// Copyright 2018 The go-ethereum Authors
// (original work)
// Copyright 2024 The Erigon Authors
// (modifications)
// This file is part of Erigon.
//
// Erigon is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Erigon is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Erigon. If not, see <http://www.gnu.org/licenses/>.

package pipes

import (
	"net"
)

// TCPPipe creates an in process full duplex pipe based on a localhost TCP socket
func TCPPipe() (_ net.Conn, _ net.Conn, err error) {
	l, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		return nil, nil, err
	}
	defer l.Close()

	var aconn net.Conn
	aerr := make(chan error, 1)
	go func() {
		var lErr error
		aconn, lErr = l.Accept()
		aerr <- lErr
	}()

	var dconn net.Conn
	if dconn, err = net.Dial("tcp", l.Addr().String()); err != nil {
		<-aerr
		return nil, nil, err
	}
	defer func() {
		if err != nil {
			dconn.Close()
		}
	}()
	if err = <-aerr; err != nil {
		return nil, nil, err
	}
	return aconn, dconn, nil
}
