defmodule Odinsea.Game.Events.OlaOla do
  @moduledoc """
  Ola Ola Event - Portal guessing game (similar to Survival but with portals).
  Ported from Java `server.events.MapleOla`.

  ## Gameplay
  - 3 stages with random correct portals
  - Players must guess which portal leads forward
  - Wrong portals send players back or eliminate them
  - Fastest to finish wins

  ## Maps
  - Stage 1: 109030001 (5 portals: ch00-ch04)
  - Stage 2: 109030002 (8 portals: ch00-ch07)
  - Stage 3: 109030003 (16 portals: ch00-ch15)

  ## Win Condition
  - Reach the finish map by choosing correct portals
  - First to finish gets best prize, all finishers get prize
  """

  alias Odinsea.Game.Event
  alias Odinsea.Game.Timer.EventTimer
  alias Odinsea.Game.Character

  require Logger

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

  @typedoc "OlaOla event state"
  @type t :: %__MODULE__{
    base: Event.t(),
    stages: [non_neg_integer()],  # Correct portal indices for each stage
    time_started: integer() | nil,
    event_duration: non_neg_integer(),
    schedules: [reference()]
  }

  defstruct [
    :base,
    stages: [0, 0, 0],  # Will be randomized on start
    time_started: nil,
    event_duration: 360_000,  # 6 minutes
    schedules: []
  ]

  # ============================================================================
  # Constants
  # ============================================================================

  @map_ids [109030001, 109030002, 109030003]
  @event_duration 360_000  # 6 minutes in ms

  # Stage configurations
  @stage_config [
    %{map: 109030001, portals: 5, prefix: "ch"},   # Stage 1: 5 portals
    %{map: 109030002, portals: 8, prefix: "ch"},   # Stage 2: 8 portals
    %{map: 109030003, portals: 16, prefix: "ch"}   # Stage 3: 16 portals
  ]

  # ============================================================================
  # Event Implementation
  # ============================================================================

  @doc """
  Creates a new OlaOla event for the given channel.
  """
  def new(channel_id) do
    base = Event.new(:ola_ola, channel_id, @map_ids)

    %__MODULE__{
      base: base,
      stages: [0, 0, 0],
      time_started: nil,
      event_duration: @event_duration,
      schedules: []
    }
  end

  @doc """
  Returns the map IDs for this event type.
  """
  def map_ids, do: @map_ids

  @doc """
  Resets the event state for a new game.
  """
  def reset(%__MODULE__{} = event) do
    # Cancel existing schedules
    cancel_schedules(event)

    base = %{event.base | is_running: true, player_count: 0}

    %__MODULE__{
      event |
      base: base,
      stages: [0, 0, 0],
      time_started: nil,
      schedules: []
    }
  end

  @doc """
  Cleans up the event after it ends.
  Randomizes correct portals for next game.
  """
  def unreset(%__MODULE__{} = event) do
    cancel_schedules(event)

    # Randomize correct portals for each stage
    stages = [
      random_stage_portal(0),  # Stage 1: 0-4
      random_stage_portal(1),  # Stage 2: 0-7
      random_stage_portal(2)   # Stage 3: 0-15
    ]

    # Hack check: stage 1 portal 2 is inaccessible
    stages = if Enum.at(stages, 0) == 2 do
      List.replace_at(stages, 0, 3)
    else
      stages
    end

    # Open entry portal
    set_portal_state(event, "join00", true)

    base = %{event.base | is_running: false, player_count: 0}

    %__MODULE__{
      event |
      base: base,
      stages: stages,
      time_started: nil,
      schedules: []
    }
  end

  @doc """
  Called when a player finishes (reaches end map).
  Gives prize and achievement.
  """
  def finished(%__MODULE__{} = event, character) do
    Logger.info("Player #{character.name} finished Ola Ola event!")

