Source

RubyLearning / ProjectTrak / vendor / rails / actionpack / lib / action_view / helpers / form_helper.rb

Full commit
  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
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
require 'cgi'
require 'action_view/helpers/date_helper'
require 'action_view/helpers/tag_helper'
require 'action_view/helpers/form_tag_helper'

module ActionView
  module Helpers
    # Form helpers are designed to make working with models much easier compared to using just standard HTML
    # elements by providing a set of methods for creating forms based on your models. This helper generates the HTML
    # for forms, providing a method for each sort of input (e.g., text, password, select, and so on). When the form
    # is submitted (i.e., when the user hits the submit button or <tt>form.submit</tt> is called via JavaScript), the form inputs will be bundled into the <tt>params</tt> object and passed back to the controller.
    #
    # There are two types of form helpers: those that specifically work with model attributes and those that don't.
    # This helper deals with those that work with model attributes; to see an example of form helpers that don't work
    # with model attributes, check the ActionView::Helpers::FormTagHelper documentation.
    #
    # The core method of this helper, form_for, gives you the ability to create a form for a model instance;
    # for example, let's say that you have a model <tt>Person</tt> and want to create a new instance of it:
    #
    #     # Note: a @person variable will have been created in the controller.
    #     # For example: @person = Person.new
    #     <% form_for :person, @person, :url => { :action => "create" } do |f| %>
    #       <%= f.text_field :first_name %>
    #       <%= f.text_field :last_name %>
    #       <%= submit_tag 'Create' %>
    #     <% end %>
    #
    # The HTML generated for this would be:
    #
    #     <form action="/persons/create" method="post">
    #       <input id="person_first_name" name="person[first_name]" size="30" type="text" />
    #       <input id="person_last_name" name="person[last_name]" size="30" type="text" />
    #       <input name="commit" type="submit" value="Create" />
    #     </form>
    #
    # If you are using a partial for your form fields, you can use this shortcut:
    #
    #     <% form_for :person, @person, :url => { :action => "create" } do |f| %>
    #       <%= render :partial => f %>
    #       <%= submit_tag 'Create' %>
    #     <% end %>
    #
    # This example will render the <tt>people/_form</tt> partial, setting a local variable called <tt>form</tt> which references the yielded FormBuilder.
    #
    # The <tt>params</tt> object created when this form is submitted would look like:
    #
    #     {"action"=>"create", "controller"=>"persons", "person"=>{"first_name"=>"William", "last_name"=>"Smith"}}
    #
    # The params hash has a nested <tt>person</tt> value, which can therefore be accessed with <tt>params[:person]</tt> in the controller.
    # If were editing/updating an instance (e.g., <tt>Person.find(1)</tt> rather than <tt>Person.new</tt> in the controller), the objects
    # attribute values are filled into the form (e.g., the <tt>person_first_name</tt> field would have that person's first name in it).
    #
    # If the object name contains square brackets the id for the object will be inserted. For example:
    #
    #   <%= text_field "person[]", "name" %>
    #
    # ...will generate the following ERb.
    #
    #   <input type="text" id="person_<%= @person.id %>_name" name="person[<%= @person.id %>][name]" value="<%= @person.name %>" />
    #
    # If the helper is being used to generate a repetitive sequence of similar form elements, for example in a partial
    # used by <tt>render_collection_of_partials</tt>, the <tt>index</tt> option may come in handy. Example:
    #
    #   <%= text_field "person", "name", "index" => 1 %>
    #
    # ...becomes...
    #
    #   <input type="text" id="person_1_name" name="person[1][name]" value="<%= @person.name %>" />
    #
    # An <tt>index</tt> option may also be passed to <tt>form_for</tt> and <tt>fields_for</tt>.  This automatically applies
    # the <tt>index</tt> to all the nested fields.
    #
    # There are also methods for helping to build form tags in link:classes/ActionView/Helpers/FormOptionsHelper.html,
    # link:classes/ActionView/Helpers/DateHelper.html, and link:classes/ActionView/Helpers/ActiveRecordHelper.html
    module FormHelper
      # Creates a form and a scope around a specific model object that is used as
      # a base for questioning about values for the fields.
      #
      # Rails provides succinct resource-oriented form generation with +form_for+
      # like this:
      #
      #   <% form_for @offer do |f| %>
      #     <%= f.label :version, 'Version' %>:
      #     <%= f.text_field :version %><br />
      #     <%= f.label :author, 'Author' %>:
      #     <%= f.text_field :author %><br />
      #   <% end %>
      #
      # There, +form_for+ is able to generate the rest of RESTful form parameters
      # based on introspection on the record, but to understand what it does we
      # need to dig first into the alternative generic usage it is based upon.
      #
      # === Generic form_for
      #
      # The generic way to call +form_for+ yields a form builder around a model:
      #
      #   <% form_for :person, :url => { :action => "update" } do |f| %>
      #     <%= f.error_messages %>
      #     First name: <%= f.text_field :first_name %><br />
