package tracks

import (
	"context"
	"errors"
	"io"
	"log/slog"
	"os"
	"path/filepath"
	"testing"

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

	"git.fabledsword.com/bvandeusen/minstrel/internal/db"
	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
	"git.fabledsword.com/bvandeusen/minstrel/internal/dbtest"
	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarr"
)

// --- test seed helpers (inlined; mirrors lidarrquarantine patterns) -----

func newPool(t *testing.T) *pgxpool.Pool {
	t.Helper()
	if testing.Short() {
		t.Skip("skipping integration test in -short mode")
	}
	dsn := os.Getenv("MINSTREL_TEST_DATABASE_URL")
	if dsn == "" {
		t.Skip("MINSTREL_TEST_DATABASE_URL not set")
	}
	if err := db.Migrate(dsn, slog.New(slog.NewTextHandler(io.Discard, nil))); err != nil {
		t.Fatalf("migrate: %v", err)
	}
	pool, err := pgxpool.New(context.Background(), dsn)
	if err != nil {
		t.Fatalf("pool: %v", err)
	}
	t.Cleanup(pool.Close)
	dbtest.ResetDB(t, pool)
	return pool
}

func seedAdmin(t *testing.T, pool *pgxpool.Pool, name string) dbq.User {
	t.Helper()
	u, err := dbq.New(pool).CreateUser(context.Background(), dbq.CreateUserParams{
		Username: dbtest.TestUserPrefix + name, PasswordHash: "x",
		ApiToken: name + "-token", IsAdmin: true,
	})
	if err != nil {
		t.Fatalf("seed admin %s: %v", name, err)
	}
	return u
}

// seedArtistAlbumTrack creates a (test-prefixed) artist + album + track
// row triple. mbid is set on both the album and the track when non-empty;
// empty mbid leaves both nil so the track exercises the local-delete path.
// filePath is the on-disk path stored on the track row. Returns the three
// rows. Uses unique names per call so multiple seeds in one test don't
// collide on UNIQUE (artist, name) etc.
func seedArtistAlbumTrack(t *testing.T, pool *pgxpool.Pool, prefix, mbid, filePath string) (dbq.Artist, dbq.Album, dbq.Track) {
	t.Helper()
	q := dbq.New(pool)
	artist, err := q.UpsertArtist(context.Background(), dbq.UpsertArtistParams{
		Name: prefix + " Artist", SortName: prefix + " Artist",
	})
	if err != nil {
		t.Fatalf("artist: %v", err)
	}
	var albumMBIDPtr *string
	if mbid != "" {
		s := mbid + "-album"
		albumMBIDPtr = &s
	}
	album, err := q.UpsertAlbum(context.Background(), dbq.UpsertAlbumParams{
		Title: prefix + " Album", SortTitle: prefix + " Album",
		ArtistID: artist.ID, Mbid: albumMBIDPtr,
	})
	if err != nil {
		t.Fatalf("album: %v", err)
	}
	var trackMBIDPtr *string
	if mbid != "" {
		s := mbid
		trackMBIDPtr = &s
	}
	track, err := q.UpsertTrack(context.Background(), dbq.UpsertTrackParams{
		Title: prefix + " Track", AlbumID: album.ID, ArtistID: artist.ID,
		DurationMs: 1000, FilePath: filePath, FileSize: 1, FileFormat: "mp3",
		Mbid: trackMBIDPtr,
	})
	if err != nil {
		t.Fatalf("track: %v", err)
	}
	return artist, album, track
}

// --- fake LidarrDeleter -------------------------------------------------

type fakeLidarrDeleter struct {
	calls []pgtype.UUID
	err   error
}

func (f *fakeLidarrDeleter) DeleteViaLidarr(ctx context.Context, trackID, adminID pgtype.UUID) (dbq.LidarrQuarantineAction, int, error) {
	f.calls = append(f.calls, trackID)
	if f.err != nil {
		return dbq.LidarrQuarantineAction{}, 0, f.err
	}
	return dbq.LidarrQuarantineAction{}, 1, nil
}

