module Rails::Pagination

def _discover_format(options)
  for response_format in ApiPagination.config.response_formats
    return response_format if options.key?(response_format)
  end
end

def _paginate_collection(collection, options={})
  options[:page] = ApiPagination.config.page_param(params)
  options[:per_page] ||= ApiPagination.config.per_page_param(params)
  collection, pagy = ApiPagination.paginate(collection, options)
  links = (headers['Link'] || '').split(',').map(&:strip)
  url   = base_url + request.path_info
  pages = ApiPagination.pages_from(pagy || collection, options)
  pages.each do |k, v|
    new_params = request.query_parameters.merge(:page => v)
    links << %(<#{url}?#{new_params.to_param}>; rel="#{k}")
  end
  total_header    = ApiPagination.config.total_header
  per_page_header = ApiPagination.config.per_page_header
  page_header     = ApiPagination.config.page_header
  include_total   = ApiPagination.config.include_total
  headers['Link'] = links.join(', ') unless links.empty?
  headers[per_page_header] = options[:per_page].to_s
  headers[page_header] = options[:page].to_s unless page_header.nil?
  headers[total_header] = total_count(pagy || collection, options).to_s if include_total
  return collection
end

def base_url
  ApiPagination.config.base_url || request.base_url
end

def paginate(*options_or_collection)
  options    = options_or_collection.extract_options!
  collection = options_or_collection.first
  return _paginate_collection(collection, options) if collection
  response_format = _discover_format(options)
  collection = options[response_format]
  collection = _paginate_collection(collection, options)
  options[response_format] = collection if options[response_format]
  render options
end

def paginate_with(collection)
  respond_with _paginate_collection(collection)
end

def total_count(collection, options)
  total_count = if ApiPagination.config.paginator == :kaminari
    paginate_array_options = options[:paginate_array_options]
    paginate_array_options[:total_count] if paginate_array_options
  end
  total_count || ApiPagination.total_from(collection)
end