Rename file, remove unused type

src/irc/actionTypes.go

@@ -0,0 +1,39 @@
+package irc
+
+type NickChangeAction struct {
+	User    *User
+	OldNick *Nick
+	NewNick *Nick
+}
+
+type PartAction struct {
+	User        *User
+	ChannelName ChannelName
+	Reason      *string
+}
+
+type JoinAction struct {
+	User        *User
+	ChannelName ChannelName
+}
+
+type ChatMode string
+
+const (
+	ChatModePrivmsg ChatMode = "PRIVMSG"
+	ChatModeNotice  ChatMode = "NOTICE"
+)
+
+type SendMessageToUserAction struct {
+	User        *User
+	Mode        ChatMode
+	Destination *User
+	Message     string
+}
+
+type SendMessageToChannelAction struct {
+	User        *User
+	Mode        ChatMode
+	Destination canonicalChannelName
+	Message     string
+}

src/irc/broadcast.go

@@ -0,0 +1,46 @@
+package irc
+
+import (
+	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/transport"
+)
+
+type BroadcastGroup struct {
+	channels                  []canonicalChannelName
+	users                     []*User
+	specificallyExcludedUsers []*User
+}
+
+func NewBroadcastGroup() *BroadcastGroup {
+	return &BroadcastGroup{}
+}
+
+func (bcg *BroadcastGroup) AddChannels(names ...canonicalChannelName) {
+	bcg.channels = append(bcg.channels, names...)
+}
+
+func (bcg *BroadcastGroup) AddUsers(users ...*User) {
+	bcg.users = append(bcg.users, users...)
+}
+
+func (bcg *BroadcastGroup) AddSpecificallyExcludedUsers(users ...*User) {
+	bcg.specificallyExcludedUsers = append(bcg.users, users...)
+}
+
+func Broadcast(bcg *BroadcastGroup, content transport.Content) {
+	g := GetGlobals()
+	allUsers := make(map[*User]struct{})
+	for _, c := range bcg.channels {
+		for u := range g.Users.ByCanonicalChannel(c) {
+			allUsers[u] = struct{}{}
+		}
+	}
+	for _, u := range bcg.users {
+		allUsers[u] = struct{}{}
+	}
+	for _, u := range bcg.specificallyExcludedUsers {
+		delete(allUsers, u)
+	}
+	for u := range allUsers {
+		g.Server.SendMessage(u.clientId, content)
+	}
+}

src/irc/commands/all.go

@@ -1,11 +0,0 @@
-package commands
-
-import (
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/irc/world"
-)
-
-func HandleCommands(msg world.WrappedMessage) {
-	handleAuthCommands(msg)
-	handleJoinPartCommands(msg)
-	handlePrivmsgNotifyCommands(msg)
-}

src/irc/commands/auth.go

@@ -1,84 +0,0 @@
-package commands
-
-import (
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/irc/users"
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/irc/world"
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/transport"
-)
-
-func handleAuthCommands(msg world.WrappedMessage) {
-	handleNickAndUser(msg)
-	completeHandshakeIfPossible(msg)
-}
-
-func handleNickAndUser(msg world.WrappedMessage) {
-	if msg.Sender.GetHasReceivedAuthHandshakeReply() {
-		// TODO: Send an error reply
-		return
-	}
-
-	if msg.Content.Command == "NICK" {
-		args := msg.Content.Arguments
-		if len(args) != 1 {
-			// TODO: Send an error reply
-			return
-		}
-
-		nick := args[0]
-		validNick, err := users.ValidateNick(nick)
-		if err != nil {
-			// TODO: Send an error reply
-			return
-		}
-
-		err = msg.Sender.SetNick(&validNick)
-		if err != nil {
-			msg.World.Server.TerminateClient(msg.Sender.GetClientId(), err)
-		}
-	}
-
-	if msg.Content.Command == "USER" {
-		args := msg.Content.Arguments
-		if len(args) != 4 {
-			// TODO: Send an error reply
-			return
-		}
-
-		username := args[0]
-		zero := args[1]
-		star := args[2]
-		realName := args[3]
-
-		if zero != "0" || star != "*" {
-			// TODO: Send an error reply
-			return
-		}
-
-		msg.Sender.SetUsername(&username)
-		msg.Sender.SetRealName(&realName)
-
-		// TODO: Validation? I wonder if it matters.
-	}
-}
-
-func completeHandshakeIfPossible(msg world.WrappedMessage) {
-	sender := msg.Sender
-	if msg.Sender.GetHasReceivedAuthHandshakeReply() {
-		return
-	}
-
-	isReady := sender.GetNick() != nil && sender.GetUsername() != nil && sender.GetRealName() != nil
-	if !isReady {
-		return
-	}
-
-	sender.SetHasReceivedAuthHandshakeReply(true)
-	msg.World.Server.SendMessage(sender.GetClientId(), transport.Content{
-		Command:   "NICK",
-		Arguments: []string{sender.GetNick().Value},
-	})
-	msg.World.Server.SendMessage(msg.Sender.GetClientId(), transport.Content{
-		Command:   "USER",
-		Arguments: []string{*sender.GetUsername(), "0", "*", *sender.GetRealName()},
-	})
-}

