funmow/execution_context.go

package funmow

import (
	"fmt"
	"regexp"
	"strings"
	"unicode"
)

type ExecutionContext struct {
	actor            Object
	context          Object
	inbound          chan PlayerEvent
	outbound         chan PlayerEvent
	eventDistributor *EventDistributor
	db               *DB
	factory          *ObjectFactory
	forceContext     bool
}

func NewForceContext(e *EventDistributor, w *DB, outbound chan PlayerEvent) *ExecutionContext {

	c := new(ExecutionContext)

	c.outbound = outbound
	c.eventDistributor = e
	c.db = w
	c.factory = NewObjectFactory(w)
	c.forceContext = true
	return c
}

func NewExecutionContext(actorID DBRef, e *EventDistributor, w *DB, outbound chan PlayerEvent) *ExecutionContext {

	c := new(ExecutionContext)

	actor, found := w.Fetch(actorID)
	if !found {
		return nil
	}
	
	

	c.actor = actor
	c.outbound = outbound
	c.eventDistributor = e
	c.db = w
	c.factory = NewObjectFactory(w)

	return c
}

func (c *ExecutionContext) StartInboundChannel() chan PlayerEvent {
	c.inbound = make(chan PlayerEvent)
	inboundBuffer := make(chan PlayerEvent)
	c.outbound = c.outbound

	go func() {

		// An inbound event buffer to protect the event distributor from long
		// running tasks. The alternative is to run each inbound event in a
		// separate goroutine but that has potential problems (ie, two emits
		// arrive in order;  the first one requires an extra DB lookup to sort
		// out context. Now the second one ends up sending its output event
		// before the first, and the client sees things backwards.

		queue := make([]*PlayerEvent, 0)
		running := true
		for running {
			if len(queue) == 0 {
				select {
				case newEvent, ok := <-c.inbound:
					if !ok {
						running = false
						break
					}
					queue = append(queue, &newEvent)
				}
			} else {
				event := queue[0]
				select {
				case newEvent, ok := <-c.inbound:
					if !ok {
						running = false
						break
					}
					queue = append(queue, &newEvent)
				case inboundBuffer <- *event:
					queue = queue[1:]
				}
			}
		}
		// closure of c.inbound is the signal from the event distributor that we need to die.
		// we then close  inboundBuffer to tell the event goroutine to die
		close(inboundBuffer)
	}()

	go func() {
		for {
			event, ok := <-inboundBuffer
			if !ok {
				break
			}
			c.HandleEvent(event)
		}
		// mark player as offline
		if c.actor.Type == "player" {
			c.actor.SetFlag("online", false)
			c.actor.Commit()
		}
		// and finally we tell the event distributor to delete us.
		c.outbound <- PlayerEvent{src: c.actor.ID, dst: c.actor.ID, messageType: EventTypeTeardownComplete}
	}()

	return c.inbound
}

func (c *ExecutionContext) HandleEvent(m PlayerEvent) {
	c.actor.Refresh()
	contextID, found := c.db.GetParent(c.actor.ID)
	if found {
		c.context, _ = c.db.Fetch(contextID)
	}
	
