// Copyright 2016 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package pcap

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"os"
	"reflect"
	"testing"
	"time"
)

func sprintPackets(pkts []*Packet) string {
	var buf bytes.Buffer

	for _, pkt := range pkts {
		buf.WriteString("{\n")
		p := reflect.ValueOf(pkt).Elem()
		t := p.Type()
		for i := 0; i < p.NumField(); i++ {
			v := p.Field(i).Interface()
			// Pretty-print Time, so it doesn't have a varying pointer
			// in it.
			if t, ok := v.(time.Time); ok {
				v = t.UnixNano()
			}
			fmt.Fprintf(&buf, "  %s: %#v,\n", t.Field(i).Name, v)
		}
		buf.WriteString("}\n")
	}
	return buf.String()
}

func TestFiles(t *testing.T) {
	for _, fname := range []string{"usec", "nsec"} {
		f, err := os.Open(fmt.Sprintf("testdata/%s.pcap", fname))
		if err != nil {
			t.Fatalf("Opening test input file: %s", err)
		}
		r, err := NewReader(f)
		if err != nil {
			t.Fatalf("Creating pcap reader: %s", err)
		}
		if r.LinkType != LinkEthernet {
			t.Errorf("Expected link type %d, got %d", LinkEthernet, r.LinkType)
		}

		pkts := []*Packet{}
		for r.Next() {
			pkts = append(pkts, r.Packet())
		}
		if r.Err() != nil {
			t.Fatalf("Reading packets from %s.pcap: %s", fname, r.Err())
		}
		res := sprintPackets(pkts)

		expectedFile := fmt.Sprintf("testdata/%s.parsed", fname)
		expected, err := ioutil.ReadFile(expectedFile)
		if err != nil {
			t.Fatalf("Reading expected file: %s", err)
		}
		if res != string(expected) {
			if os.Getenv("UPDATE_TESTDATA") != "" {
				ioutil.WriteFile(expectedFile, []byte(res), 0644)
				t.Errorf("%s.pcap didn't decode to %s.parsed (updated %s.parsed)", fname, fname, fname)
			} else {
				t.Fatalf("%s.pcap didn't decode to %s.parsed (rerun with UPDATE_TESTDATA=1 to get diff)", fname, fname)
			}
		}
	}
}