package xmpp

import (
	"context"
	"fmt"
	"kas/cps"
	"log"

	"gosrc.io/xmpp"
	"gosrc.io/xmpp/stanza"
)

func messageHandler(s xmpp.Sender, p stanza.Packet) {
	msg, ok := p.(stanza.Message)
	if !ok {
		log.Print("xmpp: ignore packet %T", p)
		return
	}

	response, err := cps.Handle(context.Background(), msg.Body)
	if err != nil {
		err = fmt.Errorf("xmpp message handler: %w", err)
		log.Print(err)
	}

	reply := stanza.Message{
		Attrs: stanza.Attrs{
			To: msg.From,
		},
		Body: response.String(),
	}

	err = s.Send(reply)
	if err != nil {
		log.Printf("xmpp: failed to send reply to %s: %s",
			msg.From, err)
	}
}

func logError(err error) {
	err = fmt.Errorf("xmpp: %w", err)
	log.Print(err)
}

func Start(cfg *Config) error {
	log.Printf("starting XMPP server for %s", cfg.Account)
	config, err := cfg.xmppConfig()
	if err != nil {
		return err
	}

	go func() {
		for {
			// TODO: what happens if we ask the bot to stop?
			// Best answer: systemd service.
			runClient(config)
		}
	}()

	return nil
}

func runClient(cfg *xmpp.Config) {
	router := xmpp.NewRouter()
	router.HandleFunc("message", messageHandler)

	client, err := xmpp.NewClient(cfg, router, logError)
	if err != nil {
		logError(err)
		return
	}

	// If you pass the client to a connection manager, it will handle the reconnect policy
	// for you automatically.
	cm := xmpp.NewStreamManager(client, nil)

	log.Print(cm.Run())
}