# Adapted from http://paulbarry.com/articles/2008/04/19/importing-data-with-rails

require 'faster_csv' if Object.const_defined?('FasterCSV')

module ScaffoldLogic
  class DataImport
    attr_reader :file, :fields, :row_map

    # Class Methods ==================================================================================
    def self.run(file)
      new(file).run
    end

    def self.save(upload)
      # create file path
      _path = File.join('tmp', upload['datafile'].original_filename)

      # write file
       File.open(_path, 'wb') { |f| f.write(upload['datafile'].read) }

      self.run(_path)
    end

    # Instance Methods ===============================================================================
    def initialize(file)
      @file = file
      raise 'You must specify a file' unless @file
    end

    def initialize_row!
      unless @fields_initialized
        initialize_fields!
      else
        initialize_row_map!
        process_row
      end
    end

    def create_from_row( model )
      model.create(row_map)
    end

    def run
      @errors = []
      @row_index = 1

      FasterCSV.foreach(file, :col_sep => "\t", :row_sep => :auto) do |arg|
        @row = arg
        initialize_row!
        @row_index += 1
      end

      @errors
    end

    def valid_row?
      @missing_fields = []

      @required_fields.each do |field|
        @missing_fields << field if row_map[field].blank?
      end

      @missing_fields.empty?
    end

    private

    def initialize_fields!
      @fields = @row.map{ |f| f && f.strip.downcase.to_sym }
      @fields_initialized = true
    end

    def initialize_row_map!
      @row_map ||= {}
      @row_map.clear
      @row.each_with_index do |_c, _i|
        @row_map[fields[_i]] = _c && _c.strip
      end
    end
  end
end