Implemented phase 6 for the POC prototype in the Website service.

Services/Website/Sources/Library/Public/Controllers/CollectingController.swift

@@ -64,7 +64,11 @@ extension CollectingController: RouterController {
         routes.post(.init("\(String.Route.wants)/:id/remove"), use: removeWant)
         routes.get(.init(.Route.series), use: seriesIndex)
         routes.get(.init("\(String.Route.series)/:slug"), use: series)
+        routes.post(.init("\(String.Route.series)/:slug/own"), use: toggleOwned)
         routes.get(.init(.Route.compare), use: compare)
+        routes.get(.init(.Route.collection), use: collection)
+        routes.post(.init(.Route.collection), use: addBooks)
+        routes.get(.init(.Route.events), use: events)
 
         return routes
     }
@@ -240,12 +244,18 @@ private extension CollectingController {
         let listings = try await catalogue.listings().filter { $0.seriesSlug == slug }
         let issue = request.uri.queryParameters.get("issue", as: Int.self)
         let viewer = await sessions.viewer(for: request)
+        var owned: Set<Int>?
+
+        if let user = await sessions.user(for: request) {
+            owned = try await collecting.ownedIssues(of: user)[slug] ?? []
+        }
 
         return .init(additionalHeaders: .perViewer) { [analytics, assetVersion] in
             SeriesPage(
                 series: series,
                 listings: listings,
                 issue: issue,
+                owned: owned,
                 viewer: viewer,
                 assetVersion: assetVersion,
                 analytics: analytics
@@ -277,8 +287,114 @@ private extension CollectingController {
 
 }
 
+// MARK: - Collection and events
+
+private extension CollectingController {
+
+    /// Handles books added to the collection from its form.
+    @Sendable
+    func addBooks(
+        request: Request,
+        context: Context
+    ) async throws -> Response {
+        guard let user = await sessions.user(for: request) else {
+            return .redirect(to: .Route.signIn(returningTo: .Route.collection), type: .normal)
+        }
+
+        let form = try await URLEncodedFormDecoder().decode(BooksForm.self, from: request, context: context)
+
+        try await collecting.own(issues: CollectionPage.issues(in: form.issues), ofSeries: form.series, by: user)
+
+        return .redirect(to: .Route.collection, type: .normal)
+    }
+
+    /// Handles a request for the collection tracker.
+    @Sendable
+    func collection(
+        request: Request,
+        context: Context
+    ) async throws -> Response {
+        guard let user = await sessions.user(for: request) else {
+            return .redirect(to: .Route.signIn(returningTo: .Route.collection), type: .found)
+        }
+
+        let catalogue = try await collecting.allSeries()
+        let owned = try await collecting.ownedIssues(of: user)
+        let listings = try await self.catalogue.listings()
+        let viewer = await sessions.viewer(for: request)
+
+        return HTMLResponse(additionalHeaders: .perViewer) { [analytics, assetVersion] in
+            CollectionPage(
+                catalogue: catalogue,
+                owned: owned,
+                listings: listings,
+                viewer: viewer,
+                assetVersion: assetVersion,
+                analytics: analytics
+            )
+        }
+        .response(from: request, context: context)
+    }
+
+    /// Handles a request for the events.
+    @Sendable
+    func events(
+        request: Request,
+        context: Context
+    ) async throws -> HTMLResponse {
+        let events = try await collecting.upcomingEvents()
+        let listings = try await catalogue.listings()
+        let viewer = await sessions.viewer(for: request)
+
+        return .init(additionalHeaders: .perViewer) { [analytics, assetVersion] in
+            EventsPage(
+                events: events,
+                listings: listings,
+                viewer: viewer,
+                assetVersion: assetVersion,
+                analytics: analytics
+            )
+        }
+    }
+
+    /// Handles the switch on an issue of a series: into the collection, or out of it.
+    @Sendable
+    func toggleOwned(
+        request: Request,
+        context: Context
+    ) async throws -> Response {
+        let slug = try context.parameters.require("slug")
+
+        guard let user = await sessions.user(for: request) else {
+            return .redirect(to: .Route.signIn(returningTo: .Route.series(slug)), type: .normal)
+        }
+
+        let form = try await URLEncodedFormDecoder().decode(IssueForm.self, from: request, context: context)
+
+        if try await collecting.ownedIssues(of: user)[slug]?.contains(form.issue) == true {
+            try await collecting.disown(issue: form.issue, ofSeries: slug, by: user)
+        } else {
+            try await collecting.own(issues: [form.issue], ofSeries: slug, by: user)
+        }
+
+        return .redirect(to: .Route.series(slug), type: .normal)
+    }
+
+}
+
 // MARK: - Structs
 
+/// The fields the add-books form posts.
+private struct BooksForm: Decodable {
+    let series: String
+    let issues: String
+}
+
+/// The field an issue's switch posts.
+private struct IssueForm: Decodable {
+    let issue: Int
+}
+
 /// The fields the add-a-want form posts.
 private struct WantForm: Decodable {
     let title: String