defmodule Odinsea.Scripting.EventManager do
  @moduledoc """
  Event Script Manager for handling game events and party quests.
  
  Event scripts run continuously on channel servers and manage instances
  of party quests, special events, and scheduled activities.
  
  ## Script Interface
  
  Event scripts receive an `em` (event manager) object with these callbacks:
  
  - `init/1` - Called when event is loaded
  - `schedule/3` - Schedule a method callback after delay
  - `setup/2` - Called to create a new event instance
  - `player_entry/2` - Player enters instance
  - `player_dead/2` - Player dies
  - `player_revive/2` - Player revives
  - `player_disconnected/2` - Player disconnects
  - `monster_value/2` - Monster killed, returns points
  - `all_monsters_dead/1` - All monsters killed
  - `scheduled_timeout/1` - Event timer expired
  - `left_party/2` - Player left party
  - `disband_party/1` - Party disbanded
  - `clear_pq/1` - Party quest cleared
  - `player_exit/2` - Player exits event
  - `cancel_schedule/1` - Event cancelled
  
  ## Example Event Script
  
      defmodule Odinsea.Scripting.Event.Boats do
        @behaviour Odinsea.Scripting.Behavior
        
        alias Odinsea.Scripting.EventManager
        
        @impl true
        def init(em) do
          schedule_new(em)
        end
        
        @impl true
        def schedule(em, "stopentry", _delay) do
          set_property(em, "entry", "false")
        end
        
        def schedule(em, "takeoff", _delay) do
          warp_all_player(em, 200000112, 200090000)
          schedule(em, "arrived", 420_000)
        end
        
        def schedule(em, "arrived", _delay) do
          warp_all_player(em, 200090000, 101000300)
          schedule_new(em)
        end
        
        defp schedule_new(em) do
          set_property(em, "docked", "true")
          set_property(em, "entry", "true")
          schedule(em, "stopentry", 240_000)
          schedule(em, "takeoff", 300_000)
        end
      end
  """

  use GenServer
  require Logger

  alias Odinsea.Scripting.{Manager, EventInstance}

  # ETS tables
  @event_scripts :event_scripts
  @event_instances :event_instances
  @event_properties :event_properties

  # ============================================================================
  # Types
  # ============================================================================

  @type t :: %__MODULE__{
    name: String.t(),
    channel: integer(),
    script_module: module() | nil,
    properties: map()
  }

  defstruct [
    :name,
    :channel,
    :script_module,
    :properties
  ]

  # ============================================================================
  # Client API
  # ============================================================================

  @doc """
  Starts the event script manager.
  """
  @spec start_link(keyword()) :: GenServer.on_start()
  def start_link(opts \\ []) do
    GenServer.start_link(__MODULE__, opts, name: __MODULE__)
  end

  @doc """
  Loads and initializes event scripts.
  
  ## Parameters
    - `scripts` - List of event script names (without .js extension)
    - `channel` - Channel server number
  
  ## Returns
    - `{:ok, count}` - Number of events loaded
  """
  @spec load_events([String.t()], integer()) :: {:ok, integer()} | {:error, term()}
  def load_events(scripts, channel) do
    GenServer.call(__MODULE__, {:load_events, scripts, channel})
  end

  @doc """
  Gets an event manager for a specific event.
  
  ## Parameters
    - `event_name` - Name of the event
  
  ## Returns
    - `{:ok, em}` - Event manager struct
    - `{:error, :not_found}` - Event not loaded
  """
  @spec get_event(String.t()) :: {:ok, t()} | {:error, term()}
  def get_event(event_name) do
    case :ets.lookup(@event_scripts, event_name) do
      [{^event_name, em}] -> {:ok, em}
      [] -> {:error, :not_found}
    end
  end

  @doc """
  Creates a new event instance.
  
  ## Parameters
    - `event_name` - Name of the event
    - `instance_name` - Unique name for this instance
    - `args` - Arguments to pass to setup
  
  ## Returns
    - `{:ok, eim}` - Event instance created
    - `{:error, reason}` - Failed to create
  """
  @spec new_instance(String.t(), String.t(), term()) :: 
    {:ok, EventInstance.t()} | {:error, term()}
  def new_instance(event_name, instance_name, args \\ nil) do
    GenServer.call(__MODULE__, {:new_instance, event_name, instance_name, args})
  end

  @doc """
  Gets an existing event instance.
  """
  @spec get_instance(String.t()) :: {:ok, EventInstance.t()} | {:error, term()}
  def get_instance(instance_name) do
    case :ets.lookup(@event_instances, instance_name) do
      [{^instance_name, eim}] -> {:ok, eim}
      [] -> {:error, :not_found}
    end
  end

  @doc """
  Disposes of an event instance.
  """
  @spec dispose_instance(String.t()) :: :ok
  def dispose_instance(instance_name) do
    GenServer.call(__MODULE__, {:dispose_instance, instance_name})
  end

  @doc """
  Schedules a method callback on an event.
  