      #     Last name : <%= f.text_field :last_name %><br />
      #     Biography : <%= f.text_area :biography %><br />
      #     Admin?    : <%= f.check_box :admin %><br />
      #   <% end %>
      #
      # There, the first argument is a symbol or string with the name of the
      # object the form is about, and also the name of the instance variable the
      # object is stored in.
      #
      # The form builder acts as a regular form helper that somehow carries the
      # model. Thus, the idea is that
      #
      #   <%= f.text_field :first_name %>
      #
      # gets expanded to
      #
      #   <%= text_field :person, :first_name %>
      #
      # If the instance variable is not <tt>@person</tt> you can pass the actual
      # record as the second argument:
      #
      #   <% form_for :person, person, :url => { :action => "update" } do |f| %>
      #     ...
      #   <% end %>
      #
      # In that case you can think
      #
      #   <%= f.text_field :first_name %>
      #
      # gets expanded to
      #
      #   <%= text_field :person, :first_name, :object => person %>
      #
      # You can even display error messages of the wrapped model this way:
      #
      #   <%= f.error_messages %>
      #
      # In any of its variants, the rightmost argument to +form_for+ is an
      # optional hash of options:
      #
      # * <tt>:url</tt> - The URL the form is submitted to. It takes the same fields
      #   you pass to +url_for+ or +link_to+. In particular you may pass here a
      #   named route directly as well. Defaults to the current action.
      # * <tt>:html</tt> - Optional HTML attributes for the form tag.
      #
      # Worth noting is that the +form_for+ tag is called in a ERb evaluation block,
      # not an ERb output block. So that's <tt><% %></tt>, not <tt><%= %></tt>.
      #
      # Also note that +form_for+ doesn't create an exclusive scope. It's still
      # possible to use both the stand-alone FormHelper methods and methods from
      # FormTagHelper. For example:
      #
      #   <% form_for :person, @person, :url => { :action => "update" } do |f| %>
      #     First name: <%= f.text_field :first_name %>
      #     Last name : <%= f.text_field :last_name %>
      #     Biography : <%= text_area :person, :biography %>
      #     Admin?    : <%= check_box_tag "person[admin]", @person.company.admin? %>
      #   <% end %>
      #
      # This also works for the methods in FormOptionHelper and DateHelper that are
      # designed to work with an object as base, like FormOptionHelper#collection_select
      # and DateHelper#datetime_select.
      #
      # === Resource-oriented style
      #
      # As we said above, in addition to manually configuring the +form_for+ call,
      # you can rely on automated resource identification, which will use the conventions
      # and named routes of that approach. This is the preferred way to use +form_for+
      # nowadays.
      #
      # For example, if <tt>@post</tt> is an existing record you want to edit
      #
      #   <% form_for @post do |f| %>
      #     ...
      #   <% end %>
      #
      # is equivalent to something like:
      #
      #   <% form_for :post, @post, :url => post_path(@post), :html => { :method => :put, :class => "edit_post", :id => "edit_post_45" } do |f| %>
      #     ...
      #   <% end %>
      #
      # And for new records
      #
      #   <% form_for(Post.new) do |f| %>
      #     ...
      #   <% end %>
      #
      # expands to
      #
      #   <% form_for :post, Post.new, :url => posts_path, :html => { :class => "new_post", :id => "new_post" } do |f| %>
      #     ...
      #   <% end %>
      #
      # You can also overwrite the individual conventions, like this:
      #
      #   <% form_for(@post, :url => super_post_path(@post)) do |f| %>
      #     ...
      #   <% end %>
      #
      # And for namespaced routes, like +admin_post_url+:
      #
      #   <% form_for([:admin, @post]) do |f| %>
      #    ...
      #   <% end %>
      #
      # === Customized form builders
      #
      # You can also build forms using a customized FormBuilder class. Subclass FormBuilder and override or define some more helpers,
      # then use your custom builder. For example, let's say you made a helper to automatically add labels to form inputs.
      #
      #   <% form_for :person, @person, :url => { :action => "update" }, :builder => LabellingFormBuilder do |f| %>
      #     <%= f.text_field :first_name %>
      #     <%= f.text_field :last_name %>
      #     <%= text_area :person, :biography %>
      #     <%= check_box_tag "person[admin]", @person.company.admin? %>
      #   <% end %>
      #
      # In this case, if you use this:
      #
      #   <%= render :partial => f %>
      #
      # The rendered template is <tt>people/_labelling_form</tt> and the local variable referencing the form builder is called <tt>labelling_form</tt>.
      #
      # In many cases you will want to wrap the above in another helper, so you could do something like the following:
      #
      #   def labelled_form_for(record_or_name_or_array, *args, &proc)
      #     options = args.extract_options!
      #     form_for(record_or_name_or_array, *(args << options.merge(:builder => LabellingFormBuilder)), &proc)
      #   end
      #
      # If you don't need to attach a form to a model instance, then check out FormTagHelper#form_tag.
      def form_for(record_or_name_or_array, *args, &proc)
        raise ArgumentError, "Missing block" unless block_given?

