# -------------------------------------------------------------------------- #
# Copyright 2002-2012, OpenNebula Project Leads (OpenNebula.org)             #
#                                                                            #
# 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 'json'

module OpenNebula
    class DocumentJSON < Document

        TEMPLATE_TAG = "BODY"

        # Allocate a new Document containing the json inside the TEMPLATE
        #
        # @param [String] template_json json to be inserted in the TEMPLATE
        #   of the new resource
        # @param [String, nil] name name of the object, this value will be
        #   processed by the OpenNebula core
        # @return [nil, OpenNebula::Error] nil in case of success, Error
        #   otherwise
        #
        def allocate(template_json, name=nil)
            text = build_template_xml(template_json, name)

            super(text)
        end

        # Retrieves the information of the Service and all its Nodes.
        #
        # @return [nil, OpenNebula::Error] nil in case of success, Error
        #   otherwise
        #
        def info
            rc = super
            if OpenNebula.is_error?(rc)
                return rc
            end

            load_body
        end

        # Updates the current state of this Service in the OpenNebula DB
        #
        # @params [String, nil] template_json string to be inserted in the
        #   template. If nil @body will be used instead
        # @return [nil, OpenNebula::Error] nil in case of success, Error
        #   otherwise
        #
        def update(template_json=nil)
            template_json ||= @body.to_json

            text = build_template_xml(template_json)

            super(text)
        end

        # Generates a json representing the object
        #
        # @param [true, false] pretty_generate
        # @return [String] json representing the object
        #
        def to_json(pretty_generate=true)
            hash = self.to_hash

            body = hash['DOCUMENT']['TEMPLATE']["#{TEMPLATE_TAG}"]
            if body
                body_hash = JSON.parse(body)
                hash['DOCUMENT']['TEMPLATE']["#{TEMPLATE_TAG}"] = body_hash
            end

            if pretty_generate
                JSON.pretty_generate hash
            else
                hash.to_json
            end
        end


        # Fill the @body hash with the values of the template
        def load_body
            body_str = self["TEMPLATE/#{TEMPLATE_TAG}"]

            if body_str
                begin
                    @body = JSON.parse(body_str)
                rescue JSON::JSONError
                    return OpenNebula::Error.new($!)
                end
            end

            return nil
        end

        private

        # Build an xml string incluiding the provided json
        #
        # @param [String] template_json The template to be inserted
        # @param [String, nil] name The string to be inserted as name
        # @return [String] The xml containing the json
        #
        def build_template_xml(template_json, name=nil)
            template_json ||= ""

            text = "<TEMPLATE>"

            text << "<NAME>#{name}</NAME>" if name

            text << "<#{TEMPLATE_TAG}>"
            text << "<![CDATA[#{template_json}]]>"
            text << "</#{TEMPLATE_TAG}>"

            text << "</TEMPLATE>"

            text
        end
    end
end
