wasmlet 0.0.2

use core::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6};

use std::net::ToSocketAddrs;

use rustix::fd::AsFd;
use rustix::io::Errno;
use rustix::net::sockopt;
use tracing::debug;

use crate::engine::bindings::wasi::sockets::network::{self, ErrorCode};
use crate::engine::wasi::sockets::SocketAddressFamily;

fn is_deprecated_ipv4_compatible(addr: Ipv6Addr) -> bool {
    matches!(addr.segments(), [0, 0, 0, 0, 0, 0, _, _])
        && addr != Ipv6Addr::UNSPECIFIED
        && addr != Ipv6Addr::LOCALHOST
}

pub fn is_valid_address_family(addr: IpAddr, socket_family: SocketAddressFamily) -> bool {
    match (socket_family, addr) {
        (SocketAddressFamily::Ipv4, IpAddr::V4(..)) => true,
        (SocketAddressFamily::Ipv6, IpAddr::V6(ipv6)) => {
            !is_deprecated_ipv4_compatible(ipv6) && ipv6.to_ipv4_mapped().is_none()
        }
        _ => false,
    }
}

pub fn is_valid_remote_address(addr: SocketAddr) -> bool {
    !addr.ip().to_canonical().is_unspecified() && addr.port() != 0
}

pub fn is_valid_unicast_address(addr: IpAddr) -> bool {
    match addr.to_canonical() {
        IpAddr::V4(ipv4) => !ipv4.is_multicast() && !ipv4.is_broadcast(),
        IpAddr::V6(ipv6) => !ipv6.is_multicast(),
    }
}

pub fn to_ipv4_addr(addr: network::Ipv4Address) -> Ipv4Addr {
    let (x0, x1, x2, x3) = addr;
    Ipv4Addr::new(x0, x1, x2, x3)
}

pub fn from_ipv4_addr(addr: Ipv4Addr) -> network::Ipv4Address {
    let [x0, x1, x2, x3] = addr.octets();
    (x0, x1, x2, x3)
}

pub fn to_ipv6_addr(addr: network::Ipv6Address) -> Ipv6Addr {
    let (x0, x1, x2, x3, x4, x5, x6, x7) = addr;
    Ipv6Addr::new(x0, x1, x2, x3, x4, x5, x6, x7)
}

pub fn from_ipv6_addr(addr: Ipv6Addr) -> network::Ipv6Address {
    let [x0, x1, x2, x3, x4, x5, x6, x7] = addr.segments();
    (x0, x1, x2, x3, x4, x5, x6, x7)
}

pub fn normalize_get_buffer_size(value: usize) -> usize {
    if cfg!(target_os = "linux") {
        // Linux doubles the value passed to setsockopt to allow space for bookkeeping overhead.
        // getsockopt returns this internally doubled value.
        // We'll half the value to at least get it back into the same ballpark that the application requested it in.
        //
        // This normalized behavior is tested for in: test-programs/src/bin/preview2_tcp_sockopts.rs
        value / 2
    } else {
        value
    }
}

pub fn normalize_set_buffer_size(value: usize) -> usize {
    value.clamp(1, i32::MAX as usize)
}

impl From<IpAddr> for network::IpAddress {
    fn from(addr: IpAddr) -> Self {
        match addr {
            IpAddr::V4(v4) => Self::Ipv4(from_ipv4_addr(v4)),
            IpAddr::V6(v6) => Self::Ipv6(from_ipv6_addr(v6)),
        }
    }
}

impl From<network::IpAddress> for IpAddr {
    fn from(addr: network::IpAddress) -> Self {
        match addr {
            network::IpAddress::Ipv4(v4) => Self::V4(to_ipv4_addr(v4)),
            network::IpAddress::Ipv6(v6) => Self::V6(to_ipv6_addr(v6)),
        }
    }
}

impl From<network::IpSocketAddress> for SocketAddr {
    fn from(addr: network::IpSocketAddress) -> Self {
        match addr {
            network::IpSocketAddress::Ipv4(ipv4) => Self::V4(ipv4.into()),
            network::IpSocketAddress::Ipv6(ipv6) => Self::V6(ipv6.into()),
        }
    }
}

impl From<SocketAddr> for network::IpSocketAddress {
    fn from(addr: SocketAddr) -> Self {
        match addr {
            SocketAddr::V4(v4) => Self::Ipv4(v4.into()),
            SocketAddr::V6(v6) => Self::Ipv6(v6.into()),
        }
    }
}

impl From<network::Ipv4SocketAddress> for SocketAddrV4 {
    fn from(addr: network::Ipv4SocketAddress) -> Self {
        Self::new(to_ipv4_addr(addr.address), addr.port)
    }
}

