// Mount the file system based on the supplied arguments, returning a
// fuse.MountedFileSystem that can be joined to wait for unmounting.
func mount(
	ctx context.Context,
	bucketName string,
	mountPoint string,
	flags *FlagStorage) (mfs *fuse.MountedFileSystem, err error) {

	// Choose UID and GID.
	uid, gid, err := MyUserAndGroup()
	if err != nil {
		err = fmt.Errorf("MyUserAndGroup: %v", err)
		return
	}

	if int32(flags.Uid) == -1 {
		flags.Uid = uid
	}

	if int32(flags.Gid) == -1 {
		flags.Gid = gid
	}

	awsConfig := &aws.Config{
		Region: aws.String("us-west-2"),
		//LogLevel: aws.LogLevel(aws.LogDebug),
	}
	if len(flags.Endpoint) > 0 {
		awsConfig.Endpoint = &flags.Endpoint
	}
	if flags.UsePathRequest {
		awsConfig.S3ForcePathStyle = aws.Bool(true)
	}

	goofys := NewGoofys(bucketName, awsConfig, flags)
	if goofys == nil {
		err = fmt.Errorf("Mount: initialization failed")
		return
	}
	server := fuseutil.NewFileSystemServer(goofys)

	// Mount the file system.
	mountCfg := &fuse.MountConfig{
		FSName:                  bucketName,
		Options:                 flags.MountOptions,
		ErrorLogger:             log.New(os.Stderr, "fuse: ", log.Flags()),
		DisableWritebackCaching: true,
	}

	if flags.DebugFuse {
		mountCfg.DebugLogger = log.New(os.Stderr, "fuse_debug: ", 0)
	}

	mfs, err = fuse.Mount(mountPoint, server, mountCfg)
	if err != nil {
		err = fmt.Errorf("Mount: %v", err)
		return
	}

	return
}

// Create a file system with a fixed structure that looks like this:
//
//     hello
//     dir/
//         world
//
// Each file contains the string "Hello, world!".
func NewHelloFS(clock timeutil.Clock) (server fuse.Server, err error) {
	fs := &helloFS{
		Clock: clock,
	}

	server = fuseutil.NewFileSystemServer(fs)
	return
}

// Mount the file system based on the supplied arguments, returning a
// fuse.MountedFileSystem that can be joined to wait for unmounting.
func mount(
	ctx context.Context,
	bucketName string,
	mountPoint string,
	flags *FlagStorage) (mfs *fuse.MountedFileSystem, err error) {

	awsConfig := &aws.Config{
		Region: &flags.Region,
		Logger: GetLogger("s3"),
		//LogLevel: aws.LogLevel(aws.LogDebug),
	}

	if len(flags.Profile) > 0 {
		awsConfig.Credentials = credentials.NewSharedCredentials("", flags.Profile)
	}

	if len(flags.Endpoint) > 0 {
		awsConfig.Endpoint = &flags.Endpoint
	}

	// deprecate flags.UsePathRequest
	if flags.UsePathRequest {
		log.Infoln("--use-path-request is deprecated, it's always on")
	}
	awsConfig.S3ForcePathStyle = aws.Bool(true)

	goofys := NewGoofys(bucketName, awsConfig, flags)
	if goofys == nil {
		err = fmt.Errorf("Mount: initialization failed")
		return
	}
	server := fuseutil.NewFileSystemServer(goofys)

	fuseLog := GetLogger("fuse")

	// Mount the file system.
	mountCfg := &fuse.MountConfig{
		FSName:                  bucketName,
		Options:                 flags.MountOptions,
		ErrorLogger:             GetStdLogger(NewLogger("fuse"), logrus.ErrorLevel),
		DisableWritebackCaching: true,
	}

	if flags.DebugFuse {
		fuseLog.Level = logrus.DebugLevel
		log.Level = logrus.DebugLevel
		mountCfg.DebugLogger = GetStdLogger(fuseLog, logrus.DebugLevel)
	}

	mfs, err = fuse.Mount(mountPoint, server, mountCfg)
	if err != nil {
		err = fmt.Errorf("Mount: %v", err)
		return
	}

	return
}

// Create a file system whose sole contents are a file named "foo" and a
// directory named "bar".
//
// The file may be opened for reading and/or writing. Its initial contents are
// empty. Whenever a flush or fsync is received, the supplied function will be
// called with the current contents of the file and its status returned.
//
// The directory cannot be modified.
func NewFileSystem(
	reportFlush func(string) error,
	reportFsync func(string) error) (server fuse.Server, err error) {
	fs := &flushFS{
		reportFlush: reportFlush,
		reportFsync: reportFsync,
	}

	server = fuseutil.NewFileSystemServer(fs)
	return
}

func (t *InterruptFSTest) SetUp(ti *TestInfo) {
	var err error

	// Create the file system.
	t.fs = interruptfs.New()
	AssertEq(nil, err)

	t.Server = fuseutil.NewFileSystemServer(t.fs)

