module ApiPaginationHeaders

# File lib/api_pagination_headers/config.rb, line 13
def self.config
  @config ||= ApiPaginationHeaders::Configuration.new
end

# File lib/api_pagination_headers/config.rb, line 8
def self.configure(&block)
  yield @config ||= ApiPaginationHeaders::Configuration.new
end

# File lib/api_pagination_headers.rb, line 9
def set_pagination_headers(name)
  scope = instance_variable_get("@#{name}")
  pages = set_page_numbers(scope)
  links = create_links(pages, scope)

  headers['Link'] = links.join(', ') unless links.empty?
  headers[ApiPaginationHeaders.config.total_count_header] = defined?(Kaminari) ? "#{scope.total_count}" : "#{scope.total_entries}"
end

# File lib/api_pagination_headers.rb, line 20
def create_links(pages, scope)
  url_without_params = request.url.split('?').first
  if ApiPaginationHeaders.config.force_https
    url_without_params.sub! 'http://', 'https://'
  end

  if params[:per_page]
    per_page = params[:per_page].to_i
  else
    per_page = defined?(Kaminari) ? scope.default_per_page : scope.per_page
  end

  links = []
  pages.each do |key, value|
    new_params = request.query_parameters.merge({ page: value, per_page: per_page })
    links << "<#{url_without_params}?#{new_params.to_param}>; rel=\"#{key}\""
  end
  links
end

# File lib/api_pagination_headers.rb, line 40
def set_page_numbers(scope)
  pages = {}
  pages[:first] = 1 if scope.total_pages > 1 && scope.current_page > 1
  pages[:prev] = scope.current_page - 1 if scope.current_page > 1
  pages[:next] = scope.current_page + 1 if scope.current_page < scope.total_pages
  pages[:last] = scope.total_pages if scope.total_pages > 1 && scope.current_page < scope.total_pages
  pages
end