require 'fastercsv'

class Array
  
  # transforms the collection into a csv formatted string
  #
  # each column is described by a label/property pair
  # eg [["Published","created_at"]] generates a column with label "Published" and the data value being the created_at field 
  #
  def to_csv(columns)
    FasterCSV.generate do |csv|
      csv << columns.collect{|c| c.to_a.first }
      self.each do |result|
        csv << columns.collect{|c| c.to_a.last }.collect{|c| result.send(c) }
      end
    end
    
  end
  
  
  def select_with_index(&block)
    selected = []
    self.each_index do |i|
      selected << self[i] if block.call(self[i],i) == true
    end
    selected
  end
  
  
  #
  # to_auto_complete_list(:label => ["? (?)",:auditable_type,:auditable_id], :value => ["?-?",:auditable_type,:auditable_id])
  #
  def to_auto_complete_list(opts = {})
    
    if opts.blank? || opts[:label].blank? || opts[:value].blank? || (opts[:label].kind_of?(Array) && opts[:label].size < 2)
      return []
    end
    
    list = collect do |obj|      
      [active_record_type_condition_rendering(opts[:label],obj), active_record_type_condition_rendering(opts[:value],obj)]
    end
    
    # a :include_blank key
    # if it == true then just include a blank array (ie all elements)
    # if it == Array then render it using the AR rendering eg ["?",property]
    if opts[:include_blank] == true
      list.unshift(["All",""])
    elsif opts[:include_blank]
      list = collect {|obj| [active_record_type_condition_rendering(opts[:include_blank],obj), active_record_type_condition_rendering(opts[:include_blank],obj)] }.uniq + list
    end
    
    list.compact.uniq
    
  end
  
  private
  
  def active_record_type_condition_rendering(format, obj)
    if format.kind_of?(Array)
      label = format.clone
      label_format = label.shift
      label_split = label_format.split('?')
      label_values = label.collect{|p| obj.respond_to?(p) ? obj.send(p) : "" }
      label_split.zip(label_values).join
    else
      obj.respond_to?(format) ? obj.send(format) : ""
    end
  end
  
end