feat(commands): add dispatcher and request/result contracts

pkg/commands/definition.go

@@ -6,4 +6,5 @@ type Definition struct {
 	Usage       string
 	Aliases     []string
 	Channels    []string
+	Handler     Handler
 }

pkg/commands/dispatcher.go

@@ -0,0 +1,59 @@
+package commands
+
+import (
+	"context"
+	"strings"
+)
+
+type Handler func(ctx context.Context, req Request) error
+
+type Request struct {
+	Channel   string
+	ChatID    string
+	SenderID  string
+	Text      string
+	MessageID string
+}
+
+type Result struct {
+	Matched bool
+	Command string
+	Err     error
+}
+
+type Dispatcher struct {
+	reg *Registry
+}
+
+func NewDispatcher(reg *Registry) *Dispatcher {
+	return &Dispatcher{reg: reg}
+}
+
+func (d *Dispatcher) Dispatch(ctx context.Context, req Request) Result {
+	token := firstToken(req.Text)
+	if token == "" {
+		return Result{Matched: false}
+	}
+
+	cmdName := strings.TrimPrefix(token, "/")
+	for _, def := range d.reg.ForChannel(req.Channel) {
+		if def.Name != cmdName {
+			continue
+		}
+		if def.Handler == nil {
+			return Result{Matched: true, Command: def.Name}
+		}
+		err := def.Handler(ctx, req)
+		return Result{Matched: true, Command: def.Name, Err: err}
+	}
+
+	return Result{Matched: false}
+}
+
+func firstToken(input string) string {
+	parts := strings.Fields(strings.TrimSpace(input))
+	if len(parts) == 0 {
+		return ""
+	}
+	return parts[0]
+}

pkg/commands/dispatcher_test.go

@@ -0,0 +1,28 @@
+package commands
+
+import (
+	"context"
+	"testing"
+)
+
+func TestDispatcher_MatchSlashCommand(t *testing.T) {
+	called := false
+	defs := []Definition{
+		{
+			Name: "help",
+			Handler: func(context.Context, Request) error {
+				called = true
+				return nil
+			},
+		},
+	}
+	d := NewDispatcher(NewRegistry(defs))
+
+	res := d.Dispatch(context.Background(), Request{
+		Channel: "telegram",
+		Text:    "/help",
+	})
+	if !res.Matched || !called || res.Err != nil {
+		t.Fatalf("dispatch result = %+v, called=%v", res, called)
+	}
+}