TIKTOK_BASE = "https://www.tiktok.com"


def sound_url(sound_id: str) -> str:
    """Build a TikTok sound page URL from a sound ID."""
    return f"{TIKTOK_BASE}/music/-{sound_id}"


def video_url(username: str, video_id: str) -> str:
    """Build a TikTok video page URL from username and video ID."""
    return f"{TIKTOK_BASE}/@{username}/video/{video_id}"


def tag_url(tag: str) -> str:
    """Build a TikTok hashtag challenge page URL."""
    return f"{TIKTOK_BASE}/tag/{tag.lstrip('#')}"