// Copyright 2022 PingCAP, 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 task

import (
	"context"
	"encoding/binary"
	"fmt"
	"path/filepath"
	"testing"

	"github.com/golang/protobuf/proto"
	"github.com/pingcap/errors"
	backuppb "github.com/pingcap/kvproto/pkg/brpb"
	berrors "github.com/pingcap/tidb/br/pkg/errors"
	"github.com/pingcap/tidb/br/pkg/metautil"
	"github.com/pingcap/tidb/br/pkg/storage"
	"github.com/pingcap/tidb/br/pkg/stream"
	"github.com/stretchr/testify/require"
	"github.com/tikv/client-go/v2/oracle"
)

func TestShiftTS(t *testing.T) {
	var startTS uint64 = 433155751280640000
	shiftTS := ShiftTS(startTS)
	require.Equal(t, true, shiftTS < startTS)

	delta := oracle.GetTimeFromTS(startTS).Sub(oracle.GetTimeFromTS(shiftTS))
	require.Equal(t, delta, streamShiftDuration)
}

func TestCheckLogRange(t *testing.T) {
	cases := []struct {
		restoreFrom uint64
		restoreTo   uint64
		logMinTS    uint64
		logMaxTS    uint64
		result      bool
	}{
		{
			logMinTS:    1,
			restoreFrom: 10,
			restoreTo:   99,
			logMaxTS:    100,
			result:      true,
		},
		{
			logMinTS:    1,
			restoreFrom: 1,
			restoreTo:   99,
			logMaxTS:    100,
			result:      true,
		},
		{
			logMinTS:    1,
			restoreFrom: 10,
			restoreTo:   10,
			logMaxTS:    100,
			result:      true,
		},
		{
			logMinTS:    11,
			restoreFrom: 10,
			restoreTo:   99,
			logMaxTS:    100,
			result:      false,
		},
		{
			logMinTS:    1,
			restoreFrom: 10,
			restoreTo:   9,
			logMaxTS:    100,
			result:      false,
		},
		{
			logMinTS:    1,
			restoreFrom: 9,
			restoreTo:   99,
			logMaxTS:    99,
			result:      true,
		},
		{
			logMinTS:    1,
			restoreFrom: 9,
			restoreTo:   99,
			logMaxTS:    98,
			result:      false,
		},
	}

	for _, c := range cases {
		err := checkLogRange(c.restoreFrom, c.restoreTo, c.logMinTS, c.logMaxTS)
		if c.result {
			require.Nil(t, err)
		} else {
			require.NotNil(t, err)
		}
	}
}

type fakeResolvedInfo struct {
	storeID    int64
	resolvedTS uint64
}

func fakeMetaFiles(ctx context.Context, tempDir string, infos []fakeResolvedInfo) error {
	backupMetaDir := filepath.Join(tempDir, stream.GetStreamBackupMetaPrefix())
	s, err := storage.NewLocalStorage(backupMetaDir)
	if err != nil {
		return errors.Trace(err)
	}

	for _, info := range infos {
		meta := &backuppb.Metadata{
			StoreId:    info.storeID,
			ResolvedTs: info.resolvedTS,
		}
		buff, err := meta.Marshal()
		if err != nil {
			return errors.Trace(err)
		}
		filename := fmt.Sprintf("%d_%d.meta", info.storeID, info.resolvedTS)
		if err = s.WriteFile(ctx, filename, buff); err != nil {
			return errors.Trace(err)
		}
	}
	return nil
}

func TestGetGlobalResolvedTS(t *testing.T) {
	ctx := context.Background()
	tmpdir := t.TempDir()
	s, err := storage.NewLocalStorage(tmpdir)
	require.Nil(t, err)
	helper := stream.NewMetadataHelper()

	stores := []fakeResolvedInfo{
		{
			storeID:    1,
			resolvedTS: 100,
		},
		{
			storeID:    2,
			resolvedTS: 101,
		},
		{
			storeID:    1,
			resolvedTS: 70,
		},
	}

	err = fakeMetaFiles(ctx, tmpdir, stores)
	require.Nil(t, err)
	globalResolvedTS, err := getGlobalResolvedTS(ctx, s, helper)
	require.Nil(t, err)
	require.Equal(t, uint64(101), globalResolvedTS)
}

