feat: /u/carts surfaces product list, checked-out marker, Activate button

- New mps_invoice.cart_id (nullable FK to mps_cart.id, idempotent migration 2dbdb8c89e66). Invoice.apply_cart_negotiation(cart) now also tags the source cart, so we have a one→many Cart.invoices back-ref — every checkout flow already routes through that method. - /u/carts list: each row now renders the cart's product titles as links (so the user can re-open them). When a cart is empty but has invoices (the json_cart was cleared / replaced after checkout), the row falls back to listing the line items from those invoices plus a "View receipt" button, so the user can repurchase without digging through their invoice history. - Status indicators: a green "active" tag on the current cart, a navy "checked out" tag on rows with linked invoices. - Activate button alongside Delete on every non-active row (POSTs to the existing /u/cart/{id}/activate route). - Layout uses grid-template-areas (summary | actions / products span both) and collapses to a single column at ≤600px. Tests: TestUserCartsList grows three new cases — Activate flips the active flag, non-empty rows show product titles + links, checked-out empty carts surface the invoice line items + receipt link. 6 in class pass; full Checkout/Cart slice (42 tests) still green.
2026-05-15 10:01:35 -04:00 · 2026-05-15 10:01:35 -04:00 · 55137af986
commit 55137af986
parent bb54152d47
6 changed files with 230 additions and 27 deletions
--- a/make_post_sell/models/cart.py
+++ b/make_post_sell/models/cart.py
@ -69,6 +69,14 @@ class Cart(RBase, Base):
    user = relationship(argument="User", uselist=False, lazy="joined")
    shop = relationship(argument="Shop", uselist=False, lazy="joined")

+    # One cart can produce many invoices (multi-shop checkouts split into
+    # one invoice per shop). lazy=dynamic so /u/carts can cheaply check
+    # `cart.invoices.count()` without loading rows.
+    invoices = relationship(
+        argument="Invoice", lazy="dynamic", foreign_keys="Invoice.cart_id",
+        back_populates="cart",
+    )
+
    def __init__(self, user=None):
        # since shopping carts are a private thing which may optionally
        # be granted public access, we use random uuid4 UUIDs to prevent
--- a/make_post_sell/models/invoice.py
+++ b/make_post_sell/models/invoice.py
@ -93,6 +93,12 @@ class Invoice(RBase, Base):
    # the marketplace is responsible for charging the customer
    # and paying out the shop owner, while taking a 15-35% cut.
    market_id = Column(UUIDType, foreign_key("Market", "id"), nullable=True)
+    # the source cart this invoice was built from. nullable: historical
+    # invoices predate the link, and tests may build an invoice without
+    # a cart. apply_cart_negotiation() sets it during checkout so the
+    # /u/carts listing can mark a cart as "checked out" and surface a
+    # link to the resulting receipt.
+    cart_id = Column(UUIDType, foreign_key("Cart", "id"), nullable=True)
    # the timestamp when the invoice was created.
    created_timestamp = Column(BigInteger, nullable=False)

@ -129,6 +135,12 @@ class Invoice(RBase, Base):
    # one to one.
    market = relationship(argument="Market", uselist=False, lazy="joined")

+    # back-ref to the source cart, if known.
+    cart = relationship(
+        argument="Cart", uselist=False, foreign_keys=[cart_id],
+        back_populates="invoices",
+    )
+
    # one to many.
    # returns all the InvoiceLineItems.
    # lazy="dynamic" returns a query object instead of an InstrumentedList.
@ -200,13 +212,22 @@ class Invoice(RBase, Base):
        )

