package recommendation

import (
	"context"
	"testing"
	"time"

	"github.com/jackc/pgx/v5/pgtype"
)

func TestHomeData_NewUser_AllSectionsEmpty(t *testing.T) {
	pool := newPool(t)
	user := seedUser(t, pool, "home-newuser")

	got, err := HomeData(context.Background(), pool, user.ID)
	if err != nil {
		t.Fatalf("HomeData: %v", err)
	}
	if got == nil {
		t.Fatal("HomeData returned nil payload")
	}
	if len(got.RecentlyAddedAlbums) != 0 {
		t.Errorf("RecentlyAddedAlbums len = %d, want 0", len(got.RecentlyAddedAlbums))
	}
	if len(got.RediscoverAlbums) != 0 {
		t.Errorf("RediscoverAlbums len = %d, want 0", len(got.RediscoverAlbums))
	}
	if len(got.RediscoverArtists) != 0 {
		t.Errorf("RediscoverArtists len = %d, want 0", len(got.RediscoverArtists))
	}
	if len(got.MostPlayedTracks) != 0 {
		t.Errorf("MostPlayedTracks len = %d, want 0", len(got.MostPlayedTracks))
	}
	if len(got.LastPlayedArtists) != 0 {
		t.Errorf("LastPlayedArtists len = %d, want 0", len(got.LastPlayedArtists))
	}
}

// Compile-time assert that pgtype.UUID is a valid map key — used by the
// service when de-duping rediscover fallback rows. If this changes, the
// service needs to switch to keying by string.
var _ map[pgtype.UUID]struct{}

func TestHomeData_RecentlyAdded_OrderedByCreatedAt(t *testing.T) {
	pool := newPool(t)
	user := seedUser(t, pool, "home-recents")
	a1 := seedArtist(t, pool, "ArtistA", "")
	// Three albums, oldest first — created_at increases naturally with each insert.
	al1 := seedAlbumForArtist(t, pool, a1.ID, "Older")
	al2 := seedAlbumForArtist(t, pool, a1.ID, "Middle")
	al3 := seedAlbumForArtist(t, pool, a1.ID, "Newest")

	got, err := HomeData(context.Background(), pool, user.ID)
	if err != nil {
		t.Fatalf("HomeData: %v", err)
	}
	if len(got.RecentlyAddedAlbums) != 3 {
		t.Fatalf("len = %d, want 3", len(got.RecentlyAddedAlbums))
	}
	if got.RecentlyAddedAlbums[0].Album.ID != al3.ID ||
		got.RecentlyAddedAlbums[1].Album.ID != al2.ID ||
		got.RecentlyAddedAlbums[2].Album.ID != al1.ID {
		t.Errorf("order = [%s, %s, %s], want newest→oldest",
			got.RecentlyAddedAlbums[0].Album.Title,
			got.RecentlyAddedAlbums[1].Album.Title,
			got.RecentlyAddedAlbums[2].Album.Title)
	}
}

func TestHomeData_MostPlayed_RanksByCount_HonorsQuarantine(t *testing.T) {
	pool := newPool(t)
	user := seedUser(t, pool, "home-mostplayed")
	artist := seedArtist(t, pool, "ArtistB", "")
	album := seedAlbumForArtist(t, pool, artist.ID, "AlbumB")
	tHigh := seedTrackOnAlbum(t, pool, album.ID, artist.ID, "High")
	tLow := seedTrackOnAlbum(t, pool, album.ID, artist.ID, "Low")
	tQuar := seedTrackOnAlbum(t, pool, album.ID, artist.ID, "Quarantined")
	now := time.Now()
	for i := 0; i < 3; i++ {
		insertPlayEvent(t, pool, user.ID, tHigh.ID, now.Add(-time.Duration(i)*time.Minute))
	}
	insertPlayEvent(t, pool, user.ID, tLow.ID, now)
	for i := 0; i < 5; i++ {
		insertPlayEvent(t, pool, user.ID, tQuar.ID, now)
	}
	if _, err := pool.Exec(context.Background(),
		`INSERT INTO lidarr_quarantine (user_id, track_id, reason) VALUES ($1, $2, 'bad_rip')`,
		user.ID, tQuar.ID,
	); err != nil {
		t.Fatalf("insert quarantine: %v", err)
	}

	got, err := HomeData(context.Background(), pool, user.ID)
	if err != nil {
		t.Fatalf("HomeData: %v", err)
	}
	if len(got.MostPlayedTracks) != 2 {
		t.Fatalf("len = %d, want 2 (quarantined excluded)", len(got.MostPlayedTracks))
	}
	if got.MostPlayedTracks[0].Track.ID != tHigh.ID || got.MostPlayedTracks[1].Track.ID != tLow.ID {
		t.Errorf("ranking wrong: got [%s, %s], want [High, Low]",
			got.MostPlayedTracks[0].Track.Title,
			got.MostPlayedTracks[1].Track.Title)
	}
}

func TestHomeData_RediscoverAlbums_FallbackWhenSparse(t *testing.T) {
	pool := newPool(t)
	user := seedUser(t, pool, "home-rediscover")
	artist := seedArtist(t, pool, "ArtistC", "")
	// Like one album NOW (won't satisfy >30d eligibility) — should still
	// surface via fallback because primary returns 0 rows.
	al := seedAlbumForArtist(t, pool, artist.ID, "RecentLike")
	if _, err := pool.Exec(context.Background(),
		`INSERT INTO general_likes_albums (user_id, album_id, liked_at) VALUES ($1, $2, now())`,
		user.ID, al.ID,
	); err != nil {
		t.Fatalf("insert like: %v", err)
	}
	got, err := HomeData(context.Background(), pool, user.ID)
	if err != nil {
		t.Fatalf("HomeData: %v", err)
	}
	if len(got.RediscoverAlbums) != 1 {
		t.Fatalf("len = %d, want 1 (from fallback)", len(got.RediscoverAlbums))
	}
	if got.RediscoverAlbums[0].Album.ID != al.ID {
		t.Errorf("got %s, want %s", got.RediscoverAlbums[0].Album.Title, al.Title)
	}
}