/*
   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 wal

import (
	"bytes"
	"io/ioutil"
	"os"
	"path"
	"reflect"
	"testing"

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

func TestNew(t *testing.T) {
	p, err := ioutil.TempDir(os.TempDir(), "waltest")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(p)

	w, err := Create(p, []byte("somedata"))
	if err != nil {
		t.Fatalf("err = %v, want nil", err)
	}
	if g := path.Base(w.f.Name()); g != walName(0, 0) {
		t.Errorf("name = %+v, want %+v", g, walName(0, 0))
	}
	defer w.Close()
	gd, err := ioutil.ReadFile(w.f.Name())
	if err != nil {
		t.Fatalf("err = %v, want nil", err)
	}

	var wb bytes.Buffer
	e := newEncoder(&wb, 0)
	err = e.encode(&walpb.Record{Type: crcType, Crc: 0})
	if err != nil {
		t.Fatalf("err = %v, want nil", err)
	}
	err = e.encode(&walpb.Record{Type: metadataType, Data: []byte("somedata")})
	if err != nil {
		t.Fatalf("err = %v, want nil", err)
	}
	e.flush()
	if !reflect.DeepEqual(gd, wb.Bytes()) {
		t.Errorf("data = %v, want %v", gd, wb.Bytes())
	}
}

func TestNewForInitedDir(t *testing.T) {
	p, err := ioutil.TempDir(os.TempDir(), "waltest")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(p)

	os.Create(path.Join(p, walName(0, 0)))
	if _, err = Create(p, nil); err == nil || err != os.ErrExist {
		t.Errorf("err = %v, want %v", err, os.ErrExist)
	}
}

func TestOpenAtIndex(t *testing.T) {
	dir, err := ioutil.TempDir(os.TempDir(), "waltest")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(dir)

	f, err := os.Create(path.Join(dir, walName(0, 0)))
	if err != nil {
		t.Fatal(err)
	}
	f.Close()

	w, err := OpenAtIndex(dir, 0)
	if err != nil {
		t.Fatalf("err = %v, want nil", err)
	}
	if g := path.Base(w.f.Name()); g != walName(0, 0) {
		t.Errorf("name = %+v, want %+v", g, walName(0, 0))
	}
	if w.seq != 0 {
		t.Errorf("seq = %d, want %d", w.seq, 0)
	}
	w.Close()

	wname := walName(2, 10)
	f, err = os.Create(path.Join(dir, wname))
	if err != nil {
		t.Fatal(err)
	}
	f.Close()

	w, err = OpenAtIndex(dir, 5)
	if err != nil {
		t.Fatalf("err = %v, want nil", err)
	}
	if g := path.Base(w.f.Name()); g != wname {
		t.Errorf("name = %+v, want %+v", g, wname)
	}
	if w.seq != 2 {
		t.Errorf("seq = %d, want %d", w.seq, 2)
	}
	w.Close()

	emptydir, err := ioutil.TempDir(os.TempDir(), "waltestempty")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(emptydir)
	if _, err = OpenAtIndex(emptydir, 0); err != ErrFileNotFound {
		t.Errorf("err = %v, want %v", err, ErrFileNotFound)
	}
}

// TODO: split it into smaller tests for better readability
func TestCut(t *testing.T) {
	p, err := ioutil.TempDir(os.TempDir(), "waltest")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(p)

	w, err := Create(p, nil)
	if err != nil {
		t.Fatal(err)
	}
	defer w.Close()

	// TODO(unihorn): remove this when cut can operate on an empty file
	if err := w.SaveEntry(&raftpb.Entry{}); err != nil {
		t.Fatal(err)
	}
	state := raftpb.HardState{Term: 1}
	if err := w.SaveState(&state); err != nil {
		t.Fatal(err)
	}
	if err := w.Cut(); err != nil {
		t.Fatal(err)
	}
	wname := walName(1, 1)
	if g := path.Base(w.f.Name()); g != wname {
		t.Errorf("name = %s, want %s", g, wname)
	}

	e := &raftpb.Entry{Index: 1, Term: 1, Data: []byte{1}}
	if err := w.SaveEntry(e); err != nil {
		t.Fatal(err)
	}
	if err := w.Cut(); err != nil {
		t.Fatal(err)
	}
	wname = walName(2, 2)
	if g := path.Base(w.f.Name()); g != wname {
		t.Errorf("name = %s, want %s", g, wname)
	}

	// check the state in the last WAL
	// We do check before closing the WAL to ensure that Cut syncs the data
	// into the disk.
	f, err := os.Open(path.Join(p, wname))
	if err != nil {
		t.Fatal(err)
	}
	defer f.Close()
	nw := &WAL{
		decoder: newDecoder(f),
		ri:      2,
	}
	_, gst, _, err := nw.ReadAll()
	if err != nil {
		t.Fatal(err)
	}
	if !reflect.DeepEqual(gst, state) {
		t.Errorf("state = %+v, want %+v", gst, state)
	}
}

func TestRecover(t *testing.T) {
	p, err := ioutil.TempDir(os.TempDir(), "waltest")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(p)

	w, err := Create(p, []byte("metadata"))
	if err != nil {
		t.Fatal(err)
	}
	ents := []raftpb.Entry{{Index: 0, Term: 0}, {Index: 1, Term: 1, Data: []byte{1}}, {Index: 2, Term: 2, Data: []byte{2}}}
	for _, e := range ents {
		if err = w.SaveEntry(&e); err != nil {
			t.Fatal(err)
		}
	}
	sts := []raftpb.HardState{{Term: 1, Vote: 1, Commit: 1}, {Term: 2, Vote: 2, Commit: 2}}
	for _, s := range sts {
		if err = w.SaveState(&s); err != nil {
			t.Fatal(err)
		}
	}
	w.Close()