	
	switch m.messageType {
	case EventTypeLogin:
		if c.actor.Type == "player" {
			c.actor.SetFlag("online", true)
			c.actor.Commit()
			c.system("Yay! %s has connected! Oh boy!", c.actor.Name)
			c.oemit(c.context.ID, "You hear a rustling as %s awakens from a slumber.", c.actor.Name)
		}
	case EventTypeEmit:
		fallthrough
	case EventTypeOEmit:
		if m.dst == c.context.ID {
			c.output("%s", m.message)
		}
	case EventTypePEmit:
		c.output("%s", m.message)
	case EventTypeWall:
		speaker, found := c.db.Fetch(m.src)
		if !found {
			break
		}
		c.output("In the distance, you hear %s bellow out: \"%s\"", speaker.Name, m.message)
	case EventTypeSystem:
		c.output(m.message)
	case EventTypePage:
		speaker, found := c.db.Fetch(m.src)
		if !found {
			break
		}
		c.output("%s pages you: \"%s\"", speaker.Name, m.message)
	case EventTypeSay:
		if m.dst == c.context.ID {
			speaker, found := c.db.Fetch(m.src)
			if !found {
				break
			}
			c.output("%s says \"%s\"", speaker.Name, m.message)
		}
	case EventTypePose:
		if m.dst == c.context.ID {
			if m.src == c.actor.ID {
				c.output("%s %s", c.actor.Name, m.message)
			} else {
				speaker, found := c.db.Fetch(m.src)
				if !found {
					break
				}
				c.output("%s %s", speaker.Name, m.message)
			}
		}
	case EventTypeForce:
		actor, found := c.db.Fetch(m.dst)
		if !found {
			break
		}
		c.actor = actor
		c.evaluateCommand(m)
	case EventTypeCommand:
		c.evaluateCommand(m)
	}
}

func (c *ExecutionContext) evaluateCommand(m PlayerEvent) {
	message := m.message
	switch {
	case message == "whoami":
		c.output(c.actor.Name)
	case message == "l":
		c.lookCmd("")
	case message == "look":
		c.lookCmd("")
	case strings.HasPrefix(message, "l "): // look at
		c.lookCmd(strings.TrimPrefix(message, "l "))
	case strings.HasPrefix(message, "look "): // look at
		c.lookCmd(strings.TrimPrefix(message, "look "))
	case strings.HasPrefix(message, "ex "):
		c.examineCmd(strings.TrimPrefix(message, "ex "))
	case strings.HasPrefix(message, "examine "):
		c.examineCmd(strings.TrimPrefix(message, "examine "))
	case strings.HasPrefix(message, "\""):
		c.sayCmd(strings.TrimPrefix(message, "\""))
	case strings.HasPrefix(message, "say "):
		c.sayCmd(strings.TrimPrefix(message, "say "))
	case strings.HasPrefix(message, ":"):
		c.poseCmd(strings.TrimPrefix(message, ":"))
	case strings.HasPrefix(message, "pose "):
		c.poseCmd(strings.TrimPrefix(message, "pose "))
	case message == "i":
		c.inventoryCmd()
	case message == "inventory":
		c.inventoryCmd()
	case strings.HasPrefix(message, "get "):
		c.getCmd(strings.TrimPrefix(message, "get "))
	case strings.HasPrefix(message, "drop "):
		c.dropCmd(strings.TrimPrefix(message, "drop "))
	case strings.HasPrefix(message, "give "):
		c.giveCmd(message)
	case strings.HasPrefix(message, "put "):
		c.putCmd(message)
	case strings.HasPrefix(message, "enter "):
		c.enterCmd(strings.TrimPrefix(message, "enter "))
	case message == "leave":
		c.leaveCmd()
	case message == "quit":
		c.quitCmd(m.connectionID)
	case message == "WHO":
		c.whoCmd()
	case strings.HasPrefix(message, "@create "):
		c.createCmd(strings.TrimPrefix(message, "@create "))
	case strings.HasPrefix(message, "@dig "):
		c.digCmd(message)
	case strings.HasPrefix(message, "@open "):
		c.openCmd(message)
	case strings.HasPrefix(message, "@name "):
		c.nameCmd(message)
	case strings.HasPrefix(message, "@desc "):
		c.descCmd(message)
	case strings.HasPrefix(message, "@set "):
		c.setCmd(message)
	case strings.HasPrefix(message, "@tel "):
		c.telCmd(strings.TrimPrefix(message, "@tel "))
	case strings.HasPrefix(message, "@dump "):
		c.dumpCmd(strings.TrimPrefix(message, "@dump "))
	case strings.HasPrefix(message, "@destroy "):
		c.destroyCmd(strings.TrimPrefix(message, "@destroy "))
	case strings.HasPrefix(message, "@force "):
		c.forceCmd(message)
	
