Calendar generator for mitsui. RubyにカレンダーっぽいHTMLを吐き出さすまで物語 - c4se記：さっちゃんですよ☆ http://c4se.hatenablog.com/entry/2013/07/01/193049

.gitignore

.bundle/
vendor/

.vimprojects

setl et
setl sw=2
setl sts=2
setl ff=unix

calendar.erb

<table>
  <tr>
    <td colspan="7"><%=weeks.year%>年<%=weeks.month%>月</td>
  </tr>
  <tr class="dow">
    <td class="holiday">日</td>
    <td class="weekend">月</td>
    <td class="weekend">火</td>
    <td class="weekend">水</td>
    <td class="weekend">木</td>
    <td class="weekend">金</td>
    <td class="holiday">土</td>
  </tr>
<% weeks.each do |week| %>
  <tr>
  <% week.each do |date|
       class_name =
         weeks.miss?(date) ? 'null' :
         (date.holiday? ? 'holiday' : 'weekday') %>
    <td class="<%=class_name%>"><%=date.day%></td>
  <% end %>
  </tr>
<% end %>
</table>

calendar.rb

# encoding=utf-8

require 'date'
require 'holiday_jp'
require 'erubis'

class Date
  # A Date which is the end of the month.
  #
  # return [Date]
  def end_of_month
    next_month.prev_day
  end

  # Is Japanese holiday?
  #
  # return [Boolean]
  def holiday?
    wday == 0 || wday == 6 || HolidayJp.holiday?(self)
  end
end

# Weeks of a month.
class Weeks
  include Enumerable
  attr_accessor :year, :month, :weeks

  # param [Number] year
  # param [Number] month
  def initialize year, month
    @year = year
    @month = month
    @weeks = generate_weeks
  end

  # Isn't the date in current month?
  #
  # param [Date] date
  def miss? date
    @month != date.month
  end

  # Each week (7 Date).
  #
  # param [block] &proc
  def each &proc
    @weeks.each &proc
  end

private
  # Generate weeks.
  #
  # return [Array] of weeks (7 Date)
  def generate_weeks
    dates = gen_prev_month + gen_current_month + gen_next_month
    dates.each_slice(7).to_a
  end

  # Generate a Date sequence of prev month.
  #
  # return [Array] of Date
  def gen_prev_month
    prev_month_end_day = Date.new(@year, @month).prev_month.end_of_month.day
    start_date = Date.new @year, @month, 1
    gen_sequence (1 - start_date.wday .. 0).map{|n| n + prev_month_end_day }, @month - 1
  end

  # Generate a Date sequence of current month.
  #
  # return [Array] of Date
  def gen_current_month
    end_date = Date.new(@year, @month).end_of_month
    gen_sequence 1 .. end_date.day
  end

  # Generate a Date sequence of next month.
  #
  # return [Array] of Date
  def gen_next_month
    end_date = Date.new(@year, @month).end_of_month
    gen_sequence (end_date.wday + 1 .. 6).each_with_index.map{|n, date| date + 1 }, @month + 1
  end

  # Generate a Date sequence.
  #
  # param [Enumerable] days of Number
  # param [Number] month
  # param [Number] year
  # return [Array] of Date
  def gen_sequence days, month=@month, year=@year
    if month <= 0
      year -= 1
      month += 12
    elsif month > 12
      year += 1
      month %= 12
    end
    days.map{|day| Date.new year, month, day }
  end
end

# Render a calendar from a template.
#
# param [Weeks] weeks
# return [String]
def render_calendar weeks
  open 'calendar.erb', 'r:utf-8' do |file|
    eruby = Erubis::Eruby.new file.read
    eruby.result binding
  end
end

# Copy html String to a clip board.
#
# param [String] html
def copy html
  if RbConfig::CONFIG['target_os'] =~ /mswin|mingw|cygwin/
    open('tmp.html', 'w:cp932'){|file| file.write html }
    system 'clip < tmp.html'
    File.delete 'tmp.html'
  else
    system "echo '#{html}' | pbcopy"
  end
end

if ARGV[0]
  match = ARGV[0].match %r{(?:(\d{4})[-/])?(\d{1,2})}
  year = match[1] ? match[1].to_i : Date.today.year
  month = match[2].to_i
else
  year = Date.today.year
  month = Date.today.month
end
weeks = Weeks.new year, month
html = render_calendar weeks
copy html
puts 'calendar copyed!'

Gemfile

source 'https://rubygems.org'

gem 'holiday_jp'
gem 'erubis'

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    erubis (2.7.0)
    holiday_jp (0.3.1)

PLATFORMS
  x86-mingw32

DEPENDENCIES
  erubis
  holiday_jp