surface

defmodule Surface.Formatter.NodeTranslator do
  @behaviour Surface.Compiler.NodeTranslator

  def handle_init(state), do: state

  def handle_expression(expression, meta, state) do
    {{:expr, expression, to_meta(meta)}, state}
  end

  def handle_tagged_expression("^", expression, meta, state) do
    {{:expr, "^" <> expression, to_meta(meta)}, state}
  end

  def handle_comment(comment, meta, state) do
    {{:comment, comment, meta}, state}
  end

  def handle_node(name, attributes, body, meta, state, _context) do
    {{name, attributes, body, to_meta(meta)}, state}
  end

  def handle_block(name, expr, body, meta, state, _context) do
    {{:block, name, expr, body, to_meta(meta)}, state}
  end

  def handle_subblock(:default, expr, _children, meta, state, %{parent_block: "case"}) do
    {{:block, :default, expr, [], to_meta(meta)}, state}
  end

  def handle_subblock(:default, expr, children, meta, state, _context) do
    {{:block, :default, expr, children, to_meta(meta)}, state}
  end

  def handle_subblock(name, expr, children, meta, state, _context) do
    {{:block, name, expr, children, to_meta(meta)}, state}
  end

  def handle_text(text, state) do
    {text, state}
  end

  # TODO: Update these after accepting the expression directly instead of the :root attribute
  def handle_block_expression(_block_name, nil, _state, _context) do
    []
  end

  def handle_block_expression(_block_name, {:expr, expr, expr_meta}, _state, _context) do
    meta = to_meta(expr_meta)
    [{:root, {:attribute_expr, expr, meta}, meta}]
  end

  def handle_attribute(
        :root,
        {:tagged_expr, "...", expr, _marker_meta},
        attr_meta,
        _state,
        context
      ) do
    {:expr, value, expr_meta} = expr
    %{tag_name: tag_name} = context

    directive =
      case tag_name do
        <<first, _::binary>> when first in ?A..?Z ->
          ":props"

        _ ->
          ":attrs"
      end

    {directive, {:attribute_expr, value, to_meta(expr_meta)}, to_meta(attr_meta)}
  end

  def handle_attribute(
        :root,
        {:tagged_expr, "=", expr, _marker_meta},
        attr_meta,
        _state,
        context
      ) do
    {:expr, value, expr_meta} = expr
    %{tag_name: tag_name} = context

    original_name = strip_name_from_tagged_expr_equals!(value)

    name =
      case tag_name do
        <<first, _::binary>> when first in ?A..?Z ->
          original_name

        _ ->
          String.replace(original_name, "_", "-")
      end

    expr_meta = Map.put(expr_meta, :tagged_expr?, true)

    {name, {:attribute_expr, value, to_meta(expr_meta)}, to_meta(attr_meta)}
  end

  def handle_attribute(
        name,
        {:tagged_expr, "^", {:expr, value, expr_meta}, _marker_meta},
        attr_meta,
        _state,
        _context
      ) do
    {name, {:attribute_expr, "^" <> value, to_meta(expr_meta)}, to_meta(attr_meta)}
  end

  def handle_attribute(name, {:expr, expr, expr_meta}, attr_meta, _state, _context) do
    {name, {:attribute_expr, expr, to_meta(expr_meta)}, to_meta(attr_meta)}
  end

  def handle_attribute(name, value, attr_meta, _state, _context) do
    {name, value, to_meta(attr_meta)}
  end

  def context_for_node(name, _meta, _state) do
    %{tag_name: name}
  end

  def context_for_subblock(name, _meta, _state, parent_context) do
    %{sub_block: name, parent_block: Map.get(parent_context, :block_name)}
  end

  def context_for_block(name, _meta, _state) do
    %{block_name: name}
  end

  def to_meta(%{void_tag?: true} = meta) do
    drop_common_keys(meta)
  end

  def to_meta(meta) do
    meta
    |> Map.drop([:void_tag?])
    |> drop_common_keys()
  end

  defp drop_common_keys(meta) do
    Map.drop(meta, [
      :column,
      :file,
      :line,
      :self_close,
      :line_end,
      :column_end,
      :node_line_end,
      :node_column_end,
      :macro?,
      :ignored_body?
    ])
  end

  defp strip_name_from_tagged_expr_equals!(value) do
    case Code.string_to_quoted(value) do
      {:ok, {:@, _, [{name, _, _}]}} when is_atom(name) ->
        to_string(name)

      {:ok, {name, _, _}} when is_atom(name) ->
        to_string(name)
    end
  end
end