src/irc/commands/joinPart.go

@@ -1,59 +0,0 @@
-package commands
-
-import (
-	"strings"
-
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/irc/users"
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/irc/world"
-)
-
-func handleJoinPartCommands(msg world.WrappedMessage) {
-	if msg.Content.Command == "JOIN" {
-		if len(msg.Content.Arguments) != 1 {
-			// TODO: Wrong number of arguments
-			return
-		}
-		channelsToJoin := parseChannelList(msg.Content.Arguments[0])
-
-		for _, channel := range channelsToJoin {
-			err := msg.Sender.Join(channel)
-			if err != nil {
-				msg.World.Server.TerminateClient(msg.Sender.GetClientId(), err)
-				return
-			}
-			msg.World.RelayToChannel(msg, channel, nil)
-		}
-	}
-
-	if msg.Content.Command == "PART" {
-		n := len(msg.Content.Arguments)
-		if !(n == 1 || n == 2) {
-			return
-		}
-		channelsToPart := parseChannelList(msg.Content.Arguments[0])
-
-		for _, channel := range channelsToPart {
-			err := msg.Sender.Part(channel)
-			if err != nil {
-				msg.World.Server.TerminateClient(msg.Sender.GetClientId(), err)
-				return
-			}
-			msg.World.RelayToChannel(msg, channel, nil)
-			// the user won't see their own #part because they left, so send it
-			msg.World.RelayToClient(msg, msg.Sender.GetClientId(), nil)
-		}
-	}
-}
-
-func parseChannelList(arg string) []users.ChannelName {
-	var channels []users.ChannelName
-	for _, channelName := range strings.Split(arg, ",") {
-		validChannel, err := users.ValidateChannelName(channelName)
-		if err != nil { // can't join, not a channel
-			continue
-		}
-
-		channels = append(channels, validChannel)
-	}
-	return channels
-}

src/irc/commands/privmsgNotify.go

@@ -1,21 +0,0 @@
-package commands
-
-import (
-	"log"
-
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/irc/world"
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/transport"
-)
-
-func handlePrivmsgNotifyCommands(msg world.WrappedMessage) {
-	if msg.Content.Command == "PRIVMSG" || msg.Content.Command == "NOTIFY" || msg.Content.Command == "CTCP" {
-		log.Printf("message-like command")
-		if len(msg.Content.Arguments) == 0 {
-			// TODO: Error reply
-			return
-		}
-
-		// Was this message to a user?
-		msg.World.RelayToVagueDestination(msg, msg.Content.Arguments[0], []transport.ClientId{msg.Sender.GetClientId()})
-	}
-}

src/irc/errors.go

@@ -1,7 +1,9 @@
-package errors
+package irc
 
 import "fmt"
 
 var ErrAlreadyInChannel = fmt.Errorf("already in channel")
+var ErrMalformedCommand = fmt.Errorf("malformed command")
+var ErrNotANick = fmt.Errorf("does not look like a nickname")
 var ErrNickAlreadyInUse = fmt.Errorf("nick already in use")
 var ErrNotInChannel = fmt.Errorf("not in channel")

src/irc/globals.go

@@ -0,0 +1,41 @@
+package irc
+
+import (
+	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/logic"
+	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/transport"
+)
+
+type Globals struct {
+	Server        *transport.Server
+	Rulebook      *logic.Rulebook
+	Users         *UsersSystem
+	Notifications *NotificationsSystem
+}
+
+var globals *Globals = nil
+
+func InitializeGlobals(server *transport.Server) {
+	globals = &Globals{
+		Server:        server,
+		Rulebook:      logic.NewRulebook(),
+		Users:         NewUsersSystem(),
+		Notifications: NewNotificationsSystem(),
+	}
+	globals.Users.InitializeRules()
+	globals.Notifications.InitializeRules()
+}
+
+func GetGlobals() *Globals {
+	if globals == nil {
+		panic("globals not initialized")
+	}
+	return globals
+}
+
+func AddNewRule[T any](check func(T) error, carryOut func(T)) {
+	GetGlobals().Rulebook.Add(logic.NewRule(check, carryOut))
+}
+
+func Perform[T any](action T) error {
+	return GetGlobals().Rulebook.Perform(action)
+}

