aboutsummaryrefslogtreecommitdiffstats
path: root/actionpack/lib/action_view/helpers/form_options_helper.rb
blob: 5be3da9b9429ffba1b371e03ecca192063288404 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
require 'cgi'
require 'erb'
require 'action_view/helpers/form_helper'
require 'active_support/core_ext/object/blank'
require 'active_support/core_ext/string/output_safety'

module ActionView
  # = Action View Form Option Helpers
  module Helpers
    # Provides a number of methods for turning different kinds of containers into a set of option tags.
    # == Options
    # The <tt>collection_select</tt>, <tt>select</tt> and <tt>time_zone_select</tt> methods take an <tt>options</tt> parameter, a hash:
    #
    # * <tt>:include_blank</tt> - set to true or a prompt string if the first option element of the select element is a blank. Useful if there is not a default value required for the select element.
    #
    # For example,
    #
    #   select("post", "category", Post::CATEGORIES, {:include_blank => true})
    #
    # could become:
    #
    #   <select name="post[category]">
    #     <option></option>
    #     <option>joke</option>
    #     <option>poem</option>
    #   </select>
    #
    # Another common case is a select tag for an <tt>belongs_to</tt>-associated object.
    #
    # Example with @post.person_id => 2:
    #
    #   select("post", "person_id", Person.all.collect {|p| [ p.name, p.id ] }, {:include_blank => 'None'})
    #
    # could become:
    #
    #   <select name="post[person_id]">
    #     <option value="">None</option>
    #     <option value="1">David</option>
    #     <option value="2" selected="selected">Sam</option>
    #     <option value="3">Tobias</option>
    #   </select>
    #
    # * <tt>:prompt</tt> - set to true or a prompt string. When the select element doesn't have a value yet, this prepends an option with a generic prompt -- "Please select" -- or the given prompt string.
    #
    # Example:
    #
    #   select("post", "person_id", Person.all.collect {|p| [ p.name, p.id ] }, {:prompt => 'Select Person'})
    #
    # could become:
    #
    #   <select name="post[person_id]">
    #     <option value="">Select Person</option>
    #     <option value="1">David</option>
    #     <option value="2">Sam</option>
    #     <option value="3">Tobias</option>
    #   </select>
    #
    # Like the other form helpers, +select+ can accept an <tt>:index</tt> option to manually set the ID used in the resulting output. Unlike other helpers, +select+ expects this
    # option to be in the +html_options+ parameter.
    #
    # Example:
    #
    #   select("album[]", "genre", %w[rap rock country], {}, { :index => nil })
    #
    # becomes:
    #
    #   <select name="album[][genre]" id="album__genre">
    #     <option value="rap">rap</option>
    #     <option value="rock">rock</option>
    #     <option value="country">country</option>
    #   </select>
    #
    # * <tt>:disabled</tt> - can be a single value or an array of values that will be disabled options in the final output.
    #
    # Example:
    #
    #   select("post", "category", Post::CATEGORIES, {:disabled => 'restricted'})
    #
    # could become:
    #
    #   <select name="post[category]">
    #     <option></option>
    #     <option>joke</option>
    #     <option>poem</option>
    #     <option disabled="disabled">restricted</option>
    #   </select>
    #
    # When used with the <tt>collection_select</tt> helper, <tt>:disabled</tt> can also be a Proc that identifies those options that should be disabled.
    #
    # Example:
    #
    #   collection_select(:post, :category_id, Category.all, :id, :name, {:disabled => lambda{|category| category.archived? }})
    #
    # If the categories "2008 stuff" and "Christmas" return true when the method <tt>archived?</tt> is called, this would return:
    #   <select name="post[category_id]">
    #     <option value="1" disabled="disabled">2008 stuff</option>
    #     <option value="2" disabled="disabled">Christmas</option>
    #     <option value="3">Jokes</option>
    #     <option value="4">Poems</option>
    #   </select>
    #
    module FormOptionsHelper
      # ERB::Util can mask some helpers like textilize. Make sure to include them.
      include TextHelper

