defmodule Odinsea.Game.Reactor do
  @moduledoc """
  Represents a reactor instance on a map.
  
  Reactors are map objects (boxes, rocks, plants) that can be hit/activated by players.
  They have states, can drop items, trigger scripts, and respawn after time.
  
  Ported from Java: src/server/maps/MapleReactor.java
  """

  alias Odinsea.Game.ReactorStats

  @typedoc "Reactor instance struct"
  @type t :: %__MODULE__{
    # Identity
    oid: integer() | nil,          # Object ID (assigned by map)
    reactor_id: integer(),         # Reactor template ID
    
    # State
    state: integer(),              # Current state (byte)
    alive: boolean(),              # Whether reactor is active
    timer_active: boolean(),       # Whether timeout timer is running
    
    # Position
    x: integer(),                  # X position
    y: integer(),                  # Y position
    facing_direction: integer(),   # Facing direction (0 or 1)
    
    # Properties
    name: String.t(),              # Reactor name
    delay: integer(),              # Respawn delay in milliseconds
    custom: boolean(),             # Custom spawned (not from template)
    
    # Stats reference
    stats: ReactorStats.t() | nil  # Template stats
  }

  defstruct [
    :oid,
    :reactor_id,
    :stats,
    state: 0,
    alive: true,
    timer_active: false,
    x: 0,
    y: 0,
    facing_direction: 0,
    name: "",
    delay: -1,
    custom: false
  ]

  @doc """
  Creates a new reactor instance from template stats.
  """
  @spec new(integer(), ReactorStats.t()) :: t()
  def new(reactor_id, stats) do
    %__MODULE__{
      reactor_id: reactor_id,
      stats: stats
    }
  end

  @doc """
  Creates a copy of a reactor (for respawning).
  """
  @spec copy(t()) :: t()
  def copy(reactor) do
    %__MODULE__{
      reactor_id: reactor.reactor_id,
      stats: reactor.stats,
      state: 0,
      alive: true,
      timer_active: false,
      x: reactor.x,
      y: reactor.y,
      facing_direction: reactor.facing_direction,
      name: reactor.name,
      delay: reactor.delay,
      custom: reactor.custom
    }
  end

  @doc """
  Sets the reactor's object ID.
  """
  @spec set_oid(t(), integer()) :: t()
  def set_oid(reactor, oid) do
    %{reactor | oid: oid}
  end

  @doc """
  Sets the reactor's position.
  """
  @spec set_position(t(), integer(), integer()) :: t()
  def set_position(reactor, x, y) do
    %{reactor | x: x, y: y}
  end

  @doc """
  Sets the reactor's state.
  """
  @spec set_state(t(), integer()) :: t()
  def set_state(reactor, state) do
    %{reactor | state: state}
  end

  @doc """
  Sets whether the reactor is alive.
  """
  @spec set_alive(t(), boolean()) :: t()
  def set_alive(reactor, alive) do
    %{reactor | alive: alive}
  end

  @doc """
  Sets the facing direction.
  """
  @spec set_facing_direction(t(), integer()) :: t()
  def set_facing_direction(reactor, direction) do
    %{reactor | facing_direction: direction}
  end

  @doc """
  Sets the reactor name.
  """
  @spec set_name(t(), String.t()) :: t()
  def set_name(reactor, name) do
    %{reactor | name: name}
  end

  @doc """
  Sets the respawn delay.
  """
  @spec set_delay(t(), integer()) :: t()
  def set_delay(reactor, delay) do
    %{reactor | delay: delay}
  end

  @doc """
  Sets whether this is a custom reactor.
  """
  @spec set_custom(t(), boolean()) :: t()
  def set_custom(reactor, custom) do
    %{reactor | custom: custom}
  end

  @doc """
  Sets timer active status.
  """
  @spec set_timer_active(t(), boolean()) :: t()
  def set_timer_active(reactor, active) do
    %{reactor | timer_active: active}
  end

  @doc """
  Gets the reactor type for the current state.
  Returns the type value or -1 if stats not loaded.
  """
  @spec get_type(t()) :: integer()
  def get_type(reactor) do
    if reactor.stats do
      ReactorStats.get_type(reactor.stats, reactor.state)
    else
      -1
    end
  end

  @doc """
  Gets the next state for the current state.
  """
  @spec get_next_state(t()) :: integer()
  def get_next_state(reactor) do
    if reactor.stats do
      ReactorStats.get_next_state(reactor.stats, reactor.state)
    else
      -1
    end
  end

  @doc """
  Gets the timeout for the current state.
  """
  @spec get_timeout(t()) :: integer()
  def get_timeout(reactor) do
    if reactor.stats do
      ReactorStats.get_timeout(reactor.stats, reactor.state)
    else
      -1
    end
  end

  @doc """
  Gets the touch mode for the current state.
  Returns: 0 = hit only, 1 = click/touch, 2 = touch only
  """
  @spec can_touch(t()) :: integer()
  def can_touch(reactor) do
    if reactor.stats do
      ReactorStats.can_touch(reactor.stats, reactor.state)
    else
      0
    end
  end

  @doc """
  Gets the required item to react for the current state.
  Returns {item_id, quantity} or nil.
  """
  @spec get_react_item(t()) :: {integer(), integer()} | nil
  def get_react_item(reactor) do
    if reactor.stats do
      ReactorStats.get_react_item(reactor.stats, reactor.state)
    else
      nil
    end
  end

  @doc """
  Advances to the next state.
  Returns the updated reactor.
  """
  @spec advance_state(t()) :: t()
  def advance_state(reactor) do
    next_state = get_next_state(reactor)
    if next_state >= 0 do
      set_state(reactor, next_state)
    else
      reactor
    end
  end

  @doc """
  Checks if the reactor should trigger a script for the current state.
  """
  @spec should_trigger_script?(t()) :: boolean()
  def should_trigger_script?(reactor) do
    type = get_type(reactor)
    # Type < 100 or type == 999 typically trigger scripts
    type < 100 or type == 999
  end

  @doc """
  Checks if this reactor is in a looping state (state == next_state).
  """
  @spec is_looping?(t()) :: boolean()
  def is_looping?(reactor) do
    reactor.state == get_next_state(reactor)
  end

  @doc """
  Checks if the reactor should be destroyed (next state is -1 or final state).
  """
  @spec should_destroy?(t()) :: boolean()
  def should_destroy?(reactor) do
    next = get_next_state(reactor)
    next == -1 or get_type(reactor) == 999
  end

  @doc """
  Gets the reactor's area of effect (hit box).
  Returns {tl_x, tl_y, br_x, br_y} or nil if not defined.
  """
  @spec get_area(t()) :: {integer(), integer(), integer(), integer()} | nil
  def get_area(reactor) do
    if reactor.stats and reactor.stats.tl and reactor.stats.br do
      {reactor.stats.tl.x, reactor.stats.tl.y, reactor.stats.br.x, reactor.stats.br.y}
    else
      nil
    end
  end

  @doc """
  Resets the reactor to initial state (for respawning).
  """
  @spec reset(t()) :: t()
  def reset(reactor) do
    %{reactor | 
      state: 0, 
      alive: true, 
      timer_active: false
    }
  end
end