class Aws::Pager

def empty_value?(value)
  value.nil? || value == '' || value == [] || value == {}
end

def initialize(options)
  @tokens = options.fetch(:tokens)
  @limit_key = options.fetch(:limit_key, nil)
  @more_results = options.fetch(:more_results, nil)
end

def next_tokens(response)
  @tokens.each.with_object({}) do |(source, target), next_tokens|
    value = JMESPath.search(source, response.data)
    next_tokens[target.to_sym] = value unless empty_value?(value)
  end
end

def prev_tokens(response)
  @tokens.each.with_object({}) do |(_, target), tokens|
    value = JMESPath.search(target, response.context.params)
    tokens[target.to_sym] = value unless empty_value?(value)
  end
end

def truncated?(response)
  if @more_results
    JMESPath.search(@more_results, response.data)
  else
    next_t = next_tokens(response)
    prev_t = prev_tokens(response)
    !(next_t.empty? || next_t == prev_t)
  end
end