src/irc/identifiers.go

@@ -1,61 +0,0 @@
-package irc
-
-import (
-	"fmt"
-	"regexp"
-	"strings"
-)
-
-var ErrNotANick = fmt.Errorf("does not look like a nickname")
-
-var regexpNick = regexp.MustCompile("^[a-zA-Z0-9]+$") // NOTE: more constrained than real character set
-
-type Nick string
-type CanonicalNick string
-
-func ValidateNick(s string) (Nick, error) {
-	// TODO: Fail if the string doesn't look like a nick
-	if !regexpNick.MatchString(s) {
-		return "", fmt.Errorf("%w: %s", ErrNotANick, s)
-	}
-	return Nick(s), nil
-}
-
-func (n Nick) Canonize() CanonicalNick {
-	return CanonicalNick(strings.ToLower(string(n)))
-}
-
-func (n *Nick) CanonizeNullable() *CanonicalNick {
-	if n == nil {
-		return nil
-	}
-	result := n.Canonize()
-	return &result
-}
-
-var ErrNotAChannel = fmt.Errorf("does not look like a channel name")
-
-var regexpChannel = regexp.MustCompile("^#[a-zA-Z0-9]+$") // NOTE: more constrained than real character set
-
-type Channel string
-type CanonicalChannel string
-
-func ValidateChannel(s string) (Channel, error) {
-	// TODO: Fail if the string doesn't look like a channel name
-	if !regexpChannel.MatchString(s) {
-		return "", fmt.Errorf("%w: %s", ErrNotAChannel, s)
-	}
-	return Channel(s), nil
-}
-
-func (c Channel) Canonize() CanonicalChannel {
-	return CanonicalChannel(strings.ToLower(string(c)))
-}
-
-func (c *Channel) CanonizeNullable() *CanonicalChannel {
-	if c == nil {
-		return nil
-	}
-	result := c.Canonize()
-	return &result
-}

src/irc/main.go

@@ -1,15 +1,15 @@
 package irc
 
 import (
+	"fmt"
 	"log"
+	"strings"
 
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/irc/commands"
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/irc/world"
 	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/transport"
 )
 
 func ServeIrc(server *transport.Server) {
-	world := world.NewWorld(server)
+	InitializeGlobals(server)
 
 	for {
 		rawMessage, err := server.ReceiveMessage()
@@ -18,8 +18,180 @@ func ServeIrc(server *transport.Server) {
 			return
 		}
 
-		wrappedMessage := world.Wrap(rawMessage)
-
-		commands.HandleCommands(wrappedMessage)
+		err = handleMessage(rawMessage)
+		if err != nil {
+			server.TerminateClient(rawMessage.Sender, err)
+		}
 	}
 }
+
+func handleMessage(m transport.IncomingMessage) error {
+	g := GetGlobals()
+	user := g.Users.ByClientIdOrCreate(m.Sender)
+	command := m.Content.Command
+	args := m.Content.Arguments
+
+	if command == "NICK" {
+		if len(args) != 1 {
+			return fmt.Errorf("%w: needs 1 argument", ErrMalformedCommand)
+		}
+
+		nick, err := ValidateNick(args[0])
+		if err != nil {
+			return err
+		}
+
+		err = user.SetNick(&nick)
+		if err != nil {
+			return err
+		}
+		return completeHandshakeIfPossible(user)
+	}
+
+	if command == "USER" {
+		if len(args) != 4 {
+			return fmt.Errorf("%w: needs 4 arguments", ErrMalformedCommand)
+		}
+
+		username := args[0]
+		zero := args[1]
+		star := args[2]
+		realName := args[3]
+
+		if zero != "0" || star != "*" {
+			return fmt.Errorf("%w: needs zero and star", ErrMalformedCommand)
+		}
+
+		user.SetUsername(&username)
+		user.SetRealName(&realName)
+		return completeHandshakeIfPossible(user)
+	}
+
+	if command == "JOIN" {
+		if len(args) != 1 {
+			return fmt.Errorf("%w: needs 1 argument", ErrMalformedCommand)
+		}
+
+		channelsToJoin := parseChannelList(args[0])
+		for _, channel := range channelsToJoin {
+			err := user.Join(channel)
+			log.Printf("joining %s %v", channel, err)
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
+	}
+
+	if command == "PART" {
+		if len(args) != 1 && len(args) != 2 {
+			return fmt.Errorf("%w: needs 1 or 2 arguments", ErrMalformedCommand)
+		}
+
+		channelsToPart := parseChannelList(args[0])
+		var reason *string
+		if len(args) == 2 {
+			reason = &args[1]
+		}
+
+		for _, channel := range channelsToPart {
+			err := user.Part(channel, reason)
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
+	}
+
+	if command == string(ChatModePrivmsg) || command == string(ChatModeNotice) {
+		mode := ChatMode(command)
+		if len(args) != 2 {
+			return fmt.Errorf("%w: needs 2 arguments", ErrMalformedCommand)
+		}
+
+		channelName, err := ValidateChannelName(args[0])
+		if err == nil {
+			return handleChannelMessage(user, mode, channelName.canonical, args[1])
+		}
+
+		nick, err := ValidateNick(args[0])
+		if err == nil {
+			other := g.Users.ByNick(nick)
+			if other == nil {
+				// TODO: Error for missing user
+				return nil
+			}
+			return handleUserMessage(user, mode, other, args[1])
+		}
+
+		return fmt.Errorf("%w: needs nick or channel name", ErrMalformedCommand)
+	}
+
+	// Unrecognized command
+	return nil
+}
+
+func completeHandshakeIfPossible(user *User) error {
+	if user.GetHasReceivedAuthHandshakeReply() {
+		log.Printf("has already completed handshake!")
+		return nil
+	}
+
+	nick := user.GetNick()
+	username := user.GetUsername()
+	realName := user.GetRealName()
+
+	isReady := !(nick == nil || username == nil || realName == nil)
+
+	if !isReady {
+		log.Printf("not ready to complete handshake!")
+		return nil
+	}
+	log.Printf("time to complete handshake!!")
+
+	user.SetHasReceivedAuthHandshakeReply(true)
+	group := NewBroadcastGroup()
+	group.AddUsers(user)
+	Broadcast(group, transport.Content{
+		Command:   "NICK",
+		Arguments: []string{nick.Value},
+	})
+	Broadcast(group, transport.Content{
+		Command:   "USER",
+		Arguments: []string{nick.Value, "0", "*", *realName},
+	})
+	return nil
+}
+
+func parseChannelList(arg string) []ChannelName {
+	var channels []ChannelName
+	for _, channelName := range strings.Split(arg, ",") {
+		validChannel, err := ValidateChannelName(channelName)
+		if err != nil { // can't join, not a channel
+			continue
+		}
+
+		channels = append(channels, validChannel)
+	}
+	return channels
+}
+
+func handleChannelMessage(sender *User, mode ChatMode, destination canonicalChannelName, message string) error {
+	return Perform(SendMessageToChannelAction{
+		User:        sender,
+		Mode:        mode,
+		Destination: destination,
+		Message:     message,
+	})
+}
+
+func handleUserMessage(sender *User, mode ChatMode, destination *User, message string) error {
+	return Perform(SendMessageToUserAction{
+		User:        sender,
+		Mode:        mode,
+		Destination: destination,
+		Message:     message,
+	})
+}

