Money formatting to preferred currency.

src/tjts5901/currency.py

@@ -20,11 +20,23 @@ from currency_converter import (
     CurrencyConverter,
 )
 
+from flask_babel import (
+    get_locale,
+    format_currency,
+)
+
+from babel.numbers import get_territory_currencies
+
 from flask import (
     Flask,
     current_app,
+    render_template,
 )
 
+from markupsafe import Markup
+
+from .auth import current_user
+
 
 REF_CURRENCY = 'EUR'
 "Reference currency for the currency converter."
@@ -102,9 +114,65 @@ def init_currency(app: Flask):
     # Register the currency converter as an extension
     app.extensions['currency_converter'] = CurrencyProxy(app)
 
+    # Register the currency converter as a template filter
+    app.add_template_filter(format_converted_currency, name='localcurrency')
+
     app.cli.add_command(update_currency_rates)
 
 
+def format_converted_currency(value, currency=None, **kwargs):
+    """
+    Render a currency value in the preferred currency.
+
+    This function renders a currency value in the preferred currency for the
+    current locale. If the preferred currency is not the reference currency,
+    the value is converted to the preferred currency.
+    """
+
+    if currency is None:
+        currency = get_preferred_currency()
+
+    # Convert the value to the preferred currency
+    local_value = convert_currency(value, currency)
+
+    # Format the value
+    html = render_template("money-tag.html",
+                           base_amount=format_currency(value, currency=REF_CURRENCY, format_type='name', **kwargs),
+                           local_amount=format_currency(local_value, currency=currency, **kwargs))
+    return Markup(html)
+
+
+def convert_currency(value, currency=None, from_currency=REF_CURRENCY):
+    """
+    Convert a currency value to the preferred currency.
+
+    This function converts a currency value to the preferred currency for the
+    current locale. If the preferred currency is not the reference currency,
+    the value is converted to the preferred currency.
+    """
+
+    if currency != REF_CURRENCY:
+        return current_app.extensions['currency_converter'].convert(value, from_currency, currency)
+
+    return value
+
+
+def get_preferred_currency():
+    """
+    Get the preferred currency.
+
+    This function returns the preferred currency for the current locale.
+
+    :return: The preferred currency.
+    """
+
+    if current_user.is_authenticated and current_user.currency:
+        return str(current_user.currency)
+
+    # Fall back to the default currency for the locale
+    return get_territory_currencies(get_locale().territory)[0]
+
+
 @click.command()
 def update_currency_rates():
     """

src/tjts5901/models.py

@@ -30,6 +30,8 @@ class User(UserMixin, db.Document):
     password = StringField(required=True)
 
     locale = EnumField(SupportedLocales)
+    currency = StringField(max_length=3)
+    "The user's preferred currency."
 
     created_at = DateTimeField(required=True, default=datetime.utcnow)
 

src/tjts5901/templates/items/index.html

@@ -46,10 +46,10 @@
                   {% endif %}
               </td>
               <td>{{ item.description }}</td>
-              <td>{{ item.starting_bid }}</td>
+              <td>{{ item.starting_bid|localcurrency }}</td>
               <td>{{ item.seller.email }}</td>
-              <td>{{ item.created_at }}</td>
-              <td>{{ item.closes_at }}</td>
+              <td>{{ item.created_at|datetimeformat }}</td>
+              <td>{{ item.closes_at|datetimeformat }}</td>
             </tr>
             {% endfor %}
           </tbody>

src/tjts5901/templates/money-tag.html

+<span title="{{ base_amount|e }}">{{ local_amount }}</span>