require_dependency "entry"
require 'forwardable'

class CostQuery < ActiveRecord::Base
  extend Forwardable
  include Enumerable
  #belongs_to :user
  #belongs_to :project
  #attr_protected :user_id, :project_id, :created_at, :updated_at

  def self.accepted_properties
    @accepted_properties ||= []
  end

  def available_filters
    CostQuery::Filter.all
  end

  def transformer
    @transformer ||= CostQuery::Transformer.new self
  end
  
  def walker
    @walker ||= CostQuery::Walker.new self
  end

  def add_chain(type, name, options)
    chain type.const_get(name.to_s.camelcase), options
    @transformer, @table = nil, nil
    self
  end

  def chain(klass = nil, options = {})
    @chain ||= Filter::NoFilter.new
    @chain = klass.new @chain, options if klass
    @chain = @chain.parent until @chain.top?
    @chain
  end

  def filter(name, options = {})
    add_chain Filter, name, options
  end

  def group_by(name, options = {})
    add_chain GroupBy, name, options.reverse_merge(:type => :column)
  end

  def column(name, options = {})
    group_by name, options.merge(:type => :column)
  end

  def row(name, options = {})
    group_by name, options.merge(:type => :row)
  end

  def table
    @table = Table.new(self)
  end
  
  def group_bys
    return [] if chain.nil?
    
    [chain].tap do |ary|
      while !(ary.last.bottom? || ary.last.child.filter?)
        ary << ary.last.child
      end
    end
  end
  
  def filters    
    last_group_by = group_bys.last
    return [] if last_group_by.nil? || last_group_by.bottom?
    
    [last_group_by.child].tap do |ary|
      while !ary.last.bottom?
        ary << ary.last.child
      end
    end
  end

  def_delegators  :transformer, :column_first, :row_first
  def_delegators  :chain, :top, :bottom, :chain_collect, :sql_statement, :all_group_fields, :child, :clear, :result
  def_delegators  :result, :each_direct_result, :recursive_each, :recursive_each_with_level, :each, :each_row, :count,
                    :units, :real_costs, :size, :depth_of, :final_number
  def_delegators  :table, :row_index, :colum_index

  def to_a
    chain.to_a
  end

  def to_s
    chain.to_s
  end

end