use futures::join;
use test_programs::p3::sockets::attempt_random_port;
use test_programs::p3::wasi::sockets::types::{
    ErrorCode, IpAddress, IpAddressFamily, IpSocketAddress, TcpSocket,
};
use test_programs::p3::wit_stream;
use test_programs::sockets::supports_ipv6;

struct Component;

test_programs::p3::export!(Component);

/// Bind a socket and let the system determine a port.
fn test_tcp_bind_ephemeral_port(ip: IpAddress) {
    let bind_addr = IpSocketAddress::new(ip, 0);

    let sock = TcpSocket::create(ip.family()).unwrap();
    sock.bind(bind_addr).unwrap();

    let bound_addr = sock.get_local_address().unwrap();

    assert_eq!(bind_addr.ip(), bound_addr.ip());
    assert_ne!(bind_addr.port(), bound_addr.port());
}

/// Bind a socket on a specified port.
fn test_tcp_bind_specific_port(ip: IpAddress) {
    let sock = TcpSocket::create(ip.family()).unwrap();

    let bind_addr = attempt_random_port(ip, |bind_addr| sock.bind(bind_addr)).unwrap();

    let bound_addr = sock.get_local_address().unwrap();

    assert_eq!(bind_addr.ip(), bound_addr.ip());
    assert_eq!(bind_addr.port(), bound_addr.port());
}

/// Two sockets may not be actively bound to the same address at the same time.
fn test_tcp_bind_addrinuse(ip: IpAddress) {
    let bind_addr = IpSocketAddress::new(ip, 0);

    let sock1 = TcpSocket::create(ip.family()).unwrap();
    sock1.bind(bind_addr).unwrap();
    sock1.listen().unwrap();

    let bound_addr = sock1.get_local_address().unwrap();

    let sock2 = TcpSocket::create(ip.family()).unwrap();
    assert!(matches!(
        sock2.bind(bound_addr),
        Err(ErrorCode::AddressInUse)
    ));
}

// The WASI runtime should set SO_REUSEADDR for us
async fn test_tcp_bind_reuseaddr(ip: IpAddress) {
    let client = TcpSocket::create(ip.family()).unwrap();

    let bind_addr = {
        let listener1 = TcpSocket::create(ip.family()).unwrap();

        listener1
            .bind(IpSocketAddress::new(
                IpAddress::new_loopback(ip.family()),
                0,
            ))
            .unwrap();

        let bind_addr = listener1.get_local_address().unwrap();

        // The listener socket must have at least one connection for the TIME_WAIT
        // mechanism to kick in. So we'll create & accept a dummy connection
        // before closing the listener:
        {
            let mut accept = listener1.listen().unwrap();

            let connect_addr =
                IpSocketAddress::new(IpAddress::new_loopback(ip.family()), bind_addr.port());
            join!(
                async {
                    client.connect(connect_addr).await.unwrap();
                },
                async {
                    let sock = accept.next().await.unwrap();
                    let (mut data_tx, data_rx) = wit_stream::new();
                    join!(
                        async {
                            sock.send(data_rx).await.unwrap();
                        },
                        async {
                            let remaining = data_tx.write_all(vec![0; 10]).await;
                            assert!(remaining.is_empty());
                            drop(data_tx);
                        }
                    );
                },
            );
        }

        bind_addr
    };

    // If SO_REUSEADDR was configured correctly, the following lines
    // shouldn't be affected by the TIME_WAIT state of the just closed
    // `listener1` socket:
    let listener2 = TcpSocket::create(ip.family()).unwrap();
    listener2.bind(bind_addr).unwrap();
    listener2.listen().unwrap();
}

// Try binding to an address that is not configured on the system.
fn test_tcp_bind_addrnotavail(ip: IpAddress) {
    let bind_addr = IpSocketAddress::new(ip, 0);

    let sock = TcpSocket::create(ip.family()).unwrap();

    assert!(matches!(
        sock.bind(bind_addr),
        Err(ErrorCode::AddressNotBindable)
    ));
}

