lib/recommendable/rater/disliker.rb
module Recommendable
module Rater
module Disliker
# Dislike an object. This will remove the item from a user's set of likes
# or hidden items
#
# @param [Object] obj the object to be disliked
# @return true if object was disliked successfully
# @raise [ArgumentError] if the passed object was not declared ratable
def dislike(obj)
raise(ArgumentError, 'Object has not been declared ratable.') unless obj.respond_to?(:recommendable?) && obj.recommendable?
return if dislikes?(obj)
run_hook(:before_dislike, obj)
Recommendable.redis.sadd(Recommendable::Helpers::RedisKeyMapper.disliked_set_for(obj.class, id), obj.id)
Recommendable.redis.sadd(Recommendable::Helpers::RedisKeyMapper.disliked_by_set_for(obj.class, obj.id), id)
run_hook(:after_dislike, obj)
true
end
# Check whether the user has disliked an object.
#
# @param [Object] obj the object in question
# @return true if the user has disliked obj, false if not
def dislikes?(obj)
Recommendable.redis.sismember(Recommendable::Helpers::RedisKeyMapper.disliked_set_for(obj.class, id), obj.id)
end
# Undislike an object. This removes the object from a user's set of dislikes.
#
# @param [Object] obj the object to be undisliked
# @return true if the object was disliked successfully, nil if the object wasn't already disliked
def undislike(obj)
return unless dislikes?(obj)
run_hook(:before_undislike, obj)
Recommendable.redis.srem(Recommendable::Helpers::RedisKeyMapper.disliked_set_for(obj.class, id), obj.id)
Recommendable.redis.srem(Recommendable::Helpers::RedisKeyMapper.disliked_by_set_for(obj.class, obj.id), id)
run_hook(:after_undislike, obj)
true
end
# Retrieve an array of objects the user has disliked
#
# @return [Array] an array of records
def dislikes
Recommendable.config.ratable_classes.map { |klass| disliked_for(klass) }.flatten
end
# Retrieve an array of objects both this user and another user have disliked
#
# @return [Array] an array of records
def dislikes_in_common_with(user)
Recommendable.config.ratable_classes.map { |klass| disliked_in_common_with(klass, user) }.flatten
end
# Get the number of items the user has disliked
#
# @return [Fixnum] the number of disliked items
def dislikes_count
Recommendable.config.ratable_classes.inject(0) do |sum, klass|
sum + disliked_count_for(klass)
end
end
# Fetch IDs for objects belonging to a passed class that the user has disliked
#
# @param [String, Symbol, Class] the class for which you want IDs
# @return [Array] an array of IDs
def disliked_ids_for(klass)
ids = Recommendable.redis.smembers(Recommendable::Helpers::RedisKeyMapper.disliked_set_for(klass, id))
ids.map!(&:to_i) if [:active_record, :data_mapper, :sequel].include?(Recommendable.config.orm)
ids
end
# Fetch records belonging to a passed class that the user has disliked
#
# @param [String, Symbol, Class] the class for which you want disliked records
# @return [Array] an array of disliked records
def disliked_for(klass)
Recommendable.query(klass, disliked_ids_for(klass))
end
# Get the number of items belonging to a passed class that the user has disliked
#
# @param [String, Symbol, Class] the class for which you want a count of dislikes
# @return [Fixnum] the number of dislikes
def disliked_count_for(klass)
Recommendable.redis.scard(Recommendable::Helpers::RedisKeyMapper.disliked_set_for(klass, id))
end
# Get a list of records that both this user and a passed user have disliked
#
# @param [User] the other user
# @param [String, Symbol, Class] the class of common disliked items
# @return [Array] an array of records both users have disliked
def disliked_in_common_with(klass, user)
Recommendable.query(klass, disliked_ids_in_common_with(klass, user))
end
# Get a list of IDs for records that both this user and a passed user have
# disliked
#
# @param [User, Fixnum] the other user (or its ID)
# @param [String, Symbol, Class] the class of common disliked items
# @return [Array] an array of IDs for records that both users have disliked
def disliked_ids_in_common_with(klass, user_id)
user_id = user_id.id if user_id.is_a?(Recommendable.config.user_class)
Recommendable.redis.sinter(Recommendable::Helpers::RedisKeyMapper.disliked_set_for(klass, id), Recommendable::Helpers::RedisKeyMapper.disliked_set_for(klass, user_id))
end
end
end
end