ROSBuzz_MISTLab/buzz_scripts/graphform.bzz

#
# Include files
#
include "string.bzz"
include "vec2.bzz"
include "update.bzz"
include "barrier.bzz"	# don't use a stigmergy id=11 with this header.
include "uavstates.bzz"	# require an 'action' function to be defined here.
include "vstigenv.bzz"

include "graphs/shapes_Y.bzz"

ROBOT_RADIUS=50
ROBOT_DIAMETER=2.0*ROBOT_RADIUS
ROBOT_SAFETYDIST=2.0*ROBOT_DIAMETER

# max velocity in cm/step
ROBOT_MAXVEL = 250.0

#
# Global variables
#

#
# Save message from all neighours
#the indexes are as 1,2,3..., while each value is a table that store the information of a neighbour robot
m_MessageState={}#store received neighbour message
m_MessageLabel={}#store received neighbour message
m_MessageReqLabel={}#store received neighbour message
m_MessageReqID={}#store received neighbour message
m_MessageResponse={}#store received neighbour message
m_MessageRange={}#store received neighbour message
m_MessageBearing={}#store received neighbour message
m_neighbourCount=0#used to cunt neighbours
#Save message from one neighbour
#the indexes are as State(received state),Label(received Label),ReqLabel,ReqID,Response,Range,Bearing
m_receivedMessage={.State=s2i("STATE_FREE"),.Label=0,.ReqLabel=0,.ReqID=0,.Response=r2i("REQ_NONE"),.Range=0,.Bearing=0}

#
#Save the message to send
#The keys of the talbe is State(current state),Label(current Label),ReqLabel(requested Label),ReqID(request id),Response(reply message{REQ_NONE,REQ_GRANTED,REQ_RESEND})
m_selfMessage={.State=s2i("STATE_FREE"),.Label=0,.ReqLabel=0,.ReqID=0,.Response=r2i("REQ_NONE")}

#Current robot state
m_eState="STATE_FREE"

#navigation vector
m_navigation={.x=0,.y=0}

#Debug message to be displayed in qt-opengl
#m_ossDebugMsg

#Debug vector to draw
#CVector2 m_cDebugVector

#Current label being requested or chosen (-1 when none)
m_nLabel=-1
m_messageID={}
#neighbor distance to lock the current pattern
lock_neighbor_id={}
lock_neighbor_dis={}

#Label request id
m_unRequestId=0

#Global bias, used to map local coordinate to global coordinate
m_bias=0

#Vector to predecessor,range is the distance between robots, bearing is the angle of pred wrt self in local coordinate of self, globalbearing is the angle of self wrt pred in global coordinate
m_cMeToPred={.Range=0.0,.Bearing=0.0,.GlobalBearing=0.0}

#Counter to wait for something to happen
m_unWaitCount=0

#Number of steps to wait before looking for a free label
m_unLabelSearchWaitTime=0

#Number of steps to wait for an answer to be received
m_unResponseTimeThreshold=0

#Number of steps to wait until giving up joining
m_unJoiningLostPeriod=0

#Tolerance distance to a target location
m_fTargetDistanceTolerance=0

#step cunt
step_cunt=0

#virtual stigmergy
m_lockstig = 1

# Lennard-Jones parameters, may need change
EPSILON	= 4000 #13.5 the LJ parameter for other robots

# Lennard-Jones interaction magnitude

function FlockInteraction(dist,target,epsilon){
	var mag = -(epsilon / dist) * ((target / dist)^4 - (target / dist)^2)
	return mag
}

function LimitAngle(angle){
	if(angle>2*math.pi)
		return angle-2*math.pi
	else if (angle<0)
		return angle+2*math.pi
	else
		return angle
}

#
# Calculates the angle of the given vector2.
# PARAM v: The vector2.
# RETURN: The angle of the vector.
#
Angle = function(v) {
  return math.atan(v.y, v.x)
}

#
#return the number of value in table
#
function count(table,value){
	var number=0
	var i=0
	while(i<size(table)){
		if(table[i]==value){
			number=number+1
		}
		i=i+1
	}
	return number
}

#map from int to state
function i2s(value){
	if(value==1){
	return "STATE_FREE"
	}
	else if(value==2){
	return "STATE_ASKING"
	}
	else if(value==3){
	return "STATE_JOINING"
	}
	else if(value==4){
	return "STATE_JOINED"
	}
	else if(value==5){
	return "STATE_LOCK"
	}
}

