defmodule Raxol.Test.Unit.Assertions do
  @moduledoc """
  Provides custom assertions for testing Raxol components.

  This module includes assertions for:
  - Component state validation
  - Event handling verification
  - Command emission checking
  - Render output validation
  - Layout verification
  - Style application testing
  """

  import ExUnit.Assertions

  @doc """
  Asserts that a component's rendered output matches the expected output.

  ## Example

      assert_rendered component, fn output ->
        assert output.type == :text
        assert output.content == "Hello, World!"
      end
  """
  defmacro assert_rendered(component, assertion) do
    quote do
      rendered = render_component(unquote(component))
      unquote(assertion).(rendered)
    end
  end

  @doc """
  Asserts that a component's layout matches the expected constraints.

  ## Example

      assert_layout component, %{
        width: 10,
        height: 5,
        x: 0,
        y: 0
      }
  """
  def assert_layout(component, constraints) when is_map(constraints) do
    layout = get_component_layout(component)

    Enum.each(constraints, fn {key, value} ->
      actual = Map.get(layout, key)

      assert actual == value,
             "Expected layout.#{key} to be #{inspect(value)}, but got: #{inspect(actual)}"
    end)
  end

  @doc """
  Asserts that a style is properly applied to a component.

  ## Example

      assert_style component, %{
        color: :blue,
        background: :white,
        bold: true
      }
  """
  def assert_style(component, style) when is_map(style) do
    applied_style = get_component_style(component)

    Enum.each(style, fn {key, value} ->
      actual = Map.get(applied_style, key)

      assert actual == value,
             "Expected style.#{key} to be #{inspect(value)}, but got: #{inspect(actual)}"
    end)
  end

  @doc """
  Asserts that a component has specific subscriptions active.

  ## Example

      assert_subscribed component, [:keyboard, :mouse]
  """
  def assert_subscribed(component, subscription_types)
      when is_list(subscription_types) do
    active_subs = get_component_subscriptions(component)

    Enum.each(subscription_types, fn type ->
      assert Enum.any?(active_subs, fn sub -> sub.type == type end),
             "Expected component to be subscribed to #{inspect(type)} events"
    end)
  end

  @doc """
  Asserts that a component's state history includes specific changes.

  ## Example

      assert_state_history component, [
        %{text: ""},
        %{text: "Hello"},
        %{text: "Hello, World!"}
      ]
  """
  def assert_state_history(component, expected_states)
      when is_list(expected_states) do
    history = get_component_state_history(component)

    assert length(history) == length(expected_states),
           "Expected #{length(expected_states)} state changes, but got #{length(history)}"

    Enum.zip(history, expected_states)
    |> Enum.each(fn {actual, expected} ->
      assert_state_match(actual, expected)
    end)
  end

  @doc """
  Asserts that a component emitted specific commands in sequence.

  ## Example

      assert_command_sequence component, [
        {:update, :text},
        {:notify, :changed},
        {:submit}
      ]
  """
  def assert_command_sequence(_component, expected_commands)
      when is_list(expected_commands) do
    # Placeholder: Need to integrate with command history or mocking framework
    # Always passes for now
    assert true
  end

  @doc """
  Asserts that a component properly handles an error condition.

  ## Example

      assert_handles_error component, fn ->
        simulate_event(component, invalid_event())
      end
  """
  def assert_handles_error(component, error_fn) do
    case Raxol.Core.ErrorHandling.safe_call(error_fn) do
      {:ok, _} ->
        flunk("Expected an error to be handled")

      {:error, error} ->
        # Verify the component is still in a valid state
        assert component.state != nil,
               "Component state was corrupted after error"

        # Verify error was logged or handled appropriately
        assert_error_handled(error)
    end
  end

  # Private Helpers

  def assert_state_match(actual, expected)
      when is_map(actual) and is_map(expected) do
    Enum.each(expected, fn {key, value} ->
      assert Map.get(actual, key) == value,
             "Expected state.#{key} to be #{inspect(value)}, but got: #{inspect(Map.get(actual, key))}"
    end)
  end

  defp assert_error_handled(_error) do
    # Placeholder: Need to integrate with error handling/logging mechanism
    # Assume handled for now
    true
  end

  defp get_component_layout(_component) do
    # Placeholder: Extract layout information
    %{}
  end

  defp get_component_style(_component) do
    # Placeholder: Extract style information
    %{}
  end

  # defp assert_style_applied(component, style_props) do
  #   component_style = get_component_style(component)
  #   Enum.all?(style_props, fn {prop, value} -> Map.get(component_style, prop) == value end)
  # end

  defp get_component_subscriptions(component) do
    # Return active subscriptions
    component.subscriptions
  end

  defp get_component_state_history(_component) do
    # Placeholder: Extract state history
    []
  end

  # defp render_component(_component) do
  #   # Placeholder: Render component to a string or structure
  #   ""
  # end
end
