fcce/bos

# encoding: UTF-8
require 'openssl'
require 'typhoeus'
require 'uri'
module BosClient
  class Authable
    def self.authorize_request(request)
      default_headers = get_default_headers request
      request.options[:headers].merge! default_headers
      authorization = sign(request)
      request.options[:headers]['Authorization'] = authorization
      request
    end

    class << self
      def get_canonical_time(t = Time.now.to_i)
        Time.at(t).utc.strftime('%FT%TZ')
      end

      def get_default_headers(request)
        {
          'content-type' => 'text/plain',
          'x-bce-date' => get_canonical_time,
          'content-length' => (request.options[:body] || '').length
        }
      end

      def get_canonical_uri(request)
        uri = URI(request.base_url)
        url_path = URI.encode(uri.path)
        url_path == '' ? '/' : url_path
      end

      def get_canonical_query_string(request)
        params = request.options[:params]
        params = params.map do |k, v|
          "#{URI.encode(k.to_s)}=#{encode_slash(URI.encode(v.to_s))}"
        end.compact.sort.join('&')
        params
      end

      def get_canonical_headers(request)
        headers_to_sign_keys = ['host',
                                'content-md5',
                                'content-length',
                                'content-type']
        headers_to_sign = []
        request.options[:headers].each do |k, v|
          if headers_to_sign_keys.include?(k) || k.start_with?('x-bce')
            headers_to_sign << "#{encode(k.to_s.downcase)}:#{encode(v.to_s)}"
          end
        end
        headers_to_sign.compact.sort.join("\n")
      end

      def get_http_method(request)
        (request.options[:method] || 'get').upcase
      end

      def encode(string)
        URI.encode(string, Regexp.new("[^#{URI::PATTERN::UNRESERVED}]"))
      end

      def encode_slash(str)
        # str.gsub(/\//, '%2F')
        str.gsub(%r{/}, '%2F')
      end

      def sign(request)
        digest = OpenSSL::Digest.new('sha256')
        sign_key_prefix = "bce-auth-v1/#{BosClient.access_key_id}/#{get_canonical_time}/#{BosClient.expiration_in_seconds}"
        sign_key = OpenSSL::HMAC.hexdigest digest, BosClient.secret_access_key, sign_key_prefix

        http_method = get_http_method request

        canonical_uri = get_canonical_uri request
        canonical_query_string = get_canonical_query_string request
        canonical_headers = get_canonical_headers request
        string_to_sign = [http_method,
                          canonical_uri,
                          canonical_query_string,
                          canonical_headers].join("\n")
        sign_result = OpenSSL::HMAC.hexdigest digest, sign_key, string_to_sign
        "#{sign_key_prefix}//#{sign_result}"
      end
    end
  end
end