        options = args.extract_options!

        case record_or_name_or_array
        when String, Symbol
          object_name = record_or_name_or_array
        when Array
          object = record_or_name_or_array.last
          object_name = ActionController::RecordIdentifier.singular_class_name(object)
          apply_form_for_options!(record_or_name_or_array, options)
          args.unshift object
        else
          object = record_or_name_or_array
          object_name = ActionController::RecordIdentifier.singular_class_name(object)
          apply_form_for_options!([object], options)
          args.unshift object
        end

        concat(form_tag(options.delete(:url) || {}, options.delete(:html) || {}))
        fields_for(object_name, *(args << options), &proc)
        concat('</form>')
      end

      def apply_form_for_options!(object_or_array, options) #:nodoc:
        object = object_or_array.is_a?(Array) ? object_or_array.last : object_or_array

        html_options =
          if object.respond_to?(:new_record?) && object.new_record?
            { :class  => dom_class(object, :new),  :id => dom_id(object), :method => :post }
          else
            { :class  => dom_class(object, :edit), :id => dom_id(object, :edit), :method => :put }
          end

        options[:html] ||= {}
        options[:html].reverse_merge!(html_options)
        options[:url] ||= polymorphic_path(object_or_array)
      end

      # Creates a scope around a specific model object like form_for, but doesn't create the form tags themselves. This makes
      # fields_for suitable for specifying additional model objects in the same form:
      #
      # ==== Examples
      #   <% form_for @person, :url => { :action => "update" } do |person_form| %>
      #     First name: <%= person_form.text_field :first_name %>
      #     Last name : <%= person_form.text_field :last_name %>
      #
      #     <% fields_for @person.permission do |permission_fields| %>
      #       Admin?  : <%= permission_fields.check_box :admin %>
      #     <% end %>
      #   <% end %>
      #
      # ...or if you have an object that needs to be represented as a different parameter, like a Client that acts as a Person:
      #
      #   <% fields_for :person, @client do |permission_fields| %>
      #     Admin?: <%= permission_fields.check_box :admin %>
      #   <% end %>
      #
      # ...or if you don't have an object, just a name of the parameter
      #
      #   <% fields_for :person do |permission_fields| %>
      #     Admin?: <%= permission_fields.check_box :admin %>
      #   <% end %>
      #
      # Note: This also works for the methods in FormOptionHelper and DateHelper that are designed to work with an object as base,
      # like FormOptionHelper#collection_select and DateHelper#datetime_select.
      def fields_for(record_or_name_or_array, *args, &block)
        raise ArgumentError, "Missing block" unless block_given?
        options = args.extract_options!