    # Give prize
    Event.give_prize(character)

    # Give achievement (ID 21)
    Character.finish_achievement(character, 21)

    :ok
  end

  @doc """
  Called when a player loads into an event map.
  Sends clock if timer is running.
  """
  def on_map_load(%__MODULE__{} = event, character) do
    if is_timer_started(event) do
      time_left = get_time_left(event)
      Logger.debug("Sending Ola Ola clock to #{character.name}: #{div(time_left, 1000)}s remaining")
    end

    :ok
  end

  @doc """
  Starts the Ola Ola event gameplay.
  """
  def start_event(%__MODULE__{} = event) do
    Logger.info("Starting Ola Ola event on channel #{event.base.channel_id}")

    now = System.system_time(:millisecond)

    # Close entry portal
    set_portal_state(event, "join00", false)

    # Broadcast start
    Event.broadcast_to_event(event.base, :event_started)
    Event.broadcast_to_event(event.base, {:clock, div(@event_duration, 1000)})
    Event.broadcast_to_event(event.base, {:server_notice, "The portal has now opened. Press the up arrow key at the portal to enter."})
    Event.broadcast_to_event(event.base, {:server_notice, "Fall down once, and never get back up again! Get to the top without falling down!"})

    # Schedule event end
    end_ref = EventTimer.schedule(
      fn -> end_event(event) end,
      @event_duration
    )

    %__MODULE__{
      event |
      time_started: now,
      schedules: [end_ref]
    }
  end

  @doc """
  Checks if a character chose the correct portal for their current stage.

  ## Parameters
  - event: The OlaOla event state
  - portal_name: The portal name (e.g., "ch00", "ch05")
  - map_id: Current map ID

  ## Returns
  - true if correct portal
  - false if wrong portal
  """
  def correct_portal?(%__MODULE__{stages: stages}, portal_name, map_id) do
    # Get stage index from map ID
    stage_index = get_stage_index(map_id)

    if stage_index == nil do
      false
    else
      # Get correct portal for this stage
      correct = Enum.at(stages, stage_index)

      # Format correct portal name
      correct_name = format_portal_name(correct)

      portal_name == correct_name
    end
  end

  @doc """
  Gets the correct portal name for a stage.
  """
  def get_correct_portal(%__MODULE__{stages: stages}, stage_index) when stage_index in 0..2 do
    correct = Enum.at(stages, stage_index)
    format_portal_name(correct)
  end

  def get_correct_portal(_, _), do: nil

  @doc """
  Checks if the timer has started.
  """
  def is_timer_started(%__MODULE__{time_started: nil}), do: false
  def is_timer_started(%__MODULE__{}), do: true

  @doc """
  Gets the total event duration in milliseconds.
  """
  def get_time(%__MODULE__{event_duration: duration}), do: duration

  @doc """
  Gets the time remaining in milliseconds.
  """
  def get_time_left(%__MODULE__{time_started: nil}), do: @event_duration
  def get_time_left(%__MODULE__{time_started: started, event_duration: duration}) do
    elapsed = System.system_time(:millisecond) - started
    max(0, duration - elapsed)
  end

  @doc """
  Gets the current stage (0-2) for a map ID.
  """
  def get_stage_index(map_id) do
    Enum.find_index(@map_ids, &(&1 == map_id))
  end

  @doc """
  Gets the stage configuration.
  """
  def stage_config, do: @stage_config

  @doc """
  Handles a player attempting to use a portal.
  Returns {:ok, destination_map} for correct portal, :error for wrong portal.
  """
  def attempt_portal(%__MODULE__{} = event, portal_name, current_map_id) do
    if correct_portal?(event, portal_name, current_map_id) do
      # Correct portal - advance to next stage
      stage = get_stage_index(current_map_id)

      if stage < 2 do
        next_map = Enum.at(@map_ids, stage + 1)
        {:ok, next_map}
      else
        # Finished all stages
        {:finished, 109050000}  # Finish map
      end
    else
      # Wrong portal - fail
      :error
    end
  end

  # ============================================================================
  # Private Functions
  # ============================================================================

  defp random_stage_portal(stage_index) do
    portal_count = Enum.at(@stage_config, stage_index).portals
    :rand.uniform(portal_count) - 1  # 0-based
  end

  defp format_portal_name(portal_num) do
    # Format as ch00, ch01, etc.
    if portal_num < 10 do
      "ch0#{portal_num}"
    else
      "ch#{portal_num}"
    end
  end

  defp cancel_schedules(%__MODULE__{schedules: schedules} = event) do
    Enum.each(schedules, fn ref ->
      EventTimer.cancel(ref)
    end)

    %{event | schedules: []}
  end

  defp set_portal_state(%__MODULE__{}, _portal_name, _state) do
    # In real implementation, update map portal state
    :ok
  end

  defp end_event(%__MODULE__{} = event) do
    Logger.info("Ola Ola event ended on channel #{event.base.channel_id}")

    # Warp out all remaining players
    # In real implementation, get all players on event maps and warp them

    # Unreset event
    unreset(event)
  end
end