      # Create a select tag and a series of contained option tags for the provided object and method.
      # The option currently held by the object will be selected, provided that the object is available.
      #
      # There are two possible formats for the choices parameter, corresponding to other helpers' output:
      #   * A flat collection: see options_for_select
      #   * A nested collection: see grouped_options_for_select
      #
      # Example with @post.person_id => 1:
      #   select("post", "person_id", Person.all.collect {|p| [ p.name, p.id ] }, { :include_blank => true })
      #
      # could become:
      #
      #   <select name="post[person_id]">
      #     <option value=""></option>
      #     <option value="1" selected="selected">David</option>
      #     <option value="2">Sam</option>
      #     <option value="3">Tobias</option>
      #   </select>
      #
      # This can be used to provide a default set of options in the standard way: before rendering the create form, a
      # new model instance is assigned the default options and bound to @model_name. Usually this model is not saved
      # to the database. Instead, a second model object is created when the create request is received.
      # This allows the user to submit a form page more than once with the expected results of creating multiple records.
      # In addition, this allows a single partial to be used to generate form inputs for both edit and create forms.
      #
      # By default, <tt>post.person_id</tt> is the selected option. Specify <tt>:selected => value</tt> to use a different selection
      # or <tt>:selected => nil</tt> to leave all options unselected. Similarly, you can specify values to be disabled in the option
      # tags by specifying the <tt>:disabled</tt> option. This can either be a single value or an array of values to be disabled.
      #
      # ==== Gotcha
      #
      # The HTML specification says when +multiple+ parameter passed to select and all options got deselected
      # web browsers do not send any value to server. Unfortunately this introduces a gotcha:
      # if an +User+ model has many +roles+ and have +role_ids+ accessor, and in the form that edits roles of the user
      # the user deselects all roles from +role_ids+ multiple select box, no +role_ids+ parameter is sent. So,
      # any mass-assignment idiom like
      #
      #   @user.update_attributes(params[:user])
      #
      # wouldn't update roles.
      #
      # To prevent this the helper generates an auxiliary hidden field before
      # every multiple select. The hidden field has the same name as multiple select and blank value.
      #
      # This way, the client either sends only the hidden field (representing
      # the deselected multiple select box), or both fields. Since the HTML specification
      # says key/value pairs have to be sent in the same order they appear in the
      # form, and parameters extraction gets the last occurrence of any repeated
      # key in the query string, that works for ordinary forms.
      #
      def select(object, method, choices, options = {}, html_options = {})
        Tags::Select.new(object, method, self, choices, options, html_options).render
      end

      # Returns <tt><select></tt> and <tt><option></tt> tags for the collection of existing return values of
      # +method+ for +object+'s class. The value returned from calling +method+ on the instance +object+ will
      # be selected. If calling +method+ returns +nil+, no selection is made without including <tt>:prompt</tt>
      # or <tt>:include_blank</tt> in the +options+ hash.
      #
      # The <tt>:value_method</tt> and <tt>:text_method</tt> parameters are methods to be called on each member
      # of +collection+. The return values are used as the +value+ attribute and contents of each
      # <tt><option></tt> tag, respectively. They can also be any object that responds to +call+, such
      # as a +proc+, that will be called for each member of the +collection+ to
      # retrieve the value/text.
      #
      # Example object structure for use with this method:
      #   class Post < ActiveRecord::Base
      #     belongs_to :author
      #   end
      #   class Author < ActiveRecord::Base
      #     has_many :posts
      #     def name_with_initial
      #       "#{first_name.first}. #{last_name}"
      #     end
      #   end
      #
      # Sample usage (selecting the associated Author for an instance of Post, <tt>@post</tt>):
      #   collection_select(:post, :author_id, Author.all, :id, :name_with_initial, :prompt => true)
      #
      # If <tt>@post.author_id</tt> is already <tt>1</tt>, this would return:
      #   <select name="post[author_id]">
      #     <option value="">Please select</option>
      #     <option value="1" selected="selected">D. Heinemeier Hansson</option>
      #     <option value="2">D. Thomas</option>
      #     <option value="3">M. Clark</option>
      #   </select>
      def collection_select(object, method, collection, value_method, text_method, options = {}, html_options = {})
        Tags::CollectionSelect.new(object, method, self, collection, value_method, text_method, options, html_options).render
      end