	// Mount it.
	t.SampleTest.SetUp(ti)
}

// Mount the file system based on the supplied arguments, returning a
// fuse.MountedFileSystem that can be joined to wait for unmounting.
func mount(
	ctx context.Context,
	bucketName string,
	mountPoint string,
	flags *flagStorage) (mfs *fuse.MountedFileSystem, err error) {

	// Choose UID and GID.
	uid, gid, err := MyUserAndGroup()
	if err != nil {
		err = fmt.Errorf("MyUserAndGroup: %v", err)
		return
	}

	if flags.Uid >= 0 {
		uid = uint32(flags.Uid)
	}

	if flags.Gid >= 0 {
		gid = uint32(flags.Gid)
	}

	if err != nil {
		err = fmt.Errorf("setUpBucket: %v", err)
		return
	}

	awsConfig := &aws.Config{
		Region: aws.String("us-west-2"),
		//LogLevel: aws.LogLevel(aws.LogDebug),
	}
	server := fuseutil.NewFileSystemServer(NewGoofys(bucketName, awsConfig, uid, gid))

	// Mount the file system.
	mountCfg := &fuse.MountConfig{
		FSName:      bucketName,
		Options:     flags.MountOptions,
		ErrorLogger: log.New(os.Stderr, "fuse: ", log.Flags()),
	}

	if flags.DebugFuse {
		mountCfg.DebugLogger = log.New(os.Stderr, "fuse_debug: ", 0)
	}

	mfs, err = fuse.Mount(mountPoint, server, mountCfg)
	if err != nil {
		err = fmt.Errorf("Mount: %v", err)
		return
	}

	return
}

func (s *GoofysTest) mount(t *C, mountPoint string) {
	server := fuseutil.NewFileSystemServer(s.fs)

	// Mount the file system.
	mountCfg := &fuse.MountConfig{
		FSName:                  s.fs.bucket,
		Options:                 s.fs.flags.MountOptions,
		ErrorLogger:             GetStdLogger(NewLogger("fuse"), logrus.ErrorLevel),
		DisableWritebackCaching: true,
	}

	_, err := fuse.Mount(mountPoint, server, mountCfg)
	t.Assert(err, IsNil)
}

func (t *TraceFS) Mount() (*fuse.MountedFileSystem, error) {
	r, _ := t.newTrace(nil, "Mount", "Path=%s", t.MountPath)
	defer r.Finish()

	server := fuseutil.NewFileSystemServer(t)
	fs, err := fuse.Mount(t.MountPath, server, t.MountConfig)
	if err != nil {
		r.LazyPrintf("KodingNetworkFS#Mount: err '%s'", err)
		r.SetError()

		return nil, err
	}

	return fs, nil
}

// Mount the file system based on the supplied arguments, returning a
// fuse.MountedFileSystem that can be joined to wait for unmounting.
func mount(
	ctx context.Context,
	bucketName string,
	mountPoint string,
	flags *FlagStorage) (mfs *fuse.MountedFileSystem, err error) {

	awsConfig := &aws.Config{
		Region: aws.String("us-west-2"),
		Logger: GetLogger("s3"),
		//LogLevel: aws.LogLevel(aws.LogDebug),
	}
	if len(flags.Endpoint) > 0 {
		awsConfig.Endpoint = &flags.Endpoint
	}
	if flags.UsePathRequest {
		awsConfig.S3ForcePathStyle = aws.Bool(true)
	}

	goofys := NewGoofys(bucketName, awsConfig, flags)
	if goofys == nil {
		err = fmt.Errorf("Mount: initialization failed")
		return
	}
	server := fuseutil.NewFileSystemServer(goofys)

	fuseLog := GetLogger("fuse")

