# 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/vision/annotation/vertex"

module Google
  module Cloud
    module Vision
      class Annotation
        ##
        # # Text
        #
        # The result of text, or optical character recognition (OCR), detection.
        #
        # @example
        #   require "google/cloud"
        #
        #   gcloud = Google::Cloud.new
        #   vision = gcloud.vision
        #
        #   image = vision.image "path/to/text.png"
        #
        #   text = image.text
        #   text.locale #=> "en"
        #   text.words.count #=> 28
        #   text.text
        #   #=> "Google Cloud Client for Ruby an idiomatic, intuitive... "
        #
        class Text
          ##
          # @private The EntityAnnotation Google API Client object.
          attr_accessor :gapi

          ##
          # @private Creates a new Text instance.
          def initialize
            @gapi = {}
            @words = []
          end

          ##
          # The text detected in an image.
          #
          # @return [String] The entire text including newline characters.
          #
          def text
            @gapi.description
          end

          ##
          # The language code detected for `text`.
          #
          # @return [String] The [ISO
          #   639-1](https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes)
          #   language code.
          #
          def locale
            @gapi.locale
          end

          ##
          # The bounds for the detected text in the image.
          #
          # @return [Array<Vertex>]
          #
          def bounds
            return [] unless @gapi.bounding_poly
            @bounds ||= Array(@gapi.bounding_poly.vertices).map do |v|
              Vertex.from_gapi v
            end
          end

          ##
          # Each word in the detected text, with the bounds for each word.
          #
          # @return [Array<Word>]
          #
          def words
            @words
          end

          ##
          # Deeply converts object to a hash. All keys will be symbolized.
          #
          # @return [Hash]
          #
          def to_h
            { text: text, locale: locale, bounds: bounds.map(&:to_h),
              words: words.map(&:to_h) }
          end

          # @private
          def to_s
            to_str
          end

          # @private
          def to_str
            text
          end

          # @private
          def inspect
            format "#<Text text: %s, locale: %s, bounds: %i, words: %i>",
                   text.inspect, locale.inspect, bounds.count, words.count
          end

          ##
          # @private New Annotation::Text from an array of Google API Client
          # objects.
          def self.from_gapi gapi_list
            text, *words = Array gapi_list
            return nil if text.nil?
            new.tap do |t|
              t.instance_variable_set :@gapi, text
              t.instance_variable_set :@words,
                                      words.map { |w| Word.from_gapi w }
            end
          end

          ##
          # # Word
          #
          # A word within a detected text (OCR). See {Text}.
          #
          # @example
          #   require "google/cloud"
          #
          #   gcloud = Google::Cloud.new
          #   vision = gcloud.vision
          #
          #   image = vision.image "path/to/text.png"
          #   text = image.text
          #
          #   words = text.words
          #   words.count #=> 28
          #
          #   word = words.first
          #   word.text #=> "Google"
          #   word.bounds.count #=> 4
          #   word.bounds.first #=> #<Vertex (x: 13, y: 8)>
          #
          class Word
            ##
            # @private The EntityAnnotation Google API Client object.
            attr_accessor :gapi

            ##
            # @private Creates a new Word instance.
            def initialize
              @gapi = {}
            end

            ##
            # The text of the word.
            #
            # @return [String]
            #
            def text
              @gapi.description
            end

            ##
            # The bounds of the word within the detected text.
            #
            # @return [Array<Vertex>]
            #
            def bounds
              return [] unless @gapi.bounding_poly
              @bounds ||= Array(@gapi.bounding_poly.vertices).map do |v|
                Vertex.from_gapi v
              end
            end

            ##
            # Deeply converts object to a hash. All keys will be symbolized.
            #
            # @return [Hash]
            #
            def to_h
              { text: text, bounds: bounds.map(&:to_h) }
            end

            # @private
            def to_s
              to_str
            end

            # @private
            def to_str
              text
            end

            # @private
            def inspect
              format "#<Word text: %s, bounds: %i>", text.inspect, bounds.count
            end

            ##
            # @private New Annotation::Text::Word from a Google API Client
            # object.
            def self.from_gapi gapi
              new.tap { |w| w.instance_variable_set :@gapi, gapi }
            end
          end
        end
      end
    end
  end
end