module ActiveSupport #:nodoc:
  module CoreExtensions #:nodoc:
    module Time #:nodoc:
      # Getting times in different convenient string representations and other objects
      module Conversions
        DATE_FORMATS = {
          :db           => "%Y-%m-%d %H:%M:%S",
          :time         => "%H:%M",
          :short        => "%d %b %H:%M",
          :long         => "%B %d, %Y %H:%M",
          :long_ordinal => lambda { |time| time.strftime("%B #{time.day.ordinalize}, %Y %H:%M") },
          :rfc822       => "%a, %d %b %Y %H:%M:%S %z"
        }

        def self.included(base)
          base.class_eval do
            alias_method :to_default_s, :to_s
            alias_method :to_s, :to_formatted_s
          end
        end

        # Convert to a formatted string - see DATE_FORMATS for predefined formats.
        # You can also add your own formats to the DATE_FORMATS constant and use them with this method.
        #
        # This method is also aliased as <tt>to_s</tt>.
        #
        # ==== Examples:
        #   time = Time.now                     # => Thu Jan 18 06:10:17 CST 2007
        #
        #   time.to_formatted_s(:time)          # => "06:10:17"
        #   time.to_s(:time)                    # => "06:10:17"
        #
        #   time.to_formatted_s(:db)            # => "2007-01-18 06:10:17"
        #   time.to_formatted_s(:short)         # => "18 Jan 06:10"
        #   time.to_formatted_s(:long)          # => "January 18, 2007 06:10"
        #   time.to_formatted_s(:long_ordinal)  # => "January 18th, 2007 06:10"
        #   time.to_formatted_s(:rfc822)        # => "Thu, 18 Jan 2007 06:10:17 -0600"
        def to_formatted_s(format = :default)
          if formatter = DATE_FORMATS[format]
            if formatter.respond_to?(:call)
              formatter.call(self).to_s
            else
              strftime(formatter)
            end
          else
            to_default_s
          end
        end

        # Convert a Time object to a Date, dropping hour, minute, and second precision.
        #
        # ==== Examples
        #   my_time = Time.now
        #   # => Mon Nov 12 22:59:51 -0500 2007
        #
        #   my_time.to_date
        #   #=> Mon, 12 Nov 2007
        #
        #   your_time = Time.parse("1/13/2009 1:13:03 P.M.")
        #   # => Tue Jan 13 13:13:03 -0500 2009
        #
        #   your_time.to_date
        #   # => Tue, 13 Jan 2009
        def to_date
          ::Date.new(year, month, day)
        end

        # A method to keep Time, Date and DateTime instances interchangeable on conversions.
        # In this case, it simply returns +self+.
        def to_time
          self
        end

        # Converts a Time instance to a Ruby DateTime instance, preserving UTC offset.
        #
        # ==== Examples
        #   my_time = Time.now
        #   # => Mon Nov 12 23:04:21 -0500 2007
        #
        #   my_time.to_datetime
        #   # => Mon, 12 Nov 2007 23:04:21 -0500
        #
        #   your_time = Time.parse("1/13/2009 1:13:03 P.M.")
        #   # => Tue Jan 13 13:13:03 -0500 2009
        #
        #   your_time.to_datetime
        #   # => Tue, 13 Jan 2009 13:13:03 -0500
        def to_datetime
          ::DateTime.civil(year, month, day, hour, min, sec, Rational(utc_offset, 86400))
        end
      end
    end
  end
end