diff --git a/config.go b/config.go
index 5440610..ab0395e 100644
--- a/config.go
+++ b/config.go
@@ -6,11 +6,9 @@ import (
 )
 
 type Config struct {
-	Server struct {
-		Timeout      int    `yaml:"timeout"`
-		StartCommand string `yaml:"start_command"`
-		Address      string `yaml:"address"`
-	} `yaml:"server"`
+	Timeout      int    `yaml:"timeout"` // minutes
+	StartCommand string `yaml:"start_command"`
+	Port         string `yaml:"port"`
 }
 
 // this is a global constant since it's shared
diff --git a/daemon.go b/daemon.go
new file mode 100644
index 0000000..e69de29
diff --git a/ds.go b/ds.go
new file mode 100644
index 0000000..bfcaf16
--- /dev/null
+++ b/ds.go
@@ -0,0 +1,35 @@
+package main
+
+// this DS does not provide thread security
+func NewStack[T any]() *Stack[T] {
+	return &Stack[T]{
+		items: make([]T, 0),
+	}
+}
+
+type Stack[T any] struct {
+	items []T
+}
+
+func (s *Stack[T]) Push(item T) {
+	s.items = append(s.items, item)
+}
+func (s *Stack[T]) Pop() T {
+	l := len(s.items)
+	if l == 0 {
+		panic("Stack: pop")
+	}
+	ret := s.items[l]
+	s.items = s.items[:l-1]
+	return ret
+}
+func (s Stack[T]) Peek() T {
+	l := len(s.items)
+	if l == 0 {
+		panic("Stack: peek")
+	}
+	return s.items[l]
+}
+func (s Stack[T]) IsEmpty() bool {
+	return len(s.items) == 0
+}
diff --git a/fsm.go b/fsm.go
new file mode 100644
index 0000000..96ba396
--- /dev/null
+++ b/fsm.go
@@ -0,0 +1,160 @@
+package main
+
+import (
+	"context"
+	"reflect"
+	"runtime/debug"
+	"time"
+)
+
+type globalConnEvent int
+
+const (
+	INCOMING globalConnEvent = iota
+	EMPTY
+)
+
+// luckily I use int for them all
+type GenericChan chan int
+type QueryChan chan MCState
+
+var (
+	state MCState = STOPPED
+	// we don't need mutex for cnt because with channel it's guaranteed to be processed sequently
+	CntChan   = make(chan CntEvent)
+	eventChan = make(chan globalConnEvent)
+	// the channel used to pass channel to build directional communication
+	ChanChan = make(chan QueryChan)
+)
+var cnt int
+
+func InitState() {
+	go handleCnt()
+	go handleState()
+}
+func handleCnt() { //goroutine only, handles cnt related message
+	for {
+		cntEvent := <-CntChan
+		switch cntEvent {
+		case INCREASE:
+			GetLogger().Debug("handleCnt(): connection cnt increased")
+			cnt++
+			if cnt == 1 { //which means it is 0->1
+				eventChan <- INCOMING
+			}
+		case DECREASE:
+			GetLogger().Debug("handleCnt(): connection cnt decreased")
+			cnt--
+			if cnt < 0 {
+				debug.Stack()
+				panic("cnt processor was written wrong!")
+			} else if cnt == 0 {
+				eventChan <- EMPTY
+			}
+		}
+	}
+}
+
+// STOPPED->BOOTING->RUNNING<->WAITING->STOPPING->STOPPED
+var waitChan chan struct{}
+
+// no we don't need cmdChan, we just make it work immediately
+func handleWaitingToRunning() {
+	waitChan <- struct{}{}
+	_, ok := <-waitChan
+	if ok {
+		state = RUNNING //happens immediately
+	} //else it's too late
+}
+func handleRunningToWaiting() {
+	waitChan = make(chan struct{})
+	go waitingThread()
+	state = WAITING
+}
+
+// TODO: work with daemon
+func handleWaitingToStopping() {}
+func waitingThread() {
+	defer close(waitChan)
+	ctx, cancel := context.WithTimeout(context.Background(), time.Duration(config.Timeout)*time.Minute)
+	defer cancel()
+	select {
+	case <-ctx.Done():
+		handleWaitingToStopping()
+		return
+	case <-waitChan:
+		waitChan <- struct{}{}
+		return
+	}
+}
+func handleState() { //goroutine only, handles both write and read
+	unused := NewStack[int]()
+	const (
+		// CMD must come first
+		CHANCHAN = iota
+		EVENTCHAN
+		SIZE
+	)
+
+	selectCases := make([]reflect.SelectCase, SIZE)
+	selectCases[CHANCHAN] = reflect.SelectCase{
+		Dir:  reflect.SelectRecv, // readonly
+		Chan: reflect.ValueOf(ChanChan),
+	}
+	selectCases[EVENTCHAN] = reflect.SelectCase{
+		Dir:  reflect.SelectRecv, // readonly
+		Chan: reflect.ValueOf(eventChan),
+	}
+	//selectCases[CMDCHAN] = reflect.SelectCase{
+	//	Dir:  reflect.SelectRecv,
+	//	Chan: reflect.ValueOf(cmdChan),
+	//}
+	addChan := func(Chan QueryChan) {
+		logger.Debug("handleState():adding new chanchan")
+		nelem := reflect.SelectCase{
+			Dir:  reflect.SelectDefault,
+			Chan: reflect.ValueOf(Chan),
+		}
+		if unused.IsEmpty() {
+			selectCases = append(selectCases, nelem)
+		} else {
+			selectCases[unused.Pop()] = nelem
+		}
+	}
+	logger.Debug("handleState(): ready")
+	for {
+		id, recv, ok := reflect.Select(selectCases)
+		if !ok {
+			unused.Push(id)
+			continue
+		}
+		switch id {
+		case CHANCHAN:
+			nchan := *(*QueryChan)(recv.UnsafePointer())
+			addChan(nchan)
+		case EVENTCHAN:
+			// wait until transformation finishes
+			event := globalConnEvent(recv.Int())
+			switch event {
+			case INCOMING:
+				switch state {
+				case STOPPED:
+				// case STOPPING: // it shouldn't be there, too, should be handled with conn.go
+				case WAITING:
+					handleWaitingToRunning()
+				default:
+					panic("handleState():written wrong!")
+				}
+			case EMPTY:
+				switch state {
+				case RUNNING:
+					handleRunningToWaiting()
+				default:
+					panic("handleState():written wrong!")
+				}
+			}
+		default:
+		}
+	}
+
+}
diff --git a/state.go b/state.go
index 885992f..dfe1774 100644
--- a/state.go
+++ b/state.go
@@ -1,8 +1,10 @@
 package main
 
