Implement shopping cart

pyproject.toml

@@ -22,6 +22,7 @@ build-backend = "uv_build"
 [dependency-groups]
 dev = [
     "black>=25.9.0",
+    "faker>=38.2.0",
     "httpx>=0.28.1",
     "isort>=7.0.0",
     "pytest>=8.4.2",

src/allmende_payment_system/api/__init__.py

@@ -11,7 +11,6 @@ templates = get_jinja_renderer()
 
 @root_router.get("/")
 async def landing_page(request: Request, user: UserDep, session: SessionDep):
-    print(f"User {user.username} ({user.display_name}) accessed landing page")
     transactions = []
     for account in user.accounts:
         transactions += account.transactions

src/allmende_payment_system/api/dependencies.py

@@ -13,6 +13,7 @@ def get_session() -> Session:
     try:
         yield db
     finally:
+        db.commit()
         db.close()
 
 

src/allmende_payment_system/api/shop.py

@@ -1,8 +1,12 @@
+from decimal import Decimal
+
 from fastapi import APIRouter, Request
 from sqlalchemy import select
+from starlette import status
+from starlette.responses import RedirectResponse
 
-from allmende_payment_system.api import SessionDep
+from allmende_payment_system.api.dependencies import SessionDep, UserDep
-from allmende_payment_system.models import Area
+from allmende_payment_system.models import Area, OrderItem, Product
 from allmende_payment_system.tools import get_jinja_renderer
 
 shop_router = APIRouter()
@@ -20,6 +24,26 @@ async def get_shop(request: Request, session: SessionDep):
     )
 
 
+@shop_router.get("/shop/cart")
+async def get_cart(request: Request, session: SessionDep, user: UserDep):
+
+    return templates.TemplateResponse(
+        "cart.html.jinja",
+        context={"request": request, "user": user},
+    )
+
+
+@shop_router.get("/shop/finalize_order")
+async def get_cart(request: Request, session: SessionDep, user: UserDep):
+
+    cart = user.shopping_cart
+
+    # TODO: Implement
+    cart.finalize_order()
+
+    return RedirectResponse(url=f"/", status_code=status.HTTP_302_FOUND)
+
+
 @shop_router.get("/shop/area/{area_id}")
 async def get_shop(request: Request, session: SessionDep, area_id: int):
     query = select(Area).where(Area.id == area_id)
@@ -28,3 +52,27 @@ async def get_shop(request: Request, session: SessionDep, area_id: int):
         "area.html.jinja",
         context={"request": request, "area": area},
     )
+
+
+@shop_router.post("/shop/cart/add")
+async def add_to_cart(request: Request, session: SessionDep, user: UserDep):
+    form_data = await request.form()
+
+    query = select(Product).where(Product.id == form_data["product_id"])
+    product = session.scalars(query).one()
+
+    quantity = Decimal(form_data["quantity"])
+    total_amount = product.price * quantity
+
+    order_item = OrderItem(
+        product=product, quantity=quantity, total_amount=total_amount
+    )
+    session.add(order_item)
+    cart = user.shopping_cart
+    cart.items.append(order_item)
+
+    session.flush()
+
+    return RedirectResponse(
+        url=f"/shop/area/{form_data['area_id']}", status_code=status.HTTP_302_FOUND
+    )

src/allmende_payment_system/database.py

@@ -24,6 +24,6 @@ def ensure_user(user_info: dict, session: Session) -> User:
         username=user_info["username"], display_name=user_info.get("display_name")
     )
     session.add(user)
-    session.commit()
+    session.flush()
 
     return user

src/allmende_payment_system/models.py

@@ -82,6 +82,7 @@ class Area(Base):
 UnitsOfMeasure = typing.Literal[
     "g",
     "kg",
+    "l",
     "piece",
 ]
 
@@ -121,6 +122,10 @@ class Order(Base):
     def is_in_shopping_cart(self):
         return self.account is None
 
