Implement recommendation 9.2

Close #6

Author: lmrodriguezr

app/models/name.rb

@@ -218,14 +218,14 @@ def fuzzy_match(
       when :similarity
         threshold ||= 0.7
         selection
-          .select("name, similarity(name, #{clean_query}) AS score")
+          .select("id, name, similarity(name, #{clean_query}) AS score")
           .where('similarity(name, ?) > ?', query, threshold)
           .order('score DESC')
           .limit(limit)
       when :levenshtein
         threshold ||= 3
         selection
-          .select("name, levenshtein(name, #{clean_query}) AS score")
+          .select("id, name, levenshtein(name, #{clean_query}) AS score")
           .where('levenshtein(name, ?) <= ?', query, threshold)
           .order('score ASC')
           .limit(limit)
@@ -650,6 +650,47 @@ def is_variant?(alt_spelling)
     false
   end
 
+  ##
+  # This method always return +nil+ for names that are not at (inferred) rank
+  # of genus or species
+  # 
+  # Find names similar to the current one (using the cannonical spelling
+  # from +base_name+) with Levenshtein ≤ 3, considering a search space
+  # defined by the taxonomic rank and +among+:
+  # - valid: All validly published names of genera or species of the same genus
+  # - public: All publicly visible names of genera or species of the same genus
+  # - register: All names names of genera or species of the same genus in the
+  #   same register list as this name (if any)
+  def similar_names(among: :valid)
+    selection =
+      case among.to_sym
+      when :valid
+        self.class.all_valid
+      when :public
+        self.class.all_public
+      when :register
+        return unless register.present?
+        register.names
+      else
+        raise ArgumentError, "Unsupported search space (among): #{among}"
+      end
+
+    case inferred_rank.to_sym
+    when :genus
+      selection = selection.where(rank: :genus)
+    when :species
+      return unless parent.present?
+      selection = selection.where(parent_id: parent.id)
+    else
+      return
+    end
+
+    selection = selection.where.not(id: id)
+    self.class.fuzzy_match(
+      base_name, method: :levenshtein, selection: selection
+    )
+  end
+
   # ============ --- OUTLINKS --- ============
 
   def ncbi_search_url

app/models/name/quality_checks.rb

@@ -176,6 +176,26 @@ class QcWarning
       }.merge(@@link_to_edit_spelling),
       # - Recommendation 9.1 covered in § Rule 9b
       # - Recommendation 9.2 [TODO: issue #6]:
+      similar_names_validly_published: {
+        message: lambda { |w|
+          similar = w.name.similar_names(:valid).limit(5).map(&:name)
+          <<~MSG.html_safe
+            Name is similar in spelling to: #{similar.to_sentence}.
+            Consider variations that are less prone to confusion
+          MSG
+        },
+        recommendations: %w[9.2]
+      }.merge(@@link_to_edit_spelling),
+      similar_names_in_register_list: {
+        message: lambda { |w|
+          similar = w.name.similar_names(:register).limit(5).map(&:name)
+          <<~MSG.html_safe
+            Name is similar in spelling to: #{similar.to_sentence}.
+            Consider variations that are less prone to confusion
+          MSG
+        },
+        recommendations: %w[9.2]
+      }.merge(@@link_to_edit_spelling),
       #   Names should differ by at least three characters from existing names
       #   of genera or species within the same genus.
       # - Recommendation 9.3 [Checklist-N]
@@ -1006,6 +1026,14 @@ def qc_warnings
     @qc_warnings.add(:long_name) if long_word?
     @qc_warnings.add(:difficult_to_pronounce) if hard_to_pronounce?
 
+    if similar_names(:valid).present?
+      @qc_warnings.add(:similar_names_validly_published)
+    end
+
+    if similar_names(:register).present?
+      @qc_warnings.add(:similar_names_in_register_list)
+    end
+
     if rank? && %w[species subspecies].include?(rank)
       unless consistent_species_name?
         @qc_warnings.add(:inconsistent_species_name)