// +build !plan9

package cache_test

import (
	"bytes"
	"fmt"
	"io"
	"io/ioutil"
	"math/rand"
	"path"
	"path/filepath"
	"strconv"
	"sync"
	"testing"
	"time"

	"github.com/ncw/rclone/cache"
	"github.com/ncw/rclone/fs"
	"github.com/ncw/rclone/fstest"
	"github.com/ncw/rclone/local"
	flag "github.com/spf13/pflag"
	"github.com/stretchr/testify/require"
)

var (
	WrapRemote   = flag.String("wrap-remote", "", "Remote to wrap")
	RemoteName   = flag.String("remote-name", "TestCacheInternal", "Root remote")
	SkipTimeouts = flag.Bool("skip-waits", false, "To skip tests that have wait times")
	rootFs       fs.Fs
	boltDb       *cache.Persistent
	metaAge      = time.Second * 30
	infoAge      = time.Second * 10
	chunkAge     = time.Second * 10
	okDiff       = time.Second * 9 // really big diff here but the build machines seem to be slow. need a different way for this
	workers      = 2
	warmupRate   = 3
	warmupSec    = 10
)

// prepare the test server and return a function to tidy it up afterwards
func TestInternalInit(t *testing.T) {
	var err error

	// delete the default path
	dbPath := filepath.Join(fs.CacheDir, "cache-backend", *RemoteName+".db")
	boltDb, err = cache.GetPersistent(dbPath, true)
	require.NoError(t, err)
	fstest.Initialise()

	if len(*WrapRemote) == 0 {
		*WrapRemote = "localInternal:/var/tmp/rclone-cache"
		fs.ConfigFileSet("localInternal", "type", "local")
		fs.ConfigFileSet("localInternal", "nounc", "true")
	}

	remoteExists := false
	for _, s := range fs.ConfigFileSections() {
		if s == *RemoteName {
			remoteExists = true
		}
	}

	if !remoteExists {
		fs.ConfigFileSet(*RemoteName, "type", "cache")
		fs.ConfigFileSet(*RemoteName, "remote", *WrapRemote)
		fs.ConfigFileSet(*RemoteName, "chunk_size", "1024")
		fs.ConfigFileSet(*RemoteName, "chunk_age", chunkAge.String())
		fs.ConfigFileSet(*RemoteName, "info_age", infoAge.String())
	}

	_ = flag.Set("cache-warm-up-age", metaAge.String())
	_ = flag.Set("cache-warm-up-rps", fmt.Sprintf("%v/%v", warmupRate, warmupSec))
	_ = flag.Set("cache-chunk-no-memory", "true")
	_ = flag.Set("cache-workers", strconv.Itoa(workers))

	// Instantiate root
	rootFs, err = fs.NewFs(*RemoteName + ":")
	_ = rootFs.Features().Purge()
	require.NoError(t, err)
	err = rootFs.Mkdir("")
	require.NoError(t, err)

	// flush cache
	_, err = getCacheFs(rootFs)
	require.NoError(t, err)
}

func TestInternalListRootAndInnerRemotes(t *testing.T) {
	// Instantiate inner fs
	innerFolder := "inner"
	err := rootFs.Mkdir(innerFolder)
	require.NoError(t, err)
	innerFs, err := fs.NewFs(*RemoteName + ":" + innerFolder)
	require.NoError(t, err)

	obj := writeObjectString(t, innerFs, "one", "content")

	listRoot, err := rootFs.List("")
	require.NoError(t, err)
	listRootInner, err := rootFs.List(innerFolder)
	require.NoError(t, err)
	listInner, err := innerFs.List("")
	require.NoError(t, err)

	require.Lenf(t, listRoot, 1, "remote %v should have 1 entry", rootFs.Root())
	require.Lenf(t, listRootInner, 1, "remote %v should have 1 entry in %v", rootFs.Root(), innerFolder)
	require.Lenf(t, listInner, 1, "remote %v should have 1 entry", innerFs.Root())

	err = obj.Remove()
	require.NoError(t, err)

	err = innerFs.Features().Purge()
	require.NoError(t, err)
	innerFs = nil
}

func TestInternalObjWrapFsFound(t *testing.T) {
	reset(t)
	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)
	wrappedFs := cfs.UnWrap()
	data := "content"
	writeObjectString(t, wrappedFs, "second", data)

	listRoot, err := rootFs.List("")
	require.NoError(t, err)
	require.Lenf(t, listRoot, 1, "remote %v should have 1 entry", rootFs.Root())

