auto_increment.rb

module Protokoll

  class AutoIncrement    
    attr_accessor :options
    attr_accessor :count
    
    # Class initializer
    # creates counter (starts with 0) and when before 
    # the model is created runs @count+1
    def initialize
      @count = 0
    end
    
    # sets the pattern to be used. Default: %Y%m##### = 20110900001, 20110900002...
    def pattern=(p)
      options[:pattern] = p
    end
    
    # get the pattern
    def pattern
      options[:pattern]
    end
    
    # sets the symbol to be used as a counter digit. Default: #
    def number_symbol=(s)
      options[:number_symbol] = s
    end
    
    # get the symbol to be used as a counter digit. Default: #
    def number_symbol
      options[:number_symbol]
    end
    
    # gets the next number.
    # it prepends the prefix + counter + sufix
    # ex:
    #   "%Y####BANK" 
    #   %Y => prefix (year)
    #   #### => counter (starts with 0001)
    #   BANK => sufix
    # 
    # if we are in 2011, the first model to be saved will get "20110001BANK"
    # the next model to be saved will get "20110002BANK", "20110003BANK"...
    #
    #   number => is the counter
    #   
    #   next_custom_number(1) 
    #   => "20110001BANK"
    def next_custom_number(number)
      prefix(options[:pattern]).to_s + 
      counter(options[:pattern], number).to_s + 
      sufix(options[:pattern]).to_s
    end
    
    def prefix(pattern)
      prefx = extract_prefix(pattern)
      expand_times(prefx.to_s)
    end
    
    def counter(pattern, n)
      format_counter(digits_size(pattern), n)
    end

    def sufix(pattern)
      sufx = extract_sufix(pattern)
      expand_times(sufx.to_s)
    end
    
    def format_counter(zeros, value)
      "%0#{zeros}d" % value
    end

    def extract_prefix(pattern)
      # Company#### => Company
      symbol = options[:number_symbol]
      (pattern =~ /^(\s|\d)*[^#{symbol}]+/ and $&)
    end

    def extract_sufix(pattern)
      # ###Company => Company
      symbol = options[:number_symbol]
      (pattern =~ /[^#{symbol}]+$/ and $&)
    end

    def expand_times(pattern)
      pattern.sub!("%y", Time.now.strftime("%y"))
      pattern.sub!("%Y", Time.now.strftime("%Y"))
      pattern.sub!("%d", Time.now.strftime("%d"))
      pattern.sub!("%m", Time.now.strftime("%m"))
      pattern.sub!("%M", Time.now.strftime("%M"))
      pattern.sub("%H", Time.now.strftime("%H"))
    end

    def digits_size(pattern)
      symbol = options[:number_symbol]
      (pattern =~ /[#{symbol}]+/ and $&).length
    end

    def outdated?(record)
      Time.now.strftime(update_event).to_i > record.created_at.strftime(update_event).to_i
    end

    def update_event
      pattern = options[:pattern]
      event = String.new
      
      event += "%Y" if pattern.include? "%y" or pattern.include? "%Y"
      event += "%m" if pattern.include? "%m"
      event += "%H" if pattern.include? "%H"
      event += "%M" if pattern.include? "%M"
      event
    end

  end
end