impl From<SocketAddrV4> for network::Ipv4SocketAddress {
    fn from(addr: SocketAddrV4) -> Self {
        Self {
            address: from_ipv4_addr(*addr.ip()),
            port: addr.port(),
        }
    }
}

impl From<network::Ipv6SocketAddress> for SocketAddrV6 {
    fn from(addr: network::Ipv6SocketAddress) -> Self {
        Self::new(
            to_ipv6_addr(addr.address),
            addr.port,
            addr.flow_info,
            addr.scope_id,
        )
    }
}

impl From<SocketAddrV6> for network::Ipv6SocketAddress {
    fn from(addr: SocketAddrV6) -> Self {
        Self {
            address: from_ipv6_addr(*addr.ip()),
            port: addr.port(),
            flow_info: addr.flowinfo(),
            scope_id: addr.scope_id(),
        }
    }
}

impl ToSocketAddrs for network::IpSocketAddress {
    type Iter = <SocketAddr as ToSocketAddrs>::Iter;

    fn to_socket_addrs(&self) -> std::io::Result<Self::Iter> {
        SocketAddr::from(*self).to_socket_addrs()
    }
}

impl ToSocketAddrs for network::Ipv4SocketAddress {
    type Iter = <SocketAddrV4 as ToSocketAddrs>::Iter;

    fn to_socket_addrs(&self) -> std::io::Result<Self::Iter> {
        SocketAddrV4::from(*self).to_socket_addrs()
    }
}

impl ToSocketAddrs for network::Ipv6SocketAddress {
    type Iter = <SocketAddrV6 as ToSocketAddrs>::Iter;

    fn to_socket_addrs(&self) -> std::io::Result<Self::Iter> {
        SocketAddrV6::from(*self).to_socket_addrs()
    }
}

impl From<network::IpAddressFamily> for cap_net_ext::AddressFamily {
    fn from(family: network::IpAddressFamily) -> Self {
        match family {
            network::IpAddressFamily::Ipv4 => Self::Ipv4,
            network::IpAddressFamily::Ipv6 => Self::Ipv6,
        }
    }
}

impl From<cap_net_ext::AddressFamily> for network::IpAddressFamily {
    fn from(family: cap_net_ext::AddressFamily) -> Self {
        match family {
            cap_net_ext::AddressFamily::Ipv4 => Self::Ipv4,
            cap_net_ext::AddressFamily::Ipv6 => Self::Ipv6,
        }
    }
}

impl From<std::io::Error> for network::ErrorCode {
    fn from(value: std::io::Error) -> Self {
        (&value).into()
    }
}

impl From<&std::io::Error> for network::ErrorCode {
    fn from(value: &std::io::Error) -> Self {
        // Attempt the more detailed native error code first:
        if let Some(errno) = Errno::from_io_error(value) {
            return errno.into();
        }

        match value.kind() {
            std::io::ErrorKind::AddrInUse => Self::AddressInUse,
            std::io::ErrorKind::AddrNotAvailable => Self::AddressNotBindable,
            std::io::ErrorKind::ConnectionAborted => Self::ConnectionAborted,
            std::io::ErrorKind::ConnectionRefused => Self::ConnectionRefused,
            std::io::ErrorKind::ConnectionReset => Self::ConnectionReset,
            std::io::ErrorKind::InvalidInput => Self::InvalidArgument,
            std::io::ErrorKind::NotConnected => Self::InvalidState,
            std::io::ErrorKind::OutOfMemory => Self::OutOfMemory,
            std::io::ErrorKind::PermissionDenied => Self::AccessDenied,
            std::io::ErrorKind::TimedOut => Self::Timeout,
            std::io::ErrorKind::Unsupported => Self::NotSupported,
            _ => {
                debug!("unknown I/O error: {value}");
                Self::Unknown
            }
        }
    }
}

impl From<Errno> for network::ErrorCode {
    fn from(value: Errno) -> Self {
        (&value).into()
    }
}