	co, err := rootFs.NewObject("second")
	require.NoError(t, err)
	r, err := co.Open()
	require.NoError(t, err)
	cachedData, err := ioutil.ReadAll(r)
	require.NoError(t, err)
	err = r.Close()
	require.NoError(t, err)

	strCached := string(cachedData)
	require.Equal(t, data, strCached)

	err = co.Remove()
	require.NoError(t, err)

	listRoot, err = wrappedFs.List("")
	require.NoError(t, err)
	require.Lenf(t, listRoot, 0, "remote %v should have 0 entries: %v", wrappedFs.Root(), listRoot)
}

func TestInternalObjNotFound(t *testing.T) {
	reset(t)
	obj, err := rootFs.NewObject("404")
	require.Error(t, err)
	require.Nil(t, obj)
}

func TestInternalCachedWrittenContentMatches(t *testing.T) {
	reset(t)
	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)
	chunkSize := cfs.ChunkSize()

	// create some rand test data
	testData := make([]byte, (chunkSize*4 + chunkSize/2))
	testSize, err := rand.Read(testData)
	require.Equal(t, len(testData), testSize, "data size doesn't match")
	require.NoError(t, err)

	// write the object
	o := writeObjectBytes(t, rootFs, "data.bin", testData)
	require.Equal(t, o.Size(), int64(testSize))

	// check sample of data from in-file
	sampleStart := chunkSize / 2
	sampleEnd := chunkSize
	testSample := testData[sampleStart:sampleEnd]
	checkSample := readDataFromObj(t, o, sampleStart, sampleEnd, false)
	require.Equal(t, int64(len(checkSample)), sampleEnd-sampleStart)
	require.Equal(t, checkSample, testSample)
}

func TestInternalCachedUpdatedContentMatches(t *testing.T) {
	reset(t)

	// create some rand test data
	testData1 := []byte(fstest.RandomString(100))
	testData2 := []byte(fstest.RandomString(200))

	// write the object
	o := updateObjectBytes(t, rootFs, "data.bin", testData1, testData2)
	require.Equal(t, o.Size(), int64(len(testData2)))

	// check data from in-file
	reader, err := o.Open()
	require.NoError(t, err)
	checkSample, err := ioutil.ReadAll(reader)
	_ = reader.Close()
	require.NoError(t, err)
	require.Equal(t, checkSample, testData2)
}

func TestInternalWrappedWrittenContentMatches(t *testing.T) {
	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)
	chunkSize := cfs.ChunkSize()

	reset(t)

	// create some rand test data
	testData := make([]byte, (chunkSize*4 + chunkSize/2))
	testSize, err := rand.Read(testData)
	require.Equal(t, len(testData), testSize)
	require.NoError(t, err)

	// write the object
	o := writeObjectBytes(t, cfs.UnWrap(), "data.bin", testData)
	require.Equal(t, o.Size(), int64(testSize))

	o2, err := rootFs.NewObject("data.bin")
	require.NoError(t, err)
	require.Equal(t, o2.Size(), o.Size())

	// check sample of data from in-file
	sampleStart := chunkSize / 2
	sampleEnd := chunkSize
	testSample := testData[sampleStart:sampleEnd]
	checkSample := readDataFromObj(t, o2, sampleStart, sampleEnd, false)
	require.Equal(t, len(checkSample), len(testSample))

	for i := 0; i < len(checkSample); i++ {
		require.Equal(t, testSample[i], checkSample[i])
	}
}

func TestInternalLargeWrittenContentMatches(t *testing.T) {
	t.Skip("FIXME disabled because it is unreliable")

	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)
	chunkSize := cfs.ChunkSize()

	reset(t)

	// create some rand test data
	testData := make([]byte, (chunkSize*10 + chunkSize/2))
	testSize, err := rand.Read(testData)
	require.Equal(t, len(testData), testSize)
	require.NoError(t, err)

	// write the object
	o := writeObjectBytes(t, cfs.UnWrap(), "data.bin", testData)
	require.Equal(t, o.Size(), int64(testSize))

	o2, err := rootFs.NewObject("data.bin")
	require.NoError(t, err)
	require.Equal(t, o2.Size(), o.Size())

	// check data from in-file
	checkSample := readDataFromObj(t, o2, int64(0), int64(testSize), false)
	require.Equal(t, len(checkSample), len(testData))

	for i := 0; i < len(checkSample); i++ {
		require.Equal(t, testData[i], checkSample[i], "byte: %d (%d), chunk: %d", int64(i)%chunkSize, i, int64(i)/chunkSize)
	}
}

func TestInternalWrappedFsChangeNotSeen(t *testing.T) {
	reset(t)
	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)
	chunkSize := cfs.ChunkSize()

