DMAC/internal/pkg/server/system.go

package server

import (
	_ "fmt"
)

// allows for multiple readers/writers
type DeviceInfo struct {
	Id            int
	Type          string
	Status        string
	Data          string
	Index         int
	TransactionId uint32
}

/*

type StatusMonitor struct {
	// allows for embedding into managers
	TransactionId chan uint32      // monotonically increases to track outdated reqs
	DevChan       chan *DeviceInfo // channel for device status
	ReactorChan   chan *DeviceInfo // channel for reactor status
	*SystemViewer
	DevBuf *devbuf
	sync.Mutex
}

type devbuf struct {
	ReactorId int                            // reactor we are looking at, if any
	Buf       map[string]map[int]*DeviceInfo // convienent way to store/seperate device data
	sync.Mutex
}

func NewBuffer() map[string]map[int]*DeviceInfo {
	rbuf := make(map[int]*DeviceInfo)
	dbuf := make(map[int]*DeviceInfo)
	sbuf := make(map[string]map[int]*DeviceInfo)
	sbuf["Reactor"] = rbuf
	sbuf["Device"] = dbuf
	return sbuf
}

func NewStatusMonitor(t string, id int, sys *SystemViewer) *StatusMonitor {
	tid := make(chan uint32)
	sm := &StatusMonitor{TransactionId: tid}
	sm.SystemViewer = sys
	logging.Debug(logging.DClient, "SYS Creating new status monitor")
	if t == "Reactor" {
		// reactor status monitor
		sm.ReactorChan = sys.AddReactorSender()
		sm.DevChan = sys.AddDeviceSender(id)
		go sm.GenerateIds()
	} else {
		// tui status monitor
		sbuf := NewBuffer()
		//sm.ReactorChan, sbuf["Reactor"] = sys.AddListener(id,0)
		sm.DevBuf = &devbuf{Buf: sbuf} // makes it easier to work with
		go sm.UpdateListener(id, 0)
	}
	return sm
}

func (s *StatusMonitor) GenerateIds() {
	var id uint32
	id = 0
	for {
		s.TransactionId <- id
		id += 1
	}
}

func (s *StatusMonitor) Send(d *DeviceInfo, dtype string) {
	d.TransactionId = <-s.TransactionId
	logging.Debug(logging.DClient, "SYS 01 Sending update for: %s (%s)", d.Type, d.Status)
	if dtype == "Reactor" {
		s.ReactorChan <- d
	} else {
		s.DevChan <- d
	}
}

func (s *StatusMonitor) GetBuffer() []*DeviceInfo {
	// also clears buffer
	s.DevBuf.Lock()
	defer s.DevBuf.Unlock()
	res := []*DeviceInfo{}
	if len(s.DevBuf.Buf["Reactor"]) != 0 || len(s.DevBuf.Buf["Device"]) != 0 {
		logging.Debug(logging.DClient, "Clearing buff %v", s.DevBuf.Buf)
	}
	for _, devs := range s.DevBuf.Buf {
		for _, dev := range devs {
			// loops over reactors then devices
			res = append(res, dev)
		}
	}
	s.DevBuf.Buf = NewBuffer() // clearing old buffer
	return res
}

func (s *StatusMonitor) UpdateListener(tid, reactorId uint32) {
	s.DevBuf.Lock()
	defer s.DevBuf.Unlock()
	// clearing proper buffer
	if reactorId == 0 {
		logging.Debug(logging.DClient, "SYS 01 Adding %v as reactor listener", tid)
		s.DevBuf.Buf["Reactor"] = make(map[uint32]*DeviceInfo)
		s.ReactorChan, s.DevBuf.Buf["Reactor"] = s.SystemViewer.AddListener(tid, reactorId)
		go s.Listen(s.ReactorChan)
	} else {
		logging.Debug(logging.DClient, "SYS 01 Adding %v as reactor %v listener", tid, reactorId)
		s.DevBuf.Buf["Device"] = make(map[uint32]*DeviceInfo) // clearing old devices
		if s.DevBuf.ReactorId != reactorId && s.DevBuf.ReactorId != 0 {
			go s.SystemViewer.RemoveListener(s.DevBuf.ReactorId, tid)
		}
		s.DevBuf.ReactorId = reactorId
		s.DevChan, s.DevBuf.Buf["Device"] = s.SystemViewer.AddListener(tid, reactorId)
		go s.Listen(s.DevChan)
	}
}

func (s *StatusMonitor) UpdateBuffer(d *DeviceInfo, dtype string, ch chan *DeviceInfo) {
	s.DevBuf.Lock()
	defer s.DevBuf.Unlock()
	logging.Debug(logging.DClient, "SYS 01 Dev %v update requested", d)
	if dev, exists := s.DevBuf.Buf[dtype][d.Id]; exists {
		// already a device in the buffer
		if dev.TransactionId > d.TransactionId {
			logging.Debug(logging.DClient, "SYS 01 Update Processed. Old: %v, New: %v \n", dev, d)
			d = dev // not sure if i can do this lol
		}
	}
	if ch == s.ReactorChan || ch == s.DevChan {
		// hacky way to check if the device came from a listener of a current channel
		s.DevBuf.Buf[dtype][d.Id] = d
	} else {
		logging.Debug(logging.DClient, "Dev out of date!")
	}
}

