feat(api): add GET /api/home composite handler

Wires recommendation.HomeData into handleGetHome; maps dbq row types to
the five HomePayload wire-type slices (AlbumRef/ArtistRef/TrackRef).
All slices are non-nil so the SPA never receives JSON null for empty sections.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/api/home.go

@@ -0,0 +1,55 @@
+package api
+
+import (
+	"net/http"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/recommendation"
+)
+
+// handleGetHome implements GET /api/home. Returns five sections in one
+// payload; sections that have no rows render as []. 500 on any underlying
+// DB failure — the SPA should render either empty states or full content,
+// not a half-broken page.
+func (h *handlers) handleGetHome(w http.ResponseWriter, r *http.Request) {
+	user, ok := auth.UserFromContext(r.Context())
+	if !ok {
+		writeErr(w, http.StatusUnauthorized, "unauthorized", "authentication required")
+		return
+	}
+	data, err := recommendation.HomeData(r.Context(), h.pool, user.ID)
+	if err != nil {
+		h.logger.Error("api: home data", "err", err)
+		writeErr(w, http.StatusInternalServerError, "server_error", "failed to load home")
+		return
+	}
+
+	out := HomePayload{
+		RecentlyAddedAlbums: make([]AlbumRef, 0, len(data.RecentlyAddedAlbums)),
+		RediscoverAlbums:    make([]AlbumRef, 0, len(data.RediscoverAlbums)),
+		RediscoverArtists:   make([]ArtistRef, 0, len(data.RediscoverArtists)),
+		MostPlayedTracks:    make([]TrackRef, 0, len(data.MostPlayedTracks)),
+		LastPlayedArtists:   make([]ArtistRef, 0, len(data.LastPlayedArtists)),
+	}
+	for _, row := range data.RecentlyAddedAlbums {
+		out.RecentlyAddedAlbums = append(out.RecentlyAddedAlbums, albumRefFrom(row.Album, row.ArtistName, 0, 0))
+	}
+	for _, row := range data.RediscoverAlbums {
+		out.RediscoverAlbums = append(out.RediscoverAlbums, albumRefFrom(row.Album, row.ArtistName, 0, 0))
+	}
+	for _, row := range data.RediscoverArtists {
+		out.RediscoverArtists = append(out.RediscoverArtists, artistRefFromCovered(row.Artist, int(row.AlbumCount), row.CoverAlbumID))
+	}
+	for _, row := range data.MostPlayedTracks {
+		out.MostPlayedTracks = append(out.MostPlayedTracks, trackRefFrom(row.Track, row.AlbumTitle, row.ArtistName))
+	}
+	for _, row := range data.LastPlayedArtists {
+		out.LastPlayedArtists = append(out.LastPlayedArtists, artistRefFromCovered(row.Artist, int(row.AlbumCount), row.CoverAlbumID))
+	}
+	writeJSON(w, http.StatusOK, out)
+}
+
+// Compile-time guard that dbq has the row types we need; if the SQL is
+// regenerated with a different name, this fails fast at build time.
+var _ = dbq.ListMostPlayedTracksForUserRow{}.Track

internal/api/home_test.go

@@ -0,0 +1,79 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/go-chi/chi/v5"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+)
+
+func newHomeRouter(h *handlers) chi.Router {
+	r := chi.NewRouter()
+	r.Get("/api/home", h.handleGetHome)
+	return r
+}
+
+func doGetHome(h *handlers, user dbq.User) *httptest.ResponseRecorder {
+	req := httptest.NewRequest(http.MethodGet, "/api/home", nil)
+	req = withUser(req, user)
+	w := httptest.NewRecorder()
+	newHomeRouter(h).ServeHTTP(w, req)
+	return w
+}
+
+func TestHome_EmptyForNewUser(t *testing.T) {
+	h, pool := testHandlers(t)
+	user := seedUser(t, pool, "alice", "pw", false)
+
+	w := doGetHome(h, user)
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d, want 200; body = %s", w.Code, w.Body.String())
+	}
+	var got HomePayload
+	if err := json.Unmarshal(w.Body.Bytes(), &got); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	// All slices must be non-nil so the SPA branches consistently on
+	// length rather than dealing with null.
+	if got.RecentlyAddedAlbums == nil || got.RediscoverAlbums == nil ||
+		got.RediscoverArtists == nil || got.MostPlayedTracks == nil ||
+		got.LastPlayedArtists == nil {
+		t.Errorf("payload has nil slice: %+v", got)
+	}
+	if len(got.RecentlyAddedAlbums) != 0 {
+		t.Errorf("RecentlyAddedAlbums len = %d, want 0", len(got.RecentlyAddedAlbums))
+	}
+}
+
+func TestHome_RecentlyAddedSurfacesAlbums(t *testing.T) {
+	h, pool := testHandlers(t)
+	user := seedUser(t, pool, "alice", "pw", false)
+	q := dbq.New(pool)
+	artist, _ := q.UpsertArtist(context.Background(), dbq.UpsertArtistParams{
+		Name: "ArtistOne", SortName: "ArtistOne",
+	})
+	_, _ = q.UpsertAlbum(context.Background(), dbq.UpsertAlbumParams{
+		Title: "Newest", SortTitle: "Newest", ArtistID: artist.ID,
+	})
+
+	w := doGetHome(h, user)
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d, body = %s", w.Code, w.Body.String())
+	}
+	var got HomePayload
+	_ = json.Unmarshal(w.Body.Bytes(), &got)
+	if len(got.RecentlyAddedAlbums) != 1 {
+		t.Fatalf("len = %d, want 1", len(got.RecentlyAddedAlbums))
+	}
+	if got.RecentlyAddedAlbums[0].Title != "Newest" {
+		t.Errorf("title = %q, want Newest", got.RecentlyAddedAlbums[0].Title)
+	}
+	if got.RecentlyAddedAlbums[0].ArtistName != "ArtistOne" {
+		t.Errorf("artist_name = %q, want ArtistOne", got.RecentlyAddedAlbums[0].ArtistName)
+	}
+}