func TestGetGlobalResolvedTS2(t *testing.T) {
	ctx := context.Background()
	tmpdir := t.TempDir()
	s, err := storage.NewLocalStorage(tmpdir)
	require.Nil(t, err)
	helper := stream.NewMetadataHelper()

	stores := []fakeResolvedInfo{
		{
			storeID:    1,
			resolvedTS: 95,
		},
		{
			storeID:    1,
			resolvedTS: 98,
		},
		{
			storeID:    2,
			resolvedTS: 90,
		},
		{
			storeID:    2,
			resolvedTS: 99,
		},
	}

	err = fakeMetaFiles(ctx, tmpdir, stores)
	require.Nil(t, err)
	globalResolvedTS, err := getGlobalResolvedTS(ctx, s, helper)
	require.Nil(t, err)
	require.Equal(t, uint64(99), globalResolvedTS)
}

func fakeCheckpointFiles(
	ctx context.Context,
	tmpDir string,
	infos []fakeGlobalCheckPoint,
) error {
	cpDir := filepath.Join(tmpDir, stream.GetStreamBackupGlobalCheckpointPrefix())
	s, err := storage.NewLocalStorage(cpDir)
	if err != nil {
		return errors.Trace(err)
	}

	// create normal files belong to global-checkpoint files
	for _, info := range infos {
		filename := fmt.Sprintf("%v.ts", info.storeID)
		buff := make([]byte, 8)
		binary.LittleEndian.PutUint64(buff, info.global_checkpoint)
		if _, err := s.Create(ctx, filename); err != nil {
			return errors.Trace(err)
		}
		if err := s.WriteFile(ctx, filename, buff); err != nil {
			return errors.Trace(err)
		}
	}

	// create a file not belonging to global-checkpoint-ts files
	filename := fmt.Sprintf("%v.tst", 1)
	err = s.WriteFile(ctx, filename, []byte("ping"))
	return errors.AddStack(err)
}

type fakeGlobalCheckPoint struct {
	storeID           int64
	global_checkpoint uint64
}

func TestGetGlobalCheckpointFromStorage(t *testing.T) {
	ctx := context.Background()
	tmpdir := t.TempDir()
	s, err := storage.NewLocalStorage(tmpdir)
	require.Nil(t, err)

	infos := []fakeGlobalCheckPoint{
		{
			storeID:           1,
			global_checkpoint: 98,
		},
		{
			storeID:           2,
			global_checkpoint: 90,
		},
		{
			storeID:           2,
			global_checkpoint: 99,
		},
	}

	err = fakeCheckpointFiles(ctx, tmpdir, infos)
	require.Nil(t, err)

	ts, err := getGlobalCheckpointFromStorage(ctx, s)
	require.Nil(t, err)
	require.Equal(t, ts, uint64(99))
}

func TestGetLogRangeWithFullBackupDir(t *testing.T) {
	var fullBackupTS uint64 = 123456
	testDir := t.TempDir()
	storage, err := storage.NewLocalStorage(testDir)
	require.Nil(t, err)

	m := backuppb.BackupMeta{
		EndVersion: fullBackupTS,
	}
	data, err := proto.Marshal(&m)
	require.Nil(t, err)

	err = storage.WriteFile(context.TODO(), metautil.MetaFile, data)
	require.Nil(t, err)

	cfg := Config{
		Storage: testDir,
	}
	_, err = getLogRange(context.TODO(), &cfg)
	require.Error(t, err, errors.Annotate(berrors.ErrStorageUnknown,
		"the storage has been used for full backup"))
}

func TestGetLogRangeWithLogBackupDir(t *testing.T) {
	var startLogBackupTS uint64 = 123456
	testDir := t.TempDir()
	storage, err := storage.NewLocalStorage(testDir)
	require.Nil(t, err)

	m := backuppb.BackupMeta{
		StartVersion: startLogBackupTS,
	}
	data, err := proto.Marshal(&m)
	require.Nil(t, err)

	err = storage.WriteFile(context.TODO(), metautil.MetaFile, data)
	require.Nil(t, err)

	cfg := Config{
		Storage: testDir,
	}
	logInfo, err := getLogRange(context.TODO(), &cfg)
	require.Nil(t, err)
	require.Equal(t, logInfo.logMinTS, startLogBackupTS)
}