    def apply_cart_negotiation(self, cart):
-        """MPS-20 + MPS-21: if cart is offer- or auction-bound, copy
-        the negotiated override total onto this invoice so payment
-        processors charge the agreed price, not the list-price sum
-        of line items. Idempotent — safe to call after invoice
-        construction at any point. Coupons / gift cards don't stack
-        on a negotiated price; this short-circuits both.
+        """Bind this invoice to the source cart.
+
+        Two jobs (one method, called at exactly one place per checkout
+        flow, so it's where we wire both):
+        1. Tag self.cart_id so /u/carts can flag the cart as "checked
+           out" and link to this receipt.
+        2. MPS-20 + MPS-21: if the cart is offer- or auction-bound,
+           copy the negotiated override total so payment processors
+           charge the agreed price, not the list-price sum of line
+           items. Coupons / gift cards don't stack on a negotiated
+           price; this short-circuits both.
+
+        Idempotent — safe to call multiple times during construction.
        """
+        if cart is not None:
+            self.cart_id = cart.id
        if cart.is_negotiated:
            self.negotiation_override_in_cents = (
                cart.auction_offer_override_in_cents
--- a/make_post_sell/scripts/alembic/versions/2dbdb8c89e66_add_invoice_cart_id_linking_checkouts_.py
+++ b/make_post_sell/scripts/alembic/versions/2dbdb8c89e66_add_invoice_cart_id_linking_checkouts_.py
@ -0,0 +1,43 @@
+"""add invoice.cart_id linking checkouts to source cart
+
+Revision ID: 2dbdb8c89e66
+Revises: 73c5cb973915
+Create Date: 2026-05-15 09:49:59.440555
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+from make_post_sell.models.meta import UUIDType
+
+
+# revision identifiers, used by Alembic.
+revision = '2dbdb8c89e66'
+down_revision = '73c5cb973915'
+branch_labels = None
+depends_on = None
+
+
+def _column_exists(table, column):
+    conn = op.get_bind()
+    result = conn.execute(sa.text(f"PRAGMA table_info({table})"))
+    return any(row[1] == column for row in result.fetchall())
+
+
+def upgrade():
+    """Add nullable mps_invoice.cart_id (FK to mps_cart.id).
+
+    Historical invoices have NULL cart_id — fine, the /u/carts listing
+    just won't link to a receipt for those rows. New checkouts set it
+    via Invoice.apply_cart_negotiation(cart)."""
+    if not _column_exists("mps_invoice", "cart_id"):
+        op.add_column(
+            "mps_invoice",
+            sa.Column("cart_id", UUIDType, nullable=True),
+        )
+
+
+def downgrade():
+    if _column_exists("mps_invoice", "cart_id"):
+        with op.batch_alter_table("mps_invoice") as batch:
+            batch.drop_column("cart_id")
--- a/make_post_sell/static/css/common.css
+++ b/make_post_sell/static/css/common.css
@ -2378,33 +2378,90 @@ section.checkout-page .well {
    justify-self: start;
 }

