//! `IObjectExporter::ResolveOxid` transport wrappers.
//!
//! Direct port of the codec-driving methods from
//! `src/MxNativeClient/ObjectExporterClient.cs`. Two methods land here:
//!
//! - [`resolve_oxid_unauthenticated`] — mirrors `cs:14-30`
//!   (`ResolveOxidUnauthenticated`).
//! - [`resolve_oxid_with_managed_ntlm_packet_integrity`] — mirrors
//!   `cs:66-81` (`ResolveOxidWithManagedNtlmPacketIntegrity`).
//!
//! The two SSPI flavours (`ResolveOxidWithNtlmConnect` at `cs:32-47` and
//! `ResolveOxidWithNtlmPacketIntegrity` at `cs:49-64`) wrap
//! `System.Net.Security.SspiClientContext` — explicitly out of scope for
//! the Rust port. Resolves `design/followups.md` F9 down to the items
//! that are .NET-specific.

#![allow(clippy::indexing_slicing)]

use std::net::SocketAddr;

use crate::ntlm::NtlmClientContext;
use crate::object_exporter::{
    IOBJECT_EXPORTER_IID, RESOLVE_OXID_OPNUM, ResolveOxidFailure, ResolveOxidResult,
    encode_resolve_oxid_request, parse_resolve_oxid_failure, parse_resolve_oxid_result,
};
use crate::transport::{DceRpcTcpClient, TransportError};

/// Outcome of a `ResolveOxid` call. Either the server returned a typed
/// `DUALSTRINGARRAY` (success or empty) or a 4-byte `RPC_C_NS_*` failure
/// status word.
#[derive(Debug, Clone)]
pub enum ResolveOxidOutcome {
    /// Decoded `DUALSTRINGARRAY` (per `ResolveOxidResult`).
    Result(ResolveOxidResult),
    /// 4-byte trailing status (per `ResolveOxidFailure`). Returned when
    /// the response stub is too short for a full result but matches the
    /// failure tail shape.
    Failure(ResolveOxidFailure),
}

/// Drive a single `ResolveOxid` round-trip without authentication.
/// Mirrors `ObjectExporterClient.ResolveOxidUnauthenticated`
/// (`ObjectExporterClient.cs:14-30`).
///
/// Steps (mirroring `cs:16-29`):
///
/// 1. Open a TCP connection to `(host, port)`.
/// 2. Bind to `IObjectExporter` (version 0.0).
/// 3. Build a `ResolveOxid` request with the supplied `oxid` + `protseqs`
///    (defaults to `[ProtseqNcacnIpTcp]` when empty — per `cs:26`).
/// 4. Call opnum 0 on the bound context.
/// 5. Try [`parse_resolve_oxid_result`] first; if it fails with a typed
///    decode error, fall back to [`parse_resolve_oxid_failure`] over the
///    last 4 bytes per the .NET reference's two-shape return type.
///
/// # Errors
/// I/O, codec, or fault from the server.
pub async fn resolve_oxid_unauthenticated(
    addr: SocketAddr,
    oxid: u64,
    requested_protseqs: &[u16],
) -> Result<ResolveOxidOutcome, TransportError> {
    let mut client = DceRpcTcpClient::connect(addr).await?;
    let _bind = client.bind(IOBJECT_EXPORTER_IID, 0, 0).await?;
    let request = encode_resolve_oxid_request(oxid, default_protseqs(requested_protseqs))?;
    let response = client.call_bound(RESOLVE_OXID_OPNUM, &request).await?;
    decode_resolve_oxid_response(&response.stub_data)
}

/// Drive a single `ResolveOxid` round-trip with NTLMv2 packet-integrity
/// authentication. Mirrors `ObjectExporterClient.ResolveOxidWithManagedNtlmPacketIntegrity`
/// (`cs:66-81`).
///
/// Steps mirror the unauthenticated variant but the bind is replaced
/// with [`DceRpcTcpClient::bind_with_managed_ntlm_packet_integrity`],
/// causing every subsequent call to be NTLM-signed.
///
/// `ntlm` must be a fresh [`NtlmClientContext`] — it is consumed by the
/// transport for the lifetime of the connection.
///
/// # Errors
/// I/O, codec, NTLM, or fault from the server.
pub async fn resolve_oxid_with_managed_ntlm_packet_integrity(
    addr: SocketAddr,
    oxid: u64,
    requested_protseqs: &[u16],
    ntlm: NtlmClientContext,
) -> Result<ResolveOxidOutcome, TransportError> {
    let mut client = DceRpcTcpClient::connect(addr).await?;
    let _bind = client
        .bind_with_managed_ntlm_packet_integrity(IOBJECT_EXPORTER_IID, 0, 0, ntlm)
        .await?;
    let request = encode_resolve_oxid_request(oxid, default_protseqs(requested_protseqs))?;
    let response = client.call_bound(RESOLVE_OXID_OPNUM, &request).await?;
    decode_resolve_oxid_response(&response.stub_data)
}

