package ipns

import (
	"bytes"
	"crypto/rand"
	"io/ioutil"
	"os"
	"runtime"
	"strings"
	"testing"
	"time"

	fstest "github.com/jbenet/go-ipfs/Godeps/_workspace/src/bazil.org/fuse/fs/fstestutil"
	core "github.com/jbenet/go-ipfs/core"
	u "github.com/jbenet/go-ipfs/util"
)

func maybeSkipFuseTests(t *testing.T) bool {
	v := "TEST_NO_FUSE"
	n := strings.ToLower(os.Getenv(v))
	skip := n != "" && n != "false" && n != "f"

	if skip {
		t.Skipf("Skipping FUSE tests (%s=%s)", v, n)
	}
	return skip
}

func randBytes(size int) []byte {
	b := make([]byte, size)
	rand.Read(b)
	return b
}

func writeFile(t *testing.T, size int, path string) []byte {
	return writeFileData(t, randBytes(size), path)
}

func writeFileData(t *testing.T, data []byte, path string) []byte {
	fi, err := os.Create(path)
	if err != nil {
		t.Fatal(err)
	}

	n, err := fi.Write(data)
	if err != nil {
		t.Fatal(err)
	}

	if n != len(data) {
		t.Fatal("Didnt write proper amount!")
	}

	err = fi.Close()
	if err != nil {
		t.Fatal(err)
	}

	return data
}

func setupIpnsTest(t *testing.T, node *core.IpfsNode) (*core.IpfsNode, *fstest.Mount) {
	maybeSkipFuseTests(t)

	var err error
	if node == nil {
		node, err = core.NewMockNode()
		if err != nil {
			t.Fatal(err)
		}
	}

	fs, err := NewIpns(node, "")
	if err != nil {
		t.Fatal(err)
	}
	mnt, err := fstest.MountedT(t, fs)
	if err != nil {
		t.Fatal(err)
	}

	return node, mnt
}

// Test writing a file and reading it back
func TestIpnsBasicIO(t *testing.T) {
	_, mnt := setupIpnsTest(t, nil)
	defer mnt.Close()

	fname := mnt.Dir + "/local/testfile"
	data := writeFile(t, 12345, fname)

	rbuf, err := ioutil.ReadFile(fname)
	if err != nil {
		t.Fatal(err)
	}

	if !bytes.Equal(rbuf, data) {
		t.Fatal("Incorrect Read!")
	}
}

// Test to make sure file changes persist over mounts of ipns
func TestFilePersistence(t *testing.T) {
	node, mnt := setupIpnsTest(t, nil)

	fname := "/local/atestfile"
	data := writeFile(t, 127, mnt.Dir+fname)

	// Wait for publish: TODO: make publish happen faster in tests
	time.Sleep(time.Millisecond * 40)

	mnt.Close()

	node, mnt = setupIpnsTest(t, node)
	defer mnt.Close()

	rbuf, err := ioutil.ReadFile(mnt.Dir + fname)
	if err != nil {
		t.Fatal(err)
	}

	if !bytes.Equal(rbuf, data) {
		t.Fatalf("File data changed between mounts! sizes differ: %d != %d", len(data), len(rbuf))
	}
}

// Test to make sure the filesystem reports file sizes correctly
func TestFileSizeReporting(t *testing.T) {
	_, mnt := setupIpnsTest(t, nil)
	defer mnt.Close()

	fname := mnt.Dir + "/local/sizecheck"
	data := writeFile(t, 5555, fname)

	finfo, err := os.Stat(fname)
	if err != nil {
		t.Fatal(err)
	}

	if finfo.Size() != int64(len(data)) {
		t.Fatal("Read incorrect size from stat!")
	}
}

// Test to make sure you cant create multiple entries with the same name
func TestDoubleEntryFailure(t *testing.T) {
	_, mnt := setupIpnsTest(t, nil)
	defer mnt.Close()

	dname := mnt.Dir + "/local/thisisadir"
	err := os.Mkdir(dname, 0777)
	if err != nil {
		t.Fatal(err)
	}

	err = os.Mkdir(dname, 0777)
	if err == nil {
		t.Fatal("Should have gotten error one creating new directory.")
	}
}

func TestAppendFile(t *testing.T) {
	_, mnt := setupIpnsTest(t, nil)
	defer mnt.Close()

	fname := mnt.Dir + "/local/file"
	data := writeFile(t, 1300, fname)

	fi, err := os.OpenFile(fname, os.O_RDWR|os.O_APPEND, 0666)
	if err != nil {
		t.Fatal(err)
	}

	nudata := randBytes(500)

	n, err := fi.Write(nudata)
	if err != nil {
		t.Fatal(err)
	}
	err = fi.Close()
	if err != nil {
		t.Fatal(err)
	}

	if n != len(nudata) {
		t.Fatal("Failed to write enough bytes.")
	}

	data = append(data, nudata...)