        case record_or_name_or_array
        when String, Symbol
          object_name = record_or_name_or_array
          object = args.first
        else
          object = record_or_name_or_array
          object_name = ActionController::RecordIdentifier.singular_class_name(object)
        end

        builder = options[:builder] || ActionView::Base.default_form_builder
        yield builder.new(object_name, object, self, options, block)
      end

      # Returns a label tag tailored for labelling an input field for a specified attribute (identified by +method+) on an object
      # assigned to the template (identified by +object+). The text of label will default to the attribute name unless you specify
      # it explicitly. Additional options on the label tag can be passed as a hash with +options+. These options will be tagged
      # onto the HTML as an HTML element attribute as in the example shown.
      #
      # ==== Examples
      #   label(:post, :title)
      #   # => <label for="post_title">Title</label>
      #
      #   label(:post, :title, "A short title")
      #   # => <label for="post_title">A short title</label>
      #
      #   label(:post, :title, "A short title", :class => "title_label")
      #   # => <label for="post_title" class="title_label">A short title</label>
      #
      def label(object_name, method, text = nil, options = {})
        InstanceTag.new(object_name, method, self, options.delete(:object)).to_label_tag(text, options)
      end

      # Returns an input tag of the "text" type tailored for accessing a specified attribute (identified by +method+) on an object
      # assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
      # hash with +options+. These options will be tagged onto the HTML as an HTML element attribute as in the example
      # shown.
      #
      # ==== Examples
      #   text_field(:post, :title, :size => 20)
      #   # => <input type="text" id="post_title" name="post[title]" size="20" value="#{@post.title}" />
      #
      #   text_field(:post, :title, :class => "create_input")
      #   # => <input type="text" id="post_title" name="post[title]" value="#{@post.title}" class="create_input" />
      #
      #   text_field(:session, :user, :onchange => "if $('session[user]').value == 'admin' { alert('Your login can not be admin!'); }")
      #   # => <input type="text" id="session_user" name="session[user]" value="#{@session.user}" onchange = "if $('session[user]').value == 'admin' { alert('Your login can not be admin!'); }"/>
      #
      #   text_field(:snippet, :code, :size => 20, :class => 'code_input')
      #   # => <input type="text" id="snippet_code" name="snippet[code]" size="20" value="#{@snippet.code}" class="code_input" />
      #
      def text_field(object_name, method, options = {})
        InstanceTag.new(object_name, method, self, options.delete(:object)).to_input_field_tag("text", options)
      end

      # Returns an input tag of the "password" type tailored for accessing a specified attribute (identified by +method+) on an object
      # assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
      # hash with +options+. These options will be tagged onto the HTML as an HTML element attribute as in the example
      # shown.
      #
      # ==== Examples
      #   password_field(:login, :pass, :size => 20)
      #   # => <input type="text" id="login_pass" name="login[pass]" size="20" value="#{@login.pass}" />
      #
      #   password_field(:account, :secret, :class => "form_input")
      #   # => <input type="text" id="account_secret" name="account[secret]" value="#{@account.secret}" class="form_input" />
      #
      #   password_field(:user, :password, :onchange => "if $('user[password]').length > 30 { alert('Your password needs to be shorter!'); }")
      #   # => <input type="text" id="user_password" name="user[password]" value="#{@user.password}" onchange = "if $('user[password]').length > 30 { alert('Your password needs to be shorter!'); }"/>
      #
      #   password_field(:account, :pin, :size => 20, :class => 'form_input')
      #   # => <input type="text" id="account_pin" name="account[pin]" size="20" value="#{@account.pin}" class="form_input" />
      #
      def password_field(object_name, method, options = {})
        InstanceTag.new(object_name, method, self, options.delete(:object)).to_input_field_tag("password", options)
      end

