CommandHandler func -> Command struct

chat/command.go

@@ -18,52 +18,59 @@ var ErrNoOwner = errors.New("command without owner")
 // of arguments.
 var ErrMissingArg = errors.New("missing argument")
 
-// CommandHandler is the function signature for command handlers..
+// The error returned when a command is added without a prefix.
-type CommandHandler func(*Channel, CommandMsg) error
+var ErrMissingPrefix = errors.New("command missing prefix")
+
+// Command is a definition of a handler for a command.
+type Command struct {
+	Prefix     string
+	PrefixHelp string
+	Help       string
+	Handler    func(*Channel, CommandMsg) error
+}
 
 // Commands is a registry of available commands.
 type Commands struct {
-	handlers map[string]CommandHandler
+	commands map[string]Command
-	help     map[string]string
 	sync.RWMutex
 }
 
 // NewCommands returns a new Commands registry.
 func NewCommands() *Commands {
 	return &Commands{
-		handlers: map[string]CommandHandler{},
+		commands: map[string]Command{},
-		help:     map[string]string{},
 	}
 }
 
 // Add will register a command. If help string is empty, it will be hidden from
 // Help().
-func (c Commands) Add(command string, help string, handler CommandHandler) {
+func (c *Commands) Add(cmd Command) error {
 	c.Lock()
 	defer c.Unlock()
 
-	c.handlers[command] = handler
+	if cmd.Prefix == "" {
-
+		return ErrMissingPrefix
-	if help != "" {
-		c.help[command] = help
 	}
+
+	c.commands[cmd.Prefix] = cmd
+	return nil
 }
 
 // Alias will add another command for the same handler, won't get added to help.
-func (c Commands) Alias(command string, alias string) error {
+func (c *Commands) Alias(command string, alias string) error {
 	c.Lock()
 	defer c.Unlock()
 
-	handler, ok := c.handlers[command]
+	cmd, ok := c.commands[command]
 	if !ok {
 		return ErrInvalidCommand
 	}
-	c.handlers[alias] = handler
+	c.commands[alias] = cmd
 	return nil
 }
 
 // Run executes a command message.
-func (c Commands) Run(channel *Channel, msg CommandMsg) error {
+func (c *Commands) Run(channel *Channel, msg CommandMsg) error {
 	if msg.From == nil {
 		return ErrNoOwner
 	}
@@ -71,22 +78,22 @@ func (c Commands) Run(channel *Channel, msg CommandMsg) error {
 	c.RLock()
 	defer c.RUnlock()
 
-	handler, ok := c.handlers[msg.Command()]
+	cmd, ok := c.commands[msg.Command()]
 	if !ok {
 		return ErrInvalidCommand
 	}
 
-	return handler(channel, msg)
+	return cmd.Handler(channel, msg)
 }
 
 // Help will return collated help text as one string.
-func (c Commands) Help() string {
+func (c *Commands) Help() string {
 	c.RLock()
 	defer c.RUnlock()
 
 	r := []string{}
-	for cmd, line := range c.help {
+	for _, cmd := range c.commands {
-		r = append(r, fmt.Sprintf("%s %s", cmd, line))
+		r = append(r, fmt.Sprintf("%s %s - %s", cmd.Prefix, cmd.PrefixHelp, cmd.Help))
 	}
 	sort.Strings(r)
 
@@ -98,12 +105,17 @@ var defaultCmdHandlers *Commands
 func init() {
 	c := NewCommands()
 
-	c.Add("/help", "", func(channel *Channel, msg CommandMsg) error {
+	c.Add(Command{
+		Prefix: "/help",
+		Handler: func(channel *Channel, msg CommandMsg) error {
 			channel.Send(NewSystemMsg("Available commands:"+Newline+c.Help(), msg.From()))
 			return nil
+		},
 	})
 
-	c.Add("/me", "", func(channel *Channel, msg CommandMsg) error {
+	c.Add(Command{
+		Prefix: "/me",
+		Handler: func(channel *Channel, msg CommandMsg) error {
 			me := strings.TrimLeft(msg.body, "/me")
 			if me == "" {
 				me = " is at a loss for words."
@@ -113,15 +125,24 @@ func init() {
 
 			channel.Send(NewEmoteMsg(me, msg.From()))
 			return nil
+		},
 	})
 
-	c.Add("/exit", "- Exit the chat.", func(channel *Channel, msg CommandMsg) error {
+	c.Add(Command{
+		Prefix: "/exit",
+		Help:   "Exit the chat.",
+		Handler: func(channel *Channel, msg CommandMsg) error {
 			msg.From().Close()
 			return nil
+		},
 	})
 	c.Alias("/exit", "/quit")
 
-	c.Add("/nick", "NAME - Rename yourself.", func(channel *Channel, msg CommandMsg) error {
+	c.Add(Command{
+		Prefix:     "/nick",
+		PrefixHelp: "NAME",
+		Help:       "Rename yourself.",
+		Handler: func(channel *Channel, msg CommandMsg) error {
 			args := msg.Args()
 			if len(args) != 1 {
 				return ErrMissingArg
@@ -133,18 +154,27 @@ func init() {
 			body := fmt.Sprintf("%s is now known as %s.", oldName, u.Name())
 			channel.Send(NewAnnounceMsg(body))
 			return nil
+		},
 	})
 
-	c.Add("/names", "- List users who are connected.", func(channel *Channel, msg CommandMsg) error {
+	c.Add(Command{
+		Prefix: "/names",
+		Help:   "List users who are connected.",
+		Handler: func(channel *Channel, msg CommandMsg) error {
 			// TODO: colorize
 			names := channel.NamesPrefix("")
 			body := fmt.Sprintf("%d connected: %s", len(names), strings.Join(names, ", "))
 			channel.Send(NewSystemMsg(body, msg.From()))
 			return nil
+		},
 	})
 	c.Alias("/names", "/list")
 
-	c.Add("/theme", "[mono|colors] - Set your color theme.", func(channel *Channel, msg CommandMsg) error {
+	c.Add(Command{
+		Prefix:     "/theme",
+		PrefixHelp: "[mono|colors]",
+		Help:       "Set your color theme.",
+		Handler: func(channel *Channel, msg CommandMsg) error {
 			user := msg.From()
 			args := msg.Args()
 			if len(args) == 0 {
@@ -167,6 +197,7 @@ func init() {
 				}
 			}
 			return errors.New("theme not found")
+		},
 	})
 
 	defaultCmdHandlers = c