class ErrorHighlight::Spotter

# File lib/error_highlight/base.rb, line 103
def initialize(node, point_type: :name, name: nil)
  @node = node
  @point_type = point_type
  @name = name

  # Not-implemented-yet options
  @arg = nil # Specify the index or keyword at which argument caused the TypeError/ArgumentError
  @multiline = false # Allow multiline spot

  @fetch = -> (lineno, last_lineno = lineno) do
    snippet = @node.script_lines[lineno - 1 .. last_lineno - 1].join("")
    snippet += "\n" unless snippet.end_with?("\n")

    # It require some work to support Unicode (or multibyte) characters.
    # Tentatively, we stop highlighting if the code snippet has non-ascii characters.
    # See https://github.com/ruby/error_highlight/issues/4
    raise NonAscii unless snippet.ascii_only?

    snippet
  end
end

# File lib/error_highlight/base.rb, line 128
def spot
  return nil unless @node

  if OPT_GETCONSTANT_PATH
    # In Ruby 3.2 or later, a nested constant access (like `Foo::Bar::Baz`)
    # is compiled to one instruction (opt_getconstant_path).
    # @node points to the node of the whole `Foo::Bar::Baz` even if `Foo`
    # or `Foo::Bar` causes NameError.
    # So we try to spot the sub-node that causes the NameError by using
    # `NameError#name`.
    case @node.type
    when :COLON2
      subnodes = []
      node = @node
      while node.type == :COLON2
        node2, const = node.children
        subnodes << node if const == @name
        node = node2
      end
      if node.type == :CONST || node.type == :COLON3
        if node.children.first == @name
          subnodes << node
        end

        # If we found only one sub-node whose name is equal to @name, use it
        return nil if subnodes.size != 1
        @node = subnodes.first
      else
        # Do nothing; opt_getconstant_path is used only when the const base is
        # NODE_CONST (`Foo`) or NODE_COLON3 (`::Foo`)
      end
    when :constant_path_node
      subnodes = []
      node = @node

      begin
        subnodes << node if node.name == @name
      end while (node = node.parent).is_a?(Prism::ConstantPathNode)

      if node.is_a?(Prism::ConstantReadNode) && node.name == @name
        subnodes << node
      end

      # If we found only one sub-node whose name is equal to @name, use it
      return nil if subnodes.size != 1
      @node = subnodes.first
    end
  end

  case @node.type

  when :CALL, :QCALL
    case @point_type
    when :name
      spot_call_for_name
    when :args
      spot_call_for_args
    end

  when :ATTRASGN
    case @point_type
    when :name
      spot_attrasgn_for_name
    when :args
      spot_attrasgn_for_args
    end

  when :OPCALL
    case @point_type
    when :name
      spot_opcall_for_name
    when :args
      spot_opcall_for_args
    end

  when :FCALL
    case @point_type
    when :name
      spot_fcall_for_name
    when :args
      spot_fcall_for_args
    end

  when :VCALL
    spot_vcall

  when :OP_ASGN1
    case @point_type
    when :name
      spot_op_asgn1_for_name
    when :args
      spot_op_asgn1_for_args
    end

  when :OP_ASGN2
    case @point_type
    when :name
      spot_op_asgn2_for_name
    when :args
      spot_op_asgn2_for_args
    end

  when :CONST
    spot_vcall

  when :COLON2
    spot_colon2

  when :COLON3
    spot_vcall

  when :OP_CDECL
    spot_op_cdecl

  when :call_node
    case @point_type
    when :name
      prism_spot_call_for_name
    when :args
      prism_spot_call_for_args
    end

  when :local_variable_operator_write_node
    case @point_type
    when :name
      prism_spot_local_variable_operator_write_for_name
    when :args
      prism_spot_local_variable_operator_write_for_args
    end

  when :call_operator_write_node
    case @point_type
    when :name
      prism_spot_call_operator_write_for_name
    when :args
      prism_spot_call_operator_write_for_args
    end

  when :index_operator_write_node
    case @point_type
    when :name
      prism_spot_index_operator_write_for_name
    when :args
      prism_spot_index_operator_write_for_args
    end

  when :constant_read_node
    prism_spot_constant_read

  when :constant_path_node
    prism_spot_constant_path

  when :constant_path_operator_write_node
    prism_spot_constant_path_operator_write

  end

  if @snippet && @beg_column && @end_column && @beg_column < @end_column
    return {
      first_lineno: @beg_lineno,
      first_column: @beg_column,
      last_lineno: @end_lineno,
      last_column: @end_column,
      snippet: @snippet,
      script_lines: @node.script_lines,
    }
  else
    return nil
  end

rescue NonAscii
  nil
end