package health

import (
	"encoding/json"
	"net/http"
	"time"
)

// Status of the service liveness.
type LivenessStatus string

const (
	// Service is alive and functioning properly.
	LivenessStatusAlive LivenessStatus = "ok"
)

// Result of a liveness check.
type LivenessResult struct {
	// Status of the service (always LivenessStatusAlive)
	Status LivenessStatus
	// Timestamp of the liveness check in milliseconds since Unix epoch
	Timestamp int64
}

// Checks if the service is alive.
func Liveness() LivenessResult {
	return LivenessResult{
		Status:    LivenessStatusAlive,
		Timestamp: time.Now().UnixMilli(),
	}
}

// Handler for liveness HTTP requests.
// Returns a response with status 200 and a JSON body matching LivenessResult.
func LivenessHandler() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		result := Liveness()
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusOK)
		json.NewEncoder(w).Encode(result)
	}
}