+    @property
+    def total_amount(self):
+        return sum(item.total_amount for item in self.items)
+
 
 class OrderItem(Base):
     __tablename__ = TABLE_PREFIX + "order_item"
@@ -130,7 +135,7 @@ class OrderItem(Base):
 
     product_id: Mapped[int] = mapped_column(ForeignKey(TABLE_PREFIX + "product.id"))
     product: Mapped[Product] = relationship("Product")
-    quantity: Mapped[int] = mapped_column(nullable=False)
+    quantity: Mapped[decimal.Decimal] = mapped_column(nullable=False)
     total_amount: Mapped[decimal.Decimal] = mapped_column(
         Numeric(10, 2), nullable=False
     )

src/allmende_payment_system/templates/area.html.jinja

@@ -25,12 +25,85 @@
                         <p class="card-text text-muted small mb-3">{{ product.description }}</p>
                         <div class="d-flex justify-content-between align-items-center">
                             <span class="fw-bold">{{ product.price|format_number }} € pro {{ product.unit_of_measure|units_of_measure_de }}</span>
-                            <button class="btn btn-sm btn-outline-primary">Add to Cart</button>
+                            <button class="btn btn-sm btn-outline-primary"
+                                    data-bs-toggle="modal"
+                                    data-bs-target="#productModal{{ product.id }}">
+                                In den Warenkorb
+                            </button>
+
                         </div>
                     </div>
                 </a>
             </div>
         </div>
+
+        <!-- Product Modal -->
+        <div class="modal fade" id="productModal{{ product.id }}" tabindex="-1" aria-labelledby="productModalLabel{{ product.id }}" aria-hidden="true">
+            <div class="modal-dialog modal-dialog-centered">
+                <div class="modal-content">
+                    <form method="POST" action="/shop/cart/add">
+                        <div class="modal-header">
+                            <h5 class="modal-title" id="productModalLabel{{ product.id }}">{{ product.name }}</h5>
+                            <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
+                        </div>
+                        <div class="modal-body">
+                            <!-- Product Image -->
+                            <img
+                                src="/static/img/{{ product.image_path if product.image_path else 'placeholder.jpg' }}"
+                                alt="{{ product.name }}"
+                                class="img-fluid rounded mb-3"
+                                style="max-height: 200px; width: 100%; object-fit: cover;"
+                            >
+
+                            <!-- Product Description -->
+                            <p class="text-muted mb-3">{{ product.description }}</p>
+
+                            <!-- Price -->
+                            <div class="mb-3">
+                                <h6 class="fw-bold">Preis: {{ product.price|format_number }} € pro {{ product.unit_of_measure|units_of_measure_de }}</h6>
+                            </div>
+
+                            <!-- Quantity Selector -->
+                            <input type="hidden" name="product_id" value="{{ product.id }}">
+                            <input type="hidden" name="area_id" value="{{ area.id }}">
+                            <div class="mb-3">
+                                <label for="quantity{{ product.id }}" class="form-label">Menge</label>
+                                <input type="number"
+                                       class="form-control"
+                                       id="quantity{{ product.id }}"
+                                       name="quantity"
+                                       value="1"
+                                       min="1"
+                                       max="999"
+                                       oninput="updateTotal{{ product.id }}(this.value)"
+                                       style="max-width: 150px;">
+                            </div>
+                            <!-- Total Price -->
+                            <div class="mb-3">
+                                <h6>Gesamt: <span id="total{{ product.id }}" class="fw-bold">{{ '%.2f' | format(product.price) }} €</span></h6>
+                            </div>
+
+                        </div>
+                        <div class="modal-footer">
+                            <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Abbrechen</button>
+                            <button type="submit" class="btn btn-primary">
+                                In den Warenkorb legen
+                            </button>
+                        </div>
+                    </form>
+                </div>
+            </div>
+        </div>
+        {# TODO: Make this a global function #}
+        <script>
+            function updateTotal{{ product.id }}(quantity) {
+                const price = {{ product.price }};
+                const total = (price * quantity).toFixed(2);
+                document.getElementById('total{{ product.id }}').textContent = total + ' €';
+            }
+        </script>
         {% endfor %}
+
+
     </div>
 {% endblock %}

