add help command

cmd/command.go

@@ -28,6 +28,8 @@ type Command struct {
 	Func  func(CmdArgs) (int, error)
 	Flags *flag.FlagSet
 	Use   string
+	Short string
+	Long  string
 }
 
 var commandRegistry = make(map[string]Command)

cmd/help.go

@@ -0,0 +1,60 @@
+package lumecmd
+
+import (
+	"flag"
+	"fmt"
+)
+
+func init() {
+	var cmdName string = "help"
+	fs := flag.NewFlagSet(cmdName, flag.ExitOnError)
+
+	RegisterCommand(cmdName, Command{
+		Func:  HelpCmd,
+		Flags: fs,
+		Use:   "<command>",
+		Short: "Show help for a command",
+	})
+}
+
+func HelpCmd(args CmdArgs) (int, error) {
+	argv := args.Flags.Args()
+
+	if len(argv) == 0 {
+		printHelp(commandRegistry)
+	} else if len(argv) >= 1 {
+		subCmd, ok := commandRegistry[argv[0]]
+		if !ok {
+			fmt.Printf("unknown command: %s\n", argv[0])
+			return 1, nil
+		}
+
+		if subCmd.Use != "" {
+			fmt.Printf("usage:\n  lume %s %s\n", subCmd.Name, subCmd.Use)
+			fmt.Println()
+		}
+
+		fmt.Print("flags:\n")
+		subCmd.Flags.PrintDefaults()
+	}
+
+	return 0, nil
+}
+
+func printHelp(commands map[string]Command) {
+	var maxLen, cmdLen int
+	for _, c := range commands {
+		cmdLen = len(c.Name)
+		if cmdLen > maxLen {
+			maxLen = cmdLen
+		}
+	}
+
+	fmt.Printf("usage:\n  lume <command> [<args...>]")
+	fmt.Println()
+
+	fmt.Println("\ncommands:")
+	for _, c := range commands {
+		fmt.Printf("  %-*s    %s\n", maxLen, c.Name, c.Short)
+	}
+}

cmd/ls.go

@@ -18,6 +18,7 @@ func init() {
 		Func:  LsCmd,
 		Flags: fs,
 		Use:   "[--selector=<selector>",
+		Short: "List the lights",
 	})
 }
 

cmd/setcolor.go

@@ -43,6 +43,7 @@ func init() {
 		Func:  SetColorCmd,
 		Flags: fs,
 		Use:   "[--selector <selector>] [--power (on|off)] [--hue <hue>] [--saturation <saturation>] [--rgb <rbg>] [--name <color>] [--brightness <brightness>] [--duration <sec>] [--fast]",
+		Short: "Set the color",
 	})
 }
 

cmd/setstate.go

@@ -36,6 +36,7 @@ func init() {
 		Func:  SetStateCmd,
 		Flags: fs,
 		Use:   "[--selector <selector>] [--power (on|off)] [--color <color>] [--brightness <brightness>] [--duration <sec>] [--infrared <infrared>] [--fast]",
+		Short: "Set various state attributes",
 	})
 }
 

cmd/setwhite.go

@@ -39,6 +39,7 @@ func init() {
 		Func:  SetWhiteCmd,
 		Flags: fs,
 		Use:   "[--selector <selector>] [--power (on|off)] [--kelvin <kelvin>] [--name <color>] [--brightness <brightness>] [--duration <sec>] [--infrared] [--fast]",
+		Short: "Set the white level",
 	})
 }
 

cmd/toggle.go

@@ -19,6 +19,7 @@ func init() {
 		Func:  ToggleCmd,
 		Flags: fs,
 		Use:   "[--selector <selector>] [--duration <sec>]",
+		Short: "Toggle the power on/off",
 	})
 }