      # Returns <tt><select></tt>, <tt><optgroup></tt> and <tt><option></tt> tags for the collection of existing return values of
      # +method+ for +object+'s class. The value returned from calling +method+ on the instance +object+ will
      # be selected. If calling +method+ returns +nil+, no selection is made without including <tt>:prompt</tt>
      # or <tt>:include_blank</tt> in the +options+ hash.
      #
      # Parameters:
      # * +object+ - The instance of the class to be used for the select tag
      # * +method+ - The attribute of +object+ corresponding to the select tag
      # * +collection+ - An array of objects representing the <tt><optgroup></tt> tags.
      # * +group_method+ - The name of a method which, when called on a member of +collection+, returns an
      #   array of child objects representing the <tt><option></tt> tags.
      # * +group_label_method+ - The name of a method which, when called on a member of +collection+, returns a
      #   string to be used as the +label+ attribute for its <tt><optgroup></tt> tag.
      # * +option_key_method+ - The name of a method which, when called on a child object of a member of
      #   +collection+, returns a value to be used as the +value+ attribute for its <tt><option></tt> tag.
      # * +option_value_method+ - The name of a method which, when called on a child object of a member of
      #   +collection+, returns a value to be used as the contents of its <tt><option></tt> tag.
      #
      # Example object structure for use with this method:
      #   class Continent < ActiveRecord::Base
      #     has_many :countries
      #     # attribs: id, name
      #   end
      #   class Country < ActiveRecord::Base
      #     belongs_to :continent
      #     # attribs: id, name, continent_id
      #   end
      #   class City < ActiveRecord::Base
      #     belongs_to :country
      #     # attribs: id, name, country_id
      #   end
      #
      # Sample usage:
      #   grouped_collection_select(:city, :country_id, @continents, :countries, :name, :id, :name)
      #
      # Possible output:
      #   <select name="city[country_id]">
      #     <optgroup label="Africa">
      #       <option value="1">South Africa</option>
      #       <option value="3">Somalia</option>
      #     </optgroup>
      #     <optgroup label="Europe">
      #       <option value="7" selected="selected">Denmark</option>
      #       <option value="2">Ireland</option>
      #     </optgroup>
      #   </select>
      #
      def grouped_collection_select(object, method, collection, group_method, group_label_method, option_key_method, option_value_method, options = {}, html_options = {})
        Tags::GroupedCollectionSelect.new(object, method, self, collection, group_method, group_label_method, option_key_method, option_value_method, options, html_options).render
      end

      # Return select and option tags for the given object and method, using
      # #time_zone_options_for_select to generate the list of option tags.
      #
      # In addition to the <tt>:include_blank</tt> option documented above,
      # this method also supports a <tt>:model</tt> option, which defaults
      # to ActiveSupport::TimeZone. This may be used by users to specify a
      # different time zone model object. (See +time_zone_options_for_select+
      # for more information.)
      #
      # You can also supply an array of ActiveSupport::TimeZone objects
      # as +priority_zones+, so that they will be listed above the rest of the
      # (long) list. (You can use ActiveSupport::TimeZone.us_zones as a convenience
      # for obtaining a list of the US time zones, or a Regexp to select the zones
      # of your choice)
      #
      # Finally, this method supports a <tt>:default</tt> option, which selects
      # a default ActiveSupport::TimeZone if the object's time zone is +nil+.
      #
      # Examples:
      #   time_zone_select( "user", "time_zone", nil, :include_blank => true)
      #
      #   time_zone_select( "user", "time_zone", nil, :default => "Pacific Time (US & Canada)" )
      #
      #   time_zone_select( "user", 'time_zone', ActiveSupport::TimeZone.us_zones, :default => "Pacific Time (US & Canada)")
      #
      #   time_zone_select( "user", 'time_zone', [ ActiveSupport::TimeZone['Alaska'], ActiveSupport::TimeZone['Hawaii'] ])
      #
      #   time_zone_select( "user", 'time_zone', /Australia/)
      #
      #   time_zone_select( "user", "time_zone", ActiveSupport::TimeZone.all.sort, :model => ActiveSupport::TimeZone)
      def time_zone_select(object, method, priority_zones = nil, options = {}, html_options = {})
        Tags::TimeZoneSelect.new(object, method, self, priority_zones, options, html_options).render
      end

