use ntex::http::Method;
use ntex::http::header::LOCATION;
use ntex::web::{self, HttpRequest};

use crate::util::hanime_resolve::{fetch_sources, pick_source, source_url};
use crate::util::requester::Requester;

/// `{slug}[/{height}][.m3u8]`.
fn parse_endpoint(endpoint: &str) -> Option<(String, Option<u32>)> {
    let endpoint = endpoint.trim_matches('/').trim_end_matches(".m3u8");
    let mut parts = endpoint.split('/');
    let slug = parts
        .next()
        .filter(|slug| {
            !slug.is_empty()
                && slug
                    .chars()
                    .all(|c| c.is_ascii_alphanumeric() || c == '-' || c == '_')
        })?;
    let height = parts.next().and_then(|h| h.parse::<u32>().ok());
    Some((slug.to_string(), height))
}

/// hanime's stream links expire, so the channel hands out this stable URL and a
/// fresh handshake happens on every play: redirects to the current playlist.
pub async fn redirect_to_media(
    req: HttpRequest,
    requester: web::types::State<Requester>,
) -> Result<impl web::Responder, web::Error> {
    let endpoint = req.match_info().query("endpoint").to_string();
    let Some((slug, height)) = parse_endpoint(&endpoint) else {
        return Ok(web::HttpResponse::BadRequest().finish());
    };
    if req.method() == Method::HEAD {
        return Ok(web::HttpResponse::Ok().finish());
    }

    let mut requester = requester.get_ref().clone();
    let Ok(sources) = fetch_sources(&mut requester, &slug).await else {
        return Ok(web::HttpResponse::BadGateway().finish());
    };
    let Some(source) = pick_source(&sources, height) else {
        return Ok(web::HttpResponse::NotFound().finish());
    };
    Ok(web::HttpResponse::Found()
        .header(LOCATION, source_url(source))
        .finish())
}

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

    #[test]
    fn parses_slug_and_height() {
        assert_eq!(
            parse_endpoint("natsu-zuma-2/720.m3u8"),
            Some(("natsu-zuma-2".to_string(), Some(720)))
        );
        assert_eq!(
            parse_endpoint("/natsu-zuma-2"),
            Some(("natsu-zuma-2".to_string(), None))
        );
    }

    #[test]
    fn rejects_unsafe_slugs() {
        assert_eq!(parse_endpoint("../etc/720.m3u8"), None);
        assert_eq!(parse_endpoint(""), None);
    }
}