use super::{Display, Formatter};

/// Errors raised while parsing tracker announce, scrape, or UDP payloads.
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum TrackerParseError {
    /// The tracker bencode payload was malformed.
    InvalidBencode(String),
    /// A required field was missing from the payload.
    MissingField(&'static str),
    /// A hex-encoded value was malformed.
    InvalidHex(String),
    /// A peer entry was malformed.
    InvalidPeer(String),
    /// A UDP tracker packet was malformed.
    InvalidUdpPacket(String),
    /// A UDP tracker action code was unknown.
    InvalidUdpAction(u32),
    /// The response transaction identifier differed from the request identifier.
    TransactionIdMismatch {
        /// Transaction identifier the caller expected to receive.
        expected: u32,
        /// Transaction identifier that was actually received.
        actual: u32,
    },
}

impl Display for TrackerParseError {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::InvalidBencode(reason) => write!(f, "invalid tracker bencode: {reason}"),
            Self::MissingField(field) => write!(f, "missing tracker field: {field}"),
            Self::InvalidHex(value) => write!(f, "invalid hex string: {value}"),
            Self::InvalidPeer(reason) => write!(f, "invalid peer entry: {reason}"),
            Self::InvalidUdpPacket(reason) => write!(f, "invalid udp tracker packet: {reason}"),
            Self::InvalidUdpAction(action) => write!(f, "invalid udp tracker action id: {action}"),
            Self::TransactionIdMismatch { expected, actual } => write!(
                f,
                "udp tracker transaction id mismatch: expected {expected}, got {actual}"
            ),
        }
    }
}

impl std::error::Error for TrackerParseError {}