package main

import (
	"encoding/json"
	"sync"
)

// Broker is a simple in-memory pub/sub for SSE events.
type Broker struct {
	mu      sync.Mutex
	clients map[chan []byte]struct{}
}

func newBroker() *Broker {
	return &Broker{clients: make(map[chan []byte]struct{})}
}

func (b *Broker) subscribe() chan []byte {
	ch := make(chan []byte, 8)
	b.mu.Lock()
	b.clients[ch] = struct{}{}
	b.mu.Unlock()
	return ch
}

func (b *Broker) unsubscribe(ch chan []byte) {
	b.mu.Lock()
	delete(b.clients, ch)
	b.mu.Unlock()
	close(ch)
}

func (b *Broker) publish(event string, data any) {
	payload, _ := json.Marshal(map[string]any{"event": event, "data": data})
	b.mu.Lock()
	defer b.mu.Unlock()
	for ch := range b.clients {
		select {
		case ch <- payload:
		default:
		}
	}
}