Give the user better error messages for CSV files

Makes uses of the additions to utils in https://github.com/alphagov/notifications-utils/pull/9

This commit strips out a lot of the complex stuff that the views and templates
in this app were doing. There is now a cleaner separation of concerns:

- utils returns the number and type of errors in the csv
- `get_errors_for_csv` helper in this app maps the number and type of errors
  onto human-friendly error messages
- the view and template just doing the glueing-together of all the pieces

This is (hopefully) easier to understand, definitely makes the component
parts easier to test in isolation, and makes it easier to give more specific
error messages.

app/templates/views/check.html

@@ -1,38 +1,53 @@
 {% extends "withnav_template.html" %}
+{% from "components/banner.html" import banner_wrapper %}
 {% from "components/email-message.html" import email_message %}
 {% from "components/sms-message.html" import sms_message %}
-{% from "components/table.html" import list_table, field %}
+{% from "components/table.html" import list_table, field, text_field, hidden_field_heading %}
 {% from "components/placeholder.html" import placeholder %}
 {% from "components/file-upload.html" import file_upload %}
 {% from "components/page-footer.html" import page_footer %}
 
 {% block page_title %}
-  {{ "Check and confirm" if upload_result.valid else page_heading }} – GOV.UK Notify
+  {{ page_heading if errors else "Check and confirm" }} – GOV.UK Notify
 {% endblock %}
 
 {% block maincolumn_content %}
 
-
-  {% if template.additional_data %}
-    {{ banner(
-      "Remove these columns from your CSV file:" + ", ".join(template.missing_data),
-      type="dangerous"
-    ) }}
-  {% elif not upload_result.valid %}
-    {{ banner(
-      "Your CSV file contained missing or invalid data",
-      type="dangerous"
-    ) }}
+  {% if errors %}
+    <div class="bottom-gutter">
+      {% call banner_wrapper(type='dangerous') %}
+        {% if errors|length == 1 %}
+          <h1 class='banner-title'>
+            There was a problem with {{ original_file_name }}
+          </h1>
+          <p>
+            You need to {{ errors[0] }}
+          </p>
+        {% else %}
+          <h1 class='banner-title'>
+            There were some problems with {{ original_file_name }}
+          </h1>
+          <p>
+            You need to:
+          </p>
+          <ul class="list-bullet">
+            {% for error in errors %}
+              <li>{{ error }}</li>
+            {% endfor %}
+          </ul>
+        {% endif %}
+      {% endcall %}
+    </div>
+  {% else %}
+    <h1 class="heading-large">
+      Check and confirm
+    </h1>
   {% endif %}
 
-  <h1 class="heading-large">
-    {{ "Check and confirm" if upload_result.valid else page_heading }}
-  </h1>
-
   {% if 'email' == template.template_type %}
     {{ email_message(
       template.subject,
-      template.replaced if upload_result.valid else template.formatted_as_markup,
+      template.formatted_as_markup if errors else template.replaced,
       from_address='{}@notifications.service.gov.uk'.format(service.email_from),
       from_name=service.name
     )}}
@@ -40,51 +55,52 @@
     <div class="grid-row">
       <div class="column-two-thirds">
         {{ sms_message(
-          template.replaced if upload_result.valid else template.formatted_as_markup
+          template.formatted_as_markup if errors else template.replaced
         )}}
       </div>
     </div>
   {% endif %}
 
-  {% if upload_result.valid %}
+  {% if errors %}
+    {{file_upload(form.file, button_text='Re-upload your file')}}
+  {% else %}
     <form method="post" enctype="multipart/form-data">
       <input type="hidden" name="csrf_token" value="{{ csrf_token() }}" />
-      <input type="submit" class="button" value="{{ "Send {} message{}".format(upload_result.rows|count, '' if upload_result.rows|count == 1 else 's') }}" />
+      <input type="submit" class="button" value="{{ "Send {} message{}".format(count_of_recipients, '' if count_of_recipients == 1 else 's') }}" />
       <a href="{{url_for('.send_messages', service_id=service_id, template_id=template.id)}}" class="page-footer-back-link">Back</a>
     </form>
-  {% else %}
-    {{file_upload(form.file, button_text='Upload a CSV file')}}
   {% endif %}
 
   {% call(item) list_table(
-    upload_result.rows,
+    recipients.rows_annotated_and_truncated,
     caption=original_file_name,
-    field_headings=column_headers
+    field_headings=['Row'] + recipients.column_headers_with_placeholders_highlighted
   ) %}
-    {% if item.get('phone number', '')|valid_phone_number %}
-      {% call field() %}
-        {{ item['phone number'] }}
-      {% endcall %}
-    {% elif item.get('email address') %}
-      {% call field() %}
-        {{ item['email address'] }}
-      {% endcall %}
-    {% else %}
-      {% call field(status='missing') %}
-        {{ item['phone number'] }}
-      {% endcall %}
-    {% endif %}
-    {% for column in template.placeholders %}
-      {% if item.get(column) %}
+    {% call field() %}
+      {{ item.index + 1 }}
+    {% endcall %}
+    {% for column in recipients.column_headers %}
+      {% if item[column].error %}
         {% call field() %}
-          {{ item.get(column) }}
+          <span class="table-field-error">
+            <span class="table-field-error-label">{{ item[column].error }}</span>
+            {{ item[column].data if item[column].data != None }}
+          </span>
+        {% endcall %}
+      {% elif item[column].ignore %}
+        {% call field(status='default') %}
+          {{ item[column].data if item[column].data != None }}
         {% endcall %}
       {% else %}
-        {% call field(status='missing') %}
-          missing
-        {% endcall %}
+        {{ text_field(item[column].data) }}
       {% endif %}
     {% endfor %}
   {% endcall %}
 
+  {% if count_of_displayed_recipients < count_of_recipients %}
+    <p class="table-show-more-link">
+      {{ count_of_recipients - count_of_displayed_recipients }} more {{ "row" if 1 == (count_of_recipients - count_of_displayed_recipients) else "rows"}} not shown
+    </p>
+  {% endif %}
+
 {% endblock %}