	// create some rand test data
	co := writeObjectRandomBytes(t, rootFs, (chunkSize*4 + chunkSize/2))

	// update in the wrapped fs
	o, err := cfs.UnWrap().NewObject(co.Remote())
	require.NoError(t, err)
	err = o.SetModTime(co.ModTime().Truncate(time.Hour))
	require.NoError(t, err)

	// get a new instance from the cache
	co2, err := rootFs.NewObject(o.Remote())
	require.NoError(t, err)

	require.NotEqual(t, o.ModTime(), co.ModTime())
	require.NotEqual(t, o.ModTime(), co2.ModTime())
	require.Equal(t, co.ModTime(), co2.ModTime())
}

func TestInternalChangeSeenAfterDirCacheFlush(t *testing.T) {
	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)

	cfs.DirCacheFlush() // flush the cache

	l, err := cfs.UnWrap().List("")
	require.NoError(t, err)
	require.Len(t, l, 1)
	o := l[0]

	// get a new instance from the cache
	co, err := rootFs.NewObject(o.Remote())
	require.NoError(t, err)
	require.Equal(t, o.ModTime(), co.ModTime())
}

func TestInternalWarmUp(t *testing.T) {
	if *SkipTimeouts {
		t.Skip("--skip-waits set")
	}

	reset(t)
	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)
	chunkSize := cfs.ChunkSize()

	o1 := writeObjectRandomBytes(t, rootFs, (chunkSize * 3))
	o2 := writeObjectRandomBytes(t, rootFs, (chunkSize * 4))
	o3 := writeObjectRandomBytes(t, rootFs, (chunkSize * 6))

	_ = readDataFromObj(t, o1, 0, chunkSize, false)
	_ = readDataFromObj(t, o2, 0, chunkSize, false)

	// validate a fresh chunk
	expectedExpiry := time.Now().Add(chunkAge)
	ts, err := boltDb.GetChunkTs(path.Join(rootFs.Root(), o2.Remote()), 0)
	require.NoError(t, err)
	require.WithinDuration(t, expectedExpiry, ts, okDiff)

	// validate that we entered a warm up state
	_ = readDataFromObj(t, o3, 0, chunkSize, false)
	require.True(t, cfs.InWarmUp())
	expectedExpiry = time.Now().Add(metaAge)
	ts, err = boltDb.GetChunkTs(path.Join(rootFs.Root(), o3.Remote()), 0)
	require.NoError(t, err)
	require.WithinDuration(t, expectedExpiry, ts, okDiff)

	// validate that we cooled down and exit warm up
	// we wait for the cache to expire
	t.Logf("Waiting 10 seconds for warm up to expire\n")
	time.Sleep(time.Second * 10)

	_ = readDataFromObj(t, o3, chunkSize, chunkSize*2, false)
	require.False(t, cfs.InWarmUp())
	expectedExpiry = time.Now().Add(chunkAge)
	ts, err = boltDb.GetChunkTs(path.Join(rootFs.Root(), o3.Remote()), chunkSize)
	require.NoError(t, err)
	require.WithinDuration(t, expectedExpiry, ts, okDiff)
}

func TestInternalWarmUpInFlight(t *testing.T) {
	if *SkipTimeouts {
		t.Skip("--skip-waits set")
	}

	reset(t)
	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)
	chunkSize := cfs.ChunkSize()

	o1 := writeObjectRandomBytes(t, rootFs, (chunkSize * 3))
	o2 := writeObjectRandomBytes(t, rootFs, (chunkSize * 4))
	o3 := writeObjectRandomBytes(t, rootFs, (chunkSize * int64(workers) * int64(2)))

	_ = readDataFromObj(t, o1, 0, chunkSize, false)
	_ = readDataFromObj(t, o2, 0, chunkSize, false)
	require.False(t, cfs.InWarmUp())

	// validate that we entered a warm up state
	_ = readDataFromObj(t, o3, 0, chunkSize, false)
	require.True(t, cfs.InWarmUp())
	expectedExpiry := time.Now().Add(metaAge)
	ts, err := boltDb.GetChunkTs(path.Join(rootFs.Root(), o3.Remote()), 0)
	require.NoError(t, err)
	require.WithinDuration(t, expectedExpiry, ts, okDiff)

	checkSample := make([]byte, chunkSize)
	reader, err := o3.Open(&fs.SeekOption{Offset: 0})
	require.NoError(t, err)
	rs, ok := reader.(*cache.Handle)
	require.True(t, ok)