	// Mount the file system.
	mountCfg := &fuse.MountConfig{
		FSName:                  bucketName,
		Options:                 flags.MountOptions,
		ErrorLogger:             GetStdLogger(NewLogger("fuse"), logrus.ErrorLevel),
		DisableWritebackCaching: true,
	}

	if flags.DebugFuse {
		fuseLog.Level = logrus.DebugLevel
		mountCfg.DebugLogger = GetStdLogger(fuseLog, logrus.DebugLevel)
	}

	mfs, err = fuse.Mount(mountPoint, server, mountCfg)
	if err != nil {
		err = fmt.Errorf("Mount: %v", err)
		return
	}

	return
}

// Create a file system whose sole contents are a file named "foo" and a
// directory named "bar".
//
// The file "foo" may be opened for reading and/or writing, but reads and
// writes aren't supported. Additionally, any non-existent file or directory
// name may be created within any directory, but the resulting inode will
// appear to have been unlinked immediately.
//
// The file system maintains reference counts for the inodes involved. It will
// panic if a reference count becomes negative or if an inode ID is re-used
// after we expect it to be dead. Its Check method may be used to check that
// there are no inodes with unexpected reference counts remaining, after
// unmounting.
func NewFileSystem() (fs *ForgetFS) {
	// Set up the actual file system.
	impl := &fsImpl{
		inodes: map[fuseops.InodeID]*inode{
			cannedID_Root: &inode{
				attributes: fuseops.InodeAttributes{
					Nlink: 1,
					Mode:  0777 | os.ModeDir,
				},
			},
			cannedID_Foo: &inode{
				attributes: fuseops.InodeAttributes{
					Nlink: 1,
					Mode:  0777,
				},
			},
			cannedID_Bar: &inode{
				attributes: fuseops.InodeAttributes{
					Nlink: 1,
					Mode:  0777 | os.ModeDir,
				},
			},
		},
		nextInodeID: cannedID_Next,
	}

	// The root inode starts with a lookup count of one.
	impl.inodes[cannedID_Root].IncrementLookupCount()

	// The canned inodes are supposed to be stable from the user's point of view,
	// so we should allow them to be looked up at any point even if the kernel
	// has balanced its lookups with its forgets. Ensure that they never go to
	// zero until the file system is destroyed.
	impl.inodes[cannedID_Foo].IncrementLookupCount()
	impl.inodes[cannedID_Bar].IncrementLookupCount()

	// Set up the mutex.
	impl.mu = syncutil.NewInvariantMutex(impl.checkInvariants)

	// Set up a wrapper that exposes only certain methods.
	fs = &ForgetFS{
		impl:   impl,
		server: fuseutil.NewFileSystemServer(impl),
	}

	return
}

func (s *GoofysTest) runFuseTest(t *C, mountPoint string, umount bool, cmdArgs ...string) {
	server := fuseutil.NewFileSystemServer(s.fs)

	// Mount the file system.
	mountCfg := &fuse.MountConfig{
		FSName:                  s.fs.bucket,
		Options:                 s.fs.flags.MountOptions,
		ErrorLogger:             GetStdLogger(NewLogger("fuse"), logrus.ErrorLevel),
		DisableWritebackCaching: true,
	}

	_, err := fuse.Mount(mountPoint, server, mountCfg)
	t.Assert(err, IsNil)

	if umount {
		defer func() {
			err := fuse.Unmount(mountPoint)
			t.Assert(err, IsNil)
		}()
	}

	cmd := exec.Command(cmdArgs[0], cmdArgs[1:]...)
	cmd.Env = append(cmd.Env, os.Environ()...)
	cmd.Env = append(cmd.Env, "TRAVIS=true")
	cmd.Env = append(cmd.Env, "FAST=true")

	if isTravis() {
		logger := NewLogger("test")
		lvl := logrus.InfoLevel
		logger.Formatter.(*logHandle).lvl = &lvl
		w := logger.Writer()

		cmd.Stdout = w
		cmd.Stderr = w
	}

	err = cmd.Run()
	t.Assert(err, IsNil)
}

func (t *cachingFSTest) setUp(
	ti *TestInfo,
	lookupEntryTimeout time.Duration,
	getattrTimeout time.Duration) {
	var err error

	// We assert things about whether or not mtimes are cached, but writeback
	// caching causes them to always be cached. Turn it off.
	t.MountConfig.DisableWritebackCaching = true

	// Create the file system.
	t.fs, err = cachingfs.NewCachingFS(lookupEntryTimeout, getattrTimeout)
	AssertEq(nil, err)

	t.Server = fuseutil.NewFileSystemServer(t.fs)

	// Mount it.
	t.SampleTest.SetUp(ti)

	// Set up the mtime.
	t.initialMtime = time.Date(2012, 8, 15, 22, 56, 0, 0, time.Local)
	t.fs.SetMtime(t.initialMtime)
}