#map from state to int
function s2i(value){
	if(value=="STATE_FREE"){
	return 1
	}
	else if(value=="STATE_ASKING"){
	return 2
	}
	else if(value=="STATE_JOINING"){
	return 3
	}
	else if(value=="STATE_JOINED"){
	return 4
	}
	else if(value=="STATE_LOCK"){
	return 5
	}
}
#map form int to response
function i2r(value){
	if(value==1){
	return "REQ_NONE"
	}
	else if(value==2){
	return "REQ_GRANTED"
	}
}
#map from response to int
function r2i(value){
	if(value=="REQ_NONE"){
	return 1
	}
	else if(value=="REQ_GRANTED"){
	return 2
	}
}


#
#return the index of value
#
function find(table,value){
	var index=nil
	var i=0
	while(i<size(table)){
		if(table[i]==value)
			index=i
		i=i+1
	}
	return index
}

function pow(base,exponent){
	var i=0
	var renturn_val=1
	if(exponent==0)
		return 1
	else{
		while(i<exponent){
			renturn_val=renturn_val*base
			i=i+1
		}
		return renturn_val
	}
}

#
#pack message into 1 number
#
function packmessage(send_table){
    var send_value
    send_value=10000*send_table.State+1000*send_table.Label+100*send_table.ReqLabel+10*send_table.ReqID+send_table.Response
    return send_value
}
#
#pack guide message into 1 number
#
function pack_guide_msg(send_table){
    var send_value
    var r_id=send_table.Label#id of target robot
    var pon#positive or negative ,0 postive, 1 negative
    if(send_table.Bearing>=0){
    pon=0
    }
    else{
    pon=1
    }
    var b=math.abs(send_table.Bearing) 
    send_value=r_id*1000+pon*100+b
    return send_value
}
#
#unpack message
#
function unpackmessage(recv_value){
    var wan=(recv_value-recv_value%10000)/10000
    recv_value=recv_value-wan*10000
    var qian=(recv_value-recv_value%1000)/1000
    recv_value=recv_value-qian*1000
    var bai=(recv_value-recv_value%100)/100
    recv_value=recv_value-bai*100
    var shi=(recv_value-recv_value%10)/10
    recv_value=recv_value-shi*10
    var ge=recv_value
    var return_table={.State=0.0,.Label=0.0,.ReqLabel=0.0,.ReqID=0.0,.Response=0.0}
    return_table.State=wan
    return_table.Label=qian
    return_table.ReqLabel=bai
    return_table.ReqID=shi
    return_table.Response=ge
    return return_table
}
#
#unpack guide message
#
function unpack_guide_msg(recv_value){
log(id,"I pass value=",recv_value)
    var qian=(recv_value-recv_value%1000)/1000
    recv_value=recv_value-qian*1000
    var bai=(recv_value-recv_value%100)/100
    recv_value=recv_value-bai*100
    var b=recv_value
    var return_table={.Label=0.0,.Bearing=0.0}
    return_table.Label=qian
    if(bai==1){
    	b=b*-1.0
    }
    return_table.Bearing=b
    return return_table
}

#get the target distance to neighbr nei_id
function target4label(nei_id){
    var return_val="miss"
    var i=0
    while(i<size(lock_neighbor_id)){
		if(lock_neighbor_id[i]==nei_id){
			return_val=lock_neighbor_dis[i]
		}
		i=i+1
    }
    return return_val
}
#calculate LJ vector for neibhor stored in i
function LJ_vec(i){
    var dis=m_MessageRange[i]
    var bearing=m_MessageBearing[i]
    var nei_id=m_messageID[i]
    var target=target4label(nei_id)
    var cDir={.x=0.0,.y=0.0}
    if(target!="miss"){
    	cDir=math.vec2.newp(FlockInteraction(dis,target,EPSILON),bearing)   
    }
       #log(id,"dis=",dis,"target=",target,"label=",nei_id)
		#log("x=",cDir.x,"y=",cDir.y)  
    return cDir
}
#calculate the motion vector
function motion_vector(){
    var i=0
    var m_vector={.x=0.0,.y=0.0}
    while(i<m_neighbourCount){
		#calculate and add the motion vector
		m_vector=math.vec2.add(m_vector,LJ_vec(i))
		#log(id,"x=",m_vector.x,"y=",m_vector.y)    
		i=i+1
    }
    m_vector=math.vec2.scale(m_vector,1.0/m_neighbourCount)
	#log(id,"fnal=","x=",m_vector.x,"y=",m_vector.y)    
    return m_vector
}

