#[must_use]
#[non_exhaustive]
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[repr(i64)]
pub enum KernelError {
    SlotOccupied = -1,
    SlotEmpty = -2,
    InvalidObject = -3,
    InsufficientRights = -4,
    StaleGeneration = -5,
    PoolExhausted = -6,
    InvalidType = -7,
    InvalidSlot = -8,
    InvalidAddress = -9,
    WouldBlock = -10,
    ResourceExhausted = -11,
    #[allow(dead_code)]
    NotFound = -12,
    PermissionDenied = -13,
    BadState = -14,
    InvalidParameter = -15,
    NotInitialized = -16,
    IommuFault = -17,
    AlreadyExists = -18,
}

impl KernelError {
    pub const fn to_errno(self) -> i64 {
        self as i64
    }
}

impl core::fmt::Display for KernelError {
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        match self {
            Self::SlotOccupied => write!(f, "slot occupied"),
            Self::SlotEmpty => write!(f, "slot empty"),
            Self::InvalidObject => write!(f, "invalid object"),
            Self::InsufficientRights => write!(f, "insufficient rights"),
            Self::StaleGeneration => write!(f, "stale generation"),
            Self::PoolExhausted => write!(f, "pool exhausted"),
            Self::InvalidType => write!(f, "invalid type"),
            Self::InvalidSlot => write!(f, "invalid slot"),
            Self::InvalidAddress => write!(f, "invalid address"),
            Self::WouldBlock => write!(f, "would block"),
            Self::ResourceExhausted => write!(f, "resource exhausted"),
            Self::NotFound => write!(f, "not found"),
            Self::PermissionDenied => write!(f, "permission denied"),
            Self::BadState => write!(f, "bad state"),
            Self::InvalidParameter => write!(f, "invalid parameter"),
            Self::NotInitialized => write!(f, "not initialized"),
            Self::IommuFault => write!(f, "iommu fault"),
            Self::AlreadyExists => write!(f, "already exists"),
        }
    }
}

impl From<KernelError> for i64 {
    fn from(e: KernelError) -> Self {
        e.to_errno()
    }
}