package bot

import (
	"context"
	"log"

	"musiclink/internal/detector"
	"musiclink/internal/resolver"
)

// Handler processes incoming messages and generates responses.
type Handler struct {
	detector *detector.Detector
	resolver *resolver.Resolver
}

// NewHandler creates a new message handler.
func NewHandler(apiURL string) *Handler {
	return &Handler{
		detector: detector.New(),
		resolver: resolver.New(apiURL),
	}
}

// Handle processes a message and returns a response if music links were found.
func (h *Handler) Handle(ctx context.Context, msg Message) *Message {
	// Detect music links in the message
	links := h.detector.Detect(msg.Text)
	if len(links) == 0 {
		return nil
	}

	log.Printf("Found %d music link(s) in message from %s", len(links), msg.Username)

	// Process the first link found
	link := links[0]

	// Resolve to other services via idonthavespotify API
	resolved, err := h.resolver.Resolve(ctx, link.URL)
	if err != nil {
		log.Printf("Error resolving link: %v", err)
		return nil
	}

	// Only respond if we found links on other services
	if len(resolved.Links) <= 1 {
		log.Printf("No additional links found for %s", link.URL)
		return nil
	}

	// Format the response
	title := ""
	if resolved.Track != nil {
		title = resolved.Track.Title
	}
	text := resolver.Format(resolved, title)

	return &Message{
		Text:    text,
		Gateway: msg.Gateway,
	}
}