      # Accepts a container (hash, array, enumerable, your type) and returns a string of option tags. Given a container
      # where the elements respond to first and last (such as a two-element array), the "lasts" serve as option values and
      # the "firsts" as option text. Hashes are turned into this form automatically, so the keys become "firsts" and values
      # become lasts. If +selected+ is specified, the matching "last" or element will get the selected option-tag. +selected+
      # may also be an array of values to be selected when using a multiple select.
      #
      # Examples (call, result):
      #   options_for_select([["Dollar", "$"], ["Kroner", "DKK"]])
      #     <option value="$">Dollar</option>\n<option value="DKK">Kroner</option>
      #
      #   options_for_select([ "VISA", "MasterCard" ], "MasterCard")
      #     <option>VISA</option>\n<option selected="selected">MasterCard</option>
      #
      #   options_for_select({ "Basic" => "$20", "Plus" => "$40" }, "$40")
      #     <option value="$20">Basic</option>\n<option value="$40" selected="selected">Plus</option>
      #
      #   options_for_select([ "VISA", "MasterCard", "Discover" ], ["VISA", "Discover"])
      #     <option selected="selected">VISA</option>\n<option>MasterCard</option>\n<option selected="selected">Discover</option>
      #
      # You can optionally provide html attributes as the last element of the array.
      #
      # Examples:
      #   options_for_select([ "Denmark", ["USA", {:class => 'bold'}], "Sweden" ], ["USA", "Sweden"])
      #     <option value="Denmark">Denmark</option>\n<option value="USA" class="bold" selected="selected">USA</option>\n<option value="Sweden" selected="selected">Sweden</option>
      #
      #   options_for_select([["Dollar", "$", {:class => "bold"}], ["Kroner", "DKK", {:onclick => "alert('HI');"}]])
      #     <option value="$" class="bold">Dollar</option>\n<option value="DKK" onclick="alert('HI');">Kroner</option>
      #
      # If you wish to specify disabled option tags, set +selected+ to be a hash, with <tt>:disabled</tt> being either a value
      # or array of values to be disabled. In this case, you can use <tt>:selected</tt> to specify selected option tags.
      #
      # Examples:
      #   options_for_select(["Free", "Basic", "Advanced", "Super Platinum"], :disabled => "Super Platinum")
      #     <option value="Free">Free</option>\n<option value="Basic">Basic</option>\n<option value="Advanced">Advanced</option>\n<option value="Super Platinum" disabled="disabled">Super Platinum</option>
      #
      #   options_for_select(["Free", "Basic", "Advanced", "Super Platinum"], :disabled => ["Advanced", "Super Platinum"])
      #     <option value="Free">Free</option>\n<option value="Basic">Basic</option>\n<option value="Advanced" disabled="disabled">Advanced</option>\n<option value="Super Platinum" disabled="disabled">Super Platinum</option>
      #
      #   options_for_select(["Free", "Basic", "Advanced", "Super Platinum"], :selected => "Free", :disabled => "Super Platinum")
      #     <option value="Free" selected="selected">Free</option>\n<option value="Basic">Basic</option>\n<option value="Advanced">Advanced</option>\n<option value="Super Platinum" disabled="disabled">Super Platinum</option>
      #
      # NOTE: Only the option tags are returned, you have to wrap this call in a regular HTML select tag.
      def options_for_select(container, selected = nil)
        return container if String === container

        selected, disabled = extract_selected_and_disabled(selected).map do |r|
          Array(r).map { |item| item.to_s }
        end

        container.map do |element|
          html_attributes = option_html_attributes(element)
          text, value = option_text_and_value(element).map { |item| item.to_s }

          html_attributes[:selected] = 'selected' if option_value_selected?(value, selected)
          html_attributes[:disabled] = 'disabled' if disabled && option_value_selected?(value, disabled)
          html_attributes[:value] = value

          content_tag(:option, text, html_attributes)
        end.join("\n").html_safe
      end

