Add letter validation preview functionality

- add get/post view
- create a pdf upload form
- add a template where user can upload the file
- check boundaries of the letter by calling template-preview
- display banner messages with boundaries validation result
- display pages of the document, with visible boundaries overlay
if the document did not pass validation, and without overlay
if they do pass validation

app/main/forms.py

@@ -766,6 +766,13 @@ class ServiceUpdateEmailBranding(StripWhitespaceForm):
     )
 
 
+class PDFUploadForm(StripWhitespaceForm):
+    file = FileField_wtf(
+        'Upload a letter in PDF format to check if it fits in the printable area',
+        validators=[FileAllowed(['pdf'], 'PDF documents only!')]
+    )
+
+
 class CreateOrUpdateOrganisation(StripWhitespaceForm):
 
     name = StringField('Name', validators=[DataRequired()])

app/main/views/platform_admin.py

@@ -13,11 +13,12 @@ from app import (
     service_api_client,
 )
 from app.main import main
-from app.main.forms import DateFilterForm, ReturnedLettersForm
+from app.main.forms import DateFilterForm, ReturnedLettersForm, PDFUploadForm
 from app.statistics_utils import (
     get_formatted_percentage,
     get_formatted_percentage_two_dp,
 )
+from app.template_previews import validate_letter
 from app.utils import (
     generate_next_dict,
     generate_previous_dict,
@@ -240,6 +241,29 @@ def platform_admin_returned_letters():
     )
 
 
+@main.route("/platform-admin/letter-validation-preview", methods=["GET", "POST"])
+@login_required
+@user_is_platform_admin
+def platform_admin_letter_validation_preview():
+    message, pages, result = None, [], None
+    form = PDFUploadForm()
+
+    if request.method == "POST":
+        pdf_file = form.file.data
+        response = validate_letter(pdf_file)
+        if response.status_code == 200:
+            pages=response.json()["pages"]
+            message = response.json()["message"]
+            result = response.json()["result"]
+
+    return render_template(
+        'views/platform-admin/letter-validation-preview.html',
+        form=form,
+        message=message,
+        pages=pages,
+        result=result
+    )
+
 def sum_service_usage(service):
     total = 0
     for notification_type in service['statistics'].keys():

app/navigation.py

@@ -80,6 +80,7 @@ class HeaderNavigation(Navigation):
             'live_services',
             'organisations',
             'platform_admin',
+            'platform_admin_letter_validation_preview',
             'platform_admin_list_complaints',
             'platform_admin_returned_letters',
             'suspend_service',
@@ -442,6 +443,7 @@ class MainNavigation(Navigation):
         'organisation_settings',
         'organisations',
         'platform_admin',
+        'platform_admin_letter_validation_preview',
         'platform_admin_list_complaints',
         'platform_admin_returned_letters',
         'pricing',
@@ -627,6 +629,7 @@ class CaseworkNavigation(Navigation):
         'organisation_settings',
         'organisations',
         'platform_admin',
+        'platform_admin_letter_validation_preview',
         'platform_admin_list_complaints',
         'platform_admin_returned_letters',
         'pricing',
@@ -853,6 +856,7 @@ class OrgNavigation(Navigation):
         'old_using_notify',
         'organisations',
         'platform_admin',
+        'platform_admin_letter_validation_preview',
         'platform_admin_list_complaints',
         'platform_admin_returned_letters',
         'pricing',

app/template_previews.py

@@ -43,3 +43,11 @@ def get_page_count_for_letter(template, values=None):
     page_count = json.loads(page_count.decode('utf-8'))['count']
 
     return page_count
+
+
+def validate_letter(pdf_file):
+    return requests.post(
+        '{}/precompiled/validate?include_preview=true'.format(current_app.config['TEMPLATE_PREVIEW_API_HOST']),
+        data=pdf_file,
+        headers={'Authorization': 'Token {}'.format(current_app.config['TEMPLATE_PREVIEW_API_KEY'])}
+    )

app/templates/components/file-upload.html

@@ -3,7 +3,9 @@
   action=None,
   button_text="Choose file",
   alternate_link=None,
-  alternate_link_text=None
+  alternate_link_text=None,
+  hint=None
+
 ) %}
   <form method="post" enctype="multipart/form-data" {% if action %}action="{{ action }}"{% endif %} class="{% if field.errors %}form-group-error{% endif %}" data-module="file-upload">
     <label class="file-upload-label" for="{{ field.name }}">

app/templates/views/platform-admin/_base_template.html

@@ -23,6 +23,7 @@
           ('Find users by email', url_for('main.find_users_by_email')),
           ('Email Complaints', url_for('main.platform_admin_list_complaints')),
           ('Returned letters', url_for('main.platform_admin_returned_letters')),
+          ('Letter validation preview', url_for('main.platform_admin_letter_validation_preview')),
         ] %}
           <li>
             <a href="{{ url }}">

app/templates/views/platform-admin/letter-validation-preview.html

@@ -0,0 +1,38 @@
+{% extends "views/platform-admin/_base_template.html" %}
+{% from "components/banner.html" import banner %}
+{% from "components/textbox.html" import textbox %}
+{% from "components/file-upload.html" import file_upload %}
+{% from "components/page-footer.html" import page_footer %}
+
+{% block per_page_title %}
+  {{ page_title|capitalize }}
+{% endblock %}
+
+{% block platform_admin_content %}
+
+<div class="grid-row">
+  <div class="column-whole">
+    <h1 class="heading-large">Letter Validation Preview</h1>
+
+    {{ file_upload(
+        form.file,
+        action = url_for('main.platform_admin_letter_validation_preview'),
+        button_text='Upload a PDF document',
+    )}}
+  </div>
+  <div class="column-whole template-container">
+    {% if result %}
+      {{ banner(message, with_tick=True) }}
+    {% elif message %}
+      {{ banner(message, 'dangerous')}}
+    {% endif %}
+
+    {% for page in pages %}
+    <div class="letter">
+      <img src="data:image/png;base64,{{ page }}">
+    </div>
+    {% endfor %}
+  </div>
+</div>
+
+{% endblock %}

tests/app/main/views/test_platform_admin.py

@@ -758,3 +758,10 @@ def test_platform_admin_submit_empty_returned_letters(mocker, client, platform_a
 
     assert response.status_code == 200
     assert "Can’t be empty" in response.get_data(as_text=True)
+
+
+def test_letter_validation_preview(mocker, client, platform_admin_user):
+    mock_get_user(mocker, user=platform_admin_user)
+    client.login(platform_admin_user)
+    response = client.get(url_for('main.platform_admin_letter_validation_preview'))
+    assert response.status_code == 200