Remove summon
  - handle_sub_summon/2 - Summon sub-skill (healing, etc.)
  - handle_pvp_summon/2 - PVP summon attack
  """

  require Logger

  alias Odinsea.Net.Packet.In
  alias Odinsea.Game.{Character, Map}

  # ============================================================================
  # Dragon Handlers
  # ============================================================================

  @doc """
  Handles dragon movement (CP_MOVE_DRAGON / 0xE7).

  Reference: SummonHandler.MoveDragon()
  """
  def handle_move_dragon(packet, client_pid) do
    # Skip 8 bytes (position data)
    _ = In.decode_long(packet)
    
    # Parse movement data
    # TODO: Implement full movement parsing
    
    case Character.get_state_by_client(client_pid) do
      {:ok, character_id, char_state} ->
        # TODO: Validate dragon exists for character
        # TODO: Update dragon position
        # TODO: Broadcast movement to other players
        
        Logger.debug("Dragon move: character #{character_id}")
        :ok

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

  # ============================================================================
  # Summon Handlers
  # ============================================================================

  @doc """
  Handles summon movement (CP_MOVE_SUMMON / 0xDF).

  Reference: SummonHandler.MoveSummon()
  """
  def handle_move_summon(packet, client_pid) do
    summon_oid = In.decode_int(packet)
    
    # Skip 8 bytes (start position)
    _ = In.decode_long(packet)
    
    # Parse movement data
    # TODO: Implement movement parsing
    
    case Character.get_state_by_client(client_pid) do
      {:ok, character_id, char_state} ->
        # TODO: Validate summon exists and belongs to character
        # TODO: Check summon movement type (skip if STATIONARY)
        # TODO: Update summon position
        # TODO: Broadcast movement to other players
        
        Logger.debug("Summon move: OID #{summon_oid}, character #{character_id}")
        :ok

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

  @doc """
  Handles summon taking damage (CP_DAMAGE_SUMMON / 0xE1).

  Puppet summons can take damage and be destroyed.

  Reference: SummonHandler.DamageSummon()
  """
  def handle_damage_summon(packet, client_pid) do
    unk_byte = In.decode_byte(packet)
    damage = In.decode_int(packet)
    monster_id_from = In.decode_int(packet)
    
    case Character.get_state_by_client(client_pid) do
      {:ok, character_id, char_state} ->
        # TODO: Find puppet summon for character
        # TODO: Apply damage to summon HP
        # TODO: Broadcast damage packet
        # TODO: Remove summon if HP <= 0
        
        Logger.debug("Summon damage: #{damage} from mob #{monster_id_from}, unk #{unk_byte}, character #{character_id}")
        :ok

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

  @doc """
  Handles summon attack (CP_SUMMON_ATTACK / 0xE0).

  Summons attack monsters with their skills.

  Reference: SummonHandler.SummonAttack()
  """
  def handle_summon_attack(packet, client_pid) do
    summon_oid = In.decode_int(packet)
    
    # Skip bytes based on game version
    _ = In.decode_long(packet)  # tick or unknown
    
    tick = In.decode_int(packet)
    _ = In.decode_long(packet)  # skip
    
    animation = In.decode_byte(packet)
    _ = In.decode_long(packet)  # CRC32 skip
    
    mob_count = In.decode_byte(packet)
    
    # Parse attack targets
    targets = parse_summon_targets(packet, mob_count)
    
    case Character.get_state_by_client(client_pid) do
      {:ok, character_id, char_state} ->
        # TODO: Validate summon exists and belongs to character
        # TODO: Check attack frequency (anti-cheat)
        # TODO: Calculate damage for each target
        # TODO: Apply damage to monsters
        # TODO: Broadcast attack packet
        # TODO: Remove summon if not multi-attack
        
        Logger.debug("Summon attack: OID #{summon_oid}, tick #{tick}, anim #{animation}, targets #{length(targets)}, character #{character_id}")
        :ok

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

  @doc """
  Handles summon removal (CP_REMOVE_SUMMON / 0xE3).

  Player manually removes their summon.

  Reference: SummonHandler.RemoveSummon()
  """
  def handle_remove_summon(packet, client_pid) do
    summon_oid = In.decode_int(packet)
    
    case Character.get_state_by_client(client_pid) do
      {:ok, character_id, char_state} ->
        # TODO: Validate summon exists and belongs to character
        # TODO: Check if summon can be removed (not rock/shock)
        # TODO: Remove summon from map
        # TODO: Broadcast removal packet
        # TODO: Cancel summon buff
        
        Logger.debug("Remove summon: OID #{summon_oid}, character #{character_id}")
        :ok

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

  @doc """
  Handles summon sub-skill (CP_SUB_SUMMON / 0xE2).

  Special summon abilities like:
  - 35121009: Mech summon extension (spawn additional summons)
  - 35111011: Healing
  - 1321007: Beholder (heal/buff)

  Reference: SummonHandler.SubSummon()
  """
  def handle_sub_summon(packet, client_pid) do
    summon_oid = In.decode_int(packet)
    
    case Character.get_state_by_client(client_pid) do
      {:ok, character_id, char_state} ->
        # TODO: Get summon by OID
        # TODO: Check summon cooldown
        # TODO: Execute sub-skill based on summon skill ID
        # TODO: Apply effects (heal, spawn, buff)
        # TODO: Broadcast skill effect
        
        Logger.debug("Sub summon: OID #{summon_oid}, character #{character_id}")
        :ok

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

  @doc """
  Handles PVP summon attack (CP_PVP_SUMMON / 0xE4).

  Summon attacks in PVP mode.

  Reference: SummonHandler.SummonPVP()
  """
  def handle_pvp_summon(packet, client_pid) do
    summon_oid = In.decode_int(packet)
    
    # Parse attack data based on packet length
    tick = if byte_size(packet.data) >= 27 do
      packet
      |> skip_bytes(23)
      |> In.decode_int()
    else
      -1
    end
    
    case Character.get_state_by_client(client_pid) do
      {:ok, character_id, char_state} ->
        # TODO: Validate player is in PVP
        # TODO: Validate summon belongs to character
        # TODO: Calculate PVP damage
        # TODO: Apply damage to targets
        # TODO: Update PVP score
        # TODO: Broadcast attack packet
        
        Logger.debug("PVP summon attack: OID #{summon_oid}, tick #{tick}, character #{character_id}")
        :ok

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

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

  defp parse_summon_targets(packet, count) do
    Enum.reduce(1..count, [], fn _, acc ->
      mob_oid = In.decode_int(packet)
      _ = In.decode_bytes(packet, 18)  # skip unknown
      damage = In.decode_int(packet)
      
      [{mob_oid, damage} | acc]
    end)
    |> Enum.reverse()
  end

  defp skip_bytes(packet, count) do
    In.decode_bytes(packet, count)
    packet
  end
end