	rbuf, err := ioutil.ReadFile(fname)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(rbuf, data) {
		t.Fatal("Data inconsistent!")
	}
}

func TestFastRepublish(t *testing.T) {

	// make timeout noticeable.
	osrt := shortRepublishTimeout
	shortRepublishTimeout = time.Millisecond * 100

	olrt := longRepublishTimeout
	longRepublishTimeout = time.Second

	node, mnt := setupIpnsTest(t, nil)

	h, err := node.Identity.PrivKey().GetPublic().Hash()
	if err != nil {
		t.Fatal(err)
	}
	pubkeyHash := u.Key(h).Pretty()

	// set them back
	defer func() {
		shortRepublishTimeout = osrt
		longRepublishTimeout = olrt
		mnt.Close()
	}()

	closed := make(chan struct{})
	dataA := []byte("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
	dataB := []byte("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb")

	fname := mnt.Dir + "/local/file"

	// get first resolved hash
	log.Debug("publishing first hash")
	writeFileData(t, dataA, fname) // random
	<-time.After(shortRepublishTimeout * 11 / 10)
	log.Debug("resolving first hash")
	resolvedHash, err := node.Namesys.Resolve(pubkeyHash)
	if err != nil {
		t.Fatal("resolve err:", pubkeyHash, err)
	}

	// constantly keep writing to the file
	go func() {
		for {
			select {
			case <-closed:
				return

			case <-time.After(shortRepublishTimeout * 8 / 10):
				writeFileData(t, dataB, fname)
			}
		}
	}()

	hasPublished := func() bool {
		res, err := node.Namesys.Resolve(pubkeyHash)
		if err != nil {
			t.Fatal("resolve err: %v", err)
		}
		return res != resolvedHash
	}

	// test things

	// at this point, should not have written dataA and not have written dataB
	rbuf, err := ioutil.ReadFile(fname)
	if err != nil || !bytes.Equal(rbuf, dataA) {
		t.Fatal("Data inconsistent! %v %v", err, string(rbuf))
	}

	if hasPublished() {
		t.Fatal("published (wrote)")
	}

	<-time.After(shortRepublishTimeout * 11 / 10)

	// at this point, should have written written dataB, but not published it
	rbuf, err = ioutil.ReadFile(fname)
	if err != nil || !bytes.Equal(rbuf, dataB) {
		t.Fatal("Data inconsistent! %v %v", err, string(rbuf))
	}

	if hasPublished() {
		t.Fatal("published (wrote)")
	}

	<-time.After(longRepublishTimeout * 11 / 10)

	// at this point, should have written written dataB, and published it
	rbuf, err = ioutil.ReadFile(fname)
	if err != nil || !bytes.Equal(rbuf, dataB) {
		t.Fatal("Data inconsistent! %v %v", err, string(rbuf))
	}

	if !hasPublished() {
		t.Fatal("not published")
	}

	close(closed)
}

// Test writing a medium sized file one byte at a time
func TestMultiWrite(t *testing.T) {
	if runtime.GOOS == "darwin" {
		link := "https://github.com/jbenet/go-ipfs/issues/147"
		t.Skipf("Skipping as is broken in OSX. See %s", link)
	}

	_, mnt := setupIpnsTest(t, nil)
	defer mnt.Close()

	fpath := mnt.Dir + "/local/file"
	fi, err := os.Create(fpath)
	if err != nil {
		t.Fatal(err)
	}

	data := randBytes(1001)
	for i := 0; i < len(data); i++ {
		n, err := fi.Write(data[i : i+1])
		if err != nil {
			t.Fatal(err)
		}
		if n != 1 {
			t.Fatal("Somehow wrote the wrong number of bytes! (n != 1)")
		}
	}
	fi.Close()

	rbuf, err := ioutil.ReadFile(fpath)
	if err != nil {
		t.Fatal(err)
	}

	if !bytes.Equal(rbuf, data) {
		t.Fatal("File on disk did not match bytes written")
	}
}