	if w, err = OpenAtIndex(p, 0); err != nil {
		t.Fatal(err)
	}
	metadata, state, entries, err := w.ReadAll()
	if err != nil {
		t.Fatal(err)
	}

	if !reflect.DeepEqual(metadata, []byte("metadata")) {
		t.Errorf("metadata = %s, want %s", metadata, "metadata")
	}
	if !reflect.DeepEqual(entries, ents) {
		t.Errorf("ents = %+v, want %+v", entries, ents)
	}
	// only the latest state is recorded
	s := sts[len(sts)-1]
	if !reflect.DeepEqual(state, s) {
		t.Errorf("state = %+v, want %+v", state, s)
	}
}

func TestSearchIndex(t *testing.T) {
	tests := []struct {
		names []string
		index uint64
		widx  int
		wok   bool
	}{
		{
			[]string{
				"0000000000000000-0000000000000000.wal",
				"0000000000000001-0000000000001000.wal",
				"0000000000000002-0000000000002000.wal",
			},
			0x1000, 1, true,
		},
		{
			[]string{
				"0000000000000001-0000000000004000.wal",
				"0000000000000002-0000000000003000.wal",
				"0000000000000003-0000000000005000.wal",
			},
			0x4000, 1, true,
		},
		{
			[]string{
				"0000000000000001-0000000000002000.wal",
				"0000000000000002-0000000000003000.wal",
				"0000000000000003-0000000000005000.wal",
			},
			0x1000, -1, false,
		},
	}
	for i, tt := range tests {
		idx, ok := searchIndex(tt.names, tt.index)
		if idx != tt.widx {
			t.Errorf("#%d: idx = %d, want %d", i, idx, tt.widx)
		}
		if ok != tt.wok {
			t.Errorf("#%d: ok = %v, want %v", i, ok, tt.wok)
		}
	}
}

func TestScanWalName(t *testing.T) {
	tests := []struct {
		str          string
		wseq, windex uint64
		wok          bool
	}{
		{"0000000000000000-0000000000000000.wal", 0, 0, true},
		{"0000000000000000.wal", 0, 0, false},
		{"0000000000000000-0000000000000000.snap", 0, 0, false},
	}
	for i, tt := range tests {
		s, index, err := parseWalName(tt.str)
		if g := err == nil; g != tt.wok {
			t.Errorf("#%d: ok = %v, want %v", i, g, tt.wok)
		}
		if s != tt.wseq {
			t.Errorf("#%d: seq = %d, want %d", i, s, tt.wseq)
		}
		if index != tt.windex {
			t.Errorf("#%d: index = %d, want %d", i, index, tt.windex)
		}
	}
}

func TestRecoverAfterCut(t *testing.T) {
	p, err := ioutil.TempDir(os.TempDir(), "waltest")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(p)

	w, err := Create(p, []byte("metadata"))
	if err != nil {
		t.Fatal(err)
	}
	// TODO(unihorn): remove this when cut can operate on an empty file
	if err = w.SaveEntry(&raftpb.Entry{}); err != nil {
		t.Fatal(err)
	}
	if err = w.Cut(); err != nil {
		t.Fatal(err)
	}
	for i := 1; i < 10; i++ {
		e := raftpb.Entry{Index: uint64(i)}
		if err = w.SaveEntry(&e); err != nil {
			t.Fatal(err)
		}
		if err = w.Cut(); err != nil {
			t.Fatal(err)
		}
	}
	w.Close()

	if err := os.Remove(path.Join(p, walName(4, 4))); err != nil {
		t.Fatal(err)
	}

	for i := 0; i < 10; i++ {
		w, err := OpenAtIndex(p, uint64(i))
		if err != nil {
			if i <= 4 {
				if err != ErrFileNotFound {
					t.Errorf("#%d: err = %v, want %v", i, err, ErrFileNotFound)
				}
			} else {
				t.Errorf("#%d: err = %v, want nil", i, err)
			}
			continue
		}
		metadata, _, entries, err := w.ReadAll()
		if err != nil {
			t.Errorf("#%d: err = %v, want nil", i, err)
			continue
		}
		if !reflect.DeepEqual(metadata, []byte("metadata")) {
			t.Errorf("#%d: metadata = %s, want %s", i, metadata, "metadata")
		}
		for j, e := range entries {
			if e.Index != uint64(j+i) {
				t.Errorf("#%d: ents[%d].Index = %+v, want %+v", i, j, e.Index, j+i)
			}
		}
	}
}

func TestOpenAtUncommittedIndex(t *testing.T) {
	p, err := ioutil.TempDir(os.TempDir(), "waltest")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(p)

	w, err := Create(p, nil)
	if err != nil {
		t.Fatal(err)
	}
	if err := w.SaveEntry(&raftpb.Entry{Index: 0}); err != nil {
		t.Fatal(err)
	}
	w.Close()

	w, err = OpenAtIndex(p, 1)
	if err != nil {
		t.Fatal(err)
	}
	// commit up to index 0, try to read index 1
	if _, _, _, err := w.ReadAll(); err != nil {
		t.Errorf("err = %v, want nil", err)
	}
	w.Close()
}

func TestSaveEmpty(t *testing.T) {
	var buf bytes.Buffer
	var est raftpb.HardState
	w := WAL{
		encoder: newEncoder(&buf, 0),
	}
	if err := w.SaveState(&est); err != nil {
		t.Errorf("err = %v, want nil", err)
	}
	if len(buf.Bytes()) != 0 {
		t.Errorf("buf.Bytes = %d, want 0", len(buf.Bytes()))
	}
}