src/allmende_payment_system/templates/base.html.jinja

@@ -29,21 +29,21 @@
                                 Einkaufen
                             </a>
                         </li>
-                        <li class="nav-item">
+{#                        <li class="nav-item">#}
-                            <a href="#" class="nav-link">
+{#                            <a href="#" class="nav-link">#}
-                                Lorem
+{#                                Lorem#}
-                            </a>
+{#                            </a>#}
-                        </li>
+{#                        </li>#}
-                        <li class="nav-item">
+{#                        <li class="nav-item">#}
-                            <a href="#" class="nav-link">
+{#                            <a href="#" class="nav-link">#}
-                                Ipsum
+{#                                Ipsum#}
-                            </a>
+{#                            </a>#}
-                        </li>
+{#                        </li>#}
                     </ul>
 
                     <!-- Shopping Cart at Bottom -->
                     <div class="mt-auto pt-3 border-top">
-                        <a href="/cart" class="btn btn-primary w-100 position-relative">
+                        <a href="/shop/cart" class="btn btn-primary w-100 position-relative">
                             <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" fill="currentColor" class="bi bi-cart3 me-2" viewBox="0 0 16 16">
                                 <path d="M0 1.5A.5.5 0 0 1 .5 1H2a.5.5 0 0 1 .485.379L2.89 3H14.5a.5.5 0 0 1 .49.598l-1 5a.5.5 0 0 1-.465.401l-9.397.472L4.415 11H13a.5.5 0 0 1 0 1H4a.5.5 0 0 1-.491-.408L2.01 3.607 1.61 2H.5a.5.5 0 0 1-.5-.5M3.102 4l.84 4.479 9.144-.459L13.89 4zM5 12a2 2 0 1 0 0 4 2 2 0 0 0 0-4m7 0a2 2 0 1 0 0 4 2 2 0 0 0 0-4m-7 1a1 1 0 1 1 0 2 1 1 0 0 1 0-2m7 0a1 1 0 1 1 0 2 1 1 0 0 1 0-2"/>
                             </svg>

src/allmende_payment_system/templates/cart.html.jinja

@@ -0,0 +1,74 @@
+{% extends "base.html.jinja" %}
+{% block content %}
+    <div class="mb-4">
+        <h2 class="h4 mb-3">Warenkorb</h2>
+        <p class="text-muted">Überprüfe deine Artikel und fahre zur Kasse fort.</p>
+    </div>
+
+    {% set items = user.shopping_cart.items %}
+
+    {% if items|length == 0 %}
+        <div class="alert alert-info">Dein Warenkorb ist leer. <a href="/shop" class="alert-link">Weiter einkaufen</a>.</div>
+    {% else %}
+        <div class="table-responsive">
+            <table class="table align-middle">
+                <thead>
+                    <tr>
+                        <th>Artikel</th>
+                        <th class="text-center">Menge</th>
+                        <th class="text-end">Einzelpreis</th>
+                        <th class="text-end">Summe</th>
+                        <th></th>
+                    </tr>
+                </thead>
+                <tbody>
+                    {% set total = namespace(value=0) %}
+                    {% for item in items %}
+                        {% set price = item.price if item.price is defined else (item.unit_price if item.unit_price is defined else 0) %}
+                        {% set qty = item.quantity if item.quantity is defined else (item.qty if item.qty is defined else 1) %}
+                        {% set subtotal = price * qty %}
+                        {% set total.value = total.value + subtotal %}
+                        <tr>
+                            <td>
+                                <div class="fw-semibold">{{ item.product.name }}</div>
+                                <div class="text-muted small">{{ item.description or '' }}</div>
+                            </td>
+                            <td class="text-center" style="width:180px;">
+                                <form method="post" action="/cart/update/{{ item.id }}" class="d-flex align-items-center justify-content-center">
+                                    <input type="number" name="quantity" value="{{ qty }}" min="1" step="0.01" class="form-control form-control-sm me-2" style="width:80px;">
+                                    <button class="btn btn-sm btn-outline-secondary" type="submit">Aktualisieren</button>
+                                </form>
+                            </td>
+                            <td class="text-end">{{ item.product.price | format_number }} €</td>
+                            <td class="text-end">{{ item.total_amount | format_number }} €</td>
+                            <td class="text-end">
+                                <a href="/cart/remove/{{ item.id }}" class="btn btn-sm btn-outline-danger">Entfernen</a>
+                            </td>
+                        </tr>
+                    {% endfor %}
+                </tbody>
+                <tfoot>
+                    <tr>
+                        <td colspan="3" class="text-end fw-semibold">Gesamtsumme</td>
+                        <td class="text-end fw-bold">{{ user.shopping_cart.total_amount | format_number }} €</td>
+                        <td></td>
+                    </tr>
+                </tfoot>
+            </table>
+        </div>
+
+        <div class="d-flex justify-content-between align-items-center mt-3">
+            <div>
+                <a href="/cart/clear" class="btn btn-outline-danger me-2">Warenkorb leeren</a>
+                <a href="/shop/finalize_order" class="btn btn-primary">Jetzt Buchen</a>
+            </div>
+        </div>
+    {% endif %}
+
+{% endblock %}
+
+{% block styles %}
+<style>
+    .card { border: none; transition: all 0.3s ease; }
+</style>
+{% endblock %}