		
	default:
		if !c.goCmd(message) {
			c.output("What?\n")
		}
	}

}

func (c *ExecutionContext) lookCmd(target string) {

	if len(target) > 0 {
		object, found := c.MatchFirst(c.context.ID, target, false, false)
		if (!found) {
			c.output("I don't see that here.")
			return
		}
		c.output("%s\n%s", object.DetailedName(), object.Description)
	} else {
		c.output("%s\n%s", c.context.DetailedName(), c.context.Description)
		contents := c.context.GetContents(c.actor.ID)
		if len(contents) > 0 {
			c.output("Contents:\n"+strings.Join(contents,"\n"))
		}
		exits := c.context.GetExits()
		if len(exits) > 0 {
			c.output("Obvious Exits:\n"+strings.Join(exits," "))
		}
	}

}

func (c *ExecutionContext) objectName(id DBRef) string {
	o, found := c.db.Fetch(id)
	if found {
		return o.DetailedName()
	} else {
		return fmt.Sprintf("MISSING OBJECT <#%d>", id)
	}
}

func (c *ExecutionContext) examineCmd(objectName string) {

	object, found := c.MatchFirst(c.context.ID, objectName, true, true)
	if (!found) {
		c.output("I don't see that here.")
		return
	}
	
	c.output("%s", object.DetailedName())
	c.output("ID: %d", object.ID)
	c.output("Type: %s", object.Type)
	c.output("@name: %s", object.Name)
	c.output("@desc: %s", object.Description)
	c.output("Inside: %s", c.objectName(c.context.ID))
	c.output("Next: %s", c.objectName(object.Next))
	c.output("Owner: %s", c.objectName(object.Owner))

	contents := object.GetContents(0)
	if len(contents) > 0 {
		c.output("Contents:\n %s", strings.Join(contents, "\n "))
	}
	
	exits := object.GetExits()
	if len(exits) > 0 {
		c.output("Exits:\n %s", strings.Join(exits, "\n "))
	}
	
	
   
    flags := make([]string, 0, len(object.Flags))
    for k, v := range object.Flags {
        if v {
        	flags = append(flags, k)
        }
    }
    c.output("Flags:\n%s", strings.Join(flags, ", "))
    
    properties := make([]string, 0, len(object.Properties))
    for k, v := range object.Properties {
        properties = append(properties, fmt.Sprintf("%s: \"%s\"", k, v))
    }
    c.output("Properties:\n%s", strings.Join(properties, ", "))

}



func (c *ExecutionContext) forceCmd(input string) {

	r, _ := regexp.Compile(`^@force\pZ+([^=]*[^=\pZ]{1})\pZ*=\pZ*(.*)\pZ*$`)
	params := r.FindStringSubmatch(input)
	if params == nil {
		return
	}

	objectName, command := params[1], params[2]

	wizard := c.actor.GetFlag("wizard")

	object, found := c.MatchFirst(c.context.ID, objectName, true, false)
	if (!found) {
		c.output("I don't see that here.")
		return
	}
	if object.Type != "thing" && object.Type != "player" {
		c.output("Some things just can't be forced.")
		return
	}
	if object.Type == "player" && !wizard {
		c.output("It's not nice to force others to do your bidding.")
		return
	} 
	if object.Owner != c.actor.ID && !wizard {
		c.output("It's not nice to touch other people's things.")
		return
	} 
	c.outbound <- PlayerEvent{src: c.actor.ID, dst: object.ID, message: command, messageType: EventTypeForce}

}

func (c *ExecutionContext) sayCmd(message string) {

	c.output("You say \"%s\"", message)
	c.outbound <- PlayerEvent{src: c.actor.ID, dst: c.context.ID, message: message, messageType: EventTypeSay}

}

func (c *ExecutionContext) poseCmd(message string) {

	c.outbound <- PlayerEvent{src: c.actor.ID, dst: c.context.ID, message: message, messageType: EventTypePose}

}

func (c *ExecutionContext) inventoryCmd() {

	inventory := c.actor.GetContents(0)

	if len(inventory) > 0 {
		c.output("Inventory:\n %s", strings.Join(inventory, "\n "))
	} else {
		c.output("You're not carrying anything.")
	}

