Extract formatters into their own module

We have lots of functions for converting various types of data into
strings to be displayed to the user somewhere.

This commit collects all these functions into their own module, rather
than having them cluttering up `app/__init__.py` or buried amongst
various other things that have ended up in `app/utils.py`.

app/utils.py

@@ -1,15 +1,9 @@
 import os
-import re
-import unicodedata
-from datetime import datetime, timedelta, timezone
+from datetime import datetime, timedelta
 from functools import wraps
 from itertools import chain
-from math import floor, log10
-from numbers import Number
 from urllib.parse import urlparse
 
-import ago
-import dateutil
 import pytz
 from dateutil import parser
 from flask import (
@@ -24,14 +18,10 @@ from flask import (
 )
 from flask_login import current_user, login_required
 from notifications_utils.field import Field
-from notifications_utils.formatters import (
-    make_quotes_smart,
-    unescaped_formatted_list,
-)
+from notifications_utils.formatters import unescaped_formatted_list
 from notifications_utils.letter_timings import letter_can_be_cancelled
 from notifications_utils.postal_address import PostalAddress
 from notifications_utils.recipients import RecipientCSV
-from notifications_utils.take import Take
 from notifications_utils.template import (
     BroadcastPreviewTemplate,
     EmailPreviewTemplate,
@@ -270,21 +260,6 @@ def generate_previous_next_dict(view, service_id, page, title, url_args):
     }
 
 
-def email_safe(string, whitespace='.'):
-    # strips accents, diacritics etc
-    string = ''.join(c for c in unicodedata.normalize('NFD', string) if unicodedata.category(c) != 'Mn')
-    string = ''.join(
-        word.lower() if word.isalnum() or word == whitespace else ''
-        for word in re.sub(r'\s+', whitespace, string.strip())
-    )
-    string = re.sub(r'\.{2,}', '.', string)
-    return string.strip('.')
-
-
-def id_safe(string):
-    return email_safe(string, whitespace='-')
-
-
 def get_help_argument():
     return request.args.get('help') if request.args.get('help') in ('1', '2', '3') else None
 
@@ -365,21 +340,6 @@ def get_current_financial_year():
     return current_year if current_month > 3 else current_year - 1
 
 
-def get_time_left(created_at, service_data_retention_days=7):
-    return ago.human(
-        (
-            datetime.now(timezone.utc)
-        ) - (
-            dateutil.parser.parse(created_at).replace(hour=0, minute=0, second=0) + timedelta(
-                days=service_data_retention_days + 1
-            )
-        ),
-        future_tense='Data available for {}',
-        past_tense='Data no longer available',  # No-one should ever see this
-        precision=1
-    )
-
-
 def get_logo_cdn_domain():
     parsed_uri = urlparse(current_app.config['ADMIN_BASE_URL'])
 
@@ -421,46 +381,6 @@ def unicode_truncate(s, length):
     return encoded.decode('utf-8', 'ignore')
 
 
-def starts_with_initial(name):
-    return bool(re.match(r'^.\.', name))
-
-
-def remove_middle_initial(name):
-    return re.sub(r'\s+.\s+', ' ', name)
-
-
-def remove_digits(name):
-    return ''.join(c for c in name if not c.isdigit())
-
-
-def normalize_spaces(name):
-    return ' '.join(name.split())
-
-
-def guess_name_from_email_address(email_address):
-
-    possible_name = re.split(r'[\@\+]', email_address)[0]
-
-    if '.' not in possible_name or starts_with_initial(possible_name):
-        return ''
-
-    return Take(
-        possible_name
-    ).then(
-        str.replace, '.', ' '
-    ).then(
-        remove_digits
-    ).then(
-        remove_middle_initial
-    ).then(
-        str.title
-    ).then(
-        make_quotes_smart
-    ).then(
-        normalize_spaces
-    )
-
-
 def should_skip_template_page(template_type):
     return (
         current_user.has_permissions('send_messages')
@@ -488,15 +408,6 @@ def printing_today_or_tomorrow(created_at):
         return 'tomorrow'
 
 
-def redact_mobile_number(mobile_number, spacing=""):
-    indices = [-4, -5, -6, -7]
-    redact_character = spacing + "•" + spacing
-    mobile_number_list = list(mobile_number.replace(" ", ""))
-    for i in indices:
-        mobile_number_list[i] = redact_character
-    return "".join(mobile_number_list)
-
-
 def get_letter_printing_statement(status, created_at, long_form=True):
     created_at_dt = parser.parse(created_at).replace(tzinfo=None)
     if letter_can_be_cancelled(status, created_at_dt):
@@ -709,14 +620,6 @@ class PermanentRedirect(RequestRedirect):
     code = 301
 
 
-def format_thousands(value):
-    if isinstance(value, Number):
-        return '{:,.0f}'.format(value)
-    if value is None:
-        return ''
-    return value
-
-
 def is_less_than_days_ago(date_from_db, number_of_days):
     return (
         datetime.utcnow().astimezone(pytz.utc) - parser.parse(date_from_db)
@@ -762,12 +665,3 @@ def merge_jsonlike(source, destination):
                 source[key] = value
 
     merge_items(source, destination)
-
-
-def round_to_significant_figures(value, number_of_significant_figures):
-    if value == 0:
-        return value
-    return int(round(
-        value,
-        number_of_significant_figures - int(floor(log10(abs(value)))) - 1
-    ))