1 files changed, 98 insertions, 0 deletions
diff --git a/app/helpers/highlight_helper.rb b/app/helpers/highlight_helper.rb
new file mode 100644
index 000000000..a98f6f320
--- /dev/null
+++ b/app/helpers/highlight_helper.rb
@@ -0,0 +1,98 @@
+module HighlightHelper
+    include ERB::Util
+
+    # Implementation of rails' highlight that allows regex to be passed to
+    # the phrases parameter.
+    # https://github.com/rails/rails/pull/11793
+    def highlight_matches(text, phrases, options = {})
+        text = ActionController::Base.helpers.sanitize(text).try(:html_safe) if options.fetch(:sanitize, true)
+
+        if text.blank? || phrases.blank?
+            text
+        else
+            match = Array(phrases).map do |p|
+                Regexp === p ? p.to_s : Regexp.escape(p)
+            end.join('|')
+
+            if block_given?
+                text.gsub(/(#{match})(?![^<]*?>)/i) { |found| yield found }
+            else
+                highlighter = options.fetch(:highlighter, '<mark>\1</mark>')
+                text.gsub(/(#{match})(?![^<]*?>)/i, highlighter)
+            end
+         end.html_safe
+    end
+
+    # Highlight words, also escapes HTML (other than spans that we add)
+    def highlight_words(t, words, html = true)
+        if html
+            highlight_matches(h(t), words, :highlighter => '<span class="highlight">\1</span>').html_safe
+        else
+            highlight_matches(t, words, :highlighter => '*\1*')
+        end
+    end
+
+    def highlight_and_excerpt(t, words, excount, html = true)
+        newt = excerpt(t, words[0], :radius => excount)
+        if not newt
+            newt = excerpt(t, '', :radius => excount)
+        end
+        t = newt
+        t = highlight_words(t, words, html)
+        return t
+    end
+
+    def excerpt(text, phrase, options = {})
+      return unless text && phrase
+
+      separator = options.fetch(:separator, nil) || ""
+      case phrase
+      when Regexp
+        regex = phrase
+      else
+        regex = /#{Regexp.escape(phrase)}/i
+      end
+
+      return unless matches = text.match(regex)
+      phrase = matches[0]
+
+      unless separator.empty?
+        text.split(separator).each do |value|
+          if value.match(regex)
+            regex = phrase = value
+            break
+          end
+        end
+      end
+
+      first_part, second_part = text.split(phrase, 2)
+
+      prefix, first_part   = cut_excerpt_part(:first, first_part, separator, options)
+      postfix, second_part = cut_excerpt_part(:second, second_part, separator, options)
+
+      affix = [first_part, separator, phrase, separator, second_part].join.strip
+      [prefix, affix, postfix].join
+    end
+
+    private
+
+    def cut_excerpt_part(part_position, part, separator, options)
+      return "", "" unless part
+
+      radius   = options.fetch(:radius, 100)
+      omission = options.fetch(:omission, "...")
+
+      part = part.split(separator)
+      part.delete("")
+      affix = part.size > radius ? omission : ""
+
+      part = if part_position == :first
+        drop_index = [part.length - radius, 0].max
+        part.drop(drop_index)
+      else
+        part.first(radius)
+      end
+
+      return affix, part.join(separator)
+    end
+end