func (s *StatusMonitor) Listen(ch chan *DeviceInfo) {
	for dev := range ch {
		if dev.Type == "Reactor" {
			go s.UpdateBuffer(dev, "Reactor", ch)
		} else {
			go s.UpdateBuffer(dev, "Device", ch)
		}
	}
}

type InfoStream struct {
	// base stream for any reactor/device
	// NewSender embedds the channel to send updates on
	// NewListener will add the statusmon to the list of devs to echo to
	Stream chan *DeviceInfo
	Layout *syslayout
	*listeners
}

type listeners struct {
	sync.RWMutex
	Listeners map[uint32]*lischan
}

type lischan struct {
	sync.WaitGroup
	StatusChan chan *DeviceInfo
}

type syslayout struct {
	Devs   map[uint32]*DeviceInfo
	uint32 //index
	sync.RWMutex
}

func NewLisChan(ch chan *DeviceInfo) *lischan {
	l := &lischan{StatusChan: ch}
	return l
}

func NewInfoStream() *InfoStream {
	dch := make(chan *DeviceInfo)
	s := &InfoStream{Stream: dch}
	m := make(map[uint32]*DeviceInfo)
	s.Layout = &syslayout{Devs: m}
	s.listeners = &listeners{Listeners: make(map[uint32]*lischan)}
	return s
}

func (s *InfoStream) Start() {
	// consistency
	go s.Listen()
}

// goal is to hook every new manager into the reactor status chan
func (s *InfoStream) AddSender() chan *DeviceInfo {
	return s.Stream
}

func (s *InfoStream) Listen() {
	for deviceInfo := range s.Stream {
		go s.Update(deviceInfo)
	}
}

func (s *InfoStream) Update(d *DeviceInfo) {
	s.Layout.Lock()
	defer s.Layout.Unlock()
	if dev, ok := s.Layout.Devs[d.Id]; !ok {
		d.Index = s.Layout.uint32
		s.Layout.uint32 += 1
	} else {
		d.Index = dev.Index
	}
	s.Layout.Devs[d.Id] = d
	go s.Echo(d)
}

func (l *listeners) Echo(d *DeviceInfo) {
	l.RLock()
	defer l.RUnlock()
	// read only lock
	for _, lis := range l.Listeners {
		lis.Add(1)
		go func(listener *lischan, dev *DeviceInfo) {
			defer listener.Done()
			listener.StatusChan <- dev
		}(lis, d)
	}
}

func (s *InfoStream) AddListener(id int, ch chan *DeviceInfo) map[uint32]*DeviceInfo {
	// if i get a memory leak ill eat my shoe
	s.listeners.Lock()
	defer s.listeners.Unlock()
	if _, ok := s.listeners.Listeners[id]; ok {
		// exists
		go s.RemoveListener(id)
	}
	s.listeners.Listeners[id] = NewLisChan(ch)
	logging.Debug(logging.DClient, "SYS 01 Getting Devices")
	//s.Layout.RLock()
	//defer s.Layout.RUnlock()
	logging.Debug(logging.DClient, "SYS 01 Returning Devices %v", s.Layout.Devs)
	return s.Layout.Devs
}

func (l *listeners) RemoveListener(id int) {
	l.Lock()
	defer l.Unlock()
	if lis, ok := l.Listeners[id]; ok {
		delete(l.Listeners, id)
		go func(ls *lischan) {
			ls.Wait()
			close(ls.StatusChan)
		}(lis)
	}
}

// status buffer maintaince

type SystemViewer struct {
	// stores system directory and provide methods to be embedded in managers
	ReactorStream *InfoStream // can add itself as a listener to provide methods
	DeviceStream  *ds
}

type ds struct {
	Reactors map[uint32]*InfoStream //map from reactor id to its device info stream
	sync.Mutex
}

func NewSystemViewer() *SystemViewer {
	rs := NewInfoStream()
	s := &SystemViewer{ReactorStream: rs}
	m := make(map[uint32]*InfoStream)
	s.DeviceStream = &ds{Reactors: m}
	return s
}

func (s *SystemViewer) Start() {
	go s.ReactorStream.Start()
}

func (s *SystemViewer) AddReactorSender() chan *DeviceInfo {
	return s.ReactorStream.AddSender()
}

func (s *SystemViewer) AddDeviceSender(reactorId uint32) chan *DeviceInfo {
	s.DeviceStream.Lock()
	defer s.DeviceStream.Unlock()
	var ds *InfoStream
	var ok bool
	if ds, ok = s.DeviceStream.Reactors[reactorId]; !ok {
		ds = NewInfoStream()
		s.DeviceStream.Reactors[reactorId] = ds
		go ds.Start()
	}
	return ds.AddSender()
}

func (s *SystemViewer) AddListener(id, rid int) (chan *DeviceInfo, map[uint32]*DeviceInfo) {
	// returns a listener for that chan
	ch := make(chan *DeviceInfo)
	if rid != 0 {
		return ch, s.DeviceStream.Reactors[rid].AddListener(id, ch)
	} else {
		return ch, s.ReactorStream.AddListener(id, ch)
	}
}

func (s *SystemViewer) RemoveListener(rid, tid int) {
	// removes chan for specific tid and rid
	s.DeviceStream.Lock()
	defer s.DeviceStream.Unlock()
	go s.DeviceStream.Reactors[rid].RemoveListener(tid)
}
*/