defmodule DaProductApp.Application do
  # See https://hexdocs.pm/elixir/Application.html
  # for more information on OTP Applications
  @moduledoc false

  use Application
  require Logger
  
  alias DaProductApp.MercuryISO8583.AsyncCorrelatorStartup
  alias DaProductApp.Startup.{EventSystemInitializer, GracefulShutdown}

  @impl true
  def start(_type, _args) do
    # Validate AsyncCorrelator configuration early
    case AsyncCorrelatorStartup.validate_configuration() do
      {:ok, _} -> 
        Logger.info("AsyncCorrelator configuration validation passed")
      
      {:error, reason} -> 
        Logger.error("AsyncCorrelator configuration validation failed: #{inspect(reason)}")
        Logger.warn("Application will start but async correlation will be disabled")
    end
    children = [
      DaProductAppWeb.Telemetry,
      DaProductApp.Repo,
      {DNSCluster, query: Application.get_env(:da_product_app, :dns_cluster_query) || :ignore},
      {Phoenix.PubSub, name: DaProductApp.PubSub},
      # Start the Finch HTTP client for sending emails
      {Finch, name: DaProductApp.Finch},
      # Start a worker by calling: DaProductApp.Worker.start_link(arg)
      # {DaProductApp.Worker, arg},
      
      # ISO8583 Switch System - Enhanced Architecture
      
      # 0. Event System: Event-driven architecture for payment processing
      DaProductApp.Events.EventDispatcher,
      
      # 0. ProcessorRegistry: Manages configurable message processor pipelines
      DaProductApp.MercuryISO8583.ProcessorRegistry,
      
      # 0.1. NetworkConnectorRegistry: Registry for network connector processes
      {Registry, keys: :unique, name: DaProductApp.NetworkConnectorRegistry},
      
      # 1. AsyncCorrelator System: Manages async correlation for high-volume networks
      # Reads configuration from config/async_correlator.exs
      DaProductApp.MercuryISO8583.AsyncCorrelatorSupervisor,
      
      # 1b. AsyncCorrelator Monitor: Runtime monitoring and management
      DaProductApp.MercuryISO8583.AsyncCorrelatorMonitor,
      
      # 2. Enhanced UpstreamSupervisor: Manages upstream network connections (VISA/MasterCard/etc)
      # Reads upstream configurations from config/upstream_networks.exs
      DaProductApp.Switch.EnhancedUpstreamSupervisor,
      
      # 2.1. Health Event Cleanup: Periodic database cleanup for health monitoring
      DaProductApp.Switch.HealthEventCleanup,
      
      # 3. Enhanced DeviceListenerSupervisor: Manages multiple protocol listeners  
      # Reads listener configurations from config/incoming_listeners.exs
      DaProductApp.Switch.EnhancedDeviceListenerSupervisor,
      
      # Start to serve requests, typically the last entry
      DaProductAppWeb.Endpoint
    ]

    Logger.info("Starting application with ISO8583 switch system - listeners configured via incoming_listeners.exs")

    # See https://hexdocs.pm/elixir/Supervisor.html
    # for other strategies and supported options
    opts = [strategy: :one_for_one, name: DaProductApp.Supervisor]
    
    case Supervisor.start_link(children, opts) do
      {:ok, pid} = result ->
        Logger.info("Application supervisor started successfully")
        
        # Register event listeners after the EventDispatcher is running
        Task.start(fn ->
          :timer.sleep(1000)  # Give EventDispatcher time to fully initialize
          EventSystemInitializer.register_event_listeners()
        end)
        
        result
      
      {:error, reason} = error ->
        Logger.error("Failed to start application supervisor: #{inspect(reason)}")
        error
    end
  end

  # Handle graceful application shutdown
  @impl true
  def stop(_state) do
    Logger.info("Application stopping - delegating to graceful shutdown handler")
    GracefulShutdown.perform_shutdown(30_000)
  end

  # Tell Phoenix to update the endpoint configuration
  # whenever the application is updated.
  @impl true
  def config_change(changed, _new, removed) do
    DaProductAppWeb.Endpoint.config_change(changed, removed)
    :ok
  end
end