-/* Saved-carts list (/u/carts). Each row is link / meta / delete on a
-   3-column grid; the active row gets a subtle accent so it's obvious
-   which cart the user is currently working in. Grid only. */
+/* Saved-carts list (/u/carts). Each row is a small grid:
+     [summary | actions]
+     [products spans both]
+   Active rows get a green accent; checked-out rows get a navy accent
+   and surface the invoice line items so the user can re-purchase from
+   here. Grid only. */
 .carts-list {
    display: grid;
    gap: var(--space-2, 8px);
 }
 .cart-row {
    display: grid;
-    grid-template-columns: 1fr auto auto;
-    align-items: center;
-    gap: var(--space-3, 12px);
-    padding: var(--space-2, 8px) var(--space-3, 12px);
+    grid-template-columns: 1fr auto;
+    grid-template-areas:
+        "summary actions"
+        "products products";
+    align-items: start;
+    column-gap: var(--space-3, 12px);
+    row-gap: var(--space-2, 8px);
+    padding: var(--space-3, 12px);
    border-radius: var(--radius-md, 8px);
    background: var(--surface-dim, #f9f9fa);
 }
+.cart-row-summary {
+    grid-area: summary;
+    display: grid;
+    gap: var(--space-1, 4px);
+}
+.cart-row-actions {
+    grid-area: actions;
+    margin: 0;
+    display: grid;
+    grid-auto-flow: column;
+    gap: var(--space-2, 8px);
+    align-items: start;
+}
+.cart-row-action-form { margin: 0; }
+.cart-row-products,
+.cart-row-products-block { grid-area: products; }
+
 .cart-row-active {
    background: color-mix(in srgb, var(--color-green, #a3c765) 14%, var(--surface-base, #fff) 86%);
    border-left: 3px solid var(--color-green, #a3c765);
    padding-left: calc(var(--space-3, 12px) - 3px);
 }
+.cart-row-checked-out {
+    background: color-mix(in srgb, var(--color-navy, #5871ad) 10%, var(--surface-base, #fff) 90%);
+    border-left: 3px solid var(--color-navy, #5871ad);
+    padding-left: calc(var(--space-3, 12px) - 3px);
+}
+
 .cart-row-link { font-weight: 600; text-decoration: none; }
 .cart-row-meta {
    color: var(--text-muted, #777);
    font-size: var(--text-sm, 0.875rem);
 }
-.cart-row-actions { margin: 0; }
+.cart-row-tag {
+    text-transform: uppercase;
+    font-size: var(--text-xs, 0.75rem);
+    letter-spacing: 0.04em;
+}
+.cart-row-tag-active { color: var(--color-green, #4d7a1f); }
+.cart-row-tag-checked-out { color: var(--color-navy, #5871ad); }
+
+.cart-row-products {
+    margin: 0;
+    padding-left: var(--space-5, 20px);
+    display: grid;
+    gap: var(--space-1, 4px);
+    font-size: var(--text-sm, 0.875rem);
+}
+.cart-row-products-block {
+    display: grid;
+    gap: var(--space-2, 8px);
+    justify-items: start;
+}
+.cart-row-receipt { justify-self: start; }
+
+.cart-row-activate {
+    background: var(--color-green, #a3c765);
+    color: #fff;
+    border: 1px solid var(--color-green, #a3c765);
+}
+.cart-row-activate:hover { filter: brightness(1.05); }
 .cart-row-delete {
    background: var(--color-danger, #CC6958);
    color: #fff;
@ -2415,8 +2472,12 @@ section.checkout-page .well {
@media (max-width: 600px) {
    .cart-row {
        grid-template-columns: 1fr;
-        gap: var(--space-1, 4px);
+        grid-template-areas:
+            "summary"
+            "products"
+            "actions";
    }
+    .cart-row-actions { justify-self: end; }
 }

