// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
// SPDX-License-Identifier: MIT

package vnet

import (
	"fmt"
	"net"
)

// Deliver directly send packet to vnet or real-server.
// For example, we can use this API to simulate the REPLAY ATTACK.
func (v *UDPProxy) Deliver(sourceAddr, destAddr net.Addr, b []byte) (nn int, err error) {
	v.workers.Range(func(_, value any) bool {
		worker, ok := value.(*aUDPProxyWorker)
		if !ok {
			return false
		}

		if nn, err = worker.Deliver(sourceAddr, destAddr, b); err != nil {
			return false // Fail, abort.
		} else if nn == len(b) {
			return false // Done.
		}

		return true // Deliver by next worker.
	})

	return
}

func (v *aUDPProxyWorker) Deliver(sourceAddr, _ net.Addr, b []byte) (nn int, err error) {
	addr, ok := sourceAddr.(*net.UDPAddr)
	if !ok {
		return 0, fmt.Errorf("invalid addr %v", sourceAddr) // nolint:err113
	}

	// nolint:godox // TODO: Support deliver packet from real server to vnet.
	// If packet is from vnet, proxy to real server.
	var realSocket *net.UDPConn
	value, ok := v.endpoints.Load(addr.String())
	if !ok {
		return 0, nil
	}

	realSocket = value.(*net.UDPConn) // nolint:forcetypeassert

	// Send to real server.
	if _, err := realSocket.Write(b); err != nil {
		return 0, err
	}

	return len(b), nil
}