supporters: Use data-binding for amount rather than events

Also tidied forms.py a little by consolidating into widget and moving help text
to template.

conservancy/supporters/forms.py

@@ -58,7 +58,17 @@ class SustainerForm(forms.ModelForm):
                 attrs={
                     'x-model': 'recurring',
                     # Reset the amount field and option when changing monthly/annually.
-                    'x-on:change': '$refs.amount.value = null; amount_option = null',
+                    'x-on:change': 'amount = ""; amount_option = null',
+                }
+            ),
+            'amount': forms.widgets.NumberInput(
+                # Keeping default widget, just neater to add many attrs here.
+                attrs={
+                    # So we can update the amount field from the amount_option selected.
+                    'x-model': 'amount',
+                    'x-bind:min': 'amount_minimum',
+                    'onblur': 'this.reportValidity()',
+                    'style': 'width: 5rem',
                 }
             ),
         }
@@ -70,15 +80,6 @@ class SustainerForm(forms.ModelForm):
 
         self.fields['recurring'].label = ''
         self.fields['amount'].initial = self.YEAR_OPTIONS[0]
-        # So we can write to this field easily from Alpine JS.
-        self.fields['amount'].widget.attrs['x-ref'] = 'amount'
-        self.fields['amount'].widget.attrs['style'] = 'width: 5rem'
-        self.fields['amount'].widget.attrs['onblur'] = 'this.reportValidity()'
-        self.fields['amount'].widget.attrs['x-bind:min'] = 'amount_minimum'
-        self.fields['email'].help_text = 'For your payment receipt'
-        self.fields['tshirt_size'].help_text = mark_safe(
-            """Sizing chart: <a href="/videos/women-2017-to-2020-t-shirt-sizing.jpg" target="_blank" class="black-60">Women's</a>, <a href="/videos/men-2017-to-2020-t-shirt-sizing.jpg" target="_blank" class="black-60">Men's</a>"""
-        )
         self.fields['tshirt_size'].widget.attrs['x-model'] = 'tshirt_size'
 
     def clean(self):

conservancy/supporters/templates/supporters/buttonradio_option.html

@@ -1,2 +1,2 @@
-<!-- Custom <span> wrapper around the label to enable radio fields to be styled like buttons. -->
+{# Custom <span> wrapper around the label to enable radio fields to be styled like buttons. #}
 {% if widget.wrap_label %}<label onclick="click()"{% if widget.attrs.id %} for="{{ widget.attrs.id }}"{% endif %}>{% endif %}{% include "django/forms/widgets/input.html" %}{% if widget.wrap_label %} <span>{{ widget.label }}</span></label>{% endif %}

conservancy/supporters/templates/supporters/field.html

@@ -1,4 +1,4 @@
-<!-- Labels on a separate line, custom help text layout -->
+{# Labels on a separate line, custom help text layout #}
 {% if field.use_fieldset %}
   <fieldset{% if field.help_text and field.auto_id and "aria-describedby" not in field.field.widget.attrs %} aria-describedby="{{ field.auto_id }}_helptext"{% endif %}>
   {% if field.label %}{{ field.legend_tag }}{% endif %}

conservancy/supporters/templates/supporters/sustainers_stripe.html

@@ -52,8 +52,9 @@
         </div>
       </noscript>
 
-      <!-- Alpine JS is used to show different payments amounts for monthly/annual, write the selected payment amount into the "amount" field, reset the seleted amount when you change monthly/annual and pop out the address when you select a T-shirt. -->
+      {# Alpine JS is used to show different payments amounts for monthly/annual, write the selected payment amount into the "amount" field, reset the seleted amount when you change monthly/annual and pop out the address when you select a T-shirt. #}
       <form method="post" action="."
+        {# Pre-fill field defaults in case of server-side validation error. Otherwise Alpine JS will override them. #}
         x-data="{
                  recurring: '{{ form.recurring.value|escapejs }}',
                  amount: parseInt('{{ form.amount.value|escapejs }}'),
@@ -82,34 +83,40 @@
               <template x-for="m in amount_options">
                 {# Additional click handler ensures a click-drag activates the radio (similar to a real button). #}
                 <label onclick="this.click()">
-                  {# It seems to be important that all radios have a unique value to avoid UI glitches. #}
+                  {# All radios have a unique value to avoid UI glitches (even though the value isn't actually used). #}
-                  <input type="radio" name="amount_option" x-bind:value="m" x-on:change="$refs.amount.value = m" x-model="amount_option" required>
+                  <input type="radio" name="amount_option" x-bind:value="m" x-on:change="amount = m" x-model="amount_option" required>
                   <span>$<span x-text="m.toLocaleString()"></span></span>
                 </label>
               </template>
               <!-- Hide if no JS -->
               <template x-if="true">
                 <label onclick="this.click()">
-                  <input type="radio" name="amount_option" value="other" x-on:change="$refs.amount.value = ''" x-model="amount_option" required>
+                  <input type="radio" name="amount_option" value="other" x-on:change="amount = ''" x-model="amount_option" required>
                   <span>Other</span>
                 </label>
               </template>
             </div>
             <div class="mt2" x-show="amount_option === 'other'">
               {{ form.amount.as_field_group }}
+              <p class="f7 black-60 mt1">Minimum $<span x-text="amount_minimum"></span>. <a href="/donate" class="black-60">Donate smaller amounts here</a>.</p>
             </div>
           </div>
 
           <div class="mt3">{{ form.name.as_field_group }}</div>
 
-          <div class="mt2">{{ form.email.as_field_group }}</div>
+          <div class="mt2">
+            {{ form.email.as_field_group }}
+          </div>
 
           <div class="mt3"><label class="lh-title">{{ form.acknowledge_publicly }} Acknowledge me on the <a href="/sponsors#sustainers" target="_blank">list of sustainers</a></label></div>
 
-          <div class="mt3"><label class="lh-title">{{ form.add_to_mailing_list }} Add me to the <a href="https://lists.sfconservancy.org/pipermail/announce/">announcements</a> email list</label></div>
+          <div class="mt3"><label class="lh-title">{{ form.add_to_mailing_list }} Add me to the <a href="https://lists.sfconservancy.org/pipermail/announce/">announcements email list</a></label></div>
 
           <div class="mt3">
             {{ form.tshirt_size.as_field_group }}
+            <p class="f7 black-60 mt1">Sizing chart:
+              <a href="/videos/women-2017-to-2020-t-shirt-sizing.jpg" target="_blank" class="black-60">Women's</a>,
+              <a href="/videos/men-2017-to-2020-t-shirt-sizing.jpg" target="_blank" class="black-60">Men's</a></p>
             <figure class="mt2">
               <img src="/static/img/tshirt-2023.png" alt="Software Freedom Conservancy T-shirt" width="200">
             </figure>
@@ -130,7 +137,7 @@
         </fieldset>
       </form>
 
-      <p class="f7 mt3">Credit card and ACH payments are processed with Stripe. We also accept payment by PayPal, paper check and wire transfer (see below). Our sustainer program has a minimum of $120 USD per year, but we also accept <a href="/donate/">donations of smaller amounts</a>.</p>
+      <p class="f7 mt3">Credit card and ACH payments are processed with Stripe. We also accept payment by PayPal, paper check and wire transfer.</p>
 
       <details id="paypal">
         <summary class="f6">PayPal</summary>