Date Range Formatter Test

date_range_formatter.rb

# Format a single date instance with an optional time
#
# @author Matt Rayner
# @since 1.0.0
#
# @attr [Date] Date The date that we are formatting
# @attr [String] Time An optional time value for this date
class DateFormatter
  attr_reader :date, :time

  # Create a new DateFormatter with an optional time
  #
  # @author Matt Rayner
  #
  # @attr [Date] Date The date to be formatter
  # @attr [String] Time The optional time string (optional || can be nil)
  def initialize date, time = nil
    @date = date
    @time = time
  end

  # Output a string representation of our date
  #
  # @author Matt Rayner
  #
  # @attr [Symbol] Format How are we formatting this date? Options are: :full, :time, :day, :no_year
  # @return [String] The formatted date string
  def to_s format = :full
    # Create a placeholder for our output string
    output_string = ''

    # How are we formatting this date?
    case format
      when :full # 1st November 2008 at 10:00
        # Format the date object into full string
        output_string += format_date_with(:day, :month, :year, :time)
      when :time # 10:00
        # Format the date so that only the time appears (unless nil)
        output_string += format_date_with(:time)
      when :day # 1st
        # Format the date so only the day appears
        output_string += format_date_with(:day)
      when :no_year # 1st November
        # Format the date object into a no-year string
        output_string += format_date_with(:day, :month)
    end

    # Return our formatted string
    output_string
  end

  private
    # Format the Date object using a number of object passed by the user
    #
    # @author Matt Rayner
    #
    # Accepted Arguments:
    #   :day    # 1st
    #   :month  # November
    #   :year   # 2008
    #   :time   # 10:00
    #
    # @param [Array<Symbol>] Args An array of the format sections you want to have included
    # @return [String] Formatted Date string
    def format_date_with(*args)
      # Which pieces are going to make up this date string?
      format_array = []

      # Add the day, month and year if it is in our array of arguments
      format_array << "#{date.day.ordinalize}" if args.include? :day
      format_array << '%B' if args.include? :month
      format_array << '%Y' if args.include? :year

      # If we have a time value set, and the user has requested time, attempt to add time formatting
      if time && args.include?(:time)
        # Add an 'at' in front the time, IF there is at least one other element in the format_array
        format_array << 'at' unless format_array.empty?

        # Add the time
        format_array << time
      end

      date.strftime(format_array.join(' '))
    end
end

# Given a start date, end date, and optional start / end times, produce a nicely formatted, abbreviated representation
# of the time span that the dates represent.
#
# @author Nature Publishing Group & Matt Rayner
# @since 0.0.0
#
# @attr [Date] Start_on The date we are starting on
# @attr [Date] End_on The date we are ending on
# @attr [String] Starting_time The time we are starting (optional || can be nil)
# @attr [String] Ending_time The time we are ending (optional || can be nil)
class DateRangeFormatter
  attr_reader :start_on, :end_on, :starting_time, :ending_time

  # Create a new DateRangeFormatter with optional times
  #
  # @author Nature Publishing Group & Matt Rayner
  #
  # @attr [String] Start_on A string representation of the starting date
  # @attr [String] End_on A string representation of the ending date
  # @attr [String] Starting_time A string representation of the starting time
  # @attr [String] Ending_time A string representation of the ending time
  def initialize start_on, end_on, starting_time = nil, ending_time = nil
    @start_on = Date.parse(start_on)
    @end_on = Date.parse(end_on)
    @starting_time, @ending_time = starting_time, ending_time
  end

  # Output a string representation of our date range which changes depending on the start and end dates and times
  #
  # @author Nature Publishing Group & Matt Rayner
  #
  # @return [String] Formatted date
  def to_s
    # Create a date formatter for our starting date and end date
    starting_date_formatter = DateFormatter.new start_on, starting_time
    end_date_formatter = DateFormatter.new end_on, ending_time

    # Get the formatting we should use (as a Hash)
    range_format = get_range_format

    # Add our starting date (based on tests this will always be present)
    output_string = starting_date_formatter.to_s range_format[:start_date_format]

    # Add our end date (unless we have a nil format)
    output_string += " #{range_format[:date_seperator]} #{end_date_formatter.to_s range_format[:end_date_format]}" unless range_format[:end_date_format].nil?

