99 lines
2.3 KiB
Ruby
99 lines
2.3 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
class LanguageDetector
|
|
include Singleton
|
|
|
|
WORDS_THRESHOLD = 4
|
|
RELIABLE_CHARACTERS_RE = /[\p{Hebrew}\p{Arabic}\p{Syriac}\p{Thaana}\p{Nko}\p{Han}\p{Katakana}\p{Hiragana}\p{Hangul}]+/m
|
|
|
|
def initialize
|
|
@identifier = CLD3::NNetLanguageIdentifier.new(1, 2048)
|
|
end
|
|
|
|
def detect(text, account)
|
|
input_text = prepare_text(text)
|
|
|
|
return if input_text.blank?
|
|
|
|
detect_language_code(input_text) || default_locale(account)
|
|
end
|
|
|
|
def language_names
|
|
@language_names = CLD3::TaskContextParams::LANGUAGE_NAMES.map { |name| iso6391(name.to_s).to_sym }.uniq
|
|
end
|
|
|
|
private
|
|
|
|
def prepare_text(text)
|
|
simplify_text(text).strip
|
|
end
|
|
|
|
def unreliable_input?(text)
|
|
!reliable_input?(text)
|
|
end
|
|
|
|
def reliable_input?(text)
|
|
sufficient_text_length?(text) || language_specific_character_set?(text)
|
|
end
|
|
|
|
def sufficient_text_length?(text)
|
|
text.split(/\s+/).size >= WORDS_THRESHOLD
|
|
end
|
|
|
|
def language_specific_character_set?(text)
|
|
words = text.scan(RELIABLE_CHARACTERS_RE)
|
|
|
|
if words.present?
|
|
words.reduce(0) { |acc, elem| acc + elem.size }.to_f / text.size.to_f > 0.3
|
|
else
|
|
false
|
|
end
|
|
end
|
|
|
|
def detect_language_code(text)
|
|
return if unreliable_input?(text)
|
|
result = @identifier.find_language(text)
|
|
iso6391(result.language.to_s).to_sym if result.reliable?
|
|
end
|
|
|
|
def iso6391(bcp47)
|
|
iso639 = bcp47.split('-').first
|
|
|
|
# CLD3 returns grandfathered language code for Hebrew
|
|
return 'he' if iso639 == 'iw'
|
|
|
|
ISO_639.find(iso639).alpha2
|
|
end
|
|
|
|
def simplify_text(text)
|
|
new_text = remove_html(text)
|
|
new_text.gsub!(FetchLinkCardService::URL_PATTERN, '')
|
|
new_text.gsub!(Account::MENTION_RE, '')
|
|
new_text.gsub!(Tag::HASHTAG_RE, '')
|
|
new_text.gsub!(/:#{CustomEmoji::SHORTCODE_RE_FRAGMENT}:/, '')
|
|
new_text.gsub!(/\s+/, ' ')
|
|
new_text
|
|
end
|
|
|
|
def new_scrubber
|
|
scrubber = Rails::Html::PermitScrubber.new
|
|
scrubber.tags = %w(br p)
|
|
scrubber
|
|
end
|
|
|
|
def scrubber
|
|
@scrubber ||= new_scrubber
|
|
end
|
|
|
|
def remove_html(text)
|
|
text = Loofah.fragment(text).scrub!(scrubber).to_s
|
|
text.gsub!('<br>', "\n")
|
|
text.gsub!('</p><p>', "\n\n")
|
|
text.gsub!(/(^<p>|<\/p>$)/, '')
|
|
text
|
|
end
|
|
|
|
def default_locale(account)
|
|
account.user_locale&.to_sym || I18n.default_locale if account.local?
|
|
end
|
|
end
|