defmodule DaProductApp.ConsoleLogger do
  @moduledoc """
  A custom Logger backend that writes log messages to the console with Apache-style formatting.

  Uses the shared LogFormatter to ensure console output matches the WeeklyLogger file format exactly.

  Features:
  - Logs are formatted in Apache style: [Day Mon DD HH:MM:SS.microseconds YYYY] [level] [pid PID] [client IP:PORT] message
  - Output is sent to standard output (IO.write)
  - Format is identical to WeeklyLogger for consistency across all logging destinations

  Configuration example:
      config :logger,
        backends: [:console, DaProductApp.ConsoleLogger]
  """

  @behaviour :gen_event

  defstruct [:pid]

  # ---------------------------------------------------------------------------
  # :gen_event callbacks
  # ---------------------------------------------------------------------------

  def init(__MODULE__) do
    {:ok, %__MODULE__{pid: System.pid()}}
  end

  def init({__MODULE__, _opts}) do
    {:ok, %__MODULE__{pid: System.pid()}}
  end

  def handle_event({level, _gl, {Logger, msg, timestamp, metadata}}, state) do
    try do
      formatted = DaProductApp.LogFormatter.format_entry(level, msg, timestamp, metadata, state.pid)
      IO.write(formatted)
      {:ok, state}
    rescue
      e ->
        IO.warn("ConsoleLogger handle_event failed: #{inspect(e)}")
        {:ok, state}
    end
  end

  def handle_event(:flush, state), do: {:ok, state}
  def handle_event(_event, state), do: {:ok, state}

  def handle_call({:configure, _opts}, state), do: {:ok, :ok, state}

  def handle_info(_msg, state), do: {:ok, state}

  def code_change(_old_vsn, state, _extra), do: {:ok, state}

  def terminate(_reason, _state), do: :ok
end