}

func (c *ExecutionContext) getCmd(objectName string) {
	
	object, found := c.MatchFirst(c.context.ID, objectName, false, false)
	if (!found) {
		c.output("I don't see that here.")
		return
	}
	
	if object.ID == c.actor.ID {
		c.output("You can't pick yourself up.")
		return
	}
	if object.Type == "room" {
		c.output("You can't carry a whole room, silly!")
		return
	}
	err := c.actor.Contains(&object)
	if err != nil {
		return
	}
	//c.actor.Refresh()
	c.output("You pick up %s.", object.Name)
	c.pemit(object.ID, "%s picked you up.", c.actor.Name)
	c.oemit(c.context.ID, "%s picks up %s.", c.actor.Name, object.Name)


}

func (c *ExecutionContext) putCmd(input string) {
	c.xferCmd(input, "put", "into")
}

func (c *ExecutionContext) giveCmd(input string) {
	c.xferCmd(input, "give", "to")
}


func (c *ExecutionContext) xferCmd(input string, verb string, preposition string) {

	r, _ := regexp.Compile(`^`+verb+`\pZ+([^=]*[^=\pZ]{1})\pZ*`+preposition+`\pZ*(.*)\pZ*$`)

	params := r.FindStringSubmatch(input)
	if params == nil {
		return
	}

	objectName, receiverName := params[1], params[2]

	object, found := c.MatchFirst(c.actor.ID, objectName, false, false)
	if (!found) {
		c.output("You can't "+verb+" what you don't have.")
		return
	}
	receiver, found := c.MatchFirst(c.context.ID, receiverName, false, false)
	if (!found) {
		c.output("I cant find who or what you want to "+verb+" this "+preposition+".")
		return
	}

	err := receiver.Contains(&object)
	if err != nil {
		return
	}
	
	c.output("You "+verb+" %s "+preposition+" %s.", object.Name, receiver.Name)
	c.pemit(object.ID, "%s "+verb+"s you "+preposition+" %s.", c.actor.Name, receiver.Name)
	
	if (verb == "give") {
		c.pemit(receiver.ID, "%s gives you %s.", c.actor.Name, object.Name)
	} else {
		c.pemit(receiver.ID, "%s puts %s into you.", c.actor.Name, object.Name)
	}
	
}

func (c *ExecutionContext) MatchFirst(context DBRef, matchName string, globalDBRefMatch bool, playerNameMatch bool) (Object, bool) {

	if matchName == "here" {
		return c.db.Fetch(context)
	}
	if matchName == "me" {
		return c.actor, true
	}	
		
	if globalDBRefMatch {
		ref, valid := NewDBRefFromHashRef(matchName)
		if valid {
			o, found := c.db.Fetch(ref)
			if found {
				return o, true
			}
		}
	}
	
	if playerNameMatch {
		playerMeta, foundMeta := c.db.GetPlayer(matchName)
		if foundMeta {
			o, found := c.db.Fetch(playerMeta.ID)
			if found {
				return o, true
			}
		}
	}

	for childID, _ := range c.db.GetChildren(context) {
		o, found := c.db.Fetch(childID)
		if found {
			_, refValid := NewDBRefFromHashRef(matchName)
			lowerObjectName := strings.ToLower(o.Name)
			lowerMatchName := strings.ToLower(matchName)
			if strings.HasPrefix(lowerObjectName, lowerMatchName) || refValid {
				return o, true
			}
		}
	}
	return Object{}, false
	
}

func (c *ExecutionContext) dropCmd(objectName string) {

	object, found := c.MatchFirst(c.actor.ID, objectName, false, false)
	if (!found) {
		c.output("You're not carrying that.")
		return
	}
	
	err := c.context.Contains(&object)
	if err != nil {
		return
	}

	c.output("You drop %s.", object.Name)
	c.pemit(object.ID, "%s drops you.", c.actor.Name)
	c.oemit(c.context.ID, "%s drops %s.", c.actor.Name, object.Name)

