=begin
Books Example

There are several Books. And there is a Table with Keywords. These are our Vertex-Classes

The Keywords are associated to the books, this is realized via an Edge »has_content«

This Example demonstrates how create a simple graph:

Book --> HasContent --> KeyWord

and to query it dynamically using OrientSupport::OrientQuery

REQUIREMENT: Configurate config/connectyml (admin/user+pass) 

There are 3 default search items provided. They are used if no parameter is given.
However, any parameter given is transmitted as serach-criteria, ie.
  ruby books.rb Juli August
defines two search criteria.

=end
require 'bundler/setup'
require 'yaml'
require 'logger'
require 'active-orient'

 class BooksExample

	 def initialize  rebuild: true
		 if rebuild
			 print "\n === REBUILD === \n"
			 ## check wether the database tables exist. Then delete Database-Class and preallocated ruby-Object
			 di =  database_instance =  V.db
			 database_classes = [ :book, :keyword, :has_content ]
			 print " creating Book and  Keyword as Vertex; HAS_CONTENT as Edge \n"
			 V.create_class :book, :keyword
			 E.create_class :has_content
			 print "\n === PROPERTY === \n"
			 Keyword.create_property  :item,  type: :string, index: :unique
			 Book.create_property     :title, type: :string, index: :unique
			 print "\n === Unique Edges === \n"
			 HAS_CONTENT.uniq_index

			 Keyword.delete( all: true )
			 Book.delete :all => true 
		 end
	 end

   # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#
	 #################  read samples  ##############
	 def read_samples
		 print "\n === READ SAMPLES === \n"
		 ## Lambda fill databasea
		 # Anaylse a sentence
		 # Split into words and upsert them to Word-Class.
		 # The Block is only performed, if a new Word is inserted. 
		 fill_database = ->(sentence, this_book ) do

			 sentence.split(' ').map do | word |
				 this_book.assign  vertex: Keyword.create( item: word ), via: HAS_CONTENT if Keyword.where( item: word ).empty?
			 end

		 end
		 ## Lambda end
		 words = 'Die Geschäfte in der Industrie im wichtigen US-Bundesstaat New York sind im August so schlecht gelaufen wie seit mehr als sechs Jahren nicht mehr Der entsprechende Empire-State-Index fiel überraschend von plus  Punkten im Juli auf minus 14,92 Zähler Dies teilte die New Yorker Notenbank Fed heute mit. Bei Werten im positiven Bereich signalisiert das Barometer ein Wachstum Ökonomen hatten eigentlich mit einem Anstieg auf 5,0 Punkte gerechnet'
		 this_book =  Book.create title: 'first'
		 fill_database[ words, this_book ]

		 words2 = 'Das Bruttoinlandsprodukt BIP in Japan ist im zweiten Quartal mit einer aufs Jahr hochgerechneten Rate von Prozent geschrumpft Zu Jahresbeginn war die nach den USA und China drittgrößte Volkswirtschaft der Welt noch um  Prozent gewachsen Der Schwächeanfall wird auch als Rückschlag für Ministerpräsident Shinzo Abe gewertet der das Land mit einem Mix aus billigem Geld und Konjunkturprogramm aus der Flaute bringen will Allerdings wirkte sich die heutige Veröffentlichung auf die Märkten nur wenig aus da Ökonomen mit einem schwächeren zweiten Quartal gerechnet hatten'
		 this_book =  Book.create title: 'second'
		 fill_database[ words2, this_book ]
		 puts "#{Keyword.count} keywords inserted into Database" 
	 end

   # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#
	 #################  display books ##############
	 def display_books_with *desired_words
		 ## Each serach criteria becomes a subquery
		 ## This is integrated into the main_query using 'let'.
		 ## Subquery:  let ${a-y} = select expand(in('has_content')) from keyword where item = {search_word} 
		 ## combine with intercect: $z =  Intercect( $a ... $y )
		 ##  Main Query is just
		 ##  select expand( $z )  followed by all let-statements and finalized by "intercect"
		 #

		  # lambda to create subqueries
      word_query = -> (arg) do
				 q= Keyword.query  where: arg
    		 q.nodes :in, via: HAS_CONTENT		
			end

			## We just create "select expand($z)"
      main_query =  OrientSupport::OrientQuery.new
			main_query.expand( '$z' )


		 print("\n === display_books_with » #{ desired_words.join "," } « === \n")

		 intersects = Array.new
		 ## Now, add subqueries to the main-query
		 desired_words.each_with_index do | word, i |
			 symbol = ( i+97 ).chr   #  convert 1 -> 'a', 2 -> 'b' ...
			 main_query.let   symbol =>  word_query[ item: word  ]
			 intersects << "$#{symbol}"
		 end
		 ## Finally add the intersects statement
		 main_query.let   "$z = Intersect(#{intersects.join(', ')}) "
		 puts "generated Query:"
		 puts main_query.to_s
		 puts "\n\n\n"
		 result = main_query.execute
		 puts '-' * 23 
		 puts "found books: "
		 puts result.map( &:title ).uniq.join("; ")
		 if result.empty?
			 puts " -- None -- "
			 puts " try » ruby books.rb japan flaute «  for a positive search in one of the two sentences"
		 else 
			 puts '-_' * 23 
			 puts "that's it folks"
		 end 
	 end
 end

 if $0 == __FILE__
	 config_file =  File.expand_path('../../config/connect.yml', __FILE__) 
	 connectyml = if File.exist?(config_file)
									YAML.load_file( config_file )[:orientdb]
								else
									puts "config/connect.yml not found "
									puts "using defaults"
									{  server: 'localhost', port: 2480, 
						database: {  development: 'temp' },
						admin:	{	user: 'root', pass: 'root' } } 
								end

begin
	ActiveOrient::Init.connect database: connectyml[:database][:development].to_s,
		user: connectyml[:admin][:user].to_s,
		password: connectyml[:admin][:pass].to_s,
		server: connectyml[:server].to_s

	ActiveOrient::Base.logger.level = Logger::INFO
	ActiveOrient::Model.keep_models_without_file = true
	ActiveOrient::OrientDB.new  model_dir: 'lib/model'
rescue RestClient::Unauthorized
	puts "Cannot connect to the server. Wrong credentials"
	Kernel.exit
rescue Errno::ECONNREFUSED
	puts "Database Server is not running on  #{connectyml[:server]} "
	Kernel.exit
end


	 search_items =  ARGV.empty? ? ['China', 'aus', 'Flaute'] : ARGV
	 ARGV = [ 'd' ]  # development-mode

	 # search_items =  ARGV.empty? ? ['China', 'aus', 'Flaute'] : ARGV
	 b = BooksExample.new  rebuild:  true

	 #    ORD.create_vertex_class "Book", "Keyword" 
	 #    ORD.create_edge_class 'has_content'

	 b.read_samples if Keyword.count.zero?
	 b.display_books_with *search_items

end