Glitch::FilterHelper -> Glitch::KeywordMuteHelper. #234.

The class helps out with keyword mutes, not just some general concept of
"filtering".

app/models/glitch/keyword_mute_helper.rb

@@ -0,0 +1,31 @@
+require 'htmlentities'
+
+class Glitch::KeywordMuteHelper
+  include ActionView::Helpers::SanitizeHelper
+
+  attr_reader :text_matcher
+  attr_reader :tag_matcher
+  attr_reader :entity_decoder
+
+  def initialize(receiver_id)
+    @text_matcher   = Glitch::KeywordMute.text_matcher_for(receiver_id)
+    @tag_matcher    = Glitch::KeywordMute.tag_matcher_for(receiver_id)
+    @entity_decoder = HTMLEntities.new
+  end
+
+  def matches?(status)
+    matchers_match?(status) || (status.reblog? && matchers_match?(status.reblog))
+  end
+
+  private
+
+  def matchers_match?(status)
+    text_matcher.matches?(prepare_text(status.text)) ||
+      text_matcher.matches?(prepare_text(status.spoiler_text)) ||
+      tag_matcher.matches?(status.tags)
+  end
+
+  def prepare_text(text)
+    entity_decoder.decode(strip_tags(text)).tap { |x| puts x }
+  end
+end