/// Bind should validate the address family.
fn test_tcp_bind_wrong_family(family: IpAddressFamily) {
    let wrong_ip = match family {
        IpAddressFamily::Ipv4 => IpAddress::IPV6_LOOPBACK,
        IpAddressFamily::Ipv6 => IpAddress::IPV4_LOOPBACK,
    };

    let sock = TcpSocket::create(family).unwrap();
    let result = sock.bind(IpSocketAddress::new(wrong_ip, 0));

    assert!(matches!(result, Err(ErrorCode::InvalidArgument)));
}

/// Bind only works on unicast addresses.
fn test_tcp_bind_non_unicast() {
    let ipv4_broadcast = IpSocketAddress::new(IpAddress::IPV4_BROADCAST, 0);
    let ipv4_multicast = IpSocketAddress::new(IpAddress::Ipv4((224, 254, 0, 0)), 0);
    let ipv6_multicast = IpSocketAddress::new(IpAddress::Ipv6((0xff00, 0, 0, 0, 0, 0, 0, 0)), 0);

    let sock_v4 = TcpSocket::create(IpAddressFamily::Ipv4).unwrap();
    let sock_v6 = TcpSocket::create(IpAddressFamily::Ipv6).unwrap();

    assert!(matches!(
        sock_v4.bind(ipv4_broadcast),
        Err(ErrorCode::InvalidArgument)
    ));
    assert!(matches!(
        sock_v4.bind(ipv4_multicast),
        Err(ErrorCode::InvalidArgument)
    ));
    assert!(matches!(
        sock_v6.bind(ipv6_multicast),
        Err(ErrorCode::InvalidArgument)
    ));
}

fn test_tcp_bind_dual_stack() {
    let sock = TcpSocket::create(IpAddressFamily::Ipv6).unwrap();
    let addr = IpSocketAddress::new(IpAddress::IPV4_MAPPED_LOOPBACK, 0);

    // Binding an IPv4-mapped-IPv6 address on a ipv6-only socket should fail:
    assert!(matches!(sock.bind(addr), Err(ErrorCode::InvalidArgument)));
}

impl test_programs::p3::exports::wasi::cli::run::Guest for Component {
    async fn run() -> Result<(), ()> {
        const RESERVED_IPV4_ADDRESS: IpAddress = IpAddress::Ipv4((192, 0, 2, 0)); // Reserved for documentation and examples.
        const RESERVED_IPV6_ADDRESS: IpAddress =
            IpAddress::Ipv6((0x2001, 0x0db8, 0, 0, 0, 0, 0, 0)); // Reserved for documentation and examples.

        test_tcp_bind_ephemeral_port(IpAddress::IPV4_LOOPBACK);
        test_tcp_bind_ephemeral_port(IpAddress::IPV4_UNSPECIFIED);
        test_tcp_bind_specific_port(IpAddress::IPV4_LOOPBACK);
        test_tcp_bind_specific_port(IpAddress::IPV4_UNSPECIFIED);
        test_tcp_bind_reuseaddr(IpAddress::IPV4_LOOPBACK).await;
        test_tcp_bind_addrinuse(IpAddress::IPV4_LOOPBACK);
        test_tcp_bind_addrinuse(IpAddress::IPV4_UNSPECIFIED);
        test_tcp_bind_addrnotavail(RESERVED_IPV4_ADDRESS);
        test_tcp_bind_wrong_family(IpAddressFamily::Ipv4);

        if supports_ipv6() {
            test_tcp_bind_ephemeral_port(IpAddress::IPV6_LOOPBACK);
            test_tcp_bind_ephemeral_port(IpAddress::IPV6_UNSPECIFIED);
            test_tcp_bind_specific_port(IpAddress::IPV6_LOOPBACK);
            test_tcp_bind_specific_port(IpAddress::IPV6_UNSPECIFIED);
            test_tcp_bind_reuseaddr(IpAddress::IPV6_LOOPBACK).await;
            test_tcp_bind_addrinuse(IpAddress::IPV6_LOOPBACK);
            test_tcp_bind_addrinuse(IpAddress::IPV6_UNSPECIFIED);
            test_tcp_bind_addrnotavail(RESERVED_IPV6_ADDRESS);
            test_tcp_bind_wrong_family(IpAddressFamily::Ipv6);
            test_tcp_bind_non_unicast();
            test_tcp_bind_dual_stack();
        }

        Ok(())
    }
}

fn main() {}