src/irc/notificationsSystem.go

@@ -0,0 +1,150 @@
+package irc
+
+import (
+	"strings"
+
+	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/transport"
+)
+
+type NotificationsSystem struct {
+}
+
+func NewNotificationsSystem() *NotificationsSystem {
+	return &NotificationsSystem{}
+}
+
+func (notifications *NotificationsSystem) InitializeRules() {
+	// nick changes
+	AddNewRule(
+		func(nc NickChangeAction) error { return nil },
+		func(nc NickChangeAction) {
+			if nc.NewNick == nil {
+				return // not expressible in the IRC protocol; probably shouldn't be allowed?
+			}
+
+			src := nc.User.GetSourceString()
+			content := transport.Content{
+				Source:    &src,
+				Command:   "NICK",
+				Arguments: []string{nc.NewNick.Value},
+			}
+			group := NewBroadcastGroup()
+			group.AddChannels(nc.User.GetChannels()...)
+			group.AddUsers(nc.User)
+			Broadcast(group, content)
+		},
+	)
+
+	// joins
+	AddNewRule(
+		func(j JoinAction) error { return nil },
+		func(j JoinAction) {
+			src := j.User.GetSourceString()
+
+			content := transport.Content{
+				Source:    &src,
+				Command:   "JOIN",
+				Arguments: []string{string(j.ChannelName.Value)},
+			}
+			group := NewBroadcastGroup()
+			group.AddChannels(j.ChannelName.canonical)
+			group.AddUsers(j.User)
+			Broadcast(group, content)
+
+			// tell the user who is here
+			group = NewBroadcastGroup()
+			group.AddUsers(j.User)
+			src2 := "server"
+
+			var nameList strings.Builder
+			var i = 0
+			for user := range GetGlobals().Users.ByChannel(j.ChannelName) {
+				if i != 0 {
+					nameList.WriteString(" ")
+				}
+				nameList.WriteString(user.nick.Value)
+				i += 1
+			}
+
+			Broadcast(group, transport.Content{
+				Source:  &src2,
+				Command: "332",
+				Arguments: []string{
+					j.User.nick.Value, j.ChannelName.Value, "TODO: topic!",
+				},
+			})
+			Broadcast(group, transport.Content{
+				Source:  &src2,
+				Command: "353",
+				Arguments: []string{
+					j.User.nick.Value, "=", j.ChannelName.Value, nameList.String(),
+				},
+			})
+			Broadcast(group, transport.Content{
+				Source:  &src2,
+				Command: "366",
+				Arguments: []string{
+					j.User.nick.Value, j.ChannelName.Value, "End of /NAMES list",
+				},
+			})
+		},
+	)
+
+	// parts
+	AddNewRule(
+		func(p PartAction) error { return nil },
+		func(p PartAction) {
+			src := p.User.GetSourceString()
+
+			var args []string
+			args = append(args, string(p.ChannelName.Value))
+			if p.Reason != nil {
+				args = append(args, *p.Reason)
+			}
+			content := transport.Content{
+				Source:    &src,
+				Command:   "PART",
+				Arguments: args,
+			}
+			group := NewBroadcastGroup()
+			group.AddChannels(p.ChannelName.canonical)
+			group.AddUsers(p.User)
+			Broadcast(group, content)
+		},
+	)
+
+	// messages (to user)
+	AddNewRule(
+		func(s SendMessageToUserAction) error { return nil },
+		func(s SendMessageToUserAction) {
+			src := s.User.GetSourceString()
+
+			content := transport.Content{
+				Source:    &src,
+				Command:   string(s.Mode),
+				Arguments: []string{s.Destination.GetNick().Value, s.Message},
+			}
+			group := NewBroadcastGroup()
+			group.AddUsers(s.Destination)
+			Broadcast(group, content)
+		},
+	)
+
+	// messages (to channel)
+	AddNewRule(
+		func(s SendMessageToChannelAction) error { return nil },
+		func(s SendMessageToChannelAction) {
+			src := s.User.GetSourceString()
+
+			content := transport.Content{
+				Source:    &src,
+				Command:   string(s.Mode),
+				Arguments: []string{string(s.Destination), s.Message},
+			}
+			group := NewBroadcastGroup()
+			group.AddChannels(s.Destination)
+			group.AddSpecificallyExcludedUsers(s.User)
+			Broadcast(group, content)
+		},
+	)
+}

