feat(viewer): the invoice page shows its number, terms, bill-to and PO (P4b S4.5)

The viewer reads the same invoice the server prints. The Money in list and
the page title name an invoice by its issued number (a legacy invoice keeps
"Invoice {id}"); a Details card shows the number, terms, the bill-to as it
was at issue (contact, address, phone, email), Ship-to, the customer's PO
and memo, and a bill's vendor number, day received, terms and memo. Save
invoice PDF still re-creates the current copy; when the issued copy is
filed (found through its link to the invoice, never by name) Save issued
copy and Open issued copy hand over those very bytes, checked against
their SHA-256. Nothing is written to the books.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp

crates/ledger-gui/tests/invoices.rs

@@ -390,3 +390,138 @@ fn a_write_off_shows_on_the_timeline() {
     h.run_steps(2);
     assert_eq!(h.state_mut().route(), &Route::Entry(entry));
 }
+
+/// Books with an invoice issued the way `books.create_invoice` issues it
+/// (plan P4b S4.5): numbered, on terms, the bill-to kept as a snapshot
+/// with its contact block, the customer's PO and a memo, and its issued
+/// PDF filed with it. A second invoice is a legacy one: no number, no
+/// issued copy.
+fn numbered_books(dir: &TempDir) -> (u64, u64) {
+    use ledger_core::{PartySnapshot, Terms};
+    let mut s = Store::create(&dir.0.join("books-data"), Currency::USD).unwrap();
+    s.add_account("1000", "Checking", AccountType::Asset, None, false)
+        .unwrap();
+    let client = s.add_customer("Harbor Coffee").unwrap();
+    let fields = InvoiceFields {
+        number: None,
+        terms: Some(Terms::parse("Net 30").unwrap()),
+        bill_to: Some(PartySnapshot {
+            name: "Harbor Coffee Roasters, Inc.".into(),
+            address: Some("455 Wharf Street\nPortland, OR 97209".into()),
+            email: Some("ap@harbor.example".into()),
+            phone: Some("503-555-0100".into()),
+            contact: Some("Ana Reyes".into()),
+            billing_address: None,
+            shipping_address: Some("Dock 4, Harbor Road".into()),
+            billing_email: None,
+        }),
+        seller: None,
+        customer_ref: Some("PO-4471".into()),
+        memo: Some("Thank you for the quick turnaround.".into()),
+    };
+    let lines = vec![line("Consulting", 50_000)];
+    let preview = s
+        .preview_invoice(
+            client,
+            d(2026, 3, 1),
+            d(2026, 3, 31),
+            lines.clone(),
+            fields.clone(),
+        )
+        .unwrap();
+    let fields = InvoiceFields {
+        number: preview.number.clone(),
+        ..fields
+    };
+    let page = ledger_package::issued_invoice_document(
+        s.ledger(),
+        &ledger_core::settings::Company::default(),
+        &preview.invoice,
+    )
+    .unwrap();
+    let pdf = ledger_import::invoice_pdf(&page).unwrap();
+    let (numbered, _, _) = s
+        .create_invoice_issued(client, d(2026, 3, 1), d(2026, 3, 31), lines, fields, pdf)
+        .unwrap();
+    let legacy = s
+        .create_invoice(
+            client,
+            d(2026, 3, 2),
+            d(2026, 4, 1),
+            vec![line("Support", 8_000)],
+        )
+        .unwrap();
+    (numbered, legacy)
+}
+
+/// Plan P4b S4.5: the invoice's page shows its number, terms, bill-to (the
+/// snapshot at issue, contact block included), ship-to and PO, and offers
+/// the issued copy beside the re-created one; the Money in list names it
+/// by its number. A legacy invoice keeps "Invoice {id}", shows no details
+/// card, and has no issued copy to save.
+#[test]
+fn a_numbered_invoice_shows_its_number_terms_bill_to_and_po() {
+    let dir = TempDir::new("numbered");
+    let (numbered, legacy) = numbered_books(&dir);
+    let number = {
+        let books = data::load_once(&Source {
+            data_dir: dir.0.join("books-data"),
+            today: Some(d(2026, 3, 15)),
+        })
+        .unwrap();
+        let inv = books.ledger.get_invoice(numbered).unwrap();
+        let n = inv.number.clone().expect("the issue numbered it");
+        // The page's facts are the invoice's own (view_model parity).
+        let facts = ledger_gui::pages::invoices::details(
+            &books.ledger,
+            ledger_core::DocRef::Invoice(numbered),
+        );
+        let get = |label: &str| {
+            facts
+                .iter()
+                .find(|(l, _)| *l == label)
+                .map(|(_, v)| v.clone())
+        };
+        assert_eq!(get("Number").as_deref(), Some(n.as_str()));
+        assert_eq!(get("Terms").as_deref(), Some("Net 30"));
+        assert_eq!(get("PO").as_deref(), Some("PO-4471"));
+        assert_eq!(
+            get("Bill to").as_deref(),
+            Some(
+                "Harbor Coffee Roasters, Inc., Ana Reyes, 455 Wharf Street, Portland, OR 97209, 503-555-0100, ap@harbor.example"
+            )
+        );
+        assert_eq!(get("Ship to").as_deref(), Some("Dock 4, Harbor Road"));
+        assert_eq!(
+            get("Memo").as_deref(),
+            Some("Thank you for the quick turnaround.")
+        );
+        n
+    };
+    let mut h = open(&dir, Route::Invoice(numbered));
+    shot(&mut h, "invoice-numbered");
+    assert!(h.query_all_by_label_contains(&number).count() >= 1);
+    assert!(h.query_by_label("Net 30").is_some());
+    assert!(h.query_by_label("PO-4471").is_some());
+    assert!(
+        h.query_by_label_contains("Harbor Coffee Roasters, Inc., Ana Reyes")
+            .is_some()
+    );
+    assert!(h.query_by_label_contains("Save invoice PDF").is_some());
+    assert!(h.query_by_label_contains("Save issued copy").is_some());
+
+    // The list names it by number; the legacy one keeps its old name.
+    let h = open(&dir, Route::Receivables);
+    assert!(h.query_all_by_label_contains(&number).count() >= 1);
+    assert!(
+        h.query_all_by_label_contains(&format!("Invoice {legacy}"))
+            .count()
+            >= 1
+    );
+
+    // A legacy invoice: no details, and no issued copy to save.
+    let h = open(&dir, Route::Invoice(legacy));
+    assert!(h.query_by_label("Details").is_none());
+    assert!(h.query_by_label_contains("Save invoice PDF").is_some());
+    assert!(h.query_by_label_contains("Save issued copy").is_none());
+}