// --- tests --------------------------------------------------------------

func TestRemoveTrack_NotFound(t *testing.T) {
	pool := newPool(t)
	admin := seedAdmin(t, pool, "alice")

	var bogus pgtype.UUID
	bogus.Bytes = [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}
	bogus.Valid = true

	svc := NewService(pool, nil, nil)
	_, _, err := svc.RemoveTrack(context.Background(), bogus, admin.ID)
	if !errors.Is(err, ErrNotFound) {
		t.Errorf("err = %v, want ErrNotFound", err)
	}
}

func TestRemoveTrack_NonLidarr_HappyPath(t *testing.T) {
	pool := newPool(t)
	admin := seedAdmin(t, pool, "alice")

	dir := t.TempDir()
	path := filepath.Join(dir, "track.mp3")
	if err := os.WriteFile(path, []byte("x"), 0o644); err != nil {
		t.Fatal(err)
	}
	// mbid empty → local-delete path.
	_, _, track := seedArtistAlbumTrack(t, pool, "Solo", "", path)

	svc := NewService(pool, nil, nil)
	_, _, err := svc.RemoveTrack(context.Background(), track.ID, admin.ID)
	if err != nil {
		t.Fatalf("RemoveTrack: %v", err)
	}
	if _, err := os.Stat(path); !errors.Is(err, os.ErrNotExist) {
		t.Errorf("file still present: %v", err)
	}
	q := dbq.New(pool)
	if _, err := q.GetTrackByID(context.Background(), track.ID); err == nil {
		t.Errorf("track row still exists")
	}
}

func TestRemoveTrack_NonLidarr_FileAlreadyMissing(t *testing.T) {
	pool := newPool(t)
	admin := seedAdmin(t, pool, "alice")

	// Path doesn't exist on disk; service should tolerate and clean up DB.
	missing := filepath.Join(t.TempDir(), "does-not-exist.mp3")
	_, _, track := seedArtistAlbumTrack(t, pool, "Ghost", "", missing)

	svc := NewService(pool, nil, nil)
	_, _, err := svc.RemoveTrack(context.Background(), track.ID, admin.ID)
	if err != nil {
		t.Fatalf("RemoveTrack: %v", err)
	}
	q := dbq.New(pool)
	if _, err := q.GetTrackByID(context.Background(), track.ID); err == nil {
		t.Errorf("track row still exists")
	}
}

func TestRemoveTrack_Lidarr_HappyPath(t *testing.T) {
	pool := newPool(t)
	admin := seedAdmin(t, pool, "alice")

	// mbid set → Lidarr path. Note: real lidarrquarantine.DeleteViaLidarr
	// would have removed the tracks row already; the fake doesn't, so we
	// use a track whose row will linger but cascadeAfterLidarr only acts
	// on album/artist parents. The DB row staying behind for this test
	// case is acceptable; the unit-of-work here is "DeleteViaLidarr was
	// called, with the right trackID".
	dir := t.TempDir()
	path := filepath.Join(dir, "lidarr.mp3")
	if err := os.WriteFile(path, []byte("x"), 0o644); err != nil {
		t.Fatal(err)
	}
	_, _, track := seedArtistAlbumTrack(t, pool, "Lidarr", "track-mbid", path)

	fake := &fakeLidarrDeleter{}
	svc := NewService(pool, nil, fake)
	_, _, err := svc.RemoveTrack(context.Background(), track.ID, admin.ID)
	if err != nil {
		t.Fatalf("RemoveTrack: %v", err)
	}
	if len(fake.calls) != 1 {
		t.Fatalf("DeleteViaLidarr call count = %d, want 1", len(fake.calls))
	}
	if fake.calls[0] != track.ID {
		t.Errorf("DeleteViaLidarr called with %v, want %v", fake.calls[0], track.ID)
	}
	// File should still exist — the fake doesn't actually delete it,
	// and the local-os.Remove fallback is not exercised on the Lidarr path.
	if _, err := os.Stat(path); err != nil {
		t.Errorf("file unexpectedly missing on lidarr path: %v", err)
	}
}

func TestRemoveTrack_Lidarr_ErrorPropagation(t *testing.T) {
	cases := []struct {
		name    string
		lidarrE error
		wantE   error
	}{
		{"unreachable", lidarr.ErrUnreachable, ErrLidarrUnreachable},
		{"unauthorized", lidarr.ErrAuthFailed, ErrLidarrUnauthorized},
		{"server", lidarr.ErrServerError, ErrLidarrServerError},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			pool := newPool(t)
			admin := seedAdmin(t, pool, "alice")

			dir := t.TempDir()
			path := filepath.Join(dir, "lidarr.mp3")
			if err := os.WriteFile(path, []byte("x"), 0o644); err != nil {
				t.Fatal(err)
			}
			_, _, track := seedArtistAlbumTrack(t, pool, "LidErr", "track-mbid-"+tc.name, path)

			fake := &fakeLidarrDeleter{err: tc.lidarrE}
			svc := NewService(pool, nil, fake)
			_, _, err := svc.RemoveTrack(context.Background(), track.ID, admin.ID)
			if !errors.Is(err, tc.wantE) {
				t.Fatalf("err = %v, want %v", err, tc.wantE)
			}
			// DB row must remain — Lidarr error means no local mutation.
			q := dbq.New(pool)
			if _, gerr := q.GetTrackByID(context.Background(), track.ID); gerr != nil {
				t.Errorf("track row missing after Lidarr error: %v", gerr)
			}
		})
	}
}

