Simple Import w/ Exceptions

import.rb

class Import

  # Mixins
  include ImportExceptions

  # 0: is the Film Festival we want to relate to a Tab
  # 1: the Regionalmovie ID
  attr_accessor :attributes
  attr_accessor :regionalmovie
  attr_accessor :tab
  
  # Any errors we come across will be added to this array
  attr_accessor :errors
  
  # Stores the results of the import
  attr_reader :results

  def initialize( file )
    @errors, @results = [], {}
    csv = parse( file )
    @attributes = collect_attributes( csv.shift )
    collect_objects
    begin_import( csv )
  end
      
  def begin_import( csv )
    # We'll clear out the previous import data if we're doing an update
    @tab.regionalmovies.destroy_all unless @tab.new_record?
    @tab.save!

    # Link FilmFestival/Tab to Regionalmovie
    @tab.regionalmovies << [ @regionalmovie ]

    run_theaters( csv )
  end
  
  #########
  protected
  #########
  
  # 0: CINEMA, 1: ADDRESS, 2: CITY, 3: POSTCODE, 4: REGION
  # 5: TICKET RESERVATION PHONE NUMBER, 6: SHOWTIME
  def run_theaters( csv )
    # Stores the values for theaters / showtimes
    region = Region.find_by_short_name( @attributes[:region][:short_name] )

    csv.each do |row|
      address = Theater.beautify_address_from_csv( row[1], row[2], row[3] )
      
      attrs = {
        :name      => row[0],
        :address   => address,
        :city      => row[2],
        :region_id => region.id,
        :phone     => row[5]
      }
      
      theater = Theater.find_or_initialize_by_name( attrs[:name] )
      theater.new_record? ? theater.save! : theater.update_attributes( attrs )
    
      # Link Showtimes to Regionalmovie & Cinema
        # TODO: Duplicated from showtime.rb - Set up a proper import method using Showtime#update_from_west_world
        
      # If there's no time entered in the CSV
      add_error( :no_time, "<b>#{theater.name}</b>" ) and next unless row[6]
      
      showtime_attrs = {
        :theater_id => theater.id,
        :date       => @attributes[:date],
        :time       => row[6]
      }
      showtime = @regionalmovie.showtimes.find_or_initialize_by_theater_id_and_date_and_time( showtime_attrs )
      showtime.new_record? ? showtime.save! : showtime.update_attributes( showtime_attrs )
    end    
    
    return true
  end
  
  def collect_attributes( csv )
    return {
      :tab           => { :name  => csv[0].strip },
      :regionalmovie => { :title => csv[1].strip },
      :date          => csv[2],
      :region        => { :short_name => csv[3] }
    }
  end
  
  def collect_objects
    @regionalmovie = Regionalmovie.where( :title => @attributes[:regionalmovie][:title] ).first
    raise RegionalMovieMismatchError, IMPORT_ERROR_MESSAGES[:rm] unless @regionalmovie
    @attributes[:regionalmovie].merge!( :id => regionalmovie.id )
    
    @tab = Tab.where( :name => @attributes[:tab][:name] ).first
    raise TabMismatchError, IMPORT_ERROR_MESSAGES[:tab] unless @tab
    @attributes[:tab].merge!( :id => tab.id )
    
    return true
  end
  
  def parse( file )
    # Converts the file from iso to utf8
    file = Iconv.new( 'utf-8', 'iso-8859-2' ).iconv( file.read )
    
    csv = []
    FasterCSV.parse( file ) { |row| csv << row }
    
    # Delete empty rows, if there is any
    csv.delete( [] )
    return csv
  end
  
  #######
  private
  #######
  
  # Collect and build a list of all discrepencies
  # Report back to user to let them know where the errors lie
  def add_error( msg, record, extra = {} )
    msg = case msg
      when Symbol then IMPORT_ERROR_MESSAGES[msg]
      when String then msg
    end
    @errors << "<li><span>#{msg}: #{record} #{extra}</span></li>"
  end
  
end

import_exceptions.rb

module ImportExceptions
  
  # Custom Exceptions
  class ImproperFileError    < StandardError; end;
  
  class TabMismatchError           < StandardError; end;
  class RegionalMovieMismatchError < StandardError; end;
  
  class InvalidShipmentError < StandardError; end;

  IMPORT_ERROR_MESSAGES = {
    :improper => "Please upload a valid CSV file.",
    :tab      => "Could not find the corresponding Tab. Please create the Tab before import.",
    :rm       => "Could not find the corresponding Regionalmovie. Please find or create the record before import.",
    :no_time  => "Showtime was missing from:"
  }
  
end