1 files changed, 84 insertions, 0 deletions
diff --git a/app/services/issuable/import_csv/base_service.rb b/app/services/issuable/import_csv/base_service.rb
new file mode 100644
index 00000000000..bf5f643a51b
--- /dev/null
+++ b/app/services/issuable/import_csv/base_service.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+module Issuable
+  module ImportCsv
+    class BaseService
+      def initialize(user, project, csv_io)
+        @user = user
+        @project = project
+        @csv_io = csv_io
+        @results = { success: 0, error_lines: [], parse_error: false }
+      end
+
+      def execute
+        process_csv
+        email_results_to_user
+
+        @results
+      end
+
+      private
+
+      def process_csv
+        with_csv_lines.each do |row, line_no|
+          issuable_attributes = {
+            title:       row[:title],
+            description: row[:description]
+          }
+
+          if create_issuable(issuable_attributes).persisted?
+            @results[:success] += 1
+          else
+            @results[:error_lines].push(line_no)
+          end
+        end
+      rescue ArgumentError, CSV::MalformedCSVError
+        @results[:parse_error] = true
+      end
+
+      def with_csv_lines
+        csv_data = @csv_io.open(&:read).force_encoding(Encoding::UTF_8)
+        verify_headers!(csv_data)
+
+        csv_parsing_params = {
+          col_sep: detect_col_sep(csv_data.lines.first),
+          headers: true,
+          header_converters: :symbol
+        }
+
+        CSV.new(csv_data, csv_parsing_params).each.with_index(2)
+      end
+
+      def verify_headers!(data)
+        headers = data.lines.first.downcase
+        return if headers.include?('title') && headers.include?('description')
+
+        raise CSV::MalformedCSVError
+      end
+
+      def detect_col_sep(header)
+        if header.include?(",")
+          ","
+        elsif header.include?(";")
+          ";"
+        elsif header.include?("\t")
+          "\t"
+        else
+          raise CSV::MalformedCSVError
+        end
+      end
+
+      def create_issuable(attributes)
+        create_issuable_class.new(@project, @user, attributes).execute
+      end
+
+      def email_results_to_user
+        # defined in ImportCsvService
+      end
+
+      def create_issuable_class
+        # defined in ImportCsvService
+      end
+    end
+  end
+end