package impl

import (
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"strings"

	"v.io/core/veyron2"
	"v.io/core/veyron2/context"
	"v.io/core/veyron2/ipc"
	"v.io/core/veyron2/naming"
	"v.io/core/veyron2/security"
	"v.io/core/veyron2/services/mgmt/application"
	"v.io/core/veyron2/services/mgmt/binary"
	"v.io/core/veyron2/services/mgmt/device"
	"v.io/core/veyron2/services/mgmt/repository"
	"v.io/core/veyron2/services/security/access"
	"v.io/core/veyron2/uniqueid"
	"v.io/lib/cmdline"
)

var cmdInstallLocal = &cmdline.Command{
	Run:      runInstallLocal,
	Name:     "install-local",
	Short:    "Install the given application from the local system.",
	Long:     "Install the given application, specified using a local path.",
	ArgsName: "<device> <title> [ENV=VAL ...] binary [--flag=val ...]",
	ArgsLong: `
<device> is the veyron object name of the device manager's app service.

<title> is the app title.

This is followed by an arbitrary number of environment variable settings, the
local path for the binary to install, and arbitrary flag settings.`,
}

func init() {
	cmdInstallLocal.Flags.Var(&configOverride, "config", "JSON-encoded device.Config object, of the form: '{\"flag1\":\"value1\",\"flag2\":\"value2\"}'")
}

type openAuthorizer struct{}

func (openAuthorizer) Authorize(security.Context) error { return nil }

type mapDispatcher map[string]interface{}

func (d mapDispatcher) Lookup(suffix string) (interface{}, security.Authorizer, error) {
	o, ok := d[suffix]
	if !ok {
		return nil, nil, fmt.Errorf("suffix %s not found", suffix)
	}
	// TODO(caprita): Do not open authorizer even for a short-lived server.
	return o, &openAuthorizer{}, nil
}

func createServer(ctx *context.T, stderr io.Writer, objects map[string]interface{}) (string, func(), error) {
	server, err := veyron2.NewServer(ctx)
	if err != nil {
		return "", nil, err
	}
	spec := veyron2.GetListenSpec(ctx)
	endpoints, err := server.Listen(spec)
	if err != nil {
		return "", nil, err
	}
	var name string
	if spec.Proxy != "" {
		id, err := uniqueid.Random()
		if err != nil {
			return "", nil, err
		}
		name = id.String()
	}
	if err := server.ServeDispatcher(name, mapDispatcher(objects)); err != nil {
		return "", nil, err
	}
	cleanup := func() {
		if err := server.Stop(); err != nil {
			fmt.Fprintf(stderr, "server.Stop failed: %v", err)
		}
	}
	if name != "" {
		// Send a name rooted in our namespace root rather than the
		// relative name (in case the device manager uses a different
		// namespace root).
		//
		// TODO(caprita): Avoid relying on a mounttable altogether, and
		// instead pull out the proxied address and just send that.
		nsRoots := veyron2.GetNamespace(ctx).Roots()
		if len(nsRoots) > 0 {
			name = naming.Join(nsRoots[0], name)
		}
		return name, cleanup, nil
	}
	if len(endpoints) == 0 {
		return "", nil, fmt.Errorf("no endpoints")
	}
	return endpoints[0].Name(), cleanup, nil
}

var errNotImplemented = fmt.Errorf("method not implemented")

type binaryInvoker string

func (binaryInvoker) Create(ipc.ServerContext, int32, repository.MediaInfo) error {
	return errNotImplemented
}

func (binaryInvoker) Delete(ipc.ServerContext) error {
	return errNotImplemented
}

func (i binaryInvoker) Download(ctx repository.BinaryDownloadContext, _ int32) error {
	fileName := string(i)
	file, err := os.Open(fileName)
	if err != nil {
		return err
	}
	defer file.Close()
	bufferLength := 4096
	buffer := make([]byte, bufferLength)
	sender := ctx.SendStream()
	for {
		n, err := file.Read(buffer)
		switch err {
		case io.EOF:
			return nil
		case nil:
			if err := sender.Send(buffer[:n]); err != nil {
				return err
			}
		default:
			return err
		}
	}
}

