Allow retrieving sub commands usage via help args

Author: motoki317

pkg/bot/command.go

@@ -182,6 +182,40 @@ func (dc *RootCommand) Execute(ctx domain.Context) error {
 	return c.Execute(ctx)
 }
 
+func (dc *RootCommand) HasSubcommands() bool {
+	return len(dc.cmds) > 0
+}
+
+func (dc *RootCommand) GetSubcommand(verb string) (domain.Command, bool) {
+	c, ok := dc.cmds[verb]
+	return c, ok
+}
+
+func (dc *RootCommand) getMatchingCommand(args []string) (domain.Command, bool) {
+	cur, ok := dc.GetSubcommand(args[0])
+	if !ok {
+		return nil, false
+	}
+	for _, arg := range args[1:] {
+		cur, ok = cur.GetSubcommand(arg)
+		if !ok {
+			return nil, false
+		}
+	}
+	return cur, true
+}
+
+func (dc *RootCommand) HelpMessage(_ int, _ bool) []string {
+	var lines []string
+	names := lo.Keys(dc.cmds)
+	slices.Sort(names)
+	for _, name := range names {
+		cmd := dc.cmds[name]
+		lines = append(lines, cmd.HelpMessage(0, false)...)
+	}
+	return lines
+}
+
 func (c *CommandInstance) Execute(ctx domain.Context) error {
 	// If this command has permitted operators defined, check operator
 	if len(c.operators) > 0 {
@@ -268,15 +302,13 @@ func (c *CommandInstance) Execute(ctx domain.Context) error {
 	return ctx.ReplySuccess(replyMessage...)
 }
 
-func (dc *RootCommand) HelpMessage(_ int, _ bool) []string {
-	var lines []string
-	names := lo.Keys(dc.cmds)
-	slices.Sort(names)
-	for _, name := range names {
-		cmd := dc.cmds[name]
-		lines = append(lines, cmd.HelpMessage(0, false)...)
-	}
-	return lines
+func (c *CommandInstance) HasSubcommands() bool {
+	return len(c.subCommands) > 0
+}
+
+func (c *CommandInstance) GetSubcommand(verb string) (domain.Command, bool) {
+	sub, ok := c.subCommands[verb]
+	return sub, ok
 }
 
 func (c *CommandInstance) HelpMessage(indent int, formatSub bool) []string {

pkg/bot/help.go

@@ -17,12 +17,43 @@ type HelpCommand struct {
 
 func (h *HelpCommand) Execute(ctx domain.Context) error {
 	var lines []string
-	lines = append(lines, fmt.Sprintf("## DevOpsBot v%s", utils.Version()))
+	args := ctx.Args()
+
+	// Root usage
+	if len(args) == 0 {
+		lines = append(lines, fmt.Sprintf("## DevOpsBot v%s", utils.Version()))
+		lines = append(lines, "")
+		lines = append(lines, h.root.HelpMessage(0, true)...)
+		lines = append(lines, "")
+		lines = append(lines, fmt.Sprintf("Type `%shelp command-name` for more help", config.C.Prefix))
+		return ctx.ReplySuccess(lines...)
+	}
+
+	// Specific command usage
+	c, ok := h.root.getMatchingCommand(args)
+	if !ok {
+		lines = append(lines, fmt.Sprintf("Command `%s%s` not found, try `%shelp`?", config.C.Prefix, strings.Join(args, " "), config.C.Prefix))
+		return ctx.ReplyBad(lines...)
+	}
+
+	lines = append(lines, fmt.Sprintf("## `%s%s` Usage", config.C.Prefix, strings.Join(args, " ")))
 	lines = append(lines, "")
-	lines = append(lines, h.root.HelpMessage(0, true)...)
+	lines = append(lines, c.HelpMessage(0, true)...)
+	if c.HasSubcommands() {
+		lines = append(lines, "")
+		lines = append(lines, fmt.Sprintf("Type `%shelp command-name [sub-commands...]` for more help", config.C.Prefix))
+	}
 	return ctx.ReplySuccess(lines...)
 }
 
+func (h *HelpCommand) HasSubcommands() bool {
+	return false
+}
+
+func (h *HelpCommand) GetSubcommand(_ string) (domain.Command, bool) {
+	return nil, false
+}
+
 func (h *HelpCommand) HelpMessage(indent int, _ bool) []string {
 	return []string{fmt.Sprintf(
 		"%s- `%shelp` - Display help message.",

pkg/domain/bot.go

@@ -51,5 +51,7 @@ type Context interface {
 // Command コマンドインターフェース
 type Command interface {
 	Execute(ctx Context) error
+	HasSubcommands() bool
+	GetSubcommand(verb string) (Command, bool)
 	HelpMessage(indent int, formatSub bool) []string
 }