function start_listen(){
neighbors.listen("m",
    function(vid,value,rid){
    #store the received message
    var temp_id=rid
    var recv_val=unpackmessage(value)
    Get_DisAndAzi(temp_id)
    #add the received message
    #
    m_MessageState[m_neighbourCount]=i2s(recv_val.State)
    m_MessageLabel[m_neighbourCount]=recv_val.Label
    m_MessageReqLabel[m_neighbourCount]=recv_val.ReqLabel
    m_MessageReqID[m_neighbourCount]=recv_val.ReqID
    m_MessageResponse[m_neighbourCount]=i2r(recv_val.Response)
    m_MessageRange[m_neighbourCount]=m_receivedMessage.Range
    m_MessageBearing[m_neighbourCount]=m_receivedMessage.Bearing
	m_messageID[m_neighbourCount]=rid
    m_neighbourCount=m_neighbourCount+1
})
}
#
#Function used to get the station info of the sender of the message
function Get_DisAndAzi(id){
	neighbors.foreach(
	function(rid, data) {
		if(rid==id){
		m_receivedMessage.Range=data.distance*100.0
		m_receivedMessage.Bearing=data.azimuth
		}
		})
}

#
#Update node info according to neighbour robots
#
function UpdateNodeInfo(){
	#Collect informaiton
	#Update information
	var i=0

	while(i<m_neighbourCount){
		if(m_MessageState[i]=="STATE_JOINED"){
			m_vecNodes[m_MessageLabel[i]].State="ASSIGNED"
			m_vecNodes[m_MessageLabel[i]].StateAge=m_unJoiningLostPeriod
		}
		else if(m_MessageState[i]=="STATE_JOINING"){
			m_vecNodes[m_MessageLabel[i]].State="ASSIGNING"
			m_vecNodes[m_MessageLabel[i]].StateAge=m_unJoiningLostPeriod
		}
		i=i+1
	}
	#Forget old information
	i=0
	while(i<size(m_vecNodes)){
		if((m_vecNodes[i].StateAge>0) and (m_vecNodes[i].State=="ASSIGNING")){
		m_vecNodes[i].StateAge=m_vecNodes[i].StateAge-1
		if(m_vecNodes[i].StateAge==0)
			m_vecNodes[i].State="UNASSIGNED"
		}
	i=i+1
	}
}

#
#Transistion to state free
#
function TransitionToFree(){
	m_eState="STATE_FREE"
	m_unWaitCount=m_unLabelSearchWaitTime
	m_selfMessage.State=s2i(m_eState)
}

#
#Transistion to state asking
#
function TransitionToAsking(un_label){
	m_eState="STATE_ASKING"
	m_nLabel=un_label
	m_unRequestId=id	#don't know why the random numbers are the same, add id to make the ReqID different
	m_selfMessage.State=s2i(m_eState)
	m_selfMessage.ReqLabel=m_nLabel
	m_selfMessage.ReqID=m_unRequestId

	m_unWaitCount=m_unResponseTimeThreshold
}

#
#Transistion to state joining
#
function TransitionToJoining(){
	m_eState="STATE_JOINING"
	m_selfMessage.State=s2i(m_eState) 
	m_selfMessage.Label=m_nLabel
	m_unWaitCount=m_unJoiningLostPeriod

	neighbors.listen("r",
        function(vid,value,rid){
        var recv_table={.Label=0,.Bearing=0.0}      
        recv_table=unpack_guide_msg(value)
        #store the received message
        if(recv_table.Label==m_nLabel){
        m_cMeToPred.GlobalBearing=recv_table.Bearing
        }
    })

}

#
#Transistion to state joined
#
function TransitionToJoined(){
	m_eState="STATE_JOINED"
	m_selfMessage.State=s2i(m_eState)
	m_selfMessage.Label=m_nLabel
	m_vecNodes[m_nLabel].State="ASSIGNED"
	neighbors.ignore("r")

	#write statues
	v_tag.put(m_nLabel, m_lockstig)

	m_navigation.x=0.0
	m_navigation.y=0.0
	uav_moveto(m_navigation.x/100.0, m_navigation.y/100.0, 0.0)
}

