Implemented phase 3 for the POC prototype in the Website service.

Services/Website/Sources/Library/Internal/Pages/ListingPage.swift

@@ -222,42 +222,62 @@ private extension ListingPage {
                     Unavailable("Save", modifier: "button--sm")
                 }
             }
-            div(.class("buy-box__actions")) {
-                a(
-                    .class("button button--primary button--lg"),
-                    .href(gated(.Route.buy(listing.slug)))
-                ) {
-                    "Buy now"
+            if !listing.isAvailable {
+                p(.class("notice")) {
+                    "This copy is sold. A sale was agreed on CCN."
                 }
-                if listing.acceptsOffers {
-                    a(
-                        .class("button button--outline button--lg"),
-                        .href(gated(.Route.offer(listing.slug)))
-                    ) {
-                        "Make an offer"
+            } else if viewer?.shopSlug == listing.shop.slug {
+                p(.class("notice")) {
+                    "This is your listing. Offers on it arrive in your "
+                    a(.href(.Route.sellerDashboard)) {
+                        "seller dashboard"
                     }
+                    "."
                 }
+            } else {
+                actions
+            }
+        }
+    }
+
+    /// The gated actions: buy, offer, message — and, signed out, why they lead to the sign-in.
+    @HTMLBuilder
+    var actions: some HTML {
+        div(.class("buy-box__actions")) {
+            a(
+                .class("button button--primary button--lg"),
+                .href(gated(.Route.buy(listing.slug)))
+            ) {
+                "Buy now"
+            }
+            if listing.acceptsOffers {
                 a(
-                    .class("button button--bare button--lg"),
-                    .href(gated(.Route.message(listing: listing.slug)))
+                    .class("button button--outline button--lg"),
+                    .href(gated(.Route.offer(listing.slug)))
                 ) {
-                    Icon(.message, size: 16)
-                    "Message seller"
+                    "Make an offer"
                 }
             }
-            if viewer == nil {
-                p(.class("gate-note")) {
-                    Icon(.lock, size: 16)
-                    span {
-                        "Buying, offers, saving and messages need a signed-in account. "
-                        a(
-                            .class("gate-note__link"),
-                            .href(.Route.signIn(returningTo: listing.path))
-                        ) {
-                            "Sign in or join with a passkey"
-                        }
-                        " — browsing stays open to everyone."
+            a(
+                .class("button button--bare button--lg"),
+                .href(gated(.Route.message(listing: listing.slug)))
+            ) {
+                Icon(.message, size: 16)
+                "Message seller"
+            }
+        }
+        if viewer == nil {
+            p(.class("gate-note")) {
+                Icon(.lock, size: 16)
+                span {
+                    "Buying, offers, saving and messages need a signed-in account. "
+                    a(
+                        .class("gate-note__link"),
+                        .href(.Route.signIn(returningTo: listing.path))
+                    ) {
+                        "Sign in or join with a passkey"
                     }
+                    " — browsing stays open to everyone."
                 }
             }
         }