crates/ledger-gui/tests/view_model.rs

@@ -924,3 +924,64 @@ fn a_write_off_is_flagged_for_the_cpa() {
     assert_eq!(st.status, ledger_core::DocStatus::WrittenOff);
     assert!(books.ledger.get_entry(entry).is_some());
 }
+
+/// Plan P4b S4.5: the viewer, which replays the journal itself, holds a
+/// numbered invoice exactly as the store that wrote it does: its number,
+/// terms, bill-to snapshot, the customer's PO and memo, and its lines'
+/// quantity and unit price. What the page shows is read from those, so
+/// the viewer and the server cannot disagree about them.
+#[test]
+fn the_viewer_holds_a_numbered_invoice_as_the_store_does() {
+    use ledger_core::arap::InvoiceFields;
+    use ledger_core::{PartySnapshot, Terms};
+    let d = dir("numbered-parity");
+    let today = NaiveDate::from_ymd_opt(2026, 3, 15).unwrap();
+    let mut s = Store::create(&d.join("books-data"), Currency::USD).unwrap();
+    s.add_account("1000", "Checking", AccountType::Asset, None, false)
+        .unwrap();
+    let cust = s.add_customer("Harbor Coffee").unwrap();
+    let inv = s
+        .create_invoice_with(
+            cust,
+            NaiveDate::from_ymd_opt(2026, 3, 1).unwrap(),
+            NaiveDate::from_ymd_opt(2026, 3, 31).unwrap(),
+            vec![DocumentLine {
+                description: "Beans".into(),
+                amount: Decimal::new(9_999, 2),
+                class_id: None,
+                account: None,
+                quantity: Some(Decimal::new(3, 0)),
+                unit_price: Some(Decimal::new(3_333, 2)),
+            }],
+            InvoiceFields {
+                number: Some("INV-0007".into()),
+                terms: Some(Terms::parse("2/10 net 30").unwrap()),
+                bill_to: Some(PartySnapshot {
+                    name: "Harbor Coffee Roasters, Inc.".into(),
+                    address: Some("455 Wharf Street".into()),
+                    email: Some("ap@harbor.example".into()),
+                    phone: None,
+                    contact: Some("Ana Reyes".into()),
+                    billing_address: None,
+                    shipping_address: Some("Dock 4".into()),
+                    billing_email: None,
+                }),
+                seller: None,
+                customer_ref: Some("PO-4471".into()),
+                memo: Some("Thanks".into()),
+            },
+        )
+        .unwrap();
+    let stored = s.ledger().get_invoice(inv).unwrap().clone();
+    drop(s);
+    let books = data::load_once(&Source {
+        data_dir: d.join("books-data"),
+        today: Some(today),
+    })
+    .unwrap();
+    let shown = books.ledger.get_invoice(inv).unwrap();
+    assert_eq!(shown, &stored);
+    assert_eq!(shown.number.as_deref(), Some("INV-0007"));
+    assert_eq!(shown.terms.as_ref().unwrap().describe(), "2/10 net 30");
+    assert_eq!(shown.lines[0].quantity, Some(Decimal::new(3, 0)));
+}