package ocpp

import (
	"net/http"
	"sync"
	"time"

	"github.com/evcc-io/evcc/util"
	"github.com/lorenzodonini/ocpp-go/ocpp"
	ocpp16 "github.com/lorenzodonini/ocpp-go/ocpp1.6"
	"github.com/lorenzodonini/ocpp-go/ocpp1.6/core"
	"github.com/lorenzodonini/ocpp-go/ocpp1.6/remotetrigger"
	"github.com/lorenzodonini/ocpp-go/ocpp1.6/security"
	"github.com/lorenzodonini/ocpp-go/ocpp1.6/smartcharging"
	"github.com/lorenzodonini/ocpp-go/ocppj"
	"github.com/lorenzodonini/ocpp-go/ws"
)

var (
	once     sync.Once
	instance *CS
)

func Instance() *CS {
	once.Do(func() {
		log := util.NewLogger("ocpp")

		server := ws.NewServer()
		server.SetCheckOriginHandler(func(r *http.Request) bool { return true })

		dispatcher := ocppj.NewDefaultServerDispatcher(ocppj.NewFIFOQueueMap(0))
		dispatcher.SetTimeout(Timeout)

		endpoint := ocppj.NewServer(server, dispatcher, nil, core.Profile, remotetrigger.Profile, smartcharging.Profile, security.Profile)
		endpoint.SetInvalidMessageHook(func(client ws.Channel, err *ocpp.Error, rawMessage string, parsedFields []any) *ocpp.Error {
			log.ERROR.Printf("%v (%s)", err, rawMessage)
			return nil
		})

		cs := ocpp16.NewCentralSystem(endpoint, server)

		instance = &CS{
			log:           log,
			regs:          make(map[string]*registration),
			CentralSystem: cs,
		}

		instance.txnId.Store(time.Now().UTC().Unix())

		ocppj.SetLogger(instance)

		cs.SetCoreHandler(instance)
		cs.SetSecurityHandler(instance)
		cs.SetNewChargePointHandler(instance.NewChargePoint)
		cs.SetChargePointDisconnectedHandler(instance.ChargePointDisconnected)

		go instance.errorHandler(cs.Errors())
		go cs.Start(8887, "/{ws}")

		// wait for server to start
		for range time.Tick(10 * time.Millisecond) {
			if dispatcher.IsRunning() {
				break
			}
		}
	})

	return instance
}