ex_esdb

defmodule ExESDB.ClusterSystem do
  @moduledoc """
  Supervisor for cluster coordination components.

  This supervisor manages cluster-specific coordination components:
  - ClusterCoordinator: Handles coordination logic and split-brain prevention
  - NodeMonitor: Monitors node health and handles failures

  Note: KhepriCluster is managed at the System level since it's mode-aware.
  """
  use Supervisor

  require Logger
  
  alias ExESDB.StoreNaming, as: StoreNaming
  alias ExESDB.Themes, as: Themes

  defp store_id(opts) do
    Keyword.get(opts, :store_id, :ex_esdb)
  end

  @impl true
  def init(opts) do
    Logger.info("[CLUSTER_SYSTEM] Initializing ClusterSystem supervisor with opts: #{inspect(opts)}")
    Logger.info("[CLUSTER_SYSTEM] ClusterSystem PID: #{inspect(self())}, Node: #{inspect(node())}")
    
    # Extract store_id for logging
    store_id = store_id(opts)
    Logger.info("[CLUSTER_SYSTEM] Store ID: #{inspect(store_id)}")
    
    Logger.info("[CLUSTER_SYSTEM] Starting cluster coordination components...")
    
    children = [
      # ClusterCoordinator handles coordination logic and split-brain prevention
      {ExESDB.StoreCoordinator, opts},
      # NodeMonitor provides fast failure detection
      {ExESDB.NodeMonitor, node_monitor_config(opts)}
    ]
    
    Logger.info("[CLUSTER_SYSTEM] Configured #{length(children)} cluster subsystems:")
    children |> Enum.with_index(1) |> Enum.each(fn {{module, _opts}, index} ->
      Logger.info("[CLUSTER_SYSTEM]   #{index}. #{inspect(module)} - #{get_component_description(module)}")
    end)
    
    Logger.info("[CLUSTER_SYSTEM] Using :one_for_one strategy - independent cluster components")

    IO.puts("#{Themes.cluster_system(self(), "is UP")}")
    
    result = Supervisor.init(children, strategy: :one_for_one)
    Logger.info("[CLUSTER_SYSTEM] ClusterSystem supervisor initialization complete")
    result
  end
  
  defp get_component_description(ExESDB.StoreCoordinator), do: "Cluster coordination and split-brain prevention"
  defp get_component_description(ExESDB.NodeMonitor), do: "Node health monitoring and failure detection"
  defp get_component_description(_), do: "Cluster component"

  def start_link(opts) do
    Supervisor.start_link(
      __MODULE__,
      opts,
      name: StoreNaming.genserver_name(__MODULE__, store_id(opts))
    )
  end

  def child_spec(opts) do
    %{
      id: StoreNaming.child_spec_id(__MODULE__, store_id(opts)),
      start: {__MODULE__, :start_link, [opts]},
      restart: :permanent,
      shutdown: :infinity,
      type: :supervisor
    }
  end

  # Helper function to configure NodeMonitor options
  defp node_monitor_config(opts) do
    store_id = store_id(opts)

    # More lenient configuration for node monitoring to prevent cascading failures
    [
      store_id: store_id,
      # 5 seconds (less frequent probing)
      probe_interval: 5_000,
      # 6 consecutive failures (more tolerance)
      failure_threshold: 6,
      # 3 second timeout per probe (more time)
      probe_timeout: 3_000
    ]
  end
end