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
}