      # Returns a string of option tags that have been compiled by iterating over the +collection+ and assigning
      # the result of a call to the +value_method+ as the option value and the +text_method+ as the option text.
      # Example:
      #   options_from_collection_for_select(@people, 'id', 'name')
      # This will output the same HTML as if you did this:
      #   <option value="#{person.id}">#{person.name}</option>
      #
      # This is more often than not used inside a #select_tag like this example:
      #   select_tag 'person', options_from_collection_for_select(@people, 'id', 'name')
      #
      # If +selected+ is specified as a value or array of values, the element(s) returning a match on +value_method+
      # will be selected option tag(s).
      #
      # If +selected+ is specified as a Proc, those members of the collection that return true for the anonymous
      # function are the selected values.
      #
      # +selected+ can also be a hash, specifying both <tt>:selected</tt> and/or <tt>:disabled</tt> values as required.
      #
      # Be sure to specify the same class as the +value_method+ when specifying selected or disabled options.
      # Failure to do this will produce undesired results. Example:
      #   options_from_collection_for_select(@people, 'id', 'name', '1')
      # Will not select a person with the id of 1 because 1 (an Integer) is not the same as '1' (a string)
      #   options_from_collection_for_select(@people, 'id', 'name', 1)
      # should produce the desired results.
      def options_from_collection_for_select(collection, value_method, text_method, selected = nil)
        options = collection.map do |element|
          [value_for_collection(element, text_method), value_for_collection(element, value_method)]
        end
        selected, disabled = extract_selected_and_disabled(selected)
        select_deselect = {
          :selected => extract_values_from_collection(collection, value_method, selected),
          :disabled => extract_values_from_collection(collection, value_method, disabled)
        }

        options_for_select(options, select_deselect)
      end

      # Returns a string of <tt><option></tt> tags, like <tt>options_from_collection_for_select</tt>, but
      # groups them by <tt><optgroup></tt> tags based on the object relationships of the arguments.
      #
      # Parameters:
      # * +collection+ - An array of objects representing the <tt><optgroup></tt> tags.
      # * +group_method+ - The name of a method which, when called on a member of +collection+, returns an
      #   array of child objects representing the <tt><option></tt> tags.
      # * group_label_method+ - The name of a method which, when called on a member of +collection+, returns a
      #   string to be used as the +label+ attribute for its <tt><optgroup></tt> tag.
      # * +option_key_method+ - The name of a method which, when called on a child object of a member of
      #   +collection+, returns a value to be used as the +value+ attribute for its <tt><option></tt> tag.
      # * +option_value_method+ - The name of a method which, when called on a child object of a member of
      #   +collection+, returns a value to be used as the contents of its <tt><option></tt> tag.
      # * +selected_key+ - A value equal to the +value+ attribute for one of the <tt><option></tt> tags,
      #   which will have the +selected+ attribute set. Corresponds to the return value of one of the calls
      #   to +option_key_method+. If +nil+, no selection is made. Can also be a hash if disabled values are
      #   to be specified.
      #
      # Example object structure for use with this method:
      #   class Continent < ActiveRecord::Base
      #     has_many :countries
      #     # attribs: id, name
      #   end
      #   class Country < ActiveRecord::Base
      #     belongs_to :continent
      #     # attribs: id, name, continent_id
      #   end
      #
      # Sample usage:
      #   option_groups_from_collection_for_select(@continents, :countries, :name, :id, :name, 3)
      #
      # Possible output:
      #   <optgroup label="Africa">
      #     <option value="1">Egypt</option>
      #     <option value="4">Rwanda</option>
      #     ...
      #   </optgroup>
      #   <optgroup label="Asia">
      #     <option value="3" selected="selected">China</option>
      #     <option value="12">India</option>
      #     <option value="5">Japan</option>
      #     ...
      #   </optgroup>
      #
      # <b>Note:</b> Only the <tt><optgroup></tt> and <tt><option></tt> tags are returned, so you still have to
      # wrap the output in an appropriate <tt><select></tt> tag.
      def option_groups_from_collection_for_select(collection, group_method, group_label_method, option_key_method, option_value_method, selected_key = nil)
        collection.map do |group|
          option_tags = options_from_collection_for_select(
            group.send(group_method), option_key_method, option_value_method, selected_key)

          content_tag(:optgroup, option_tags, :label => group.send(group_label_method))
        end.join.html_safe
      end

