// LinkHandler factories — URL parsing + URL building for YouTube
// resource categories. Mirrors NPE
// services/youtube/linkHandler/Youtube*LinkHandlerFactory.java.
//
// PORT SCOPE (per SPEC §6.6): we keep youtube.com / youtube-nocookie.com
// / youtu.be / m.youtube.com / music.youtube.com. The 27-host Invidious
// mirror list in NPE is dropped — Sulkta isn't an Invidious mirror.

pub mod channel;
pub mod search;
pub mod stream;

use thiserror::Error;

#[derive(Debug, Error)]
pub enum LinkError {
    #[error("invalid url: {0}")]
    InvalidUrl(String),
    #[error("unsupported host: {0}")]
    UnsupportedHost(String),
    #[error("missing id in url: {0}")]
    MissingId(String),
    #[error("malformed id: {0}")]
    MalformedId(String),
}

/// The acceptable hosts for first-party YT links. Audit Track D §6.
pub const ACCEPTED_HOSTS: &[&str] = &[
    "youtube.com",
    "www.youtube.com",
    "m.youtube.com",
    "music.youtube.com",
    "youtu.be",
    "www.youtube-nocookie.com",
];

pub fn host_is_youtube(host: &str) -> bool {
    let h = host.to_ascii_lowercase();
    let h = h.strip_prefix("www.").unwrap_or(&h);
    ACCEPTED_HOSTS
        .iter()
        .any(|allowed| {
            let allowed = allowed.strip_prefix("www.").unwrap_or(allowed);
            allowed == h
        })
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn accepts_first_party_hosts() {
        assert!(host_is_youtube("www.youtube.com"));
        assert!(host_is_youtube("youtube.com"));
        assert!(host_is_youtube("m.youtube.com"));
        assert!(host_is_youtube("music.youtube.com"));
        assert!(host_is_youtube("youtu.be"));
        assert!(host_is_youtube("WWW.YouTube.COM")); // case-insensitive
    }

    #[test]
    fn rejects_invidious_and_random() {
        assert!(!host_is_youtube("invidious.io"));
        assert!(!host_is_youtube("yewtu.be"));
        assert!(!host_is_youtube("piped.video"));
        assert!(!host_is_youtube("evil.com"));
    }
}