package pcap

import (
	"bytes"
	"encoding/hex"
	"testing"
	"time"
)

func TestWriter(t *testing.T) {
	var buf bytes.Buffer
	w, err := NewWriter(&buf, LinkTypeRaw)
	if err != nil {
		t.Fatal(err)
	}
	ts := time.Unix(0x01020304, 5000)
	if err := w.WritePacket(ts, []byte{0xaa, 0xbb}); err != nil {
		t.Fatal(err)
	}

	want := "d4c3b2a1" + "0200" + "0400" + "00000000" + "00000000" + "00000400" + "65000000" +
		"04030201" + "05000000" + "02000000" + "02000000" + "aabb"
	if got := hex.EncodeToString(buf.Bytes()); got != want {
		t.Errorf("got  %s\nwant %s", got, want)
	}
}

func TestWriterRejectsOversizedPacket(t *testing.T) {
	w, err := NewWriter(&bytes.Buffer{}, LinkTypeEthernet)
	if err != nil {
		t.Fatal(err)
	}
	if err := w.WritePacket(time.Now(), make([]byte, DefaultSnapLen+1)); err == nil {
		t.Error("expected error for oversized packet")
	}
}