package notify

import (
	"b612.me/stario"
	"context"
	"net"
)

type serverSessionRuntime struct {
	listener          net.Listener
	udpListener       *net.UDPConn
	transportAttached bool
	stopCtx           context.Context
	stopFn            context.CancelFunc
	transportStopCtx  context.Context
	transportStopFn   context.CancelFunc
	queue             *stario.StarQueue
	inboundDispatcher *inboundDispatcher
}

func newServerSessionRuntimeBase(stopCtx context.Context, stopFn context.CancelFunc) *serverSessionRuntime {
	return &serverSessionRuntime{
		stopCtx: stopCtx,
		stopFn:  stopFn,
	}
}

func prepareServerSessionRuntime(rt *serverSessionRuntime) *serverSessionRuntime {
	if rt == nil {
		return nil
	}
	normalizeServerSessionRuntimeTransportState(rt)
	ensureServerSessionRuntimeTransportLifecycle(rt)
	return rt
}

func (s *ServerCommon) setServerSessionRuntime(rt *serverSessionRuntime) {
	if s == nil || rt == nil {
		return
	}
	rt = prepareServerSessionRuntime(rt)
	s.sessionRuntime.Store(rt)
	s.listener = rt.listener
	s.udpListener = rt.udpListener
	s.stopCtx = rt.stopCtx
	s.stopFn = rt.stopFn
	s.queue = rt.queue
}

func (s *ServerCommon) resetServerSessionRuntimeBase() {
	if s == nil {
		return
	}
	stopCtx, stopFn := context.WithCancel(context.Background())
	s.sessionRuntime.Store(newServerSessionRuntimeBase(stopCtx, stopFn))
	s.listener = nil
	s.udpListener = nil
	s.queue = nil
	s.stopCtx = stopCtx
	s.stopFn = stopFn
}

func (s *ServerCommon) cleanupFailedServerStart() {
	if s == nil {
		return
	}
	rt := s.serverSessionRuntimeSnapshot()
	if rt != nil && rt.stopFn != nil {
		rt.stopFn()
	}
	s.cleanupServerSessionResources()
	s.rollbackServerSessionStart()
	s.resetServerSessionRuntimeBase()
}

func (s *ServerCommon) clearServerSessionRuntimeTransport() {
	if s == nil {
		return
	}
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		return
	}
	if rt.transportStopFn != nil {
		rt.transportStopFn()
	}
	next := *rt
	next.listener = nil
	next.udpListener = nil
	next.transportAttached = false
	next.transportStopCtx = nil
	next.transportStopFn = nil
	s.setServerSessionRuntime(&next)
}

func (s *ServerCommon) clearServerSessionRuntimeQueue() {
	if s == nil {
		return
	}
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		return
	}
	next := *rt
	next.queue = nil
	s.setServerSessionRuntime(&next)
}

func (s *ServerCommon) bindServerSessionTransport(listener net.Listener, udpListener *net.UDPConn) {
	if s == nil {
		return
	}
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		rt = &serverSessionRuntime{}
	}
	next := *rt
	next.listener = listener
	next.udpListener = udpListener
	s.setServerSessionRuntime(&next)
}

func (s *ServerCommon) serverSessionRuntimeSnapshot() *serverSessionRuntime {
	if s == nil {
		return nil
	}
	return s.sessionRuntime.Load()
}

func normalizeServerSessionRuntimeTransportState(rt *serverSessionRuntime) {
	if rt == nil {
		return
	}
	rt.transportAttached = rt.listener != nil || rt.udpListener != nil
}

func ensureServerSessionRuntimeTransportLifecycle(rt *serverSessionRuntime) {
	if rt == nil {
		return
	}
	if rt.listener == nil && rt.udpListener == nil {
		rt.transportStopCtx = nil
		rt.transportStopFn = nil
		return
	}
	if rt.transportStopCtx != nil && rt.transportStopFn != nil {
		return
	}
	parent := rt.stopCtx
	if parent == nil {
		parent = context.Background()
	}
	rt.transportStopCtx, rt.transportStopFn = context.WithCancel(parent)
}

func (s *ServerCommon) serverStopContextSnapshot() context.Context {
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		return nil
	}
	return rt.stopCtx
}

func (s *ServerCommon) serverTransportAttachedSnapshot() bool {
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		return false
	}
	return rt.transportAttached
}

func (s *ServerCommon) serverStopFuncSnapshot() context.CancelFunc {
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		return nil
	}
	return rt.stopFn
}

func (s *ServerCommon) serverQueueSnapshot() *stario.StarQueue {
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		return nil
	}
	return rt.queue
}

func (s *ServerCommon) serverInboundDispatcherSnapshot() *inboundDispatcher {
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		return nil
	}
	return rt.inboundDispatcher
}

func (s *ServerCommon) serverListenerSnapshot() net.Listener {
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		return nil
	}
	return rt.listener
}

func (s *ServerCommon) serverUDPListenerSnapshot() *net.UDPConn {
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		return nil
	}
	return rt.udpListener
}

func (s *ServerCommon) serverTransportStopContextSnapshot() context.Context {
	rt := s.serverSessionRuntimeSnapshot()
	if rt == nil {
		return nil
	}
	if rt.transportStopCtx != nil {
		return rt.transportStopCtx
	}
	return rt.stopCtx
}