package fingerprint

import (
	"testing"

	"github.com/google/gopacket"
	"github.com/google/gopacket/layers"
)

func TestBuildSYNPacket(t *testing.T) {
	data, err := BuildSYNPacket("192.0.2.1", "198.51.100.2", 12345, 80)
	if err != nil {
		t.Fatalf("BuildSYNPacket returned error: %v", err)
	}
	packet := gopacket.NewPacket(data, layers.LayerTypeIPv4, gopacket.Default)
	if packet == nil {
		t.Fatalf("Failed to decode packet")
	}
	if ipLayer := packet.Layer(layers.LayerTypeIPv4); ipLayer == nil {
		t.Fatalf("IPv4 layer not found")
	}
	tcpLayer := packet.Layer(layers.LayerTypeTCP)
	if tcpLayer == nil {
		t.Fatalf("TCP layer not found")
	}
	tcp, _ := tcpLayer.(*layers.TCP)
	if !tcp.SYN {
		t.Fatalf("Expected SYN flag set")
	}
}