  ## Parameters
    - `em` - Event manager or instance
    - `method_name` - Name of the method to call
    - `delay_ms` - Delay in milliseconds
  """
  @spec schedule(t() | EventInstance.t(), String.t(), integer()) :: reference()
  def schedule(em_or_eim, method_name, delay_ms) do
    GenServer.call(__MODULE__, {:schedule, em_or_eim, method_name, delay_ms})
  end

  @doc """
  Cancels all scheduled tasks for an event.
  """
  @spec cancel(t()) :: :ok
  def cancel(em) do
    GenServer.call(__MODULE__, {:cancel, em.name})
  end

  @doc """
  Sets a property on an event manager.
  """
  @spec set_property(t(), String.t(), String.t()) :: :ok
  def set_property(em, key, value) do
    GenServer.call(__MODULE__, {:set_property, em.name, key, value})
  end

  @doc """
  Gets a property from an event manager.
  """
  @spec get_property(t(), String.t()) :: String.t() | nil
  def get_property(em, key) do
    case :ets.lookup(@event_properties, {em.name, key}) do
      [{_, value}] -> value
      [] -> nil
    end
  end

  @doc """
  Warps all players from one map to another.
  
  ## Parameters
    - `em` - Event manager
    - `from_map` - Source map ID
    - `to_map` - Destination map ID
  """
  @spec warp_all_player(t(), integer(), integer()) :: :ok
  def warp_all_player(em, from_map, to_map) do
    Logger.debug("Event #{em.name}: Warp all from #{from_map} to #{to_map}")
    # TODO: Implement warp all
    :ok
  end

  @doc """
  Broadcasts a ship effect to a map.
  """
  @spec broadcast_ship(t(), integer(), integer()) :: :ok
  def broadcast_ship(em, map_id, effect) do
    Logger.debug("Event #{em.name}: Broadcast ship effect #{effect} to map #{map_id}")
    # TODO: Send boat packet
    :ok
  end

  @doc """
  Broadcasts a yellow message to the channel.
  """
  @spec broadcast_yellow_msg(t(), String.t()) :: :ok
  def broadcast_yellow_msg(em, message) do
    Logger.debug("Event #{em.name}: Yellow message: #{message}")
    # TODO: Broadcast to channel
    :ok
  end

  @doc """
  Broadcasts a server message.
  """
  @spec broadcast_server_msg(t(), integer(), String.t(), boolean()) :: :ok
  def broadcast_server_msg(em, type, message, weather \\ false) do
    Logger.debug("Event #{em.name}: Server message (#{type}): #{message}")
    # TODO: Broadcast
    :ok
  end

  @doc """
  Gets the map factory for creating map instances.
  """
  @spec get_map_factory(t()) :: term()
  def get_map_factory(_em) do
    # TODO: Return map factory
    nil
  end

  @doc """
  Gets a monster by ID.
  """
  @spec get_monster(t(), integer()) :: term()
  def get_monster(_em, mob_id) do
    # TODO: Return monster data
    %{id: mob_id}
  end

  @doc """
  Gets a reactor by ID.
  """
  @spec get_reactor(t(), integer()) :: term()
  def get_reactor(_em, reactor_id) do
    # TODO: Return reactor data
    %{id: reactor_id}
  end

  @doc """
  Creates new monster stats for overriding.
  """
  @spec new_monster_stats() :: map()
  def new_monster_stats() do
    %{}
  end

  @doc """
  Creates a new character list.
  """
  @spec new_char_list() :: list()
  def new_char_list() do
    []
  end

  @doc """
  Gets the EXP rate for the channel.
  """
  @spec get_exp_rate(t()) :: integer()
  def get_exp_rate(_em) do
    # TODO: Get from channel config
    1
  end

  @doc """
  Gets the channel server.
  """
  @spec get_channel_server(t()) :: term()
  def get_channel_server(em) do
    # TODO: Return channel server
    %{channel: em.channel}
  end

