start using HAVING instead of manually building joins

lib/text_to_sql_query.rb

@@ -1,7 +1,7 @@
 require_relative 'parser'
 
 class TextToSqlQuery
-  def initialize(text, fields, default_fields, fields_mappings = {}, joins = [], model = nil)
+  def initialize(text, fields, default_fields, fields_mappings = {}, joins = [])
     @text = text.to_s.strip
     @fields = fields.map(&:to_sym)
 
@@ -21,7 +21,6 @@ class TextToSqlQuery
       @fields_mappings[field] = value if @fields_mappings[field]
     end
     @joins = joins
-    @model = model
   end
 
   def where_clause
@@ -31,20 +30,12 @@ class TextToSqlQuery
   end
 
   def join_clause
-    return if @joins.empty?
+    return nil if @joins.empty?
 
-    table_column_mappings
-    model_association_mappings
-
-    join_clause_part = ''
-    @joins.each do |join|
-      join_sql_part = generate_join_sql_part_for join
-      join_clause_part += join_sql_part
-    end
-    join_clause_part
+    return *@joins
   end
 
-  private
+private
 
   def generate_sql(tree)
     first_key = tree.keys.first
@@ -83,7 +74,7 @@ class TextToSqlQuery
       if mapping.nil?
         raise "Unknown field '#{first_key.to_s}'"
       else
-        ["CAST(#{mapping.to_s} AS TEXT) ILIKE ?", "%#{escaped_node_value}%"]
+        ["STRING_AGG(CAST(#{mapping.to_s} AS TEXT), '') ILIKE ?", "%#{escaped_node_value}%"]
       end
     end
   end
@@ -120,50 +111,4 @@ class TextToSqlQuery
     result.gsub!(/%/, '\%')
     result
   end
-
-  def table_column_mappings
-    @table_column_mappings = {}
-    @fields_mappings.each_value do |table_with_column|
-      split_names = table_with_column.to_s.split '.'
-      table_name = split_names.first
-      column_name = split_names.second
-      @table_column_mappings[table_name] = [] if @table_column_mappings[table_name].nil?
-      @table_column_mappings[table_name] << column_name
-    end
-    @table_column_mappings
-  end
-
-  def model_association_mappings
-    @model_associations = {}
-    @model.reflect_on_all_associations.each do |association|
-      name = association.name
-
-      @model_associations[name] = {
-        option_as: association.options[:as] || name,
-        type: association.type
-      }
-    end
-    @model_associations
-  end
-
-  def generate_join_sql_part_for(join)
-    association_data = @model_associations[join]
-    join_table_name = join.to_s
-    raise "Join table #{join_table_name} has no association data" if association_data.nil?
-
-    select_sql_part = ''
-    columns_for_table = @table_column_mappings[join_table_name] || []
-
-    # TODO: Can be optimized - do not include columns that are not referenced in user query
-    columns_for_table.each do |column_name|
-      select_sql_part += "string_agg(#{column_name}, '') AS #{column_name}, "
-    end
-
-    option_as = association_data[:option_as]
-    type = association_data[:type]
-    model_name = @model.to_s
-    table_name = @model.table_name
-
-    "LEFT JOIN (SELECT #{option_as}_id, #{select_sql_part} #{type} FROM #{join_table_name} GROUP BY #{option_as}_id, #{type}) #{join_table_name} on #{join_table_name}.#{option_as}_id = #{table_name}.id AND #{join_table_name}.#{type} = '#{model_name}'"
-  end
 end