 [data-theme="dark"] .one-column.well.well-green,
--- a/make_post_sell/templates/carts.j2
+++ b/make_post_sell/templates/carts.j2
@ -12,18 +12,64 @@
    <div class="carts-list">
      {% for cart in carts %}
        {% set is_active = cart == request.active_cart %}
-        <div class="cart-row{% if is_active %} cart-row-active{% endif %}">
-          <a class="cart-row-link" href="/cart/{{ cart.id }}">
-            &#128722; Cart ${{ '%0.2f' % cart.total }} ({{ cart.count }} item{{ '' if cart.count == 1 else 's' }})
-          </a>
-          <span class="cart-row-meta">{{ cart.human_updated_timestamp }}{% if is_active %} &middot; <strong>active</strong>{% endif %}</span>
+        {% set first_invoice = cart.invoices.first() %}
+        {% set checked_out = first_invoice is not none %}
+        <div class="cart-row{% if is_active %} cart-row-active{% elif checked_out %} cart-row-checked-out{% endif %}">
+          <div class="cart-row-summary">
+            <a class="cart-row-link" href="/cart/{{ cart.id }}">
+              &#128722; Cart ${{ '%0.2f' % cart.total }} ({{ cart.count }} item{{ '' if cart.count == 1 else 's' }})
+            </a>
+            <span class="cart-row-meta">
+              {{ cart.human_updated_timestamp }}
+              {% if is_active %} &middot; <strong class="cart-row-tag cart-row-tag-active">active</strong>{% endif %}
+              {% if checked_out %} &middot; <strong class="cart-row-tag cart-row-tag-checked-out">checked out</strong>{% endif %}
+            </span>
+          </div>
+
+          {# Product list: current contents when non-empty, OR the line
+             items from the resulting invoice(s) when the cart's been
+             checked out (the json_cart was emptied / replaced but the
+             invoice line items preserve what was bought, so the user
+             can re-purchase from this view). #}
+          {% if cart.count > 0 %}
+            <ul class="cart-row-products">
+              {% for pid, product in cart.products.items() %}
+                <li>
+                  <a href="{{ product.absolute_url(request) }}">{{ product.title }}</a>
+                  {% if cart.cart[pid] > 1 %} &times; {{ cart.cart[pid] }}{% endif %}
+                </li>
+              {% endfor %}
+            </ul>
+          {% elif checked_out %}
+            <div class="cart-row-products-block">
+              <ul class="cart-row-products">
+                {% for invoice in cart.invoices %}
+                  {% for line_item in invoice.line_items %}
+                    <li>
+                      <a href="{{ line_item.product.absolute_url(request) }}">{{ line_item.product.title }}</a>
+                      {% if line_item.quantity > 1 %} &times; {{ line_item.quantity }}{% endif %}
+                    </li>
+                  {% endfor %}
+                {% endfor %}
+              </ul>
+              <a href="/i/{{ first_invoice.id }}" class="mps-button-small cart-row-receipt">View receipt</a>
+            </div>
+          {% endif %}
+
          {% if not is_active %}
-            <form method="POST"
-                  action="{{ request.route_url('user_cart_delete', cart_id=cart.uuid_str) }}"
-                  class="cart-row-actions"
-                  onsubmit="return confirm('Delete this cart? This cannot be undone.');">
-              <button type="submit" class="mps-button-small cart-row-delete">Delete</button>
-            </form>
+            <div class="cart-row-actions">
+              <form method="POST"
+                    action="{{ request.route_url('user_cart_activate', cart_id=cart.uuid_str) }}"
+                    class="cart-row-action-form">
+                <button type="submit" class="mps-button-small cart-row-activate">Activate</button>
+              </form>
+              <form method="POST"
+                    action="{{ request.route_url('user_cart_delete', cart_id=cart.uuid_str) }}"
+                    class="cart-row-action-form"
+                    onsubmit="return confirm('Delete this cart? This cannot be undone.');">
+                <button type="submit" class="mps-button-small cart-row-delete">Delete</button>
+              </form>
+            </div>
          {% endif %}
        </div>
      {% endfor %}
--- a/make_post_sell/tests/test_functional.py
+++ b/make_post_sell/tests/test_functional.py
@ -7809,6 +7809,27 @@ class TestUserCartsList(_AuthenticatedBase):
        body = self.testapp.get("/u/carts", status=200).body.decode()
        self.assertIn(active_id, body)

+    def test_activate_button_shown_for_inactive_and_swaps_active(self):
+        """Each non-active cart row shows an Activate form alongside
+        Delete; POSTing it flips the row to active."""
+        from ..models.cart import get_cart_by_id
+        _shop, active_id, inactive_id = self._two_carts_for_user1()
+
+        body = self.testapp.get("/u/carts", status=200).body.decode()
+        self.assertIn(
+            f"/u/cart/{inactive_id}/activate", body,
+        )
+        self.assertNotIn(f"/u/cart/{active_id}/activate", body)
+
+        self.testapp.post(
+            f"/u/cart/{inactive_id}/activate", status=302,
+        )
+        # Inactive cart is now active.
+        cart_inactive = get_cart_by_id(self.dbsession, inactive_id)
+        self.assertTrue(cart_inactive.active)
+        cart_active = get_cart_by_id(self.dbsession, active_id)
+        self.assertFalse(cart_active.active)
+
    def test_carts_list_shows_product_titles_with_links(self):
        """A non-empty cart row renders each product's title as a link
        to the product page so the user can re-open it."""
@ -7847,10 +7868,13 @@ class TestUserCartsList(_AuthenticatedBase):
        shop = self._create_shop_helper(user_creds=self.user1_creds)
        product = Product(title="Already Bought", description="...")
        product.shop = shop
-        product.price_in_cents = 500
        product.is_physical = False
        product.is_sellable = True
+        # set_price() also creates a Price history row; InvoiceLineItem
+        # needs that to resolve product.current_price.
+        price = product.set_price("5.00")
        self.dbsession.add(product)
+        self.dbsession.add(price)
        self.dbsession.flush()
        product_id = product.uuid_str