/// Default to `[ProtseqNcacnIpTcp]` when the caller passes an empty
/// slice — matches `cs:26` (`requestedProtseqs ?? [..]`).
fn default_protseqs(requested: &[u16]) -> &[u16] {
    if requested.is_empty() {
        &[crate::object_exporter::PROTSEQ_NCACN_IP_TCP]
    } else {
        requested
    }
}

/// Decode a `ResolveOxid` response stub. The .NET reference exposes two
/// parsers (`ParseResolveOxidResult` and `ParseResolveOxidFailure`)
/// without a discriminator on the wire — the choice is made by the
/// caller based on whether the stub looks like a typed result or just a
/// 4-byte status. The Rust port mirrors that: try the result parser
/// first; on `RpcError::ShortRead` or `RpcError::Decode` fall back to
/// the failure parser.
fn decode_resolve_oxid_response(stub: &[u8]) -> Result<ResolveOxidOutcome, TransportError> {
    match parse_resolve_oxid_result(stub) {
        Ok(result) => Ok(ResolveOxidOutcome::Result(result)),
        Err(_) => Ok(ResolveOxidOutcome::Failure(parse_resolve_oxid_failure(
            stub,
        )?)),
    }
}

#[cfg(test)]
#[allow(
    clippy::unwrap_used,
    clippy::expect_used,
    clippy::indexing_slicing,
    clippy::panic
)]
mod tests {
    use super::*;
    use crate::object_exporter::{
        IOBJECT_EXPORTER_IID, PROTSEQ_NCACN_IP_TCP, encode_resolve_oxid_request,
    };
    use crate::pdu::{PacketType, PduHeader, ResponsePdu};
    use tokio::io::{AsyncReadExt, AsyncWriteExt};
    use tokio::net::TcpListener;

    fn local_addr() -> SocketAddr {
        "127.0.0.1:0".parse().unwrap()
    }

    /// Spin a hand-rolled DCE/RPC server that accepts one connection,
    /// drains a Bind, replies with a minimal BindAck, drains a Request,
    /// and replies with a Response carrying `stub_data`.
    async fn one_shot_server(stub_data: Vec<u8>) -> (SocketAddr, tokio::task::JoinHandle<()>) {
        let listener = TcpListener::bind(local_addr()).await.unwrap();
        let addr = listener.local_addr().unwrap();
        let handle = tokio::spawn(async move {
            let (mut sock, _) = listener.accept().await.unwrap();

            // 1. Drain Bind.
            let mut hdr = [0u8; 16];
            sock.read_exact(&mut hdr).await.unwrap();
            let bind_h = PduHeader::decode(&hdr).unwrap();
            let mut body = vec![0u8; bind_h.fragment_length as usize - 16];
            sock.read_exact(&mut body).await.unwrap();
            // Reply with a 16-byte BindAck shell — DceRpcTcpClient::bind
            // only inspects the header.
            let resp_h = PduHeader {
                version: 5,
                version_minor: 0,
                packet_type: PacketType::BindAck,
                packet_flags: 0x03,
                data_representation: 0x10,
                fragment_length: 16,
                auth_length: 0,
                call_id: bind_h.call_id,
            };
            let mut out = [0u8; 16];
            resp_h.encode(&mut out).unwrap();
            sock.write_all(&out).await.unwrap();

            // 2. Drain Request.
            sock.read_exact(&mut hdr).await.unwrap();
            let req_h = PduHeader::decode(&hdr).unwrap();
            let mut body = vec![0u8; req_h.fragment_length as usize - 16];
            sock.read_exact(&mut body).await.unwrap();