func (binaryInvoker) DownloadURL(ipc.ServerContext) (string, int64, error) {
	return "", 0, errNotImplemented
}

func (i binaryInvoker) Stat(ctx ipc.ServerContext) ([]binary.PartInfo, repository.MediaInfo, error) {
	fileName := string(i)
	h := md5.New()
	bytes, err := ioutil.ReadFile(fileName)
	if err != nil {
		return []binary.PartInfo{}, repository.MediaInfo{}, err
	}
	h.Write(bytes)
	part := binary.PartInfo{Checksum: hex.EncodeToString(h.Sum(nil)), Size: int64(len(bytes))}
	return []binary.PartInfo{part}, repository.MediaInfo{Type: "application/octet-stream"}, nil
}

func (binaryInvoker) Upload(repository.BinaryUploadContext, int32) error {
	return errNotImplemented
}

func (binaryInvoker) GetACL(ctx ipc.ServerContext) (acl access.TaggedACLMap, etag string, err error) {
	return nil, "", errNotImplemented
}

func (binaryInvoker) SetACL(ctx ipc.ServerContext, acl access.TaggedACLMap, etag string) error {
	return errNotImplemented
}

type envelopeInvoker application.Envelope

func (i envelopeInvoker) Match(ipc.ServerContext, []string) (application.Envelope, error) {
	return application.Envelope(i), nil
}
func (envelopeInvoker) GetACL(ipc.ServerContext) (acl access.TaggedACLMap, etag string, err error) {
	return nil, "", errNotImplemented
}

func (envelopeInvoker) SetACL(ipc.ServerContext, access.TaggedACLMap, string) error {
	return errNotImplemented
}

// runInstallLocal creates a new envelope on the fly from the provided
// arguments, and then points the device manager back to itself for downloading
// the app envelope and binary.
//
// It sets up an app and binary server that only lives for the duration of the
// command, and listens on the profile's listen spec.  The caller should set the
// --veyron.proxy if the machine running the command is not accessible from the
// device manager.
//
// TODO(caprita/ashankar): We should use bi-directional streams to get this
// working over the same connection that the command makes to the device
// manager.
func runInstallLocal(cmd *cmdline.Command, args []string) error {
	if expectedMin, got := 2, len(args); got < expectedMin {
		return cmd.UsageErrorf("install-local: incorrect number of arguments, expected at least %d, got %d", expectedMin, got)
	}
	deviceName, title := args[0], args[1]
	args = args[2:]
	envelope := application.Envelope{Title: title}
	// Extract the environment settings, binary, and arguments.
	firstNonEnv := len(args)
	for i, arg := range args {
		if strings.Index(arg, "=") <= 0 {
			firstNonEnv = i
			break
		}
	}
	envelope.Env = args[:firstNonEnv]
	args = args[firstNonEnv:]
	if len(args) == 0 {
		return cmd.UsageErrorf("install-local: missing binary")
	}
	binary := args[0]
	envelope.Args = args[1:]
	if _, err := os.Stat(binary); err != nil {
		return fmt.Errorf("binary %v not found: %v", binary, err)
	}
	objects := map[string]interface{}{"binary": repository.BinaryServer(binaryInvoker(binary))}
	name, cancel, err := createServer(gctx, cmd.Stderr(), objects)
	if err != nil {
		return fmt.Errorf("failed to create server: %v", err)
	}
	defer cancel()
	envelope.Binary = naming.Join(name, "binary")

	objects["application"] = repository.ApplicationServer(envelopeInvoker(envelope))
	appName := naming.Join(name, "application")
	appID, err := device.ApplicationClient(deviceName).Install(gctx, appName, device.Config(configOverride))
	// Reset the value for any future invocations of "install" or
	// "install-local" (we run more than one command per process in unit
	// tests).
	configOverride = configFlag{}
	if err != nil {
		return fmt.Errorf("Install failed: %v", err)
	}
	fmt.Fprintf(cmd.Stdout(), "Successfully installed: %q\n", naming.Join(deviceName, appID))
	return nil
}