}

func (c *ExecutionContext) enterCmd(objectName string) {

	object, found := c.MatchFirst(c.context.ID, objectName, false, false)
	if (!found) {
		c.output("I don't see that here.")
		return
	}
	
	if object.Type == "player" {
		c.output("Maybe you should seek consent prior to entering another player.")
		return
	}
	if object.Type == "exit" {
		c.output("This s not how exits are meant to be used.")
		return
	}
	if object.ID == c.actor.ID {
		c.output("Entering yourself would be a bad idea.")
		return
	}
	
	err := object.Contains(&c.actor)
	if err != nil {
		return
	}
	c.output("You climb into %s.", object.Name)
	c.oemit(c.context.ID, "%s climbs into %s.", c.actor.Name, object.Name)
	c.oemit(object.ID, "%s squeezes into %s with you.", c.actor.Name, object.Name)
	
}

func (c *ExecutionContext) leaveCmd() {

	outerObjectID, _ := c.db.GetParent(c.context.ID)
	if outerObjectID == 0 { // probably trying to 'leave' a room
		c.output("You can't leave here.")
		return
	}

	container, found := c.db.Fetch(outerObjectID)
	if !found { return }

	err := container.Contains(&c.actor)
	if err != nil { return }

	c.output("You climb out of %s.", c.context.Name)
	c.oemit(c.context.ID, "%s climbs out of %s.", c.actor.Name, c.context.Name)
	c.oemit(container.ID, "%s climbs out of %s.", c.actor.Name, c.context.Name)

}

func (c *ExecutionContext) quitCmd(connectionID int) {

	c.output("So long, it's been good to know yah.")
	c.outbound <- PlayerEvent{src: c.actor.ID, dst: c.actor.ID, messageType: EventTypeQuit, connectionID: connectionID}

}

func (c *ExecutionContext) whoCmd() {
	//	onlinePlayers := c.eventDistributor.OnlinePlayers()

	c.output("Currently Online:\n")

	//for _, ref := range onlinePlayers {
	//	c.output("%s\n", c.db.GetName(ref))
	//}
}

func (c *ExecutionContext) createCmd(message string) {

	o := c.factory.NewThing()
	o.Name = strings.TrimSpace(message)
	o.Owner = c.actor.ID
	o.Commit()

	err := c.actor.Contains(&o)
	if err != nil {
		return
	}

	c.output("%s Created.", o.DetailedName())

}

func (c *ExecutionContext) openCmd(input string) {
	// @open <in1;in2;in3;etc>=#<room>,<out1;out2;out3;etc>

	r, _ := regexp.Compile(`^@open\pZ+([^=]*[^=\pZ]+)\pZ*=#([0-9]+)(?:\pZ*,\pZ*([^,]*[^,\pZ]+)\pZ*)?`)
	params := r.FindStringSubmatch(input)

	if params == nil {
		return
	}

	inExit, roomIDStr, outExit := params[1], params[2], params[3]

	if len(inExit) == 0 || len(roomIDStr) == 0 {
		c.output("Bad command or file name.")
		return
	}

	targetID, _ := NewDBRefFromString(roomIDStr) // this will never fail, the regexp guarantees that
	targetRoom, found := c.db.Fetch(targetID)
	if !found {
		c.output("Target not found.")
		return
	}

	toExit := c.factory.NewExit(inExit, targetRoom.ID, c.actor.ID)
	toExit.Commit()
	err := c.context.Contains(&toExit)
	if err != nil {
		return
	}
	c.output("%s Created.", toExit.DetailedName())

	if len(outExit) > 0 {
		fromExit := c.factory.NewExit(outExit, c.context.ID, c.actor.ID)
		fromExit.Commit()
		err = targetRoom.Contains(&fromExit)
		if err != nil {
			return
		}
		c.output("%s Created.", fromExit.DetailedName())
	}