      # Returns a string of <tt><option></tt> tags, like <tt>options_for_select</tt>, but
      # wraps them with <tt><optgroup></tt> tags.
      #
      # Parameters:
      # * +grouped_options+ - Accepts a nested array or hash of strings. The first value serves as the
      #   <tt><optgroup></tt> label while the second value must be an array of options. The second value can be a
      #   nested array of text-value pairs. See <tt>options_for_select</tt> for more info.
      #    Ex. ["North America",[["United States","US"],["Canada","CA"]]]
      # * +selected_key+ - A value equal to the +value+ attribute for one of the <tt><option></tt> tags,
      #   which will have the +selected+ attribute set. Note: It is possible for this value to match multiple options
      #   as you might have the same option in multiple groups. Each will then get <tt>selected="selected"</tt>.
      # * +prompt+ - set to true or a prompt string. When the select element doesn't have a value yet, this
      #   prepends an option with a generic prompt - "Please select" - or the given prompt string.
      #
      # Sample usage (Array):
      #   grouped_options = [
      #    ['North America',
      #      [['United States','US'],'Canada']],
      #    ['Europe',
      #      ['Denmark','Germany','France']]
      #   ]
      #   grouped_options_for_select(grouped_options)
      #
      # Sample usage (Hash):
      #   grouped_options = {
      #    'North America' => [['United States','US'], 'Canada'],
      #    'Europe' => ['Denmark','Germany','France']
      #   }
      #   grouped_options_for_select(grouped_options)
      #
      # Possible output:
      #   <optgroup label="Europe">
      #     <option value="Denmark">Denmark</option>
      #     <option value="Germany">Germany</option>
      #     <option value="France">France</option>
      #   </optgroup>
      #   <optgroup label="North America">
      #     <option value="US">United States</option>
      #     <option value="Canada">Canada</option>
      #   </optgroup>
      #
      # <b>Note:</b> Only the <tt><optgroup></tt> and <tt><option></tt> tags are returned, so you still have to
      # wrap the output in an appropriate <tt><select></tt> tag.
      def grouped_options_for_select(grouped_options, selected_key = nil, prompt = nil)
        body = "".html_safe
        body.safe_concat content_tag(:option, prompt, :value => "") if prompt

        grouped_options = grouped_options.sort if grouped_options.is_a?(Hash)

        grouped_options.each do |label, container|
          body.safe_concat content_tag(:optgroup, options_for_select(container, selected_key), :label => label)
        end

        body
      end

      # Returns a string of option tags for pretty much any time zone in the
      # world. Supply a ActiveSupport::TimeZone name as +selected+ to have it
      # marked as the selected option tag. You can also supply an array of
      # ActiveSupport::TimeZone objects as +priority_zones+, so that they will
      # be listed above the rest of the (long) list. (You can use
      # ActiveSupport::TimeZone.us_zones as a convenience for obtaining a list
      # of the US time zones, or a Regexp to select the zones of your choice)
      #
      # The +selected+ parameter must be either +nil+, or a string that names
      # a ActiveSupport::TimeZone.
      #
      # By default, +model+ is the ActiveSupport::TimeZone constant (which can
      # be obtained in Active Record as a value object). The only requirement
      # is that the +model+ parameter be an object that responds to +all+, and
      # returns an array of objects that represent time zones.
      #
      # NOTE: Only the option tags are returned, you have to wrap this call in
      # a regular HTML select tag.
      def time_zone_options_for_select(selected = nil, priority_zones = nil, model = ::ActiveSupport::TimeZone)
        zone_options = "".html_safe

        zones = model.all
        convert_zones = lambda { |list| list.map { |z| [ z.to_s, z.name ] } }

        if priority_zones
          if priority_zones.is_a?(Regexp)
            priority_zones = zones.select { |z| z =~ priority_zones }
          end

          zone_options.safe_concat options_for_select(convert_zones[priority_zones], selected)
          zone_options.safe_concat content_tag(:option, '-------------', :value => '', :disabled => 'disabled')
          zone_options.safe_concat "\n"

          zones.reject! { |z| priority_zones.include?(z) }
        end

        zone_options.safe_concat options_for_select(convert_zones[zones], selected)
      end

