# Copyright 2010 Sean Cribbs, Sonian Inc., and Basho Technologies, Inc.
#
#    Licensed under the Apache License, Version 2.0 (the "License");
#    you may not use this file except in compliance with the License.
#    You may obtain a copy of the License at
#
#        http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#    limitations under the License.
require 'riak'

begin
  require 'fiber'
rescue LoadError
  require 'riak/util/fiber1.8'
end

module Riak
  class Client
    # An HTTP backend for Riak::Client that uses the 'curb' library/gem.
    # If the 'curb' library is present, this backend will be preferred to
    # the backend based on Net::HTTP.
    # Conforms to the Riak::Client::HTTPBackend interface.
    class CurbBackend < HTTPBackend
      private
      def perform(method, uri, headers, expect, data=nil)
        # Setup
        curl.headers = create_request_headers(headers)
        curl.url = uri.to_s
        response_headers.initialize_http_header(nil)
        if block_given?
          _curl = curl
          Fiber.new {
            f = Fiber.current
            _curl.on_body {|chunk| f.resume(chunk); chunk.size }
            loop do
              yield Fiber.yield
            end
          }.resume
        else
          curl.on_body
        end
        # Perform
        case method
        when :post
          data = data.read if data.respond_to?(:read)
          curl.http_post(data)
        when :put
          # Hacks around limitations in curb's PUT semantics
          _headers, curl.headers = curl.headers, {}
          curl.put_data = data
          curl.headers = create_request_headers(curl.headers) + _headers
          curl.http("PUT")
        else
          curl.send("http_#{method}")
        end

        # Verify
        if valid_response?(expect, curl.response_code)
          result = { :headers => response_headers.to_hash, :code => curl.response_code.to_i }
          if return_body?(method, curl.response_code, block_given?)
            result[:body] = curl.body_str
          end
          result
        else
          raise FailedRequest.new(method, expect, curl.response_code, response_headers.to_hash, curl.body_str)
        end
      end

      def curl
        Thread.current[:curl_easy_handle] ||= Curl::Easy.new.tap do |c|
          c.follow_location = false
          c.on_header do |header_line|
            response_headers.parse(header_line)
            header_line.size
          end
        end
      end

      def response_headers
        Thread.current[:response_headers] ||= Riak::Util::Headers.new
      end

      def create_request_headers(hash)
        h = Riak::Util::Headers.new
        hash.each {|k,v| h.add_field(k,v) }
        [].tap do |arr|
          h.each_capitalized do |k,v|
            arr << "#{k}: #{v}"
          end
        end
      end
    end
  end
end