require File.dirname(__FILE__) + '/date_extensions'
require File.dirname(__FILE__) + '/date_finder_conditions'

class DateFinderBase
  include DateFinderConditions
  
  MAX_DATES, MAX_INTERVALS = 200, 500
  
  @@patterns = {}
  
  attr_reader :options
  
  def initialize(options = {})
    @condition_blocks = {}
    @options = options.reverse_merge :interval => 1, :start_date => Date.today
    valid_options!
  end
  
  def valid_options!(options = @options)
    options.assert_valid_keys :interval, :start_date, :end_date, :max, :max_intervals
  end
  
  class << self
    def method_missing(method_id, *args)
      subclass_name = "#{name}::" + method_id.to_s.camelize
      
      if subclasses.include?(subclass_name)
        options = args.last.is_a?(Hash) ? args.last : {}
        
        options[:interval] ||= 1
        options[:interval] = options[:interval].to_s if options[:interval].is_a?(Symbol)
        
        case options[:interval]
          when 'every_other':  options[:interval] = 2
          when /^every_(\d)+/: options[:interval] = $1.to_i
        end
        
        subclass_name.constantize.new(options)
      else
        super
      end
    end
  end
  
  def interval(interval)
    @options[:interval] = interval
  end
  
  def find(options = {})
    options = @options.merge(options)
    valid_options! options
    
    start, intervals = options[:start_date], 0
    
    returning [] do |dates|
      loop do
        break if intervals == options[:max_intervals] or intervals == MAX_INTERVALS
        break if dates.size >= MAX_DATES
        break if options[:max] and dates.size >= options[:max]
        
        if options[:end_date] and options[:end_date] < start
          dates.reject! { |d| d > options[:end_date] }
          break
        end
        
        dates.concat dates_matching_conditions(dates_to_test(start))
        
        start = next_start_date(start, options[:interval])
        intervals += 1
      end
      
      if options[:max]
        dates.pop until dates.size <= options[:max]
      end
    end
  end
  
  def dates_matching_conditions(dates)
    dates.select do |date|
      @condition_blocks.values.all? do |blocks|
        blocks.any? { |c| c.call(date) }
      end
    end
  end
  
  def condition(name, &block)
    (@condition_blocks[name] ||= []) << block
    self
  end
end

require File.dirname(__FILE__) + '/patterns'