      # Returns radio button tags for the collection of existing return values
      # of +method+ for +object+'s class. The value returned from calling
      # +method+ on the instance +object+ will be selected. If calling +method+
      # returns +nil+, no selection is made.
      #
      # The <tt>:value_method</tt> and <tt>:text_method</tt> parameters are
      # methods to be called on each member of +collection+. The return values
      # are used as the +value+ attribute and contents of each radio button tag,
      # respectively. They can also be any object that responds to +call+, such
      # as a +proc+, that will be called for each member of the +collection+ to
      # retrieve the value/text.
      #
      # Example object structure for use with this method:
      #   class Post < ActiveRecord::Base
      #     belongs_to :author
      #   end
      #   class Author < ActiveRecord::Base
      #     has_many :posts
      #     def name_with_initial
      #       "#{first_name.first}. #{last_name}"
      #     end
      #   end
      #
      # Sample usage (selecting the associated Author for an instance of Post, <tt>@post</tt>):
      #   collection_radio_buttons(:post, :author_id, Author.all, :id, :name_with_initial)
      #
      # If <tt>@post.author_id</tt> is already <tt>1</tt>, this would return:
      #   <input id="post_author_id_1" name="post[author_id]" type="radio" value="1" checked="checked" />
      #   <label for="post_author_id_1">D. Heinemeier Hansson</label>
      #   <input id="post_author_id_2" name="post[author_id]" type="radio" value="2" />
      #   <label for="post_author_id_2">D. Thomas</label>
      #   <input id="post_author_id_3" name="post[author_id]" type="radio" value="3" />
      #   <label for="post_author_id_3">M. Clark</label>
      #
      # It is also possible to customize the way the elements will be shown by
      # giving a block to the method:
      #   collection_radio_buttons(:post, :author_id, Author.all, :id, :name_with_initial) do |b|
      #     b.label { b.radio_button }
      #   end
      #
      # The argument passed to the block is a special kind of builder for this
      # collection, which has the ability to generate the label and radio button
      # for the current item in the collection, with proper text and value.
      # Using it, you can change the label and radio button display order or
      # even use the label as wrapper, as in the example above.
      #
      # The builder methods <tt>label</tt> and <tt>radio_button</tt> also accept
      # extra html options:
      #   collection_radio_buttons(:post, :author_id, Author.all, :id, :name_with_initial) do |b|
      #     b.label(:class => "radio_button") { b.radio_button(:class => "radio_button") }
      #   end
      #
      # There are also three special methods available: <tt>object</tt>, <tt>text</tt> and
      # <tt>value</tt>, which are the current item being rendered, its text and value methods,
      # respectively. You can use them like this:
      #   collection_radio_buttons(:post, :author_id, Author.all, :id, :name_with_initial) do |b|
      #      b.label(:"data-value" => b.value) { b.radio_button + b.text }
      #   end
      def collection_radio_buttons(object, method, collection, value_method, text_method, options = {}, html_options = {}, &block)
        Tags::CollectionRadioButtons.new(object, method, self, collection, value_method, text_method, options, html_options).render(&block)
      end

