#[derive(Debug)]
pub enum Error {
    // FIXME: can't even return url's ParseError directly.........
    UrlParseError(String),
    ReqwestError(reqwest::Error),
    SubsonicError(SubsonicError),
}

impl From<reqwest::Error> for Error {
    fn from(err: reqwest::Error) -> Self {
        Self::ReqwestError(err)
    }
}

#[derive(Debug, serde::Deserialize)]
pub struct SubsonicError {
    pub code: u32,
    pub message: String,
}

#[derive(Debug, serde::Deserialize)]
pub struct SubsonicResponse<T> {
    #[serde(rename = "subsonic-response")]
    inner: SubsonicResponseInner<T>,
}

#[derive(Debug, serde::Deserialize)]
#[serde(tag = "status")]
pub enum SubsonicResponseInner<T> {
    #[serde(rename = "ok")]
    Ok(T),
    #[serde(rename = "failed")]
    Failed { error: SubsonicError },
}

impl<T> SubsonicResponseInner<T> {
    fn fixup(self) -> Result<T, Error> {
        match self {
            Self::Ok(t) => Ok(t),
            Self::Failed { error } => Err(Error::SubsonicError(error)),
        }
    }
}

pub struct Client {
    client: reqwest::Client,
    base_url: reqwest::Url,
}

impl Client {
    pub fn new(url: &str, username: &str, token: &str, salt: &str) -> Result<Self, Error> {
        let base_url = reqwest::Url::parse_with_params(
            url,
            &[
                ("u", username),
                ("t", token),
                ("s", salt),
                ("v", "1.16.1"),
                ("c", "eu.callcc.audrey"),
                ("f", "json"),
            ],
        )
        .map_err(|err| Error::UrlParseError(err.to_string()))?;

        if base_url.scheme() != "http" && base_url.scheme() != "https" {
            return Err(Error::UrlParseError("Url scheme is not HTTP(s)".into()));
        }

        Ok(Client {
            client: reqwest::Client::builder()
                .user_agent("audrey/linux") // Audrey.Const.user_agent
                .build()?,
            base_url,
        })
    }

    pub async fn ping(&self) -> Result<(), Error> {
        let mut url = self.base_url.clone();
        url.path_segments_mut()
            // literally can't fail
            .unwrap_or_else(|_| unsafe { std::hint::unreachable_unchecked() })
            .extend(&["rest", "ping"]);

        self.client
            .get(url)
            .send()
            .await?
            .error_for_status()?
            .json::<SubsonicResponse<()>>()
            .await?
            .inner
            .fixup()
    }
}