	for i := 0; i <= workers; i++ {
		_, _ = rs.Seek(int64(i)*chunkSize, 0)
		_, err = io.ReadFull(reader, checkSample)
		require.NoError(t, err)

		if i == workers {
			require.False(t, rs.InWarmUp(), "iteration %v", i)
		} else {
			require.True(t, rs.InWarmUp(), "iteration %v", i)
		}
	}
	_ = reader.Close()
	require.True(t, cfs.InWarmUp())
	expectedExpiry = time.Now().Add(chunkAge)
	ts, err = boltDb.GetChunkTs(path.Join(rootFs.Root(), o3.Remote()), chunkSize*int64(workers+1))
	require.NoError(t, err)
	require.WithinDuration(t, expectedExpiry, ts, okDiff)

	// validate that we cooled down and exit warm up
	// we wait for the cache to expire
	t.Logf("Waiting 10 seconds for warm up to expire\n")
	time.Sleep(time.Second * 10)

	_ = readDataFromObj(t, o2, chunkSize, chunkSize*2, false)
	require.False(t, cfs.InWarmUp())
	expectedExpiry = time.Now().Add(chunkAge)
	ts, err = boltDb.GetChunkTs(path.Join(rootFs.Root(), o2.Remote()), chunkSize)
	require.NoError(t, err)
	require.WithinDuration(t, expectedExpiry, ts, okDiff)
}

// TODO: this is bugged
//func TestInternalRateLimiter(t *testing.T) {
//	reset(t)
//	_ = flag.Set("cache-rps", "2")
//	rootFs, err := fs.NewFs(*RemoteName + ":")
//	require.NoError(t, err)
//	defer func() {
//		_ = flag.Set("cache-rps", "-1")
//		rootFs, err = fs.NewFs(*RemoteName + ":")
//		require.NoError(t, err)
//	}()
//	cfs, err := getCacheFs(rootFs)
//	require.NoError(t, err)
//	chunkSize := cfs.ChunkSize()
//
//	// create some rand test data
//	co := writeObjectRandomBytes(t, rootFs, (chunkSize*4 + chunkSize/2))
//
//	doStuff(t, 5, time.Second, func() {
//		r, err := co.Open(&fs.SeekOption{Offset: chunkSize + 1})
//		require.NoError(t, err)
//
//		buf := make([]byte, chunkSize)
//		totalRead, err := io.ReadFull(r, buf)
//		require.NoError(t, err)
//		require.Equal(t, len(buf), totalRead)
//		_ = r.Close()
//	})
//}

func TestInternalCacheWrites(t *testing.T) {
	reset(t)
	_ = flag.Set("cache-writes", "true")
	rootFs, err := fs.NewFs(*RemoteName + ":")
	require.NoError(t, err)
	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)
	chunkSize := cfs.ChunkSize()

	// create some rand test data
	co := writeObjectRandomBytes(t, rootFs, (chunkSize*4 + chunkSize/2))
	expectedExpiry := time.Now().Add(metaAge)
	ts, err := boltDb.GetChunkTs(path.Join(rootFs.Root(), co.Remote()), 0)
	require.NoError(t, err)
	require.WithinDuration(t, expectedExpiry, ts, okDiff)

	// reset fs
	_ = flag.Set("cache-writes", "false")
	rootFs, err = fs.NewFs(*RemoteName + ":")
	require.NoError(t, err)
}

func TestInternalExpiredChunkRemoved(t *testing.T) {
	t.Skip("FIXME disabled because it is unreliable")

	if *SkipTimeouts {
		t.Skip("--skip-waits set")
	}

	reset(t)
	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)
	chunkSize := cfs.ChunkSize()
	totalChunks := 20

	// create some rand test data
	co := writeObjectRandomBytes(t, cfs, (int64(totalChunks-1)*chunkSize + chunkSize/2))
	remote := co.Remote()
	// cache all the chunks
	_ = readDataFromObj(t, co, 0, co.Size(), false)

	// we wait for the cache to expire
	t.Logf("Waiting %v for cache to expire\n", chunkAge.String())
	time.Sleep(chunkAge)
	_, _ = cfs.List("")
	time.Sleep(time.Second * 2)

	o, err := cfs.NewObject(remote)
	require.NoError(t, err)
	co2, ok := o.(*cache.Object)
	require.True(t, ok)
	require.False(t, boltDb.HasChunk(co2, 0))
}

func TestInternalExpiredEntriesRemoved(t *testing.T) {
	if *SkipTimeouts {
		t.Skip("--skip-waits set")
	}

	reset(t)
	cfs, err := getCacheFs(rootFs)
	require.NoError(t, err)