}

func (c *ExecutionContext) digCmd(input string) {
	// @dig <Room name>=<in1;in2;in3;etc>,<out1;out2;out3;etc>
	//@dig foo bar  = <F>oo;foo;f,<B>ack;back;b

	r, _ := regexp.Compile(`^@dig\pZ+([^=]*[^=\pZ]+)(\pZ*=\pZ*(?:([^,]*[^,\pZ]+)\pZ*)?(?:\pZ*,\pZ*([^,]*[^,\pZ]+)\pZ*)?)?`)
	params := r.FindStringSubmatch(input)
	if params == nil {
		return
	}

	roomName, inExit, outExit := params[1], params[2], params[3]

	if len(roomName) == 0 {
		c.output("Rooms can't not have names.")
		return
	}

	newRoom := c.factory.NewRoom()
	newRoom.Name = roomName
	newRoom.Owner = c.actor.ID
	newRoom.Commit()

	c.output("%s Created.", newRoom.DetailedName())

	if len(inExit) > 0 || len(outExit) > 0 {
		if len(inExit) > 0 {
			toExit := c.factory.NewExit(inExit, newRoom.ID, c.actor.ID)
			toExit.Commit()
			err := c.context.Contains(&toExit)
			if err != nil {
				return
			}
			c.output("%s Created.", toExit.DetailedName())
		}
		if len(outExit) > 0 {
			fromExit := c.factory.NewExit(outExit, c.context.ID, c.actor.ID)
			fromExit.Commit()
			err := newRoom.Contains(&fromExit)
			if err != nil {
				return
			}
			c.output("%s Created.", fromExit.DetailedName())
		}
	}

}


func (c *ExecutionContext) nameCmd(input string) {

	r, _ := regexp.Compile(`^@name\pZ+([^=]*[^=\pZ]{1})\pZ*=\pZ*(.*)\pZ*$`)
	params := r.FindStringSubmatch(input)
	if params == nil {
		return
	}

	searchName, newName := params[1], params[2]

	candidate, found := c.MatchFirst(c.context.ID, searchName, true, false)
	if !found {
		c.output("I don't see that here.")
		return
	}

	if candidate.Type == "player" {
		i := strings.IndexFunc(newName, func(c rune) bool {
			return unicode.IsSpace(c)
		})
		if i != -1 {
			c.output("Player names can't have spaces.")
			return
		}
		if c.actor.ID != candidate.ID && !c.actor.GetFlag("wizard") {
			c.output("Only wizards can rename other players.")
			return
		}
		err := c.db.RenamePlayer(candidate.Name, newName)
		if err != nil {
			c.output("I can't do that. Something has gone wrong.")
			return
		}
	}
	candidate.Name = newName
	candidate.Commit()
	c.output("Name set.")

}



func (c *ExecutionContext) setCmd(input string) {
	r, _ := regexp.Compile(`^@set\pZ+([^=]*[^=\pZ]{1})\pZ*=\pZ*(!)?(.*)\pZ*$`)
	params := r.FindStringSubmatch(input)
	if params == nil {
		return
	}

	objectName, value, flag := params[1], params[2]!="!", params[3]

	object, found := c.MatchFirst(c.context.ID, objectName, true, true)
	if (!found) {
		c.output("I don't know what that is")
		return
	}
	
		
	object.SetFlag(flag, value)
	object.Commit()
	
	c.output("It is so.")
	
}

func (c *ExecutionContext) descCmd(input string) {

	r, _ := regexp.Compile(`^@desc\pZ+([^=]*[^=\pZ]{1})\pZ*=\pZ*(.*)\pZ*$`)
	params := r.FindStringSubmatch(input)
	if params == nil {
		return
	}

	objectName, description := params[1], params[2]

	object, found := c.MatchFirst(c.actor.ID, objectName, false, false)
	if !found {
		c.output("I don't see that here.")
		return
	}

	object.Description = description
	object.Commit()

	c.output("Description set.")

