class FrameDiff

  def initialize(line_changes, cursor_changes)
    @line_changes = line_changes
    @cursor_changes = cursor_changes
  end

  def as_json(*)
    json = {}
    json[:lines] = optimized_line_changes unless line_changes.blank?
    json[:cursor] = cursor_changes unless cursor_changes.blank?

    json
  end

  private

  attr_reader :line_changes, :cursor_changes

  def optimized_line_changes
    line_optimizer = LineOptimizer.new

    line_changes.each_with_object({}) do |(k, v), h|
      h[k] = line_optimizer.optimize(v)
    end
  end

end