func TestRemoveTrack_Cascade_AlbumEmpty(t *testing.T) {
	pool := newPool(t)
	admin := seedAdmin(t, pool, "alice")

	q := dbq.New(pool)
	// Two-album artist: removing the sole track of album A leaves A
	// orphaned, but the artist still has album B (so the artist cascade
	// must NOT fire).
	artist, err := q.UpsertArtist(context.Background(), dbq.UpsertArtistParams{
		Name: "Cascade Artist", SortName: "Cascade Artist",
	})
	if err != nil {
		t.Fatalf("artist: %v", err)
	}
	albumA, err := q.UpsertAlbum(context.Background(), dbq.UpsertAlbumParams{
		Title: "Album A", SortTitle: "Album A", ArtistID: artist.ID,
	})
	if err != nil {
		t.Fatalf("albumA: %v", err)
	}
	albumB, err := q.UpsertAlbum(context.Background(), dbq.UpsertAlbumParams{
		Title: "Album B", SortTitle: "Album B", ArtistID: artist.ID,
	})
	if err != nil {
		t.Fatalf("albumB: %v", err)
	}
	dir := t.TempDir()
	pathA := filepath.Join(dir, "a.mp3")
	pathB := filepath.Join(dir, "b.mp3")
	_ = os.WriteFile(pathA, []byte("x"), 0o644)
	_ = os.WriteFile(pathB, []byte("x"), 0o644)
	trackA, err := q.UpsertTrack(context.Background(), dbq.UpsertTrackParams{
		Title: "TA", AlbumID: albumA.ID, ArtistID: artist.ID,
		DurationMs: 1000, FilePath: pathA, FileSize: 1, FileFormat: "mp3",
	})
	if err != nil {
		t.Fatalf("trackA: %v", err)
	}
	if _, err := q.UpsertTrack(context.Background(), dbq.UpsertTrackParams{
		Title: "TB", AlbumID: albumB.ID, ArtistID: artist.ID,
		DurationMs: 1000, FilePath: pathB, FileSize: 1, FileFormat: "mp3",
	}); err != nil {
		t.Fatalf("trackB: %v", err)
	}

	svc := NewService(pool, nil, nil)
	delAlbum, delArtist, err := svc.RemoveTrack(context.Background(), trackA.ID, admin.ID)
	if err != nil {
		t.Fatalf("RemoveTrack: %v", err)
	}
	if delAlbum == nil || *delAlbum != albumA.ID {
		t.Errorf("deletedAlbumID = %v, want %v", delAlbum, albumA.ID)
	}
	if delArtist != nil {
		t.Errorf("deletedArtistID = %v, want nil (artist still has album B)", delArtist)
	}
	// Album A should be gone; album B should still exist.
	if _, err := q.GetAlbumByID(context.Background(), albumA.ID); err == nil {
		t.Errorf("album A still exists after cascade")
	}
	if _, err := q.GetAlbumByID(context.Background(), albumB.ID); err != nil {
		t.Errorf("album B unexpectedly removed: %v", err)
	}
	if _, err := q.GetArtistByID(context.Background(), artist.ID); err != nil {
		t.Errorf("artist unexpectedly removed: %v", err)
	}
}

func TestRemoveTrack_Cascade_ArtistEmpty(t *testing.T) {
	pool := newPool(t)
	admin := seedAdmin(t, pool, "alice")

	dir := t.TempDir()
	path := filepath.Join(dir, "lone.mp3")
	if err := os.WriteFile(path, []byte("x"), 0o644); err != nil {
		t.Fatal(err)
	}
	artist, album, track := seedArtistAlbumTrack(t, pool, "Lone", "", path)

	svc := NewService(pool, nil, nil)
	delAlbum, delArtist, err := svc.RemoveTrack(context.Background(), track.ID, admin.ID)
	if err != nil {
		t.Fatalf("RemoveTrack: %v", err)
	}
	if delAlbum == nil || *delAlbum != album.ID {
		t.Errorf("deletedAlbumID = %v, want %v", delAlbum, album.ID)
	}
	if delArtist == nil || *delArtist != artist.ID {
		t.Errorf("deletedArtistID = %v, want %v", delArtist, artist.ID)
	}
	q := dbq.New(pool)
	if _, err := q.GetAlbumByID(context.Background(), album.ID); err == nil {
		t.Errorf("album still exists after cascade")
	}
	if _, err := q.GetArtistByID(context.Background(), artist.ID); err == nil {
		t.Errorf("artist still exists after cascade")
	}
}