test/conftest.py

@@ -3,34 +3,42 @@ from unittest import mock
 
 import pytest
 from fastapi.testclient import TestClient
-from sqlalchemy import StaticPool, create_engine
+from sqlalchemy import StaticPool, create_engine, event
 from sqlalchemy.orm import sessionmaker
 
 from allmende_payment_system.api.dependencies import get_session
 from allmende_payment_system.app import app
 from allmende_payment_system.models import Base
 
-
-def make_db():
 engine = create_engine(
     "sqlite:///:memory:",
     connect_args={"check_same_thread": False},
     poolclass=StaticPool,
 )
-    Base.metadata.create_all(bind=engine)  # Create tables
+
-    return sessionmaker(autocommit=False, autoflush=False, bind=engine)
+# Create a single connection and an outer transaction which we can rollback
+# at the end of the test run. Individual tests will use nested transactions
+# (SAVEPOINTs) for isolation. This ensures the TestClient (app) and the
+# test fixture sessions see the same in-memory database state.
+connection = engine.connect()
+transaction = connection.begin()
+
+Base.metadata.create_all(bind=connection)
+
+# Bind sessions to the single connection so all sessions share the same DB
+TestSessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=connection)
 
 
-def make_in_memory_session():
+def get_test_session():
-    db = make_db()
+    """Dependency override for get_session"""
-    session = db()
+    db = TestSessionLocal()
     try:
-        yield session
+        yield db
     finally:
-        session.close()
+        db.close()
 
 
-app.dependency_overrides[get_session] = make_in_memory_session
+app.dependency_overrides[get_session] = get_test_session
 
 
 @pytest.fixture(scope="session")
@@ -45,7 +53,25 @@ def unauthorized_client():
     return TestClient(app)
 
 
-@pytest.fixture
+@pytest.fixture(scope="function")
 def test_db():
-    db = make_db()
+    """Provides a database session for direct test usage"""
-    return db()
+    db = TestSessionLocal()
+
+    # Start a SAVEPOINT so test changes can be rolled back without
+    # closing the shared connection. Also restart the nested transaction
+    # when the session issues commits internally.
+    db.begin_nested()
+
+    @event.listens_for(db, "after_transaction_end")
+    def restart_savepoint(session, transaction):
+        # If the nested transaction ended, re-open it for continued isolation
+        if transaction.nested and not session.is_active:
+            session.begin_nested()
+
+    try:
+        yield db
+    finally:
+        # Rollback to the SAVEPOINT and close the session to clean up
+        db.rollback()
+        db.close()

test/test_database.py

@@ -11,7 +11,7 @@ def test_ensure_user(test_db):
 
     assert user.username == "test"
 