-import (
-	"reflect"
-	"runtime/debug"
+type CntEvent int
+
+const (
+	INCREASE CntEvent = 1
+	DECREASE CntEvent = -1
 )
 
 type MCState int
@@ -14,63 +16,3 @@ const (
 	WAITING
 	STOPPING
 )
-const QUERY = 114514
-
-type CntEvent int
-
-const (
-	INCREASE CntEvent = 1
-	DECREASE CntEvent = -1
-)
-
-type StateEvent int
-
-const (
-	INCOMING StateEvent = iota
-	EMPTY
-)
-
-type QueryChan chan MCState
-
-var (
-	state MCState = STOPPED
-	// we don't need mutex for cnt because with channel it's guaranteed to be processed sequently
-	CntChan   = make(chan CntEvent)
-	eventChan = make(chan StateEvent)
-	// the channel used to pass channel to build directional communication
-	ChanChan = make(chan QueryChan)
-)
-var cnt int
-
-func InitState() {
-	go handleCnt()
-	go handleEvent()
-}
-func handleCnt() {
-	for {
-		cntEvent := <-CntChan
-		switch cntEvent {
-		case INCREASE:
-			cnt++
-			if cnt == 1 { //which means it is 0->1
-				eventChan <- INCOMING
-			}
-		case DECREASE:
-			cnt--
-			if cnt < 0 {
-				debug.Stack()
-				panic("cnt processor was written wrong!")
-			} else if cnt == 0 {
-				eventChan <- EMPTY
-			}
-		}
-	}
-}
-func handleEvent() { //handles both write and read
-	var chanList []QueryChan
-	// TODO: create chanList vector
-	for {
-
-	}
-
-}