// Package services provides the game service layer for Snake,
// handling NATS subscriptions and chat room management.
package services

import (
	"fmt"

	"github.com/nats-io/nats.go"

	"github.com/ryanhamamura/games/chat"
	chatcomponents "github.com/ryanhamamura/games/chat/components"
	"github.com/ryanhamamura/games/snake"
)

func snakeChatColor(slot int) string {
	if slot >= 0 && slot < len(snake.SnakeColors) {
		return snake.SnakeColors[slot]
	}
	return "#666"
}

// GameService manages NATS subscriptions and chat for Snake games.
type GameService struct {
	nc *nats.Conn
}

// NewGameService creates a new game service.
func NewGameService(nc *nats.Conn) *GameService {
	return &GameService{
		nc: nc,
	}
}

// SubscribeGameUpdates returns a NATS subscription and channel for game state updates.
func (s *GameService) SubscribeGameUpdates(gameID string) (*nats.Subscription, <-chan *nats.Msg, error) {
	ch := make(chan *nats.Msg, 64)
	sub, err := s.nc.ChanSubscribe(snake.GameSubject(gameID), ch)
	if err != nil {
		return nil, nil, fmt.Errorf("subscribing to game updates: %w", err)
	}
	return sub, ch, nil
}

// ChatConfig returns the chat configuration for a game.
func (s *GameService) ChatConfig(gameID string) chatcomponents.Config {
	return chatcomponents.Config{
		CSSPrefix:          "snake",
		PostURL:            fmt.Sprintf("/snake/%s/chat", gameID),
		Color:              snakeChatColor,
		StopKeyPropagation: true,
	}
}

// ChatRoom returns a chat room for a game (ephemeral, not persisted).
func (s *GameService) ChatRoom(gameID string) *chat.Room {
	return chat.NewRoom(s.nc, snake.ChatSubject(gameID))
}

// PublishGameUpdate sends a notification that the game state has changed.
func (s *GameService) PublishGameUpdate(gameID string) error {
	return s.nc.Publish(snake.GameSubject(gameID), nil)
}