// Mount the file system based on the supplied arguments, returning a
// fuse.MountedFileSystem that can be joined to wait for unmounting.
func mount(
	ctx context.Context,
	bucketName string,
	mountPoint string,
	flags *FlagStorage) (mfs *fuse.MountedFileSystem, err error) {

	ossvfs := NewOssvfs(bucketName, flags)
	if ossvfs == nil {
		err = fmt.Errorf("Mount: initialization failed")
		return
	}
	server := fuseutil.NewFileSystemServer(ossvfs)

	fuseLog := GetLogger("fuse")

	// Mount the file system.
	mountCfg := &fuse.MountConfig{
		FSName:                  bucketName,
		Options:                 flags.MountOptions,
		ErrorLogger:             GetStdLogger(NewLogger("fuse"), logrus.ErrorLevel),
		DisableWritebackCaching: true,
	}

	if flags.DebugFuse {
		fuseLog.Level = logrus.DebugLevel
		mountCfg.DebugLogger = GetStdLogger(fuseLog, logrus.DebugLevel)
	}

	mfs, err = fuse.Mount(mountPoint, server, mountCfg)
	if err != nil {
		err = fmt.Errorf("Mount: %v", err)
		return
	}

	return
}

// Create a fuse file system server according to the supplied configuration.
func NewServer(cfg *ServerConfig) (server fuse.Server, err error) {
	// Check permissions bits.
	if cfg.FilePerms&^os.ModePerm != 0 {
		err = fmt.Errorf("Illegal file perms: %v", cfg.FilePerms)
		return
	}

	if cfg.DirPerms&^os.ModePerm != 0 {
		err = fmt.Errorf("Illegal dir perms: %v", cfg.FilePerms)
		return
	}

	// Create the object syncer.
	if cfg.TmpObjectPrefix == "" {
		err = errors.New("You must set TmpObjectPrefix.")
		return
	}

	syncer := gcsx.NewSyncer(
		cfg.AppendThreshold,
		cfg.TmpObjectPrefix,
		cfg.Bucket)

	// Set up the basic struct.
	fs := &fileSystem{
		mtimeClock:             timeutil.RealClock(),
		cacheClock:             cfg.CacheClock,
		bucket:                 cfg.Bucket,
		syncer:                 syncer,
		tempDir:                cfg.TempDir,
		implicitDirs:           cfg.ImplicitDirectories,
		inodeAttributeCacheTTL: cfg.InodeAttributeCacheTTL,
		dirTypeCacheTTL:        cfg.DirTypeCacheTTL,
		uid:                    cfg.Uid,
		gid:                    cfg.Gid,
		fileMode:               cfg.FilePerms,
		dirMode:                cfg.DirPerms | os.ModeDir,
		inodes:                 make(map[fuseops.InodeID]inode.Inode),
		nextInodeID:            fuseops.RootInodeID + 1,
		generationBackedInodes: make(map[string]inode.GenerationBackedInode),
		implicitDirInodes:      make(map[string]inode.DirInode),
		handles:                make(map[fuseops.HandleID]interface{}),
	}

	// Set up the root inode.
	root := inode.NewDirInode(
		fuseops.RootInodeID,
		"", // name
		fuseops.InodeAttributes{
			Uid:  fs.uid,
			Gid:  fs.gid,
			Mode: fs.dirMode,
		},
		fs.implicitDirs,
		fs.dirTypeCacheTTL,
		cfg.Bucket,
		fs.mtimeClock,
		fs.cacheClock)

	root.Lock()
	root.IncrementLookupCount()
	fs.inodes[fuseops.RootInodeID] = root
	fs.implicitDirInodes[root.Name()] = root
	root.Unlock()

	// Set up invariant checking.
	fs.mu = syncutil.NewInvariantMutex(fs.checkInvariants)

	// Periodically garbage collect temporary objects.
	var gcCtx context.Context
	gcCtx, fs.stopGarbageCollecting = context.WithCancel(context.Background())
	go garbageCollect(gcCtx, cfg.TmpObjectPrefix, fs.bucket)

	server = fuseutil.NewFileSystemServer(fs)
	return
}

// Mount mounts an specified folder on user VM using Fuse in the specificed
// local path.
func (k *KodingNetworkFS) Mount() (*fuse.MountedFileSystem, error) {
	server := fuseutil.NewFileSystemServer(k)
	return fuse.Mount(k.MountPath, server, k.MountConfig)
}