package rt

import (
	"flag"
	"fmt"
	"os"
	"sync"

	"veyron2"
	"veyron2/ipc"
	"veyron2/ipc/stream"
	"veyron2/mgmt"
	"veyron2/naming"
	"veyron2/product"
	"veyron2/vlog"

	imounttable "veyron/runtimes/google/naming/mounttable"
)

type mgmtRT mgmt.Runtime

type vrt struct {
	mgmtRT
	product product.T
	sm      stream.Manager
	mt      naming.MountTable
	rid     naming.RoutingID
	signals chan os.Signal
	id      veyron2.LocalIDOpt
	client  ipc.Client
}

var (
	globalR   veyron2.Runtime
	globalErr error
	once      sync.Once
)

// Implements veyron2/rt.New
func New(opts ...veyron2.ROpt) (veyron2.Runtime, error) {
	r := &vrt{}
	return r, r.init(opts...)
}

// Implements veyron2/rt.R
func R() veyron2.Runtime {
	return globalR
}

// Used to implement veyron2/rt.Init
func Init(opts ...veyron2.ROpt) (veyron2.Runtime, error) {
	once.Do(func() {
		globalR, globalErr = New(opts...)
	})
	return globalR, globalErr
}

// init initalizes the runtime instance it is invoked on.
func (rt *vrt) init(opts ...veyron2.ROpt) error {
	flag.Parse()
	// TODO(ashankar,cnicolaou): Change the default debug address to
	// the empty string.
	// In March 2014 this was temporarily set to "127.0.0.1:0" so that the debugging
	// HTTP server always runs, which was useful during initial veyron
	// development. We restrict it to localhost to avoid annoying firewall
	// warnings and to provide a modicum of security.
	debug := "127.0.0.1:0"
	mtRoots := []string{}

	for _, o := range opts {
		switch v := o.(type) {
		case veyron2.LocalIDOpt:
			rt.id = v
		case veyron2.ProductOpt:
			rt.product = v.T
		case veyron2.MountTableRoots:
			mtRoots = v
		case veyron2.HTTPDebugOpt:
			debug = string(v)
		default:
			return fmt.Errorf("option has wrong type %T", o)
		}
	}

	rt.initLogging()
	rt.initSignalHandling()

	if rt.Product() == nil {
		product, err := product.DetermineProduct()
		if err != nil {
			return err
		}
		rt.product = product
	}

	if len(mtRoots) == 0 {
		if mtRoot := os.Getenv("MOUNTTABLE_ROOT"); mtRoot != "" {
			mtRoots = append(mtRoots, mtRoot)
		}
	}

	if mt, err := imounttable.New(rt, mtRoots...); err != nil {
		return fmt.Errorf("Couldn't create mount table: %v", err)
	} else {
		rt.mt = mt
	}
	vlog.VI(2).Infof("MountTable Roots: %s", mtRoots)

	var err error
	if rt.sm, err = rt.NewStreamManager(); err != nil {
		return err
	}

	if err = rt.initIdentity(); err != nil {
		return err
	}

	if rt.client, err = rt.NewClient(rt.id); err != nil {
		return err
	}

	rt.initMgmt()

	if len(debug) > 0 {
		rt.startHTTPDebugServer(debug, rt.sm)
	}
	vlog.VI(2).Infof("rt.Init done")
	return nil
}

func (rt *vrt) Shutdown() {
	rt.sm.Shutdown()
	rt.shutdownSignalHandling()
	rt.shutdownLogging()
}