Phase 1 MVP — echo bot factory

handlers.go

@@ -0,0 +1,75 @@
+package main
+
+import (
+	"context"
+	"fmt"
+)
+
+type Handler interface {
+	Handle(ctx context.Context, update Update, bot Bot) error
+}
+
+type Bot struct {
+	Slug    string
+	Token   string
+	Secret  string
+	Handler Handler
+}
+
+type Registry struct {
+	bots map[string]Bot
+}
+
+func NewRegistry(cfg *Config) (*Registry, error) {
+	if len(cfg.Bots) == 0 {
+		return nil, fmt.Errorf("no bots configured")
+	}
+
+	tg := NewTelegramClient()
+	bots := make(map[string]Bot, len(cfg.Bots))
+
+	for slug, b := range cfg.Bots {
+		token := b.Token
+		secret := b.Secret
+		if token == "" {
+			return nil, fmt.Errorf("bot %s: token missing", slug)
+		}
+		if secret == "" {
+			return nil, fmt.Errorf("bot %s: secret missing", slug)
+		}
+
+		var h Handler
+		switch b.Handler {
+		case "echo":
+			h = &EchoHandler{tg: tg}
+		case "":
+			return nil, fmt.Errorf("bot %s: handler missing", slug)
+		default:
+			return nil, fmt.Errorf("bot %s: unknown handler %q", slug, b.Handler)
+		}
+
+		bots[slug] = Bot{
+			Slug:    slug,
+			Token:   token,
+			Secret:  secret,
+			Handler: h,
+		}
+	}
+
+	return &Registry{bots: bots}, nil
+}
+
+func (r *Registry) Get(slug string) (Bot, bool) {
+	b, ok := r.bots[slug]
+	return b, ok
+}
+
+func (r *Registry) Count() int { return len(r.bots) }
+
+func (r *Registry) Slugs() []string {
+	out := make([]string, 0, len(r.bots))
+	for s := range r.bots {
+		out = append(out, s)
+	}
+	return out
+}