      # Returns a hidden input tag tailored for accessing a specified attribute (identified by +method+) on an object
      # assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
      # hash with +options+. These options will be tagged onto the HTML as an HTML element attribute as in the example
      # shown.
      #
      # ==== Examples
      #   hidden_field(:signup, :pass_confirm)
      #   # => <input type="hidden" id="signup_pass_confirm" name="signup[pass_confirm]" value="#{@signup.pass_confirm}" />
      #
      #   hidden_field(:post, :tag_list)
      #   # => <input type="hidden" id="post_tag_list" name="post[tag_list]" value="#{@post.tag_list}" />
      #
      #   hidden_field(:user, :token)
      #   # => <input type="hidden" id="user_token" name="user[token]" value="#{@user.token}" />
      def hidden_field(object_name, method, options = {})
        InstanceTag.new(object_name, method, self, options.delete(:object)).to_input_field_tag("hidden", options)
      end

      # Returns an file upload input tag tailored for accessing a specified attribute (identified by +method+) on an object
      # assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
      # hash with +options+. These options will be tagged onto the HTML as an HTML element attribute as in the example
      # shown.
      #
      # ==== Examples
      #   file_field(:user, :avatar)
      #   # => <input type="file" id="user_avatar" name="user[avatar]" />
      #
      #   file_field(:post, :attached, :accept => 'text/html')
      #   # => <input type="file" id="post_attached" name="post[attached]" />
      #
      #   file_field(:attachment, :file, :class => 'file_input')
      #   # => <input type="file" id="attachment_file" name="attachment[file]" class="file_input" />
      #
      def file_field(object_name, method, options = {})
        InstanceTag.new(object_name, method, self, options.delete(:object)).to_input_field_tag("file", options)
      end

      # Returns a textarea opening and closing tag set tailored for accessing a specified attribute (identified by +method+)
      # on an object assigned to the template (identified by +object+). Additional options on the input tag can be passed as a
      # hash with +options+.
      #
      # ==== Examples
      #   text_area(:post, :body, :cols => 20, :rows => 40)
      #   # => <textarea cols="20" rows="40" id="post_body" name="post[body]">
      #   #      #{@post.body}
      #   #    </textarea>
      #
      #   text_area(:comment, :text, :size => "20x30")
      #   # => <textarea cols="20" rows="30" id="comment_text" name="comment[text]">
      #   #      #{@comment.text}
      #   #    </textarea>
      #
      #   text_area(:application, :notes, :cols => 40, :rows => 15, :class => 'app_input')
      #   # => <textarea cols="40" rows="15" id="application_notes" name="application[notes]" class="app_input">
      #   #      #{@application.notes}
      #   #    </textarea>
      #
      #   text_area(:entry, :body, :size => "20x20", :disabled => 'disabled')
      #   # => <textarea cols="20" rows="20" id="entry_body" name="entry[body]" disabled="disabled">
      #   #      #{@entry.body}
      #   #    </textarea>
      def text_area(object_name, method, options = {})
        InstanceTag.new(object_name, method, self, options.delete(:object)).to_text_area_tag(options)
      end