src/irc/types.go

@@ -1,4 +1,4 @@
-package users
+package irc
 
 import (
 	"fmt"
@@ -12,7 +12,6 @@ type Nick struct {
 }
 type canonicalNick string
 
-var ErrNotANick = fmt.Errorf("does not look like a nickname")
 var regexpNick = regexp.MustCompile(`^[a-zA-Z0-9\-_]+$`) // NOTE: more constrained than real character set
 
 func ValidateNick(input string) (Nick, error) {

src/irc/user.go

@@ -0,0 +1,95 @@
+package irc
+
+import (
+	"fmt"
+	"slices"
+
+	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/transport"
+)
+
+type User struct {
+	clientId     transport.ClientId
+	hostString   *string
+	sourceString *string
+	nick         *Nick
+	username     *string
+	realName     *string
+
+	hasReceivedAuthHandshakeReply bool
+
+	channels []canonicalChannelName
+}
+
+func (user *User) recomputeSourceString() {
+	nick := "unknown"
+	if user.nick != nil {
+		nick = (*user.nick).Value
+	}
+	hstr := fmt.Sprintf("clients/%d", user.clientId)
+	sstr := fmt.Sprintf("%s!%s", nick, hstr)
+	user.hostString = &hstr
+	user.sourceString = &sstr
+}
+
+func (user *User) GetClientId() transport.ClientId {
+	return user.clientId
+}
+
+func (user *User) GetHostString() string {
+	return *user.hostString
+}
+
+func (user *User) GetSourceString() string {
+	return *user.sourceString
+}
+
+func (user *User) GetNick() *Nick {
+	return user.nick
+}
+
+func (user *User) SetNick(newNick *Nick) error {
+	return Perform(NickChangeAction{User: user, OldNick: user.nick, NewNick: newNick})
+}
+
+func (user *User) GetUsername() *string {
+	return user.username
+}
+
+func (user *User) SetUsername(username *string) {
+	user.username = username
+}
+
+func (user *User) GetRealName() *string {
+	return user.realName
+}
+
+func (user *User) SetRealName(realName *string) {
+	user.realName = realName
+}
+
+func (user *User) GetHasReceivedAuthHandshakeReply() bool {
+	return user.hasReceivedAuthHandshakeReply
+}
+
+func (user *User) SetHasReceivedAuthHandshakeReply(value bool) {
+	user.hasReceivedAuthHandshakeReply = value
+}
+
+func (user *User) IsInChannel(channelName ChannelName) bool {
+	return slices.ContainsFunc(user.channels, func(existingChannel canonicalChannelName) bool {
+		return channelName.canonical == existingChannel
+	})
+}
+
+func (user *User) GetChannels() []canonicalChannelName {
+	return user.channels
+
+}
+
+func (user *User) Join(channelName ChannelName) error {
+	return Perform(JoinAction{User: user, ChannelName: channelName})
+}
+
+func (user *User) Part(channelName ChannelName, reason *string) error {
+	return Perform(PartAction{User: user, ChannelName: channelName, Reason: reason})
+}

