defmodule GameServer.Schedule do
  @moduledoc ~S"""
  Dynamic cron-like job scheduling for hooks.
  
  Use this module in your `after_startup/0` hook to register scheduled jobs
  that will call your hook functions at specified intervals.
  
  This module is safe for distributed deployments - only one instance will
  execute each job per period using database locks.
  
  Scheduled callbacks are automatically protected from user RPC calls.
  
  ## Examples
  
      def after_startup do
        # Simple intervals
        Schedule.every_minutes(5, :on_every_5m)
        Schedule.hourly(:on_hourly)
        Schedule.daily(:on_daily)
  
        # With options
        Schedule.daily(:on_morning_report, hour: 9)
        Schedule.weekly(:on_monday, day: :monday, hour: 10)
  
        # Full cron syntax
        Schedule.cron(:my_job, "0 */6 * * *", :on_every_6h)
  
        :ok
      end
  
      # Callback receives context map (public function, but protected from RPC)
      def on_hourly(context) do
        IO.puts("Triggered at #{context.triggered_at}")
        :ok
      end
  
  ## Context
  
  All callbacks receive a context map:
  
      %{
        triggered_at: ~U[2025-12-03 14:00:00Z],
        job_name: :on_hourly,
        schedule: "0 * * * *"
      }
  
  ## Distributed Safety
  
  When running multiple instances, only one will execute each job per period.
  This is achieved via database locks in the `schedule_locks` table.
  Old locks are automatically cleaned up after 7 days.
  

  **Note:** This is an SDK stub. Calling these functions will raise an error.
  The actual implementation runs on the GameServer.
  """



  @doc ~S"""
    Cancel a scheduled job.
    
    ## Examples
    
        Schedule.cancel(:my_job)
    
  """
  @spec cancel(atom()) :: :ok
  def cancel(_name) do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        :ok

      _ ->
        raise "GameServer.Schedule.cancel/1 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Clean up old schedule locks older than the specified number of days.
    
    This is called automatically during job execution, but can also be
    called manually if needed. Default is 7 days.
    
    ## Examples
    
        Schedule.cleanup_old_locks()
        Schedule.cleanup_old_locks(days: 30)
    
  """
  @spec cleanup_old_locks() :: {:ok, non_neg_integer()}
  def cleanup_old_locks() do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        {:ok, nil}

      _ ->
        raise "GameServer.Schedule.cleanup_old_locks/0 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Clean up old schedule locks older than the specified number of days.
    
    This is called automatically during job execution, but can also be
    called manually if needed. Default is 7 days.
    
    ## Examples
    
        Schedule.cleanup_old_locks()
        Schedule.cleanup_old_locks(days: 30)
    
  """
  @spec cleanup_old_locks(keyword()) :: {:ok, non_neg_integer()}
  def cleanup_old_locks(_opts) do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        {:ok, nil}

      _ ->
        raise "GameServer.Schedule.cleanup_old_locks/1 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Register a job with full cron syntax.
    
    ## Examples
    
        Schedule.cron(:my_job, "*/15 * * * *", :on_every_15m)
        Schedule.cron(:weekdays, "0 9 * * 1-5", :on_weekday_morning)
    
  """
  @spec cron(atom(), String.t(), atom()) :: :ok | {:error, term()}
  def cron(_name, _cron_expr, _hook_fn) do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        :ok

      _ ->
        raise "GameServer.Schedule.cron/3 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Run a job every day.
    
    ## Options
    
      * `:hour` - hour of the day (0-23), default: 0
      * `:minute` - minute of the hour (0-59), default: 0
    
    ## Examples
    
        Schedule.daily(:on_midnight)
        Schedule.daily(:on_morning, hour: 9)
        Schedule.daily(:on_evening, hour: 18, minute: 30)
    
  """
  @spec daily(atom()) :: :ok | {:error, term()}
  def daily(_hook_fn) do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        :ok

      _ ->
        raise "GameServer.Schedule.daily/1 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Run a job every day.
    
