add basic functionality of plugin

plugins/article_import/lib/foodsoft_article_import.rb

@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+require "deface"
+require 'foodsoft_article_import/engine'
+require 'digest/sha1'
+require 'tempfile'
+require 'csv'
+require 'yaml'
+require 'active_support/core_ext/hash/keys'
+require_relative 'foodsoft_article_import/bnn'
+require_relative 'foodsoft_article_import/utf8_encoder'
+require_relative 'foodsoft_article_import/odin'
+require_relative 'foodsoft_article_import/foodsoft'
+module FoodsoftArticleImport
+  class ConversionFailedException < StandardError; end
+
+  FORMATS = %w(bnn foodsoft odin).freeze
+  def self.enabled?
+    FoodsoftConfig[:use_article_import]
+  end
+
+  def self.file_formats
+    @@file_formats ||= {
+      'bnn' => FoodsoftArticleImport::Bnn,
+      'foodsoft' => FoodsoftArticleImport::Foodsoft,
+      'odin' => FoodsoftArticleImport::Odin,
+    }.freeze
+  end
+
+  # Parse file by type (one of {.file_formats})
+  #
+  # @param file [File, Tempfile]
+  # @option opts [String] type file format (required) (see {.file_formats})
+  # @return [File, Roo::Spreadsheet] file with encoding set if needed
+  def self.parse(file, custom_file_path: nil, type: nil, **opts, &blk)
+    @@filename = opts[:filename] if opts[:filename]
+    custom_file_path ||= nil
+    type ||= 'bnn'
+    parser = file_formats[type]
+    if block_given?
+      parser.parse(file, custom_file_path: custom_file_path, &blk)
+    else
+      data = []
+      parser.parse(file, custom_file_path: custom_file_path) { |a| data << a }
+      data
+    end
+  end
+
+  # Helper method to generate an article number for suppliers that do not have one
+  def self.generate_number(article)
+    # something unique, but not too unique
+    s = "#{article[:name]}-#{article[:unit_quantity]}x#{article[:unit]}"
+    s = s.downcase.gsub(/[^a-z0-9.]/, '')
+    # prefix abbreviated sha1-hash with colon to indicate that it's a generated number
+    article[:order_number] = ":#{Digest::SHA1.hexdigest(s)[-7..]}"
+    article
+  end
+
+  # Helper method for opening a spreadsheet file
+  #
+  # @param file [File] file to open
+  # @param filename [String, NilClass] optional filename for guessing the file format
+  # @param encoding [String, NilClass] optional CSV encoding
+  # @param col_sep [String, NilClass] optional column separator
+  # @return [Roo::Spreadsheet]
+  def self.open_spreadsheet(file, encoding: nil, col_sep: nil, liberal_parsing: nil)
+    opts = { csv_options: {} }
+    opts[:csv_options][:encoding] = encoding if encoding
+    opts[:csv_options][:col_sep] = col_sep if col_sep
+    opts[:csv_options][:liberal_parsing] = true if liberal_parsing
+    opts[:extension] = File.extname(File.basename(@@filename)) if @@filename
+    begin
+      Roo::Spreadsheet.open(file, **opts)
+    rescue StandardError => e
+      raise "Failed to parse foodsoft file. make sure file format is correct: #{e.message}"
+    end
+  end
+end