Start CSV importer feature

app/models/csv_import.rb

@@ -0,0 +1,46 @@
+# == Schema Information
+#
+# Table name: csv_imports
+#
+#  id         :integer          not null, primary key
+#  separator  :integer          not null
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+class CsvImport < ApplicationRecord
+  enum :separator, { comma: ",", semicolon: ";" }, default: :comma
+
+  has_one_attached :file
+
+  validates :file, presence: true
+  validate :acceptable_csv, on: :create
+
+  def acceptable_csv
+    return unless file.attached?
+
+    if file.blob.byte_size > 20
+      errors.add(:file, "this csv file is too large, it must be under 20MB")
+      return
+    end
+
+    if file.content_type != "text/csv"
+      errors.add(:file, :not_a_csv_file)
+      return
+    end
+
+    begin
+      csv = CSV.read(attachment_changes["file"].attachable.path, col_sep: separator)
+
+      logger = Logger.new(STDOUT)
+      logger.info(csv)
+      errors.add(:file, :empty) if csv.count < 1 || (csv.count == 1 && csv[0].count == 1 && csv[0][0] == "")
+    rescue CSV::MalformedCSVError => e
+      errors.add(:file, e.message)
+    end
+  end
+
+  def options_for_separator
+    keys = self.class.separators.keys
+    keys.map(&:humanize).zip(keys).to_h
+  end
+end