/*
   Copyright 2014 CoreOS, 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 snap

import (
	"fmt"
	"hash/crc32"
	"io/ioutil"
	"os"
	"path"
	"reflect"
	"testing"

	"github.com/coreos/etcd/raft/raftpb"
)

var testSnap = &raftpb.Snapshot{
	Data: []byte("some snapshot"),
	Metadata: raftpb.SnapshotMetadata{
		ConfState: raftpb.ConfState{
			Nodes: []uint64{1, 2, 3},
		},
		Index: 1,
		Term:  1,
	},
}

func TestSaveAndLoad(t *testing.T) {
	dir := path.Join(os.TempDir(), "snapshot")
	err := os.Mkdir(dir, 0700)
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(dir)
	ss := New(dir)
	err = ss.save(testSnap)
	if err != nil {
		t.Fatal(err)
	}

	g, err := ss.Load()
	if err != nil {
		t.Errorf("err = %v, want nil", err)
	}
	if !reflect.DeepEqual(g, testSnap) {
		t.Errorf("snap = %#v, want %#v", g, testSnap)
	}
}

func TestBadCRC(t *testing.T) {
	dir := path.Join(os.TempDir(), "snapshot")
	err := os.Mkdir(dir, 0700)
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(dir)
	ss := New(dir)
	err = ss.save(testSnap)
	if err != nil {
		t.Fatal(err)
	}
	defer func() { crcTable = crc32.MakeTable(crc32.Castagnoli) }()
	// switch to use another crc table
	// fake a crc mismatch
	crcTable = crc32.MakeTable(crc32.Koopman)

	_, err = ss.Load()
	if err == nil || err != ErrCRCMismatch {
		t.Errorf("err = %v, want %v", err, ErrCRCMismatch)
	}
}

func TestFailback(t *testing.T) {
	dir := path.Join(os.TempDir(), "snapshot")
	err := os.Mkdir(dir, 0700)
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(dir)

	large := fmt.Sprintf("%016x-%016x-%016x.snap", 0xFFFF, 0xFFFF, 0xFFFF)
	err = ioutil.WriteFile(path.Join(dir, large), []byte("bad data"), 0666)
	if err != nil {
		t.Fatal(err)
	}

	ss := New(dir)
	err = ss.save(testSnap)
	if err != nil {
		t.Fatal(err)
	}

	g, err := ss.Load()
	if err != nil {
		t.Errorf("err = %v, want nil", err)
	}
	if !reflect.DeepEqual(g, testSnap) {
		t.Errorf("snap = %#v, want %#v", g, testSnap)
	}
	if f, err := os.Open(path.Join(dir, large) + ".broken"); err != nil {
		t.Fatal("broken snapshot does not exist")
	} else {
		f.Close()
	}
}

func TestSnapNames(t *testing.T) {
	dir := path.Join(os.TempDir(), "snapshot")
	err := os.Mkdir(dir, 0700)
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(dir)
	for i := 1; i <= 5; i++ {
		if f, err := os.Create(path.Join(dir, fmt.Sprintf("%d.snap", i))); err != nil {
			t.Fatal(err)
		} else {
			f.Close()
		}
	}
	ss := New(dir)
	names, err := ss.snapNames()
	if err != nil {
		t.Errorf("err = %v, want nil", err)
	}
	if len(names) != 5 {
		t.Errorf("len = %d, want 10", len(names))
	}
	w := []string{"5.snap", "4.snap", "3.snap", "2.snap", "1.snap"}
	if !reflect.DeepEqual(names, w) {
		t.Errorf("names = %v, want %v", names, w)
	}
}

func TestLoadNewestSnap(t *testing.T) {
	dir := path.Join(os.TempDir(), "snapshot")
	err := os.Mkdir(dir, 0700)
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(dir)
	ss := New(dir)
	err = ss.save(testSnap)
	if err != nil {
		t.Fatal(err)
	}

	newSnap := *testSnap
	newSnap.Metadata.Index = 5
	err = ss.save(&newSnap)
	if err != nil {
		t.Fatal(err)
	}

	g, err := ss.Load()
	if err != nil {
		t.Errorf("err = %v, want nil", err)
	}
	if !reflect.DeepEqual(g, &newSnap) {
		t.Errorf("snap = %#v, want %#v", g, &newSnap)
	}
}

func TestNoSnapshot(t *testing.T) {
	dir := path.Join(os.TempDir(), "snapshot")
	err := os.Mkdir(dir, 0700)
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(dir)
	ss := New(dir)
	_, err = ss.Load()
	if err == nil || err != ErrNoSnapshot {
		t.Errorf("err = %v, want %v", err, ErrNoSnapshot)
	}
}

func TestEmptySnapshot(t *testing.T) {
	dir := path.Join(os.TempDir(), "snapshot")
	err := os.Mkdir(dir, 0700)
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(dir)

	err = ioutil.WriteFile(path.Join(dir, "1.snap"), []byte("shit"), 0x700)
	if err != nil {
		t.Fatal(err)
	}

	ss := New(dir)
	_, err = ss.Load()
	if err == nil || err != ErrEmptySnapshot {
		t.Errorf("err = %v, want %v", err, ErrEmptySnapshot)
	}
}