package pubsub

import (
	"context"
	"encoding/json"
	"log"

	"director/api/ws"

	"github.com/redis/go-redis/v9"
)

const Channel = "director:events"

type Event struct {
	Type string `json:"event"`
	Data any    `json:"data"`
}

type PubSub struct {
	rdb *redis.Client
	hub *ws.Hub
}

func New(redisAddr string, hub *ws.Hub) *PubSub {
	rdb := redis.NewClient(&redis.Options{
		Addr: redisAddr,
	})
	return &PubSub{rdb: rdb, hub: hub}
}

// Publish sends an event to Redis pub/sub.
// Called by the API handlers and can also be called by external agents via redis-cli.
func (ps *PubSub) Publish(ctx context.Context, event string, data any) error {
	msg, err := json.Marshal(Event{Type: event, Data: data})
	if err != nil {
		return err
	}
	return ps.rdb.Publish(ctx, Channel, msg).Err()
}

// Subscribe listens for events on Redis pub/sub and forwards them to WebSocket clients.
// This bridges external publishers (OpenClaw agents, cron jobs) to the React UI.
func (ps *PubSub) Subscribe(ctx context.Context) {
	sub := ps.rdb.Subscribe(ctx, Channel)
	ch := sub.Channel()

	log.Printf("Redis pub/sub subscribed to %s", Channel)

	for msg := range ch {
		ps.hub.Broadcast([]byte(msg.Payload))
	}
}

// Ping tests the Redis connection.
func (ps *PubSub) Ping(ctx context.Context) error {
	return ps.rdb.Ping(ctx).Err()
}

// Close shuts down the Redis client.
func (ps *PubSub) Close() error {
	return ps.rdb.Close()
}