defmodule BoamTest do
  use ExUnit.Case, async: false

  alias Boam.JS
  alias Boam.Runtime

  doctest Boam

  test "evaluates JavaScript values through the runtime wrapper" do
    runtime = start_supervised!({Runtime, []})

    assert {:ok, 3} = Runtime.eval(runtime, "1 + 2")
    assert {:ok, :undefined} = Runtime.eval(runtime, "undefined")

    assert {:ok, %{"nested" => [1, true, nil]}} =
             Runtime.eval(runtime, "({ nested: [1, true, null] })")
  end

  test "dispatches into exported BEAM handlers" do
    runtime =
      start_supervised!(
        {Runtime,
         [
           exports: %{
             sum: fn [left, right] -> left + right end
           }
         ]}
      )

    assert {:ok, 5} = Runtime.eval(runtime, "beam.call('sum', 2, 3)")
  end

  test "uses a fallback matcher for unregistered names" do
    runtime =
      start_supervised!(
        {Runtime,
         [
           fallback: fn name, args -> "#{name}:#{Enum.join(args, ",")}" end
         ]}
      )

    assert {:ok, "echo:1,two"} = Runtime.eval(runtime, "beam.call('echo', 1, 'two')")
  end

  test "turns dispatcher crashes into JavaScript errors instead of hanging" do
    runtime =
      start_supervised!(
        {Runtime,
         [
           exports: %{
             explode: fn _args -> raise "boom" end
           }
         ]}
      )

    assert {:error, message} = Runtime.eval(runtime, "beam.call('explode')")
    assert message =~ "boom"
  end

  test "rejects unsupported bridge arguments loudly" do
    runtime =
      start_supervised!(
        {Runtime,
         [
           exports: %{
             noop: fn _args -> :ok end
           }
         ]}
      )

    assert {:error, message} = Runtime.eval(runtime, "beam.call('noop', undefined)")
    assert message =~ "undefined"
  end

  test "returns a descriptive error for missing handlers" do
    runtime = start_supervised!({Runtime, []})

    assert {:error, message} = Runtime.eval(runtime, "beam.call('missing')")
    assert message =~ "no handler registered"
  end

  test "runs prelude code during startup" do
    runtime =
      start_supervised!(
        {Runtime,
         [
           prelude: "globalThis.console = { prefix: 'ready:' };"
         ]}
      )

    assert {:ok, "ready:ok"} = Runtime.eval(runtime, "console.prefix + 'ok'")
  end

  test "exposes nested Elixir handlers as JS functions" do
    runtime =
      start_supervised!(
        {Runtime,
         [
           expose: %{
             console: %{
               log: fn [message] -> "logged:" <> message end,
               warn: {:dispatch, "logger.warn", fn [message] -> "warn:" <> message end}
             }
           }
         ]}
      )

    assert {:ok, "logged:hello"} = Runtime.eval(runtime, "console.log('hello')")
    assert {:ok, "warn:careful"} = Runtime.eval(runtime, "console.warn('careful')")
  end

  test "can use a manually generated shim prelude" do
    runtime =
      start_supervised!(
        {Runtime,
         [
           fallback: fn name, args ->
             "#{name}:#{Enum.join(Enum.map(args, &to_string/1), ",")}"
           end,
           prelude: JS.export_prelude(%{console: %{log: true}})
         ]}
      )

    assert {:ok, "console.log:1,two"} = Runtime.eval(runtime, "console.log(1, 'two')")
  end

  test "fails startup when the prelude is invalid JavaScript" do
    {pid, monitor} =
      spawn_monitor(fn ->
        Runtime.start_link(prelude: "let = ;")
      end)

    assert_receive {:DOWN, ^monitor, :process, ^pid, {:startup_prelude_failed, message}}

    assert message != ""
  end

  test "rejects automatic exposure when an external dispatcher is supplied" do
    dispatcher = start_supervised!({Boam.Dispatcher, []})

    {pid, monitor} =
      spawn_monitor(fn ->
        Runtime.start_link(
          dispatcher: dispatcher,
          expose: %{console: %{log: fn _args -> :ok end}}
        )
      end)

    assert_receive {:DOWN, ^monitor, :process, ^pid, message}

    assert message =~ "cannot use :expose"
  end
end