      # Returns a checkbox tag tailored for accessing a specified attribute (identified by +method+) on an object
      # assigned to the template (identified by +object+). This object must be an instance object (@object) and not a local object.
      # It's intended that +method+ returns an integer and if that integer is above zero, then the checkbox is checked. 
      # Additional options on the input tag can be passed as a hash with +options+. The +checked_value+ defaults to 1 
      # while the default +unchecked_value+ is set to 0 which is convenient for boolean values.
      #
      # ==== Gotcha
      #
      # The HTML specification says unchecked check boxes are not successful, and
      # thus web browsers do not send them. Unfortunately this introduces a gotcha:
      # if an Invoice model has a +paid+ flag, and in the form that edits a paid
      # invoice the user unchecks its check box, no +paid+ parameter is sent. So,
      # any mass-assignment idiom like
      #
      #   @invoice.update_attributes(params[:invoice])
      #
      # wouldn't update the flag.
      #
      # To prevent this the helper generates a hidden field with the same name as
      # the checkbox after the very check box. So, the client either sends only the
      # hidden field (representing the check box is unchecked), 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 Rails parameters extraction always
      # gets the first occurrence of any given key, that works in ordinary forms.
      #
      # Unfortunately that workaround does not work when the check box goes
      # within an array-like parameter, as in
      #
      #   <% fields_for "project[invoice_attributes][]", invoice, :index => nil do |form| %>
      #     <%= form.check_box :paid %>
      #     ...
      #   <% end %>
      #
      # because parameter name repetition is precisely what Rails seeks to distinguish
      # the elements of the array.
      #
      # ==== Examples
      #   # Let's say that @post.validated? is 1:
      #   check_box("post", "validated")
      #   # => <input type="checkbox" id="post_validated" name="post[validated]" value="1" />
      #   #    <input name="post[validated]" type="hidden" value="0" />
      #
      #   # Let's say that @puppy.gooddog is "no":
      #   check_box("puppy", "gooddog", {}, "yes", "no")
      #   # => <input type="checkbox" id="puppy_gooddog" name="puppy[gooddog]" value="yes" />
      #   #    <input name="puppy[gooddog]" type="hidden" value="no" />
      #
      #   check_box("eula", "accepted", { :class => 'eula_check' }, "yes", "no")
      #   # => <input type="checkbox" class="eula_check" id="eula_accepted" name="eula[accepted]" value="yes" />
      #   #    <input name="eula[accepted]" type="hidden" value="no" />
      #
      def check_box(object_name, method, options = {}, checked_value = "1", unchecked_value = "0")
        InstanceTag.new(object_name, method, self, options.delete(:object)).to_check_box_tag(options, checked_value, unchecked_value)
      end

      # Returns a radio button tag for accessing a specified attribute (identified by +method+) on an object
      # assigned to the template (identified by +object+). If the current value of +method+ is +tag_value+ the
      # radio button will be checked. Additional options on the input tag can be passed as a
      # hash with +options+.
      #
      # ==== Examples
      #   # Let's say that @post.category returns "rails":
      #   radio_button("post", "category", "rails")
      #   radio_button("post", "category", "java")
      #   # => <input type="radio" id="post_category_rails" name="post[category]" value="rails" checked="checked" />
      #   #    <input type="radio" id="post_category_java" name="post[category]" value="java" />
      #
      #   radio_button("user", "receive_newsletter", "yes")
      #   radio_button("user", "receive_newsletter", "no")
      #   # => <input type="radio" id="user_receive_newsletter_yes" name="user[receive_newsletter]" value="yes" />
      #   #    <input type="radio" id="user_receive_newsletter_no" name="user[receive_newsletter]" value="no" checked="checked" />
      def radio_button(object_name, method, tag_value, options = {})
        InstanceTag.new(object_name, method, self, options.delete(:object)).to_radio_button_tag(tag_value, options)
      end
    end

    class InstanceTag #:nodoc:
      include Helpers::TagHelper, Helpers::FormTagHelper

      attr_reader :method_name, :object_name

      DEFAULT_FIELD_OPTIONS     = { "size" => 30 }.freeze unless const_defined?(:DEFAULT_FIELD_OPTIONS)
      DEFAULT_RADIO_OPTIONS     = { }.freeze unless const_defined?(:DEFAULT_RADIO_OPTIONS)
      DEFAULT_TEXT_AREA_OPTIONS = { "cols" => 40, "rows" => 20 }.freeze unless const_defined?(:DEFAULT_TEXT_AREA_OPTIONS)

      def initialize(object_name, method_name, template_object, object = nil)
        @object_name, @method_name = object_name.to_s.dup, method_name.to_s.dup
        @template_object = template_object
        @object = object
        if @object_name.sub!(/\[\]$/,"") || @object_name.sub!(/\[\]\]$/,"]")
          if (object ||= @template_object.instance_variable_get("@#{Regexp.last_match.pre_match}")) && object.respond_to?(:to_param)
            @auto_index = object.to_param
          else
            raise ArgumentError, "object[] naming but object param and @object var don't exist or don't respond to to_param: #{object.inspect}"
          end
        end
      end

      def to_label_tag(text = nil, options = {})
        options = options.stringify_keys
        name_and_id = options.dup
        add_default_name_and_id(name_and_id)
        options.delete("index")
        options["for"] ||= name_and_id["id"]
        content = (text.blank? ? nil : text.to_s) || method_name.humanize
        label_tag(name_and_id["id"], content, options)
      end

