merge CmdHandler changes/example

cmdhandler/cmd.go

@@ -0,0 +1,197 @@
+package cmdhandler
+
+import (
+	"errors"
+	"fmt"
+	"regexp"
+	"strings"
+	"sync"
+
+	"github.com/lrstanley/girc"
+)
+
+// Input is a wrapper for events, based around private messages.
+type Input struct {
+	Origin *girc.Event
+	Args   []string
+}
+
+// Command is an IRC command, supporting aliases, help documentation and easy
+// wrapping for message inputs.
+type Command struct {
+	// Name of command, e.g. "search" or "ping".
+	Name string
+	// Aliases for the above command, e.g. "s" for search, or "p" for "ping".
+	Aliases []string
+	// Help documentation. Should be in the format "<arg> <arg> [arg] --
+	// something useful here"
+	Help string
+	// MinArgs is the minimum required arguments for the command. Defaults to
+	// 0, which means multiple, or no arguments can be supplied. If set
+	// above 0, this means that the command handler will throw an error asking
+	// the person to check "<prefix>help <command>" for more info.
+	MinArgs int
+	// Fn is the function which is executed when the command is ran from a
+	// private message, or channel.
+	Fn func(*girc.Client, *Input)
+}
+
+func (c *Command) genHelp(prefix string) string {
+	out := "{b}" + prefix + c.Name + "{b}"
+
+	if c.Aliases != nil && len(c.Aliases) > 0 {
+		out += " ({b}" + prefix + strings.Join(c.Aliases, "{b}, {b}"+prefix) + "{b})"
+	}
+
+	out += " :: " + c.Help
+
+	return out
+}
+
+// CmdHandler is an irc command parser and execution format which you could
+// use as an example for building your own version/bot.
+//
+// An example of how you would register this with girc:
+//
+//   ch, err := cmdhandler.New("!")
+//   if err != nil {
+//   	panic(err)
+//   }
+
+//   ch.Add(&cmdhandler.Command{
+//   	Name:    "ping",
+//   	Help:    "Sends a pong reply back to the original user.",
+//   	Fn: func(c *girc.Client, input *cmdhandler.Input) {
+//   		c.Commands.ReplyTo(*input.Origin, "pong!")
+//   	},
+//   })
+//
+//   client.Handlers.AddHandler(girc.PRIVMSG, ch)
+type CmdHandler struct {
+	prefix string
+	re     *regexp.Regexp
+
+	mu   sync.Mutex
+	cmds map[string]*Command
+}
+
+var cmdMatch = `^%s([a-z0-9-_]{1,20})(?: (.*))?$`
+
+// New returns a new CmdHandler based on the specified command prefix. A good
+// prefix is a single character, and easy to remember/use. E.g. "!", or ".".
+func New(prefix string) (*CmdHandler, error) {
+	re, err := regexp.Compile(fmt.Sprintf(cmdMatch, regexp.QuoteMeta(prefix)))
+	if err != nil {
+		return nil, err
+	}
+
+	return &CmdHandler{prefix: prefix, re: re, cmds: make(map[string]*Command)}, nil
+}
+
+var validName = regexp.MustCompile(`^[a-z0-9-_]{1,20}$`)
+
+// Add registers a new command to the handler. Note that you cannot remove
+// commands once added, unless you add another CmdHandler to the client.
+func (ch *CmdHandler) Add(cmd *Command) error {
+	if cmd == nil {
+		return errors.New("nil command provided to CmdHandler")
+	}
+
+	cmd.Name = strings.ToLower(cmd.Name)
+	if !validName.MatchString(cmd.Name) {
+		return fmt.Errorf("invalid command name: %q (req: %q)", cmd.Name, validName.String())
+	}
+
+	if cmd.Aliases != nil {
+		for i := 0; i < len(cmd.Aliases); i++ {
+			cmd.Aliases[i] = strings.ToLower(cmd.Aliases[i])
+			if !validName.MatchString(cmd.Aliases[i]) {
+				return fmt.Errorf("invalid command name: %q (req: %q)", cmd.Aliases[i], validName.String())
+			}
+		}
+	}
+
+	if cmd.MinArgs < 0 {
+		cmd.MinArgs = 0
+	}
+
+	ch.mu.Lock()
+	defer ch.mu.Unlock()
+
+	if _, ok := ch.cmds[cmd.Name]; ok {
+		return fmt.Errorf("command already registered: %s", cmd.Name)
+	}
+
+	ch.cmds[cmd.Name] = cmd
+
+	// Since we'd be storing pointers, duplicates do not matter.
+	for i := 0; i < len(cmd.Aliases); i++ {
+		if _, ok := ch.cmds[cmd.Aliases[i]]; ok {
+			return fmt.Errorf("alias already registered: %s", cmd.Aliases[i])
+		}
+
+		ch.cmds[cmd.Aliases[i]] = cmd
+	}
+
+	return nil
+}
+
+// Execute satisfies the girc.Handler interface.
+func (ch *CmdHandler) Execute(client *girc.Client, event girc.Event) {
+	if event.Source == nil || event.Command != girc.PRIVMSG {
+		return
+	}
+
+	parsed := ch.re.FindStringSubmatch(event.Trailing)
+	if len(parsed) != 3 {
+		return
+	}
+
+	invCmd := strings.ToLower(parsed[1])
+	args := strings.Split(parsed[2], " ")
+	if len(args) == 1 && args[0] == "" {
+		args = []string{}
+	}
+
+	ch.mu.Lock()
+	defer ch.mu.Unlock()
+
+	if invCmd == "help" {
+		if len(args) == 0 {
+			client.Commands.ReplyTo(event, girc.Fmt("type '{b}!help {blue}<command>{c}{b}' to optionally get more info about a specific command."))
+			return
+		}
+
+		args[0] = strings.ToLower(args[0])
+
+		if _, ok := ch.cmds[args[0]]; !ok {
+			client.Commands.ReplyTof(event, girc.Fmt("unknown command {b}%q{b}."), args[0])
+			return
+		}
+
+		if ch.cmds[args[0]].Help == "" {
+			client.Commands.ReplyTof(event, girc.Fmt("there is no help documentaiton for {b}%q{b}"), args[0])
+			return
+		}
+
+		client.Commands.ReplyTo(event, girc.Fmt(ch.cmds[args[0]].genHelp(ch.prefix)))
+		return
+	}
+
+	cmd, ok := ch.cmds[invCmd]
+	if !ok {
+		return
+	}
+
+	if len(args) < cmd.MinArgs {
+		client.Commands.ReplyTof(event, girc.Fmt("not enough arguments supplied for {b}%q{b}. try '{b}%shelp %s{b}'?"), invCmd, ch.prefix, invCmd)
+		return
+	}
+
+	in := &Input{
+		Origin: &event,
+		Args:   args,
+	}
+
+	go cmd.Fn(client, in)
+}