  @doc """
  Gets the channel number.
  """
  @spec get_channel(t()) :: integer()
  def get_channel(em) do
    em.channel
  end

  # ============================================================================
  # Server Callbacks
  # ============================================================================

  @impl true
  def init(_opts) do
    # Create ETS tables
    :ets.new(@event_scripts, [:named_table, :set, :public,
             read_concurrency: true, write_concurrency: true])
    :ets.new(@event_instances, [:named_table, :set, :public,
             read_concurrency: true, write_concurrency: true])
    :ets.new(@event_properties, [:named_table, :set, :public,
             read_concurrency: true, write_concurrency: true])
    
    Logger.info("Event Script Manager initialized")
    
    {:ok, %{timers: %{}}}
  end

  @impl true
  def handle_call({:load_events, scripts, channel}, _from, state) do
    count = Enum.count(scripts, fn script_name ->
      case Manager.get_script(:event, script_name) do
        {:ok, module} ->
          em = %__MODULE__{
            name: script_name,
            channel: channel,
            script_module: module,
            properties: %{}
          }
          
          :ets.insert(@event_scripts, {script_name, em})
          
          # Call init if available
          if function_exported?(module, :init, 1) do
            Task.start(fn ->
              try do
                module.init(em)
              rescue
                e -> Logger.error("Event #{script_name} init error: #{inspect(e)}")
              end
            end)
          end
          
          true
        
        {:error, reason} ->
          Logger.warning("Failed to load event #{script_name}: #{inspect(reason)}")
          false
      end
    end)
    
    {:reply, {:ok, count}, state}
  end

  @impl true
  def handle_call({:new_instance, event_name, instance_name, args}, _from, state) do
    case :ets.lookup(@event_scripts, event_name) do
      [{^event_name, em}] ->
        # Create event instance
        eim = EventInstance.new(em, instance_name, em.channel)
        :ets.insert(@event_instances, {instance_name, eim})
        
        # Call setup
        if em.script_module && function_exported?(em.script_module, :setup, 2) do
          Task.start(fn ->
            try do
              em.script_module.setup(eim, args)
            rescue
              e -> Logger.error("Event #{event_name} setup error: #{inspect(e)}")
            end
          end)
        end
        
        {:reply, {:ok, eim}, state}
      
      [] ->
        {:reply, {:error, :event_not_found}, state}
    end
  end

  @impl true
  def handle_call({:dispose_instance, instance_name}, _from, state) do
    :ets.delete(@event_instances, instance_name)
    
    # Cancel any timers for this instance
    timers = Map.get(state.timers, instance_name, [])
    Enum.each(timers, fn ref ->
      Process.cancel_timer(ref)
    end)
    
    new_timers = Map.delete(state.timers, instance_name)
    {:reply, :ok, %{state | timers: new_timers}}
  end

  @impl true
  def handle_call({:schedule, em_or_eim, method_name, delay_ms}, _from, state) do
    instance_name = case em_or_eim do
      %{name: name} -> name
      _ -> "unknown"
    end
    
    ref = Process.send_after(self(), {:scheduled, em_or_eim, method_name}, delay_ms)
    
    timers = Map.update(state.timers, instance_name, [ref], &[ref | &1])
    
    {:reply, ref, %{state | timers: timers}}
  end

  @impl true
  def handle_call({:cancel, event_name}, _from, state) do
    timers = Map.get(state.timers, event_name, [])
    Enum.each(timers, fn ref ->
      Process.cancel_timer(ref)
    end)
    
    new_timers = Map.delete(state.timers, event_name)
    {:reply, :ok, %{state | timers: new_timers}}
  end

  @impl true
  def handle_call({:set_property, event_name, key, value}, _from, state) do
    :ets.insert(@event_properties, {{event_name, key}, value})
    {:reply, :ok, state}
  end

  @impl true
  def handle_info({:scheduled, em_or_eim, method_name}, state) do
    # Find script module
    script_module = case em_or_eim do
      %{__struct__: Odinsea.Scripting.EventManager, script_module: mod} -> mod
      %{__struct__: Odinsea.Scripting.EventInstance, event_manager: em} -> em.script_module
      _ -> nil
    end
    
    if script_module && function_exported?(script_module, :schedule, 3) do
      Task.start(fn ->
        try do
          script_module.schedule(em_or_eim, method_name, 0)
        rescue
          e -> Logger.error("Scheduled event error: #{inspect(e)}")
        end
      end)
    end
    
    {:noreply, state}
  end
end