      def to_input_field_tag(field_type, options = {})
        options = options.stringify_keys
        options["size"] = options["maxlength"] || DEFAULT_FIELD_OPTIONS["size"] unless options.key?("size")
        options = DEFAULT_FIELD_OPTIONS.merge(options)
        if field_type == "hidden"
          options.delete("size")
        end
        options["type"] = field_type
        options["value"] ||= value_before_type_cast(object) unless field_type == "file"
        options["value"] &&= html_escape(options["value"])
        add_default_name_and_id(options)
        tag("input", options)
      end

      def to_radio_button_tag(tag_value, options = {})
        options = DEFAULT_RADIO_OPTIONS.merge(options.stringify_keys)
        options["type"]     = "radio"
        options["value"]    = tag_value
        if options.has_key?("checked")
          cv = options.delete "checked"
          checked = cv == true || cv == "checked"
        else
          checked = self.class.radio_button_checked?(value(object), tag_value)
        end
        options["checked"]  = "checked" if checked
        pretty_tag_value    = tag_value.to_s.gsub(/\s/, "_").gsub(/\W/, "").downcase
        options["id"]     ||= defined?(@auto_index) ?
          "#{tag_id_with_index(@auto_index)}_#{pretty_tag_value}" :
          "#{tag_id}_#{pretty_tag_value}"
        add_default_name_and_id(options)
        tag("input", options)
      end

      def to_text_area_tag(options = {})
        options = DEFAULT_TEXT_AREA_OPTIONS.merge(options.stringify_keys)
        add_default_name_and_id(options)

        if size = options.delete("size")
          options["cols"], options["rows"] = size.split("x") if size.respond_to?(:split)
        end

        content_tag("textarea", html_escape(options.delete('value') || value_before_type_cast(object)), options)
      end

      def to_check_box_tag(options = {}, checked_value = "1", unchecked_value = "0")
        options = options.stringify_keys
        options["type"]     = "checkbox"
        options["value"]    = checked_value
        if options.has_key?("checked")
          cv = options.delete "checked"
          checked = cv == true || cv == "checked"
        else
          checked = self.class.check_box_checked?(value(object), checked_value)
        end
        options["checked"] = "checked" if checked
        add_default_name_and_id(options)
        tag("input", options) << tag("input", "name" => options["name"], "type" => "hidden", "value" => options['disabled'] && checked ? checked_value : unchecked_value)
      end

      def to_boolean_select_tag(options = {})
        options = options.stringify_keys
        add_default_name_and_id(options)
        value = value(object)
        tag_text = "<select"
        tag_text << tag_options(options)
        tag_text << "><option value=\"false\""
        tag_text << " selected" if value == false
        tag_text << ">False</option><option value=\"true\""
        tag_text << " selected" if value
        tag_text << ">True</option></select>"
      end

      def to_content_tag(tag_name, options = {})
        content_tag(tag_name, value(object), options)
      end

      def object
        @object || @template_object.instance_variable_get("@#{@object_name}")
      rescue NameError
        # As @object_name may contain the nested syntax (item[subobject]) we
        # need to fallback to nil.
        nil
      end

      def value(object)
        self.class.value(object, @method_name)
      end

      def value_before_type_cast(object)
        self.class.value_before_type_cast(object, @method_name)
      end

      class << self
        def value(object, method_name)
          object.send method_name unless object.nil?
        end

        def value_before_type_cast(object, method_name)
          unless object.nil?
            object.respond_to?(method_name + "_before_type_cast") ?
            object.send(method_name + "_before_type_cast") :
            object.send(method_name)
          end
        end

        def check_box_checked?(value, checked_value)
          case value
          when TrueClass, FalseClass
            value
          when NilClass
            false
          when Integer
            value != 0
          when String
            value == checked_value
          when Array
            value.include?(checked_value)
          else
            value.to_i != 0
          end
        end

        def radio_button_checked?(value, checked_value)
          value.to_s == checked_value.to_s
        end
      end