impl From<&Errno> for network::ErrorCode {
    fn from(value: &Errno) -> Self {
        match *value {
            #[cfg(not(windows))]
            Errno::PERM => Self::AccessDenied,
            Errno::ACCESS => Self::AccessDenied,
            Errno::ADDRINUSE => Self::AddressInUse,
            Errno::ADDRNOTAVAIL => Self::AddressNotBindable,
            Errno::TIMEDOUT => Self::Timeout,
            Errno::CONNREFUSED => Self::ConnectionRefused,
            Errno::CONNRESET => Self::ConnectionReset,
            Errno::CONNABORTED => Self::ConnectionAborted,
            Errno::INVAL => Self::InvalidArgument,
            Errno::HOSTUNREACH => Self::RemoteUnreachable,
            Errno::HOSTDOWN => Self::RemoteUnreachable,
            Errno::NETDOWN => Self::RemoteUnreachable,
            Errno::NETUNREACH => Self::RemoteUnreachable,
            #[cfg(target_os = "linux")]
            Errno::NONET => Self::RemoteUnreachable,
            Errno::ISCONN => Self::InvalidState,
            Errno::NOTCONN => Self::InvalidState,
            Errno::DESTADDRREQ => Self::InvalidState,
            Errno::MSGSIZE => Self::DatagramTooLarge,
            #[cfg(not(windows))]
            Errno::NOMEM => Self::OutOfMemory,
            Errno::NOBUFS => Self::OutOfMemory,
            Errno::OPNOTSUPP => Self::NotSupported,
            Errno::NOPROTOOPT => Self::NotSupported,
            Errno::PFNOSUPPORT => Self::NotSupported,
            Errno::PROTONOSUPPORT => Self::NotSupported,
            Errno::PROTOTYPE => Self::NotSupported,
            Errno::SOCKTNOSUPPORT => Self::NotSupported,
            Errno::AFNOSUPPORT => Self::NotSupported,

            // FYI, EINPROGRESS should have already been handled by connect.
            _ => {
                debug!("unknown I/O error: {value}");
                Self::Unknown
            }
        }
    }
}

pub fn get_ip_ttl(fd: impl AsFd) -> Result<u8, ErrorCode> {
    let v = sockopt::ip_ttl(fd)?;
    let Ok(v) = v.try_into() else {
        return Err(ErrorCode::NotSupported);
    };
    Ok(v)
}

pub fn get_ipv6_unicast_hops(fd: impl AsFd) -> Result<u8, ErrorCode> {
    let v = sockopt::ipv6_unicast_hops(fd)?;
    Ok(v)
}

pub fn get_unicast_hop_limit(fd: impl AsFd, family: SocketAddressFamily) -> Result<u8, ErrorCode> {
    match family {
        SocketAddressFamily::Ipv4 => get_ip_ttl(fd),
        SocketAddressFamily::Ipv6 => get_ipv6_unicast_hops(fd),
    }
}

pub fn set_unicast_hop_limit(
    fd: impl AsFd,
    family: SocketAddressFamily,
    value: u8,
) -> Result<(), ErrorCode> {
    if value == 0 {
        // WIT: "If the provided value is 0, an `invalid-argument` error is returned."
        //
        // A well-behaved IP application should never send out new packets with TTL 0.
        // We validate the value ourselves because OS'es are not consistent in this.
        // On Linux the validation is even inconsistent between their IPv4 and IPv6 implementation.
        return Err(ErrorCode::InvalidArgument);
    }
    match family {
        SocketAddressFamily::Ipv4 => {
            sockopt::set_ip_ttl(fd, value.into())?;
        }
        SocketAddressFamily::Ipv6 => {
            sockopt::set_ipv6_unicast_hops(fd, Some(value))?;
        }
    }
    Ok(())
}

pub fn receive_buffer_size(fd: impl AsFd) -> Result<u64, ErrorCode> {
    let v = sockopt::socket_recv_buffer_size(fd)?;
    Ok(normalize_get_buffer_size(v).try_into().unwrap_or(u64::MAX))
}

pub fn set_receive_buffer_size(fd: impl AsFd, value: u64) -> Result<usize, ErrorCode> {
    if value == 0 {
        // WIT: "If the provided value is 0, an `invalid-argument` error is returned."
        return Err(ErrorCode::InvalidArgument);
    }
    let value = value.try_into().unwrap_or(usize::MAX);
    let value = normalize_set_buffer_size(value);
    match sockopt::set_socket_recv_buffer_size(fd, value) {
        Err(Errno::NOBUFS) => {}
        Err(err) => return Err(err.into()),
        _ => {}
    };
    Ok(value)
}

pub fn send_buffer_size(fd: impl AsFd) -> Result<u64, ErrorCode> {
    let v = sockopt::socket_send_buffer_size(fd)?;
    Ok(normalize_get_buffer_size(v).try_into().unwrap_or(u64::MAX))
}

pub fn set_send_buffer_size(fd: impl AsFd, value: u64) -> Result<usize, ErrorCode> {
    if value == 0 {
        // WIT: "If the provided value is 0, an `invalid-argument` error is returned."
        return Err(ErrorCode::InvalidArgument);
    }
    let value = value.try_into().unwrap_or(usize::MAX);
    let value = normalize_set_buffer_size(value);
    match sockopt::set_socket_send_buffer_size(fd, value) {
        Err(Errno::NOBUFS) => {}
        Err(err) => return Err(err.into()),
        _ => {}
    };
    Ok(value)
}