// YoutubeSearchQueryHandlerFactory + search filters. Filter params are
// opaque base64 protobufs — NPE doesn't decode them, just sends the
// magic strings. We mirror that. See audit Track D §3.
//
// Music* filter variants were ported from NPE but never wired through
// (search_extractor rejected anything with `uses_music_endpoint()`).
// Dropped 2026-05-26 along with WEB_REMIX_* constants + the music
// charts client factory.

use url::form_urlencoded;

#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
pub enum SearchFilter {
    /// All result types — no params field sent.
    All,
    /// Videos only.
    Videos,
    /// Channels only.
    Channels,
    /// Playlists only.
    Playlists,
}

impl SearchFilter {
    /// Returns the InnerTube `params` base64 string. None means omit
    /// the field entirely (== All).
    pub fn params(&self) -> Option<&'static str> {
        match self {
            SearchFilter::All => None,
            SearchFilter::Videos => Some("EgIQAfABAQ%3D%3D"),
            SearchFilter::Channels => Some("EgIQAvABAQ%3D%3D"),
            SearchFilter::Playlists => Some("EgIQA_ABAQ%3D%3D"),
        }
    }
}

pub fn search_url(query: &str) -> String {
    let encoded: String = form_urlencoded::Serializer::new(String::new())
        .append_pair("search_query", query)
        .finish();
    format!("https://www.youtube.com/results?{encoded}")
}

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

    #[test]
    fn all_filter_omits_params() {
        assert!(SearchFilter::All.params().is_none());
    }

    #[test]
    fn typed_filters_have_params() {
        assert!(SearchFilter::Videos.params().is_some());
        assert!(SearchFilter::Channels.params().is_some());
        assert!(SearchFilter::Playlists.params().is_some());
    }

    #[test]
    fn search_url_encodes_query() {
        assert_eq!(
            search_url("rust + ferris"),
            "https://www.youtube.com/results?search_query=rust+%2B+ferris"
        );
    }
}