# Copyright 2016 Google Inc. All rights reserved.
#
# 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 "google/cloud/speech/v1beta1"

module Google
  module Cloud
    module Speech
      ##
      # # Result
      #
      # A speech recognition result corresponding to a portion of the audio.
      #
      # See {Project#recognize} and {Job#results}.
      #
      # @see https://cloud.google.com/speech/reference/rpc/google.cloud.speech.v1beta1#google.cloud.speech.v1beta1.SpeechRecognitionResult
      #   SpeechRecognitionResult
      #
      # @attr_reader [String] transcript Transcript text representing the words
      #   that the user spoke.
      # @attr_reader [Float] confidence The confidence estimate between 0.0 and
      #   1.0. A higher number means the system is more confident that the
      #   recognition is correct. This field is typically provided only for the
      #   top hypothesis. A value of 0.0 is a sentinel value indicating
      #   confidence was not set.
      # @attr_reader [Array<Result>] alternatives Additional recognition
      #   hypotheses (up to the value specified in `max_alternatives`).
      #
      # @example
      #   require "google/cloud"
      #
      #   gcloud = Google::Cloud.new
      #   speech = gcloud.speech
      #
      #   audio = speech.audio "path/to/audio.raw",
      #                        encoding: :raw, sample_rate: 16000
      #   results = audio.recognize
      #
      #   result = results.first
      #   result.transcript #=> "how old is the Brooklyn Bridge"
      #   result.confidence #=> 88.15
      #   alternative = result.alternatives.first
      #   alternative.transcript #=> "how old is the Brooklyn brim"
      #   alternative.confidence #=> 22.39
      #
      class Result
        attr_reader :transcript, :confidence, :alternatives

        ##
        # @private Creates a new Results instance.
        def initialize transcript, confidence, alternatives = []
          @transcript  = transcript
          @confidence = confidence
          @alternatives = alternatives
        end

        ##
        # @private New Results from a SpeechRecognitionAlternative object.
        def self.from_grpc grpc
          head, *tail = *grpc.alternatives
          return nil if head.nil?
          alternatives = tail.map do |alt|
            new alt.transcript, alt.confidence
          end
          new head.transcript, head.confidence, alternatives
        end
      end
    end
  end
end