-    test_db.commit()
+    test_db.flush()
 
     assert test_db.scalar(select(func.count()).select_from(User)) == 1
 

uv.lock

@@ -14,6 +14,7 @@ dependencies = [
 [package.dev-dependencies]
 dev = [
     { name = "black" },
+    { name = "faker" },
     { name = "httpx" },
     { name = "isort" },
     { name = "pytest" },
@@ -28,6 +29,7 @@ requires-dist = [
 [package.metadata.requires-dev]
 dev = [
     { name = "black", specifier = ">=25.9.0" },
+    { name = "faker", specifier = ">=38.2.0" },
     { name = "httpx", specifier = ">=0.28.1" },
     { name = "isort", specifier = ">=7.0.0" },
     { name = "pytest", specifier = ">=8.4.2" },
@@ -128,6 +130,18 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/de/15/545e2b6cf2e3be84bc1ed85613edd75b8aea69807a71c26f4ca6a9258e82/email_validator-2.3.0-py3-none-any.whl", hash = "sha256:80f13f623413e6b197ae73bb10bf4eb0908faf509ad8362c5edeb0be7fd450b4", size = 35604, upload-time = "2025-08-26T13:09:05.858Z" },
 ]
 
+[[package]]
+name = "faker"
+version = "38.2.0"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "tzdata" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/64/27/022d4dbd4c20567b4c294f79a133cc2f05240ea61e0d515ead18c995c249/faker-38.2.0.tar.gz", hash = "sha256:20672803db9c7cb97f9b56c18c54b915b6f1d8991f63d1d673642dc43f5ce7ab", size = 1941469, upload-time = "2025-11-19T16:37:31.892Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/17/93/00c94d45f55c336434a15f98d906387e87ce28f9918e4444829a8fda432d/faker-38.2.0-py3-none-any.whl", hash = "sha256:35fe4a0a79dee0dc4103a6083ee9224941e7d3594811a50e3969e547b0d2ee65", size = 1980505, upload-time = "2025-11-19T16:37:30.208Z" },
+]
+
 [[package]]
 name = "fastapi"
 version = "0.119.0"
@@ -204,6 +218,8 @@ wheels = [
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+    { url = "https://files.pythonhosted.org/packages/1c/53/f9c440463b3057485b8594d7a638bed53ba531165ef0ca0e6c364b5cc807/greenlet-3.2.4-cp313-cp313-musllinux_1_2_aarch64.whl", hash = "sha256:6e343822feb58ac4d0a1211bd9399de2b3a04963ddeec21530fc426cc121f19b", size = 1564759, upload-time = "2025-11-04T12:42:19.395Z" },
+    { url = "https://files.pythonhosted.org/packages/47/e4/3bb4240abdd0a8d23f4f88adec746a3099f0d86bfedb623f063b2e3b4df0/greenlet-3.2.4-cp313-cp313-musllinux_1_2_x86_64.whl", hash = "sha256:ca7f6f1f2649b89ce02f6f229d7c19f680a6238af656f61e0115b24857917929", size = 1634288, upload-time = "2025-11-04T12:42:21.174Z" },
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 ]
 
@@ -672,6 +688,15 @@ wheels = [
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 ]
 
+[[package]]
+name = "tzdata"
+version = "2025.2"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/95/32/1a225d6164441be760d75c2c42e2780dc0873fe382da3e98a2e1e48361e5/tzdata-2025.2.tar.gz", hash = "sha256:b60a638fcc0daffadf82fe0f57e53d06bdec2f36c4df66280ae79bce6bd6f2b9", size = 196380, upload-time = "2025-03-23T13:54:43.652Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/5c/23/c7abc0ca0a1526a0774eca151daeb8de62ec457e77262b66b359c3c7679e/tzdata-2025.2-py2.py3-none-any.whl", hash = "sha256:1a403fada01ff9221ca8044d701868fa132215d84beb92242d9acd2147f667a8", size = 347839, upload-time = "2025-03-23T13:54:41.845Z" },
+]
+
 [[package]]
 name = "urllib3"
 version = "2.5.0"