1#! /usr/bin/env ruby
2
3# cal.rb: Written by Tadayoshi Funaba 1998-2004,2006,2008
4# $Id: cal.rb,v 2.11 2008-01-06 08:42:17+09 tadf Exp $
5
6require 'date'
7
8class Cal
9
10  START =
11    {
12    'cn' => Date::GREGORIAN, # China
13    'de' => 2342032,         # Germany (protestant states)
14    'dk' => 2342032,         # Denmark
15    'es' => 2299161,         # Spain
16    'fi' => 2361390,         # Finland
17    'fr' => 2299227,         # France
18    'gb' => 2361222,         # United Kingdom
19    'gr' => 2423868,         # Greece
20    'hu' => 2301004,         # Hungary
21    'it' => 2299161,         # Italy
22    'jp' => Date::GREGORIAN, # Japan
23    'no' => 2342032,         # Norway
24    'pl' => 2299161,         # Poland
25    'pt' => 2299161,         # Portugal
26    'ru' => 2421639,         # Russia
27    'se' => 2361390,         # Sweden
28    'us' => 2361222,         # United States
29    'os' => Date::JULIAN,    # (old style)
30    'ns' => Date::GREGORIAN  # (new style)
31  }
32
33  DEFAULT_START = 'gb'
34
35  def initialize
36    opt_j; opt_m; opt_t; opt_y; opt_c
37  end
38
39  def opt_j(flag=false) @opt_j = flag end
40  def opt_m(flag=false) @opt_m = flag end
41  def opt_t(flag=false) @opt_t = flag end
42  def opt_y(flag=false) @opt_y = flag end
43
44  def opt_c(arg=DEFAULT_START) @start = START[arg] end
45
46  def set_params
47    @dw = if @opt_j then 3 else 2 end
48    @mw = (@dw + 1) * 7 - 1
49    @mn = if @opt_j then 2 else 3 end
50    @tw = (@mw + 2) * @mn - 2
51    @k  = if @opt_m then 1 else 0 end
52    @da = if @opt_j then :yday else :mday end
53  end
54
55  def pict(y, m)
56    d = (1..31).detect{|x| Date.valid_date?(y, m, x, @start)}
57    fi = Date.new(y, m, d, @start)
58    fi -= (fi.jd - @k + 1) % 7
59
60    ve  = (fi..fi +  6).collect{|cu|
61      %w(S M Tu W Th F S)[cu.wday]
62    }
63    ve += (fi..fi + 41).collect{|cu|
64      if cu.mon == m then cu.send(@da) end.to_s
65    }
66
67    ve = ve.collect{|e| e.rjust(@dw)}
68
69    gr = group(ve, 7)
70    gr = trans(gr) if @opt_t
71    ta = gr.collect{|xs| xs.join(' ')}
72
73    ca = %w(January February March April May June July
74      August September October November December)[m - 1]
75    ca = ca + ' ' + y.to_s if !@opt_y
76    ca = ca.center(@mw)
77
78    ta.unshift(ca)
79  end
80
81  def group(xs, n)
82    (0..xs.size / n - 1).collect{|i| xs[i * n, n]}
83  end
84
85  def trans(xs)
86    (0..xs[0].size - 1).collect{|i| xs.collect{|x| x[i]}}
87  end
88
89  def stack(xs)
90    if xs.empty? then [] else xs[0] + stack(xs[1..-1]) end
91  end
92
93  def block(xs, n)
94    stack(group(xs, n).collect{|ys| trans(ys).collect{|zs| zs.join('  ')}})
95  end
96
97  def unlines(xs)
98    xs.collect{|x| x + "\n"}.join
99  end
100
101  def monthly(y, m)
102    unlines(pict(y, m))
103  end
104
105  def addmon(y, m, n)
106    y, m = (y * 12 + (m - 1) + n).divmod(12)
107    return y, m + 1
108  end
109
110  def yearly(y)
111    y.to_s.center(@tw) + "\n\n" +
112      unlines(block((0..11).collect{|n| pict(*addmon(y, 1, n))}, @mn)) + "\n"
113  end
114
115  def print(y, m)
116    set_params
117    if @opt_y then yearly(y) else monthly(y, m) end
118  end
119
120end
121
122if __FILE__ == $0
123
124  require 'getoptlong'
125
126  def usage
127    warn 'usage: cal [-c iso3166] [-jmty] [[month] year]'
128    exit 1
129  end
130
131  cal = Cal.new
132
133  begin
134    GetoptLong.new(['-c', GetoptLong::REQUIRED_ARGUMENT],
135      ['-j', GetoptLong::NO_ARGUMENT],
136      ['-m', GetoptLong::NO_ARGUMENT],
137      ['-t', GetoptLong::NO_ARGUMENT],
138      ['-y', GetoptLong::NO_ARGUMENT]).
139    each do |opt, arg|
140      case opt
141      when '-c'; cal.opt_c(arg) || raise
142      when '-j'; cal.opt_j(true)
143      when '-m'; cal.opt_m(true)
144      when '-t'; cal.opt_t(true)
145      when '-y'; cal.opt_y(true)
146      end
147    end
148  rescue
149    usage
150  end
151
152  y, m = ARGV.values_at(1, 0).compact.collect{|x| x.to_i}
153  cal.opt_y(true) if y && !m
154
155  to = Date.today
156  y ||= to.year
157  m ||= to.mon
158
159  usage unless m >= 1 && m <= 12
160  usage unless y >= -4712
161
162  print cal.print(y, m)
163
164end
165
166# See Bird & Wadler's Introduction to functional programming 4.5.
167