module WulffeldSlug
  module SlugInclude
    def self.included(base)
      base.class_eval do
        if self.slug_config[:mongo]
          field :slug
        end
          
        validates_presence_of :slug

        before_validation :on => :create do
          cb_make_slug
        end
      end
    end
    
    def to_param
      slug
    end
    
    # Can override this.
    def slug_unique?(slug)
      !self.class.where(:slug => slug).first
    end

    def cb_make_slug
      return unless slug.blank?

      a = [*send(slug_config[:fields])].reject {|f| f.blank? }.map {|f| f.is_a?(String) ? f : send(f) }.flatten
      return if a.blank?

      self.slug = to_unique_slug(a.join('-'))
    end

    def to_unique_slug(s, n=nil)
      str_part = prepare_string(s)

      loop do
        slug = [str_part, n].compact.join('-')
        return slug if slug_unique?(slug)

        # First loop we do some optimistic searching.
        if n.nil?
          b = 512
          last_b = nil
          loop do
            slug = [str_part, b].join('-')
            if slug_unique?(slug) || b < 1
              last_b = b
              break if b < 1
            else
              n = last_b
              break
            end
            
            b /= 2
          end
        end
        n ||= 0
        n += 1
      end
    end

    # Use dashes.
    # http://www.mattcutts.com/blog/dashes-vs-underscores/
    def prepare_string(s)
      s.strip!

      # Blow away apostrophes
      s.gsub! /['`]/,""

      orig = s

      # @ --> at, and & --> and
      s.gsub! /\s*@\s*/, " at "
      s.gsub! /\s*&\s*/, " and "

      [
        [/[+]/, 'plus'],
        [/[ÀÁÂÃÅĀĂĄǍ]/, 'A'],
        [/[āăąàáâãǎ]/, 'a'],
        [/[ĆĈĊČÇ]/, 'C'],
        [/[ćĉċčç]/, 'c'],
        [/[ĎĐ]/, 'D'],
        [/[ďđ]/, 'd'],
        [/[ĒĔĖĘĚÈÉÊË]/, 'E'],
        [/[èéêëēĕėęě]/, 'e'],
        [/[ĜĞĠĢǤǦǴ]/, 'G'],
        [/[ĝğġģǥǧ]/, 'g'],
        [/[Ĥ]/, 'H'],
        [/[ĥĦħ]/, 'h'],
        [/[ĨĪĬĮİǏÌÍÎÏ]/, 'I'],
        [/[ĩīĭįıǐìíîï]/, 'i'],
        [/[Ĵ]/, 'J'],
        [/[ĵ]/, 'j'],
        [/[ĶǨК]/, 'K'],
        [/[ķĸǩ]/, 'k'],
        [/[ĹĻĽĿŁ]/, 'L'],
        [/[ĺļľŀł]/, 'l'],
        [/[ŃŅŇŊÑǸП]/, 'N'],
        [/[ńņňʼnŋñǹ]/, 'n'],
        [/[ŌŎŐǑÒÓÔÕÖ]/, 'O'],
        [/[ōŏőǒðòóôõ]/, 'o'],
        [/[ŔŖŘ]/, 'R'],
        [/[ŕŗř]/, 'r'],
        [/[ŚŜŞŠ]/, 'S'],
        [/[śŝşš]/, 's'],
        [/[ŢŤŦ]/, 'T'],
        [/[ţťŧ]/, 't'],
        [/[ŨŪŬŮŰŲÙÚÛÜ]/, 'U'],
        [/[ũūŭůűųùúûü]/, 'u'],
        [/[Ŵ]/, 'W'],
        [/[ŵ]/, 'w'],
        [/[ŶŸÝ]/, 'Y'],
        [/[ýÿŷ]/, 'y'],
        [/[ŹŻŽ]/, 'Z'],
        [/[źżž]/, 'z'],
        [/[ǓǕǗǙǛ]/, 'U'],
        [/[ǔǖǘǚǜ]/, 'u'],
        [/[ǢÆǼ]/, 'AE'],
        [/[ǣäæǽ]/, 'ae'],
        [/[ØǾ]/, 'OE'],
        [/[øǿö]/, 'oe'],
        [/[ÄÅ]/, 'AA'],
        [/[å]/, 'aa'],
        [/[ǪǬ]/, 'O'],
        [/[ǫǭ]/, 'o'],
        [/[^a-zA-Z0-9]+/i, '-']
      ].each do |regex, ch|
        s.gsub! regex, ch
      end

      s.strip!
      s = s.split('-').each { |word| word.sub!(/^[a-z]/) {|m| slug_config[:capitalize] ? m.tr('a-z', 'A-Z') : m} }.join('-')
      new_slug = s.blank? ? orig : s
      if new_slug.length > 240
        new_slug = new_slug[0..239]
      else
        new_slug
      end
    end
  end
end