src/irc/users/system.go

@@ -1,183 +0,0 @@
-package users
-
-import (
-	"fmt"
-	"slices"
-
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/irc/errors"
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/transport"
-)
-
-type UserId uint64
-
-type UsersSystem struct {
-	clientIdIndex    map[transport.ClientId]*User
-	nickIndex        map[canonicalNick]*User
-	channelNameIndex map[canonicalChannelName](map[*User]struct{})
-}
-
-type User struct {
-	users *UsersSystem
-
-	clientId transport.ClientId
-	nick     *Nick
-	username *string
-	realName *string
-
-	hasReceivedAuthHandshakeReply bool
-
-	channels []ChannelName
-}
-
-func NewUsersSystem() *UsersSystem {
-	return &UsersSystem{
-		clientIdIndex:    make(map[transport.ClientId]*User),
-		nickIndex:        make(map[canonicalNick]*User),
-		channelNameIndex: make(map[canonicalChannelName]map[*User]struct{}),
-	}
-}
-
-func (users *UsersSystem) ByClientIdOrCreate(clientId transport.ClientId) *User {
-	existing, ok := users.clientIdIndex[clientId]
-
-	if ok {
-		return existing
-	}
-
-	user := &User{
-		users: users,
-
-		clientId: clientId,
-		nick:     nil,
-		username: nil,
-		realName: nil,
-
-		hasReceivedAuthHandshakeReply: false,
-
-		channels: nil,
-	}
-	users.clientIdIndex[clientId] = user
-	return user
-}
-
-func (users *UsersSystem) ByNick(nick Nick) *User {
-	return users.nickIndex[nick.canonical]
-}
-
-func (users *UsersSystem) ByChannel(channelName ChannelName) map[*User]struct{} {
-	return users.channelNameIndex[channelName.canonical]
-}
-
-func (user *User) GetClientId() transport.ClientId {
-	return user.clientId
-}
-
-func (user *User) GetNick() *Nick {
-	return user.nick
-}
-
-func (user *User) SetNick(newNick *Nick) error {
-	users := user.users
-	oldNick := user.nick
-
-	// check if already in use -- if so, refuse
-	_, alreadyInUse := users.nickIndex[newNick.canonical]
-	if alreadyInUse {
-		if oldNick != nil && newNick.canonical == oldNick.canonical {
-			// it's fine, this is the user who held that nick
-			// so continue as before
-		} else {
-			return fmt.Errorf("%w: %s", errors.ErrNickAlreadyInUse, newNick.Value)
-		}
-	}
-
-	// update indexes
-	if oldNick != nil {
-		delete(users.nickIndex, oldNick.canonical)
-	}
-	if newNick != nil {
-		users.nickIndex[newNick.canonical] = user
-	}
-
-	// update me
-	user.nick = newNick
-	return nil
-}
-
-func (user *User) GetUsername() *string {
-	return user.username
-}
-
-func (user *User) SetUsername(username *string) {
-	user.username = username
-}
-
-func (user *User) GetRealName() *string {
-	return user.realName
-}
-
-func (user *User) SetRealName(realName *string) {
-	user.realName = realName
-}
-
-func (user *User) GetHasReceivedAuthHandshakeReply() bool {
-	return user.hasReceivedAuthHandshakeReply
-}
-
-func (user *User) SetHasReceivedAuthHandshakeReply(value bool) {
-	user.hasReceivedAuthHandshakeReply = value
-}
-
-func (user *User) IsInChannel(channelName ChannelName) bool {
-	return slices.ContainsFunc(user.channels, func(existingChannel ChannelName) bool {
-		return channelName.canonical == existingChannel.canonical
-	})
-}
-
-func (user *User) Join(channelName ChannelName) error {
-	users := user.users
-
-	// if I'm already in this channel, don't join
-	if user.IsInChannel(channelName) {
-		return fmt.Errorf("%w: %s", errors.ErrAlreadyInChannel, channelName.Value)
-	}
-
-	// update indexes
-	existing, ok := users.channelNameIndex[channelName.canonical]
-	if !ok {
-		existing = make(map[*User]struct{})
-		users.channelNameIndex[channelName.canonical] = existing
-	}
-	_, wasInChannel := existing[user]
-	if wasInChannel {
-		panic("tried to join a channel, but I was mysteriously already in it")
-	}
-	existing[user] = struct{}{}
-
-	// update me
-	user.channels = append(user.channels, channelName)
-
-	return nil
-}
-
-func (user *User) Part(channelName ChannelName) error {
-	users := user.users
-
-	// if i'm not in this channel, don't part
-	if !user.IsInChannel(channelName) {
-		return fmt.Errorf("%w: %s", errors.ErrNotInChannel, channelName.Value)
-	}
-
-	// update indexes
-	existing, ok := users.channelNameIndex[channelName.canonical]
-	if ok {
-		delete(existing, user)
-		if len(existing) == 0 {
-			delete(users.channelNameIndex, channelName.canonical)
-		}
-	} else {
-		panic("tried to part from a channel, but was mysteriously absent from it")
-	}
-
-	return nil
-}

