require 'net/http'
require 'mixlib/authentication/signedheaderauth'
require 'openssl'

# inspired by/cargo-culted from http://stanislavvitvitskiy.blogspot.com/2008/12/multipart-post-in-ruby.html
# TODO: confirm that code is public domain
class Chef
  class StreamingCookbookUploader

    DefaultHeaders = { 'accept' => 'application/json' }
    
    class << self

      def post(to_url, user_id, secret_key_filename, params = {}, headers = {})
        make_request(:post, to_url, user_id, secret_key_filename, params, headers)
      end
      
      def put(to_url, user_id, secret_key_filename, params = {}, headers = {})
        make_request(:put, to_url, user_id, secret_key_filename, params, headers)
      end
      
      def make_request(http_verb, to_url, user_id, secret_key_filename, params = {}, headers = {})
        boundary = '----RubyMultipartClient' + rand(1000000).to_s + 'ZZZZZ'
        parts = []
        content_file = nil
        content_body = nil
        
        timestamp = Time.now.utc.iso8601
        secret_key = OpenSSL::PKey::RSA.new(File.read(secret_key_filename))

        unless params.nil? || params.empty?
          params.each do |key, value|
            if value.kind_of?(File)
              content_file = value
              filepath = value.path
              filename = File.basename(filepath)
              parts << StringPart.new( "--" + boundary + "\r\n" +
                                       "Content-Disposition: form-data; name=\"" + key.to_s + "\"; filename=\"" + filename + "\"\r\n" +
                                       "Content-Type: application/octet-stream\r\n\r\n")
              parts << StreamPart.new(value, File.size(filepath))
              parts << StringPart.new("\r\n")
            else
              content_body = value.to_s
              parts << StringPart.new( "--" + boundary + "\r\n" +
                                       "Content-Disposition: form-data; name=\"" + key.to_s + "\"\r\n\r\n")
              parts << StringPart.new(content_body + "\r\n")
            end
          end
          parts << StringPart.new("--" + boundary + "--\r\n")
        end
        
        body_stream = MultipartStream.new(parts)
        
        timestamp = Time.now.utc.iso8601
        
        Chef::Log.logger.debug("Signing: method: #{http_verb}, file: #{content_file}, User-id: #{user_id}, Timestamp: #{timestamp}")
        
        signing_options = {
          :http_method=>http_verb,
          :user_id=>user_id,
          :timestamp=>timestamp}
        (content_file && signing_options[:file] = content_file) || (signing_options[:body] = (content_body || ""))
        
        headers.merge!(Mixlib::Authentication::SignedHeaderAuth.signing_object(signing_options).sign(secret_key))

        content_file.rewind if content_file

        # net/http doesn't like symbols for header keys, so we'll to_s each one just in case
        headers = DefaultHeaders.merge(Hash[*headers.map{ |k,v| [k.to_s, v] }.flatten])

        url = URI.parse(to_url)
        req = case http_verb
              when :put
                Net::HTTP::Put.new(url.path, headers)
              when :post
                Net::HTTP::Post.new(url.path, headers)
              end              
        req.content_length = body_stream.size
        req.content_type = 'multipart/form-data; boundary=' + boundary unless parts.empty?
        req.body_stream = body_stream
        
        http = Net::HTTP.new(url.host, url.port)
        if url.scheme == "https"
          http.use_ssl = true
          http.verify_mode = OpenSSL::SSL::VERIFY_NONE
        end
        res = http.request(req)
        #res = http.start {|http_proc| http_proc.request(req) }

        # alias status to code and to_s to body for test purposes
        # TODO: stop the following madness!
        class << res
          alias :to_s :body
          
          # BUGBUG this makes the response compatible with what respsonse_steps expects to test headers (response.headers[] -> response[])
          def headers
            self
          end
          
          def status
            code.to_i
          end
        end
        res
      end
      
    end

    class StreamPart
      def initialize(stream, size)
        @stream, @size = stream, size
      end
      
      def size
        @size
      end
      
      # read the specified amount from the stream
      def read(offset, how_much)
        @stream.read(how_much)
      end
    end

    class StringPart
      def initialize(str)
        @str = str
      end
      
      def size
        @str.length
      end

      # read the specified amount from the string startiung at the offset
      def read(offset, how_much)
        @str[offset, how_much]
      end
    end

    class MultipartStream
      def initialize(parts)
        @parts = parts
        @part_no = 0
        @part_offset = 0
      end
      
      def size
        @parts.inject(0) {|size, part| size + part.size}
      end
      
      def read(how_much)
        return nil if @part_no >= @parts.size

        how_much_current_part = @parts[@part_no].size - @part_offset
        
        how_much_current_part = if how_much_current_part > how_much
                                  how_much
                                else
                                  how_much_current_part
                                end
        
        how_much_next_part = how_much - how_much_current_part

        current_part = @parts[@part_no].read(@part_offset, how_much_current_part)
        
        # recurse into the next part if the current one was not large enough
        if how_much_next_part > 0
          @part_no += 1
          @part_offset = 0
          next_part = read(how_much_next_part)
          current_part + if next_part
                           next_part
                         else
                           ''
                         end
        else
          @part_offset += how_much_current_part
          current_part
        end
      end
    end
    
  end


end