}

func (c *ExecutionContext) telCmd(destStr string) {

	var dest Object
	var found bool
	
	dest, found = c.MatchFirst(c.context.ID, destStr, true, false)
	
	if !found {
		c.output("Invalid destination.")
		return
	}
	
	if dest.Type == "exit" {
		c.output("As fun is it sounds, you're not going to teleport into an exit.")
		return
	}
	
	if dest.Type == "player" {
		c.output("Teleporting into players is very impolite.")
		return
	}

	if dest.Owner != c.actor.ID && !dest.GetFlag("jump_ok") {
		c.output("You're not allowed to do that.")
	}
	
	c.output("You feel an intense wooshing sensation.")
	c.oemit(c.context.ID, "%s teleports out of the room.", c.actor.Name)
	c.oemit(dest.ID, "%s teleports in to the room.", c.actor.Name)

	err := dest.Contains(&c.actor)
	if err != nil {
		return
	}
	

	c.actor.Refresh()
	c.lookCmd("")

}

func (c *ExecutionContext) dumpCmd(refStr string) {

	object, found := c.MatchFirst(c.context.ID, refStr, true, true)

	if !found {
		c.output("I can't find that.")
		return
	}

	c.output("%s", c.db.DumpObject(object.ID))

}

func (c *ExecutionContext) destroyCmd(target string) {

	object, found := c.MatchFirst(c.actor.ID, target, true, false)
	if (!found) {
		c.output("I don't see that here.")
		return
	}
	
	if object.ID == c.actor.ID {
		c.output("There are alternatives to suicide.")
		return
	}
	if object.Type == "player" {
		c.output("I didn't think homicide was your thing.")
		return
	}
	name := object.DetailedName()
	err := object.Delete()
	if err == nil {
		c.output("%s vanishes into thin air.", name)
	}

}

func (c *ExecutionContext) goCmd(dir string) bool {

	exit, matchType := c.context.MatchExitNames(dir).ExactlyOne()
	switch matchType {
	case MatchOne:
		if exit.Next.Valid() {
			newRoom, found := c.db.Fetch(exit.Next)
			if !found {
				c.output("That exit appears to be broken!")
				return true
			}
			err := newRoom.Contains(&c.actor)
			if err != nil {
				return false
			}
			//c.actor.Refresh()
			c.output("You head towards %s.", newRoom.Name)
			c.oemit(c.context.ID, "%s leaves the room.", c.actor.Name)
			c.oemit(newRoom.ID, "%s enters the room.", c.actor.Name)
			return true
		}
	case MatchNone:
		return false
	case MatchMany:
		c.output("Ambiguous exit names are ambiguous.")
		return true
	}

	return false

}

func (c *ExecutionContext) wall(format string, a ...interface{}) {

	message := fmt.Sprintf(format, a...)
	c.outbound <- PlayerEvent{src: c.actor.ID, message: message, messageType: EventTypeWall}

}

func (c *ExecutionContext) system(format string, a ...interface{}) {

	message := fmt.Sprintf(format, a...)
	c.outbound <- PlayerEvent{src: c.actor.ID, message: message, messageType: EventTypeSystem}

}

func (c *ExecutionContext) oemit(audience DBRef, format string, a ...interface{}) {

	message := fmt.Sprintf(format, a...)
	c.outbound <- PlayerEvent{src: c.actor.ID, dst: audience, message: message, messageType: EventTypeOEmit}

}

func (c *ExecutionContext) output(format string, a ...interface{}) {

	message := fmt.Sprintf(format, a...)
	if !c.forceContext {
		c.outbound <- PlayerEvent{src: c.actor.ID, dst: c.actor.ID, message: message, messageType: EventTypeOutput}
	}
}

func (c *ExecutionContext) pemit(target DBRef, format string, a ...interface{}) {

	message := fmt.Sprintf(format, a...)
	c.outbound <- PlayerEvent{src: c.actor.ID, dst: target, message: message, messageType: EventTypePEmit}

}

func (c *ExecutionContext) emit(audience DBRef, format string, a ...interface{}) {

	message := fmt.Sprintf(format, a...)
	c.outbound <- PlayerEvent{src: c.actor.ID, dst: audience, message: message, messageType: EventTypeEmit}

}