      private
        def add_default_name_and_id(options)
          if options.has_key?("index")
            options["name"] ||= tag_name_with_index(options["index"])
            options["id"]   ||= tag_id_with_index(options["index"])
            options.delete("index")
          elsif defined?(@auto_index)
            options["name"] ||= tag_name_with_index(@auto_index)
            options["id"]   ||= tag_id_with_index(@auto_index)
          else
            options["name"] ||= tag_name + (options.has_key?('multiple') ? '[]' : '')
            options["id"]   ||= tag_id
          end
        end

        def tag_name
          "#{@object_name}[#{sanitized_method_name}]"
        end

        def tag_name_with_index(index)
          "#{@object_name}[#{index}][#{sanitized_method_name}]"
        end

        def tag_id
          "#{sanitized_object_name}_#{sanitized_method_name}"
        end

        def tag_id_with_index(index)
          "#{sanitized_object_name}_#{index}_#{sanitized_method_name}"
        end

        def sanitized_object_name
          @sanitized_object_name ||= @object_name.gsub(/\]\[|[^-a-zA-Z0-9:.]/, "_").sub(/_$/, "")
        end

        def sanitized_method_name
          @sanitized_method_name ||= @method_name.sub(/\?$/,"")
        end
    end

    class FormBuilder #:nodoc:
      # The methods which wrap a form helper call.
      class_inheritable_accessor :field_helpers
      self.field_helpers = (FormHelper.instance_methods - ['form_for'])

      attr_accessor :object_name, :object, :options

      def initialize(object_name, object, template, options, proc)
        @object_name, @object, @template, @options, @proc = object_name, object, template, options, proc
        @default_options = @options ? @options.slice(:index) : {}
        if @object_name.to_s.match(/\[\]$/)
          if object ||= @template.instance_variable_get("@#{Regexp.last_match.pre_match}") and object.respond_to?(:to_param)
            @auto_index = object.to_param
          else
            raise ArgumentError, "object[] naming but object param and @object var don't exist or don't respond to to_param: #{object.inspect}"
          end
        end
      end

      (field_helpers - %w(label check_box radio_button fields_for)).each do |selector|
        src = <<-end_src
          def #{selector}(method, options = {})
            @template.send(#{selector.inspect}, @object_name, method, objectify_options(options))
          end
        end_src
        class_eval src, __FILE__, __LINE__
      end

      def fields_for(record_or_name_or_array, *args, &block)
        if options.has_key?(:index)
          index = "[#{options[:index]}]"
        elsif defined?(@auto_index)
          self.object_name = @object_name.to_s.sub(/\[\]$/,"")
          index = "[#{@auto_index}]"
        else
          index = ""
        end

        case record_or_name_or_array
        when String, Symbol
          name = "#{object_name}#{index}[#{record_or_name_or_array}]"
        when Array
          object = record_or_name_or_array.last
          name = "#{object_name}#{index}[#{ActionController::RecordIdentifier.singular_class_name(object)}]"
          args.unshift(object)
        else
          object = record_or_name_or_array
          name = "#{object_name}#{index}[#{ActionController::RecordIdentifier.singular_class_name(object)}]"
          args.unshift(object)
        end

        @template.fields_for(name, *args, &block)
      end

      def label(method, text = nil, options = {})
        @template.label(@object_name, method, text, objectify_options(options))
      end

      def check_box(method, options = {}, checked_value = "1", unchecked_value = "0")
        @template.check_box(@object_name, method, objectify_options(options), checked_value, unchecked_value)
      end

      def radio_button(method, tag_value, options = {})
        @template.radio_button(@object_name, method, tag_value, objectify_options(options))
      end

      def error_message_on(method, *args)
        @template.error_message_on(@object, method, *args)
      end

      def error_messages(options = {})
        @template.error_messages_for(@object_name, objectify_options(options))
      end

      def submit(value = "Save changes", options = {})
        @template.submit_tag(value, options.reverse_merge(:id => "#{object_name}_submit"))
      end

      private
        def objectify_options(options)
          @default_options.merge(options.merge(:object => @object))
        end
    end
  end

  class Base
    cattr_accessor :default_form_builder
    self.default_form_builder = ::ActionView::Helpers::FormBuilder
  end
end