package playlists

import (
	"testing"

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

func TestTieBreakHash_Deterministic(t *testing.T) {
	id := pgtype.UUID{Bytes: [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}, Valid: true}
	a := tieBreakHash(id, "2026-05-04")
	b := tieBreakHash(id, "2026-05-04")
	if a != b {
		t.Fatalf("same inputs gave different hashes: %d vs %d", a, b)
	}
}

func TestTieBreakHash_DifferentDateChangesHash(t *testing.T) {
	id := pgtype.UUID{Bytes: [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}, Valid: true}
	may4 := tieBreakHash(id, "2026-05-04")
	may5 := tieBreakHash(id, "2026-05-05")
	if may4 == may5 {
		t.Errorf("different dates should change hash; got %d for both", may4)
	}
}

func TestTieBreakHash_DifferentTrackChangesHash(t *testing.T) {
	a := pgtype.UUID{Bytes: [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}, Valid: true}
	b := pgtype.UUID{Bytes: [16]byte{16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1}, Valid: true}
	if tieBreakHash(a, "2026-05-04") == tieBreakHash(b, "2026-05-04") {
		t.Errorf("different track ids should change hash for the same date")
	}
}