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

Services/Website/Sources/Library/Internal/Components/AnswerOffer.swift

@@ -0,0 +1,75 @@
+import Elementary
+import Persistence
+
+/// The seller's answer to an open offer: accept or decline, each a form.
+struct AnswerOffer: HTML {
+
+    // MARK: Properties
+
+    /// The offer answered.
+    let offer: Offer
+
+    /// The path to return to afterwards; accepting leads to the sale record instead.
+    let returnPath: String
+
+    // MARK: Computed
+
+    var body: some HTML {
+        form(
+            .class("answer"),
+            .action(.Route.answer(offer: offer.id)),
+            .method(.post)
+        ) {
+            input(
+                .type(.hidden),
+                .name("return"),
+                .value(returnPath)
+            )
+            button(
+                .class("button button--primary button--sm"),
+                .type(.submit),
+                .name("answer"),
+                .custom(name: "value", value: "accept")
+            ) {
+                "Accept"
+            }
+            button(
+                .class("button button--sm"),
+                .type(.submit),
+                .name("answer"),
+                .custom(name: "value", value: "decline")
+            ) {
+                "Decline"
+            }
+        }
+    }
+
+}
+
+// MARK: - Extensions
+
+extension Offer.Status {
+
+    // MARK: Computed
+
+    /// The status in a word.
+    var label: String {
+        switch self {
+        case .open: "Open"
+        case .accepted: "Accepted"
+        case .declined: "Declined"
+        case .expired: "Expired"
+        }
+    }
+
+    /// The chip colouring for the status.
+    var tone: Chip.Tone {
+        switch self {
+        case .open: .warn
+        case .accepted: .good
+        case .declined: .bad
+        case .expired: .neutral
+        }
+    }
+
+}