	// create some rand test data
	_ = writeObjectString(t, cfs, "one", "one content")
	err = cfs.Mkdir("test")
	require.NoError(t, err)
	_ = writeObjectString(t, cfs, "test/second", "second content")

	objOne, err := cfs.NewObject("one")
	require.NoError(t, err)
	require.Equal(t, int64(len([]byte("one content"))), objOne.Size())

	waitTime := infoAge + time.Second*2
	t.Logf("Waiting %v seconds for cache to expire\n", waitTime)
	time.Sleep(infoAge)

	_, err = cfs.List("test")
	require.NoError(t, err)
	time.Sleep(time.Second * 2)
	require.False(t, boltDb.HasEntry("one"))
}

func TestInternalFinalise(t *testing.T) {
	var err error

	err = rootFs.Features().Purge()
	require.NoError(t, err)
}

func writeObjectRandomBytes(t *testing.T, f fs.Fs, size int64) fs.Object {
	remote := strconv.Itoa(rand.Int()) + ".bin"
	// create some rand test data
	testData := make([]byte, size)
	testSize, err := rand.Read(testData)
	require.Equal(t, size, int64(len(testData)))
	require.Equal(t, size, int64(testSize))
	require.NoError(t, err)

	o := writeObjectBytes(t, f, remote, testData)
	require.Equal(t, size, o.Size())

	return o
}

func writeObjectString(t *testing.T, f fs.Fs, remote, content string) fs.Object {
	return writeObjectBytes(t, f, remote, []byte(content))
}

func writeObjectBytes(t *testing.T, f fs.Fs, remote string, data []byte) fs.Object {
	in := bytes.NewReader(data)
	modTime := time.Now()
	objInfo := fs.NewStaticObjectInfo(remote, modTime, int64(len(data)), true, nil, f)

	obj, err := f.Put(in, objInfo)
	require.NoError(t, err)

	return obj
}

func updateObjectBytes(t *testing.T, f fs.Fs, remote string, data1 []byte, data2 []byte) fs.Object {
	in1 := bytes.NewReader(data1)
	in2 := bytes.NewReader(data2)
	objInfo1 := fs.NewStaticObjectInfo(remote, time.Now(), int64(len(data1)), true, nil, f)
	objInfo2 := fs.NewStaticObjectInfo(remote, time.Now(), int64(len(data2)), true, nil, f)

	obj, err := f.Put(in1, objInfo1)
	require.NoError(t, err)
	obj, err = f.NewObject(remote)
	require.NoError(t, err)
	err = obj.Update(in2, objInfo2)

	return obj
}

func readDataFromObj(t *testing.T, co fs.Object, offset, end int64, useSeek bool) []byte {
	var reader io.ReadCloser
	var err error
	size := end - offset
	checkSample := make([]byte, size)

	reader, err = co.Open(&fs.SeekOption{Offset: offset})
	require.NoError(t, err)

	totalRead, err := io.ReadFull(reader, checkSample)
	require.NoError(t, err)
	_ = reader.Close()
	require.Equal(t, int64(totalRead), size, "wrong data read size from file")

	return checkSample
}

func doStuff(t *testing.T, times int, maxDuration time.Duration, stuff func()) {
	var wg sync.WaitGroup

	for i := 0; i < times; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			time.Sleep(maxDuration / 2)
			stuff()
			time.Sleep(maxDuration / 2)
		}()
	}

	wg.Wait()
}

func reset(t *testing.T) {
	var err error

	err = rootFs.Features().Purge()
	require.NoError(t, err)

	// Instantiate root
	rootFs, err = fs.NewFs(*RemoteName + ":")
	require.NoError(t, err)
	err = rootFs.Mkdir("")
	require.NoError(t, err)
}

func getCacheFs(f fs.Fs) (*cache.Fs, error) {
	cfs, ok := f.(*cache.Fs)
	if ok {
		return cfs, nil
	} else {
		if f.Features().UnWrap != nil {
			cfs, ok := f.Features().UnWrap().(*cache.Fs)
			if ok {
				return cfs, nil
			}
		}
	}

	return nil, fmt.Errorf("didn't found a cache fs")
}

func getSourceFs(f fs.Fs) (fs.Fs, error) {
	if f.Features().UnWrap != nil {
		sfs := f.Features().UnWrap()
		_, ok := sfs.(*cache.Fs)
		if !ok {
			return sfs, nil
		}

		return getSourceFs(sfs)
	}

	return nil, fmt.Errorf("didn't found a source fs")
}

var (
	_ fs.Fs = (*cache.Fs)(nil)
	_ fs.Fs = (*local.Fs)(nil)
)