// Package sse provides helpers for SSE signal handling.
package sse

import (
	"encoding/json"
	"time"

	"github.com/starfederation/datastar-go/datastar"
)

// Signals holds client-side state managed via SSE.
type Signals struct {
	LastPing int64 `json:"lastPing,omitempty"`
}

// SendPing sends a heartbeat signal with the current timestamp.
func SendPing(sse *datastar.ServerSentEventGenerator) error {
	return PatchSignals(sse, Signals{LastPing: time.Now().UnixMilli()})
}

// PatchSignals sends a signals patch to the client.
func PatchSignals(sse *datastar.ServerSentEventGenerator, s Signals) error {
	data, err := json.Marshal(s)
	if err != nil {
		return err
	}
	return sse.PatchSignals(data)
}