            // 3. Reply with Response carrying the supplied stub_data.
            let response = ResponsePdu {
                header: PduHeader {
                    version: 5,
                    version_minor: 0,
                    packet_type: PacketType::Response,
                    packet_flags: 0x03,
                    data_representation: 0x10,
                    fragment_length: 0, // overwritten by encode
                    auth_length: 0,
                    call_id: req_h.call_id,
                },
                allocation_hint: stub_data.len() as u32,
                context_id: 0,
                cancel_count: 0,
                reserved23: 0,
                stub_data,
            };
            let bytes = response.encode();
            sock.write_all(&bytes).await.unwrap();
        });
        (addr, handle)
    }

    #[tokio::test]
    async fn resolve_oxid_unauthenticated_round_trip() {
        // Build a synthetic ResolveOxid result stub: referent=1, max_count=1,
        // entries=1, security_offset=2, dual-string [0x0007, 0, 0] (8 bytes
        // padded to 12 with align_up), then 16-byte IPID + authn_hint(4) +
        // status(4) trailing.
        let mut stub = Vec::new();
        // referent_id != 0
        stub.extend_from_slice(&1u32.to_le_bytes());
        // max_count = 1
        stub.extend_from_slice(&1u32.to_le_bytes());
        // entries = 1, security_offset = 2
        stub.extend_from_slice(&1u16.to_le_bytes());
        stub.extend_from_slice(&2u16.to_le_bytes());
        // Dual-string array: 1 u16 (tower=0x0007), then need to align to 4.
        stub.extend_from_slice(&0x0007u16.to_le_bytes());
        // Per parse_resolve_oxid_result: array_offset = 12; array_bytes =
        // max_count * 2 = 2; offset after = align(14, 4) = 16.
        // We've written 14 bytes so far; pad to 16.
        stub.push(0);
        stub.push(0);
        // Trailing 24 bytes: IPID(16) + authn_hint(4) + status(4)
        stub.extend_from_slice(&[0xCC; 16]);
        stub.extend_from_slice(&0x1234u32.to_le_bytes());
        stub.extend_from_slice(&0u32.to_le_bytes());

        let (addr, handle) = one_shot_server(stub).await;
        let outcome =
            resolve_oxid_unauthenticated(addr, 0xDEAD_BEEF_CAFE_BABE, &[PROTSEQ_NCACN_IP_TCP])
                .await
                .unwrap();

        match outcome {
            ResolveOxidOutcome::Result(r) => {
                assert_eq!(r.error_status, 0);
                assert_eq!(r.authn_hint, 0x1234);
                assert_eq!(r.rem_unknown_ipid.as_bytes(), &[0xCC; 16]);
            }
            ResolveOxidOutcome::Failure(_) => panic!("expected Result variant"),
        }
        handle.await.unwrap();
    }

    #[tokio::test]
    async fn resolve_oxid_falls_back_to_failure_for_short_stub() {
        // 4-byte stub with just an error_status — too short for a full
        // result, must decode as Failure.
        let stub = 0x8004_0007u32.to_le_bytes().to_vec();
        let (addr, handle) = one_shot_server(stub).await;
        let outcome = resolve_oxid_unauthenticated(addr, 0, &[]).await.unwrap();
        match outcome {
            ResolveOxidOutcome::Failure(f) => assert_eq!(f.error_status, 0x8004_0007),
            ResolveOxidOutcome::Result(_) => panic!("expected Failure variant"),
        }
        handle.await.unwrap();
    }

    #[test]
    fn default_protseqs_falls_back_when_empty() {
        let r = default_protseqs(&[]);
        assert_eq!(r, &[PROTSEQ_NCACN_IP_TCP]);
    }

    #[test]
    fn default_protseqs_passes_through_when_provided() {
        let custom: &[u16] = &[0x0007, 0x001f];
        let r = default_protseqs(custom);
        assert_eq!(r, custom);
    }

    /// Compile-only check that the IID + opnum constants match the .NET
    /// reference values used by the wrapper (sanity guard against
    /// accidental constant drift).
    #[test]
    fn iid_and_opnum_constants_present() {
        // IID first byte is 0xC4 (LE of 0x99FCFEC4 Data1).
        assert_eq!(IOBJECT_EXPORTER_IID.as_bytes()[0], 0xC4);
        assert_eq!(RESOLVE_OXID_OPNUM, 0);
    }

    /// Verify the encode helper is callable from this module path
    /// (catches `pub use` regressions during refactors).
    #[test]
    fn encode_resolve_oxid_request_callable() {
        let buf = encode_resolve_oxid_request(0, &[PROTSEQ_NCACN_IP_TCP]).unwrap();
        assert!(!buf.is_empty());
    }
}