src/irc/usersSystem.go

@@ -0,0 +1,129 @@
+package irc
+
+import (
+	"fmt"
+	"slices"
+
+	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/transport"
+)
+
+type UsersSystem struct {
+	clientIdIndex    map[transport.ClientId]*User
+	nickIndex        map[canonicalNick]*User
+	channelNameIndex map[canonicalChannelName](map[*User]struct{})
+}
+
+func NewUsersSystem() *UsersSystem {
+	return &UsersSystem{
+		clientIdIndex:    make(map[transport.ClientId]*User),
+		nickIndex:        make(map[canonicalNick]*User),
+		channelNameIndex: make(map[canonicalChannelName]map[*User]struct{}),
+	}
+}
+
+func (users *UsersSystem) ByClientIdOrCreate(clientId transport.ClientId) *User {
+	existing, ok := users.clientIdIndex[clientId]
+
+	if ok {
+		return existing
+	}
+
+	user := &User{
+		clientId: clientId,
+		nick:     nil,
+		username: nil,
+		realName: nil,
+
+		hasReceivedAuthHandshakeReply: false,
+
+		channels: nil,
+	}
+	user.recomputeSourceString()
+	users.clientIdIndex[clientId] = user
+	return user
+}
+
+func (users *UsersSystem) ByNick(nick Nick) *User {
+	return users.nickIndex[nick.canonical]
+}
+
+func (users *UsersSystem) ByChannel(channelName ChannelName) map[*User]struct{} {
+	return users.channelNameIndex[channelName.canonical]
+}
+
+func (users *UsersSystem) ByCanonicalChannel(channelName canonicalChannelName) map[*User]struct{} {
+	return users.channelNameIndex[channelName]
+}
+
+func (users *UsersSystem) InitializeRules() {
+	// nick changes
+	AddNewRule(
+		func(nc NickChangeAction) error {
+			// users can always change from one nick to the same nick
+			if nc.OldNick != nil && nc.NewNick != nil && nc.OldNick.canonical == nc.NewNick.canonical {
+				return nil
+			}
+
+			// is this someone else's nick?
+			_, ok := users.nickIndex[nc.NewNick.canonical]
+			if ok {
+				return fmt.Errorf("%w: %s", ErrNickAlreadyInUse, nc.NewNick.Value)
+			}
+
+			return nil
+
+		},
+		func(nc NickChangeAction) {
+			if nc.OldNick != nil {
+				delete(users.nickIndex, nc.OldNick.canonical)
+			}
+			nc.User.nick = nc.NewNick
+			nc.User.recomputeSourceString()
+
+			if nc.NewNick != nil {
+				users.nickIndex[nc.NewNick.canonical] = nc.User
+			}
+		},
+	)
+
+	// joining channel
+	AddNewRule(
+		func(j JoinAction) error {
+			if slices.Contains(j.User.channels, j.ChannelName.canonical) {
+				return fmt.Errorf("%w: %s", ErrAlreadyInChannel, j.ChannelName)
+			}
+			return nil
+		},
+		func(j JoinAction) {
+			name := j.ChannelName.canonical
+			existing, ok := users.channelNameIndex[name]
+			if !ok {
+				existing = make(map[*User]struct{})
+				users.channelNameIndex[name] = existing
+			}
+			existing[j.User] = struct{}{}
+		},
+	)
+
+	// parting channel
+	AddNewRule(
+		func(p PartAction) error {
+			if !slices.Contains(p.User.channels, p.ChannelName.canonical) {
+				return fmt.Errorf("%w: %s", ErrNotInChannel, p.ChannelName.Value)
+			}
+			return nil
+		},
+		func(p PartAction) {
+			name := p.ChannelName.canonical
+			p.User.channels = slices.DeleteFunc(p.User.channels, func(ccn canonicalChannelName) bool {
+				return ccn == name
+			})
+
+			channelUsers := users.channelNameIndex[name]
+			delete(channelUsers, p.User)
+			if len(channelUsers) == 0 {
+				delete(users.channelNameIndex, name)
+			}
+		},
+	)
+}

src/irc/world/world.go

@@ -1,122 +0,0 @@
-package world
-
-import (
-	"fmt"
-	"log"
-	"slices"
-
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/irc/users"
-	"git.chromaticdragon.app/pyrex/minimal-irc-server/v2/src/transport"
-)
-
-type World struct {
-	Server      *transport.Server
-	UsersSystem *users.UsersSystem
-}
-
-type WrappedMessage struct {
-	World   *World
-	Sender  *users.User
-	Content transport.Content
-}
-
-func NewWorld(server *transport.Server) *World {
-	usersSystem := users.NewUsersSystem()
-
-	return &World{
-		Server:      server,
-		UsersSystem: usersSystem,
-	}
-}
-
-func (world *World) Wrap(msg transport.IncomingMessage) WrappedMessage {
-	sender := world.UsersSystem.ByClientIdOrCreate(msg.Sender)
-
-	return WrappedMessage{
-		World:   world,
-		Sender:  sender,
-		Content: msg.Content,
-	}
-}
-
-// transmission of messages
-func (world *World) RelayToVagueDestination(
-	msg WrappedMessage,
-	name string,
-	exclude []transport.ClientId,
-) {
-	nick, err := users.ValidateNick(name)
-	if err == nil {
-		// so it's a nick!
-		world.RelayToNick(msg, nick, exclude)
-		return
-	}
-
-	channel, err := users.ValidateChannelName(name)
-	if err == nil {
-		// so it's a channel!
-		world.RelayToChannel(msg, channel, exclude)
-		return
-	}
-
-	log.Fatalf("not sure how to send to %s", name)
-	// TODO: Error response: "what is this?"
-}
-
-func (world *World) RelayToClient(
-	msg WrappedMessage,
-	client transport.ClientId,
-	exclude []transport.ClientId,
-) {
-	content := createAnnotatedContent(msg)
-	if slices.Contains(exclude, client) {
-		return // don't relay
-	}
-	world.Server.SendMessage(client, content)
-}
-
-func (world *World) RelayToNick(
-	msg WrappedMessage,
-	nick users.Nick,
-	exclude []transport.ClientId,
-) {
-	content := createAnnotatedContent(msg)
-
-	user := world.UsersSystem.ByNick(nick)
-	if user == nil {
-		// TODO: Send an error reply. The user didn't exist
-		return
-	}
-
-	if slices.Contains(exclude, user.GetClientId()) {
-		return // don't relay
-	}
-
-	world.Server.SendMessage(user.GetClientId(), content)
-}
-
-func (world *World) RelayToChannel(
-	msg WrappedMessage,
-	channelName users.ChannelName,
-	exclude []transport.ClientId,
-) {
-	content := createAnnotatedContent(msg)
-
-	members := world.UsersSystem.ByChannel(channelName)
-	log.Printf("Members of %s: %v\n", channelName, members)
-	for member := range members {
-		if slices.Contains(exclude, member.GetClientId()) {
-			return // don't relay
-		}
-		world.Server.SendMessage(member.GetClientId(), content)
-	}
-}
-
-func createAnnotatedContent(
-	msg WrappedMessage,
-) transport.Content {
-	content := msg.Content
-	fullSource := fmt.Sprintf("%s!clients/%d", msg.Sender.GetNick().Value, msg.Sender.GetClientId())
-	content.Source = &fullSource
-	return content
-}