      # Returns check box tags for the collection of existing return values of
      # +method+ for +object+'s class. The value returned from calling +method+
      # on the instance +object+ will be selected. If calling +method+ returns
      # +nil+, no selection is made.
      #
      # The <tt>:value_method</tt> and <tt>:text_method</tt> parameters are
      # methods to be called on each member of +collection+. The return values
      # are used as the +value+ attribute and contents of each check box tag,
      # respectively. They can also be any object that responds to +call+, such
      # as a +proc+, that will be called for each member of the +collection+ to
      # retrieve the value/text.
      #
      # Example object structure for use with this method:
      #   class Post < ActiveRecord::Base
      #     has_and_belongs_to_many :author
      #   end
      #   class Author < ActiveRecord::Base
      #     has_and_belongs_to_many :posts
      #     def name_with_initial
      #       "#{first_name.first}. #{last_name}"
      #     end
      #   end
      #
      # Sample usage (selecting the associated Author for an instance of Post, <tt>@post</tt>):
      #   collection_check_boxes(:post, :author_ids, Author.all, :id, :name_with_initial)
      #
      # If <tt>@post.author_ids</tt> is already <tt>[1]</tt>, this would return:
      #   <input id="post_author_ids_1" name="post[author_ids][]" type="checkbox" value="1" checked="checked" />
      #   <label for="post_author_ids_1">D. Heinemeier Hansson</label>
      #   <input id="post_author_ids_2" name="post[author_ids][]" type="checkbox" value="2" />
      #   <label for="post_author_ids_2">D. Thomas</label>
      #   <input id="post_author_ids_3" name="post[author_ids][]" type="checkbox" value="3" />
      #   <label for="post_author_ids_3">M. Clark</label>
      #   <input name="post[author_ids][]" type="hidden" value="" />
      #
      # It is also possible to customize the way the elements will be shown by
      # giving a block to the method:
      #   collection_check_boxes(:post, :author_ids, Author.all, :id, :name_with_initial) do |b|
      #     b.label { b.check_box }
      #   end
      #
      # The argument passed to the block is a special kind of builder for this
      # collection, which has the ability to generate the label and check box
      # for the current item in the collection, with proper text and value.
      # Using it, you can change the label and check box display order or even
      # use the label as wrapper, as in the example above.
      #
      # The builder methods <tt>label</tt> and <tt>check_box</tt> also accept
      # extra html options:
      #   collection_check_boxes(:post, :author_ids, Author.all, :id, :name_with_initial) do |b|
      #     b.label(:class => "check_box") { b.check_box(:class => "check_box") }
      #   end
      #
      # There are also three special methods available: <tt>object</tt>, <tt>text</tt> and
      # <tt>value</tt>, which are the current item being rendered, its text and value methods,
      # respectively. You can use them like this:
      #   collection_check_boxes(:post, :author_ids, Author.all, :id, :name_with_initial) do |b|
      #      b.label(:"data-value" => b.value) { b.check_box + b.text }
      #   end
      def collection_check_boxes(object, method, collection, value_method, text_method, options = {}, html_options = {}, &block)
        Tags::CollectionCheckBoxes.new(object, method, self, collection, value_method, text_method, options, html_options).render(&block)
      end

      private
        def option_html_attributes(element)
          return {} unless Array === element

          Hash[element.select { |e| Hash === e }.reduce({}, :merge).map { |k, v| [k, ERB::Util.html_escape(v.to_s)] }]
        end

        def option_text_and_value(option)
          # Options are [text, value] pairs or strings used for both.
          if !option.is_a?(String) && option.respond_to?(:first) && option.respond_to?(:last)
            option = option.reject { |e| Hash === e } if Array === option
            [option.first, option.last]
          else
            [option, option]
          end
        end

        def option_value_selected?(value, selected)
          Array(selected).include? value
        end

        def extract_selected_and_disabled(selected)
          if selected.is_a?(Proc)
            [selected, nil]
          else
            selected = Array.wrap(selected)
            options = selected.extract_options!.symbolize_keys
            selected_items = options.fetch(:selected, selected)
            [selected_items, options[:disabled]]
          end
        end

        def extract_values_from_collection(collection, value_method, selected)
          if selected.is_a?(Proc)
            collection.map do |element|
              element.send(value_method) if selected.call(element)
            end.compact
          else
            selected
          end
        end

        def value_for_collection(item, value)
          value.respond_to?(:call) ? value.call(item) : item.send(value)
        end
    end

    class FormBuilder
      def select(method, choices, options = {}, html_options = {})
        @template.select(@object_name, method, choices, objectify_options(options), @default_options.merge(html_options))
      end

      def collection_select(method, collection, value_method, text_method, options = {}, html_options = {})
        @template.collection_select(@object_name, method, collection, value_method, text_method, objectify_options(options), @default_options.merge(html_options))
      end

      def grouped_collection_select(method, collection, group_method, group_label_method, option_key_method, option_value_method, options = {}, html_options = {})
        @template.grouped_collection_select(@object_name, method, collection, group_method, group_label_method, option_key_method, option_value_method, objectify_options(options), @default_options.merge(html_options))
      end

      def time_zone_select(method, priority_zones = nil, options = {}, html_options = {})
        @template.time_zone_select(@object_name, method, priority_zones, objectify_options(options), @default_options.merge(html_options))
      end

      def collection_check_boxes(method, collection, value_method, text_method, options = {}, html_options = {})
        @template.collection_check_boxes(@object_name, method, collection, value_method, text_method, objectify_options(options), @default_options.merge(html_options))
      end

      def collection_radio_buttons(method, collection, value_method, text_method, options = {}, html_options = {})
        @template.collection_radio_buttons(@object_name, method, collection, value_method, text_method, objectify_options(options), @default_options.merge(html_options))
      end
    end
  end
end