2 files changed, 133 insertions, 0 deletions
diff --git a/app/models/glitch/keyword_mute.rb b/app/models/glitch/keyword_mute.rb
new file mode 100644
index 000000000..7d0002afd
--- /dev/null
+++ b/app/models/glitch/keyword_mute.rb
@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+# == Schema Information
+#
+# Table name: glitch_keyword_mutes
+#
+#  id         :integer          not null, primary key
+#  account_id :integer          not null
+#  keyword    :string           not null
+#  whole_word :boolean          default(TRUE), not null
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+
+class Glitch::KeywordMute < ApplicationRecord
+  belongs_to :account, required: true
+
+  validates_presence_of :keyword
+
+  after_commit :invalidate_cached_matchers
+
+  def self.text_matcher_for(account_id)
+    TextMatcher.new(account_id)
+  end
+
+  def self.tag_matcher_for(account_id)
+    TagMatcher.new(account_id)
+  end
+
+  private
+
+  def invalidate_cached_matchers
+    Rails.cache.delete(TextMatcher.cache_key(account_id))
+    Rails.cache.delete(TagMatcher.cache_key(account_id))
+  end
+
+  class CachedKeywordMute
+    attr_reader :keyword
+    attr_reader :whole_word
+
+    def initialize(keyword, whole_word)
+      @keyword = keyword
+      @whole_word = whole_word
+    end
+
+    def boundary_regex_for_keyword
+      sb = keyword =~ /\A[[:word:]]/ ? '\b' : ''
+      eb = keyword =~ /[[:word:]]\Z/ ? '\b' : ''
+
+      /(?mix:#{sb}#{Regexp.escape(keyword)}#{eb})/
+    end
+
+    def matches?(str)
+      str =~ (whole_word ? boundary_regex_for_keyword : /#{Regexp.escape(keyword)}/i)
+    end
+  end
+
+  class Matcher
+    attr_reader :account_id
+    attr_reader :words
+
+    def initialize(account_id)
+      @account_id = account_id
+      @words = Rails.cache.fetch(self.class.cache_key(account_id)) { fetch_keywords }
+    end
+
+    protected
+
+    def fetch_keywords
+      Glitch::KeywordMute.where(account_id: account_id).pluck(:whole_word, :keyword).map do |whole_word, keyword|
+        CachedKeywordMute.new(transform_keyword(keyword), whole_word)
+      end
+    end
+
+    def transform_keyword(keyword)
+      keyword
+    end
+  end
+
+  class TextMatcher < Matcher
+    def self.cache_key(account_id)
+      format('keyword_mutes:regex:text:%s', account_id)
+    end
+
+    def matches?(str)
+      words.any? { |w| w.matches?(str) }
+    end
+  end
+
+  class TagMatcher < Matcher
+    def self.cache_key(account_id)
+      format('keyword_mutes:regex:tag:%s', account_id)
+    end
+
+    def matches?(tags)
+      tags.pluck(:name).any? do |n|
+        words.any? { |w| w.matches?(n) }
+      end
+    end
+
+    protected
+
+    def transform_keyword(kw)
+      Tag::HASHTAG_RE =~ kw ? $1 : kw
+    end
+  end
+end
diff --git a/app/models/glitch/keyword_mute_helper.rb b/app/models/glitch/keyword_mute_helper.rb
new file mode 100644
index 000000000..6d067947f
--- /dev/null
+++ b/app/models/glitch/keyword_mute_helper.rb
@@ -0,0 +1,27 @@
+require 'html2text'
+
+class Glitch::KeywordMuteHelper
+  attr_reader :text_matcher
+  attr_reader :tag_matcher
+
+  def initialize(receiver_id)
+    @text_matcher   = Glitch::KeywordMute.text_matcher_for(receiver_id)
+    @tag_matcher    = Glitch::KeywordMute.tag_matcher_for(receiver_id)
+  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)
+    Html2Text.convert(text)
+  end
+end