    # Return out formatted range string
    output_string
  end

  private
    # Given the two dates, decide which formatting the range should have.
    #
    # @author Matt Rayner
    #
    # @return [Hash] Formats to use within our range
    #   { start_date_format: :full,
    #     end_date_format: :full, # (can be nil if no end date should be shown)
    #     date_seperator: '-' }
    def get_range_format
      # What format should the start and end dates have? (default to :full)
      start_format = :full
      end_format = :full

      # What should the seperator be between the date string? (defaults to '-')
      #   i.e. '1st November 2008 - 3rd November 2008' or '1st November 2008 at 10:00 to 11:00'
      seperator = '-'

      # Are the main dates the same?
      if @start_on == @end_on
        # Default to no end date
        end_format = nil

        # If there is an end time, then show that and change the seperator to 'to'
        unless ending_time.nil?
          end_format = :time
          seperator = 'to'
        end
      elsif is_same_month && is_same_year && times_are_not_set # Are the months and years the same, and no times set?
        # Only show the start day
        #   e.g. '1st - 3rd November 2008'
        start_format = :day
      elsif is_same_year && times_are_not_set # Are the years the same, and no times set?
        # Only show the start day and month
        #   e.g. '1st November - 7th December 2008'
        start_format = :no_year
      end

      # Generate and return our hash
      return { start_date_format: start_format, end_date_format: end_format, date_seperator: seperator }
    end

    # A small helper function returning a boolean if time values have been set
    #
    # @author Matt Rayner
    #
    # @return [Boolean] Is there a time set?
    def times_are_not_set
      starting_time.nil? && ending_time.nil?
    end

    # A small helper function returning a boolean if the start and end dates are within the same month
    #
    # @author Matt Rayner
    #
    # @return [Boolean] Are the months for both the start and end dates the same
    def is_same_month
      start_on.month == end_on.month
    end

    # A small helper function returning a boolean if the start and end dates are within the same year
    #
    # @author Matt Rayner
    #
    # @return [Boolean] Are the years for both the start and end dates the same?
    def is_same_year
      start_on.year == end_on.year
    end
end


class Fixnum
  def ordinalize
    if (11..13).include?(self.abs % 100)
      "#{self}th"
    else
      case self.to_i.abs % 10
        when 1; "#{self}st"
        when 2; "#{self}nd"
        when 3; "#{self}rd"
        else    "#{self}th"
      end
    end
  end
end

date_range_formatter_spec.rb

require 'spec_helper'
 
describe DateRangeFormatter do
  it "formats date range for the same day" do
    formatter = DateRangeFormatter.new "2009-11-1", "2009-11-1"
    formatter.to_s.should == "1st November 2009"
  end
 
  it "formats date range for the same day with starting time" do
    formatter = DateRangeFormatter.new "2009-11-1", "2009-11-1", "10:00"
    formatter.to_s.should == "1st November 2009 at 10:00"
  end
 
  it "formats date range for the same day with starting and ending times" do
    formatter = DateRangeFormatter.new "2009-11-1", "2009-11-1", "10:00", "11:00"
    formatter.to_s.should == "1st November 2009 at 10:00 to 11:00"
  end
 
  it "formats date range for the same month" do
    formatter = DateRangeFormatter.new "2009-11-1", "2009-11-3"
    formatter.to_s.should == "1st - 3rd November 2009"
  end
 
  it "formats date range for the same month with starting time" do
    formatter = DateRangeFormatter.new "2009-11-1", "2009-11-3", "10:00"
    formatter.to_s.should == "1st November 2009 at 10:00 - 3rd November 2009"
  end
 
  it "formats date range for the same month with starting and ending times" do
    formatter = DateRangeFormatter.new "2009-11-1", "2009-11-3", "10:00", "11:00"
    formatter.to_s.should == "1st November 2009 at 10:00 - 3rd November 2009 at 11:00"
  end
 
  it "formats date range for the same year" do
    formatter = DateRangeFormatter.new "2009-11-1", "2009-12-1"
    formatter.to_s.should == "1st November - 1st December 2009"
  end
 
  it "formats date range for the same year with starting time" do
    formatter = DateRangeFormatter.new "2009-11-1", "2009-12-1", "10:00"
    formatter.to_s.should == "1st November 2009 at 10:00 - 1st December 2009"
  end
 
  it "formats date range for the same year with starting and ending times" do
    formatter = DateRangeFormatter.new "2009-11-1", "2009-12-1", "10:00", "11:00"
    formatter.to_s.should == "1st November 2009 at 10:00 - 1st December 2009 at 11:00"
  end
 
  it "formats date range for different year" do
    formatter = DateRangeFormatter.new "2009-11-1", "2010-12-1"
    formatter.to_s.should == "1st November 2009 - 1st December 2010"
  end
 
 
  it "formats date range for different year with starting time" do
    formatter = DateRangeFormatter.new "2009-11-1", "2010-12-1", "10:00"
    formatter.to_s.should == "1st November 2009 at 10:00 - 1st December 2010"
  end
 
  it "should give long date range for different year with starting and ending times" do
    formatter = DateRangeFormatter.new "2009-11-1", "2010-12-1", "10:00", "11:00"
    formatter.to_s.should == "1st November 2009 at 10:00 - 1st December 2010 at 11:00"
  end
 
end