require 'restclient'
require 'active_support/all'

module RailsConnector

  # Provides a simple wrapper for the CMS Rest API
  # using the credentials from {RailsConnector::Configuration.cms_api_options}.
  #
  # @example Request the published workspace:
  #   RailsConnector::CmsRestApi.get('workspaces/published')
  #
  # @example Create a new Obj:
  #   RailsConnector::CmsRestApi.post('revisions/001384beff9e5845/objs',
  #       {'obj' => {'_path' => '/new_obj', '_obj_class' => 'Publication'}})
  #
  # @example Update an Obj:
  #   RailsConnector::CmsRestApi.put('revisions/001384beff9e5845/objs/9e432077f0412a63',
  #       {'obj' => {'title' => 'new title'}})
  #
  # @example Delete an Obj:
  #   RailsConnector::CmsRestApi.delete('revisions/001384beff9e5845/objs/f4123622ff07b70b')
  class CmsRestApi
    cattr_accessor :credentials

    def self.get(resource_path, payload = nil)
      request_cms_api(:get, resource_path, payload)
    end

    def self.put(resource_path, payload)
      request_cms_api(:put, resource_path, payload)
    end

    def self.post(resource_path, payload)
      request_cms_api(:post, resource_path, payload)
    end

    def self.delete(resource_path, payload = nil)
      request_cms_api(:delete, resource_path, payload)
    end

    # @param [Hash] value
    # @return [void]
    def self.credentials=(value)
      @@credentials = value.symbolize_keys
    end

    private

    def self.request_cms_api(action, resource_path, payload)
      request_params = basic_request_params
      request_params[:method] = action
      request_params[:url] = url(resource_path)
      request_params[:payload] = MultiJson.encode(payload) if payload.present?

      begin
        MultiJson.decode(RestClient::Request.execute(request_params))
      rescue RestClient::ExceptionWithResponse => e
        begin
          if e.http_code == 403
            raise AccessDenied.new(e.http_body)
          elsif e.http_code.to_s.match(/4\d{2}/) &&
              (specific_output = MultiJson.decode(e.http_body)['error'])
            raise ClientError.new(specific_output, e.http_code)
          end
        rescue MultiJson::DecodeError
        end

        raise BackendNotAvailable.new(e.http_body, e.http_code)
      end
    end

    def self.basic_request_params
      headers = {
        :content_type => :json,
        :accept => :json,
      }
      headers[:host] = credentials[:http_host] if credentials[:http_host].present?

      {
        :user => credentials[:login],
        :password => credentials[:api_key],
        :headers => headers,
      }
    end

    def self.url(resource_path)
      "#{credentials[:url]}/#{resource_path}"
    end
  end

end