src/logic/rules.go

@@ -0,0 +1,115 @@
+package logic
+
+/// An Inform 7-style rulebook.
+///
+/// This is pretty icky, but basically the concept here:
+///
+/// For any action type, you can make a series of rules to:
+///
+/// (1) check if it's permissible
+/// (2) actually carry it out
+///
+/// These rules will be fired off in the order that they were added
+/// with the rule that a failed check results in an error,
+/// and a successful check results in all of the carryOut steps
+/// actually being caused to occur. (They are not allowed to fail.)
+type Rulebook struct {
+	chapters []anyChapter
+}
+
+type chapter[T any] struct {
+	check    []func(T) error
+	carryOut []func(T)
+}
+
+type anyChapter interface {
+	dispatchOn(interface{}) (bool, error)
+}
+
+type rule[T any] struct {
+	check    *func(T) error
+	carryOut *func(T)
+}
+
+type AnyRule interface {
+	addTo(rb *Rulebook)
+}
+
+func NewRulebook() *Rulebook {
+	return &Rulebook{}
+}
+
+func NewRule[T any](check func(T) error, carryOut func(T)) *rule[T] {
+	return &rule[T]{
+		check:    &check,
+		carryOut: &carryOut,
+	}
+
+}
+
+// why is this done in the rule and not the rulebook?
+// because go lacks parameterized types on methods, so we _have_ to
+// flip the control flow to put this logic in the type with the most knowledge
+// of the generic type
+func (r *rule[T]) addTo(rb *Rulebook) {
+	for i, ch := range rb.chapters {
+		if chSpecific, ok := ch.(chapter[T]); ok {
+			r.addToChapter(&chSpecific)
+			rb.chapters[i] = chSpecific
+			return
+		}
+	}
+
+	newChapter := chapter[T]{}
+	r.addToChapter(&newChapter)
+	rb.chapters = append(rb.chapters, newChapter)
+}
+
+func (r *rule[T]) addToChapter(chapter *chapter[T]) {
+	if check := r.check; check != nil {
+		chapter.check = append(chapter.check, *check)
+	}
+	if carryOut := r.carryOut; carryOut != nil {
+		chapter.carryOut = append(chapter.carryOut, *carryOut)
+	}
+}
+
+func (rb *Rulebook) Add(r AnyRule) {
+	r.addTo(rb)
+}
+
+func (rb *Rulebook) Perform(action interface{}) error {
+	for _, ch := range rb.chapters {
+		handled, err := ch.dispatchOn(action)
+		if handled {
+			return err
+		}
+	}
+
+	// there were zero rules
+	return nil
+}
+
+func (ch chapter[T]) dispatchOn(action interface{}) (bool, error) {
+	if specializedAction, ok := action.(T); ok {
+		return true, ch.dispatchOnSpecific(specializedAction)
+	}
+
+	// false: wrong dispatcher
+	return false, nil
+}
+
+func (ch chapter[T]) dispatchOnSpecific(item T) error {
+	for _, checkRule := range ch.check {
+		err := checkRule(item)
+		if err != nil {
+			return err
+		}
+	}
+
+	for _, carryOutRule := range ch.carryOut {
+		carryOutRule(item)
+	}
+
+	return nil
+}

src/transport/server.go

@@ -29,7 +29,7 @@ func NewServer(address string) (*Server, error) {
 		ctx:              ctx,
 		cancel:           cancel,
 		connectedClients: newConnectedClients(),
-		incomingMessages: make(chan IncomingMessage),
+		incomingMessages: make(chan IncomingMessage, 1024),
 	}
 
 	go (func() {
@@ -55,7 +55,7 @@ func (server *Server) handleConnection(conn net.Conn) {
 	defer conn.Close()
 
 	clientCtx, cancel := context.WithCancelCause(server.ctx)
-	outgoingMessages := make(chan OutgoingMessage)
+	outgoingMessages := make(chan OutgoingMessage, 1024)
 
 	clientId := server.connectedClients.Enroll(func(id ClientId) ConnectedClient {
 		return ConnectedClient{
@@ -141,7 +141,9 @@ func (server *Server) SendMessage(client ClientId, content Content) {
 		Content:   content,
 	}
 	server.connectedClients.BorrowIfPresent(client, func(connectedClient *ConnectedClient) {
+		log.Printf("putting in outgoing")
 		connectedClient.outgoingMessages <- outgoing
+		log.Printf("done putting in outgoing")
 	})
 }