    ## Options
    
      * `:hour` - hour of the day (0-23), default: 0
      * `:minute` - minute of the hour (0-59), default: 0
    
    ## Examples
    
        Schedule.daily(:on_midnight)
        Schedule.daily(:on_morning, hour: 9)
        Schedule.daily(:on_evening, hour: 18, minute: 30)
    
  """
  @spec daily(atom(), hour: 0..23, minute: 0..59) :: :ok | {:error, term()}
  def daily(_hook_fn, _opts) do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        :ok

      _ ->
        raise "GameServer.Schedule.daily/2 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Run a job every N minutes.
    
    ## Examples
    
        Schedule.every_minutes(5, :on_5m)
        Schedule.every_minutes(15, :on_15m)
    
  """
  @spec every_minutes(pos_integer(), atom()) :: :ok | {:error, term()}
  def every_minutes(_n, _hook_fn) do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        :ok

      _ ->
        raise "GameServer.Schedule.every_minutes/2 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Run a job every hour.
    
    ## Options
    
      * `:minute` - minute of the hour (0-59), default: 0
    
    ## Examples
    
        Schedule.hourly(:on_hourly)
        Schedule.hourly(:on_half_hour, minute: 30)
    
  """
  @spec hourly(atom()) :: :ok | {:error, term()}
  def hourly(_hook_fn) do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        :ok

      _ ->
        raise "GameServer.Schedule.hourly/1 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Run a job every hour.
    
    ## Options
    
      * `:minute` - minute of the hour (0-59), default: 0
    
    ## Examples
    
        Schedule.hourly(:on_hourly)
        Schedule.hourly(:on_half_hour, minute: 30)
    
  """
  @spec hourly(atom(), [{:minute, 0..59}]) :: :ok | {:error, term()}
  def hourly(_hook_fn, _opts) do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        :ok

      _ ->
        raise "GameServer.Schedule.hourly/2 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    List all scheduled jobs.
    
    Returns a list of job info maps.
    
  """
  @spec list() :: [%{name: atom(), schedule: String.t(), state: term()}]
  def list() do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        ""

      _ ->
        raise "GameServer.Schedule.list/0 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Returns the set of callback function names registered for scheduled jobs.
    
    These are protected from user RPC calls via `Hooks.call/3`.
    
  """
  @spec registered_callbacks() :: MapSet.t(atom())
  def registered_callbacks() do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        nil

      _ ->
        raise "GameServer.Schedule.registered_callbacks/0 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Run a job every week.
    
    ## Options
    
      * `:day` - day of week (`:sunday`, `:monday`, etc.), default: `:sunday`
      * `:hour` - hour of the day (0-23), default: 0
      * `:minute` - minute of the hour (0-59), default: 0
    
    ## Examples
    
        Schedule.weekly(:on_sunday)
        Schedule.weekly(:on_monday_morning, day: :monday, hour: 9)
    
  """
  @spec weekly(atom()) :: :ok | {:error, term()}
  def weekly(_hook_fn) do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        :ok

      _ ->
        raise "GameServer.Schedule.weekly/1 is a stub - only available at runtime on GameServer"
    end
  end


  @doc ~S"""
    Run a job every week.
    
    ## Options
    
      * `:day` - day of week (`:sunday`, `:monday`, etc.), default: `:sunday`
      * `:hour` - hour of the day (0-23), default: 0
      * `:minute` - minute of the hour (0-59), default: 0
    
    ## Examples
    
        Schedule.weekly(:on_sunday)
        Schedule.weekly(:on_monday_morning, day: :monday, hour: 9)
    
  """
  @spec weekly(atom(), day: atom(), hour: 0..23, minute: 0..59) :: :ok | {:error, term()}
  def weekly(_hook_fn, _opts) do
    case Application.get_env(:game_server_sdk, :stub_mode, :raise) do
      :placeholder ->
        :ok

      _ ->
        raise "GameServer.Schedule.weekly/2 is a stub - only available at runtime on GameServer"
    end
  end

end