#
#Transistion to state Lock, lock the current formation
#
#
#Transistion to state Lock, lock the current formation
#
function TransitionToLock(){
    m_eState="STATE_LOCK"
    m_selfMessage.State=s2i(m_eState)
    m_selfMessage.Label=m_nLabel
    m_vecNodes[m_nLabel].State="ASSIGNED"
    #record neighbor distance
lock_neighbor_id={}
lock_neighbor_dis={}
var i=0
while(i<m_neighbourCount){
  lock_neighbor_id[i]=m_messageID[i]
  lock_neighbor_dis[i]=m_MessageRange[i]
  i=i+1
}
    m_navigation.x=0.0
    m_navigation.y=0.0
    uav_moveto(m_navigation.x, m_navigation.y, 0.0)
}

#
# Do free
#
function DoFree() {
	m_selfMessage.State=s2i(m_eState)

	#wait for a while before looking for a Label
	if(m_unWaitCount>0)
		m_unWaitCount=m_unWaitCount-1

	#find a set of joined robots
	var setJoinedLabels={}
	var setJoinedIndexes={}
	var i=0
	var j=0
	while(i<m_neighbourCount){
		if(m_MessageState[i]=="STATE_JOINED"){
		setJoinedLabels[j]=m_MessageLabel[i]
		setJoinedIndexes[j]=i
		j=j+1
		}
		i=i+1
	}

	#go through the graph to look for a proper Label
	var unFoundLabel=0
#	var IDofPred=0
	i=1
	while(i<size(m_vecNodes) and (unFoundLabel==0)){
		#if the node is unassigned and the predecessor is insight
		if(m_vecNodes[i].State=="UNASSIGNED" and count(setJoinedLabels,m_vecNodes[i].Pred)==1){
			unFoundLabel=m_vecNodes[i].Label
#			IDofPred=find(m_MessageLabel,m_vecNodes[unFoundLabel].Pred)
		}
		i=i+1
	}

	if(unFoundLabel>0){
		TransitionToAsking(unFoundLabel)
		return
	}

	#navigation
	#if there is a joined robot within sight, move around joined robots
	#else, gather with other free robots
	if(size(setJoinedIndexes)>0){
		var tempvec_P={.x=0.0,.y=0.0}
		var tempvec_N={.x=0.0,.y=0.0}
		i=0
		while(i<size(setJoinedIndexes)){
			var index=setJoinedIndexes[i]
			tempvec_P=math.vec2.add(tempvec_P,math.vec2.newp(m_MessageRange[index],m_MessageBearing[index]+0.5*math.pi))
			tempvec_N=math.vec2.add(tempvec_N,math.vec2.newp(m_MessageRange[index]-5.0*ROBOT_SAFETYDIST,m_MessageBearing[index]))
			i=i+1
		}
		tempvec_P=math.vec2.scale(tempvec_P,size(setJoinedIndexes))
		tempvec_N=math.vec2.scale(tempvec_N,size(setJoinedIndexes))
		m_navigation=math.vec2.add(tempvec_P,tempvec_N)
		# Limit the mvt 
		if(math.vec2.length(m_navigation)>ROBOT_MAXVEL*2)
			m_navigation = math.vec2.scale(m_navigation, ROBOT_MAXVEL*2/math.vec2.length(m_navigation))
		uav_moveto(m_navigation.x/100.0, m_navigation.y/100.0, 0.0)
	}else{ #no joined robots in sight
		i=0
		var tempvec={.x=0.0,.y=0.0}

		while(i<m_neighbourCount){
			tempvec=math.vec2.add(tempvec,math.vec2.newp(m_MessageRange[i]-2.0*ROBOT_SAFETYDIST,m_MessageBearing[i]))
			i=i+1
		}
		m_navigation=math.vec2.scale(tempvec,1.0/i)
		uav_moveto(m_navigation.x/100.0, m_navigation.y/100.0, 0.0)
	}



	#jump the first step
	if(step_cunt<=1){
		m_navigation.x=0.0
	    m_navigation.y=0.0
		uav_moveto(m_navigation.x/100.0, m_navigation.y/100.0, 0.0)
	}
	#set message
	m_selfMessage.State=s2i(m_eState)

}




#
#Do asking
#
function DoAsking(){
	#look for response from predecessor
	var i=0
	var psResponse=-1
	while(i<m_neighbourCount and psResponse==-1){
		#the respond robot in joined state
		#the request Label be the same as requesed
		#get a respond
		if(m_MessageState[i]=="STATE_JOINED"){
			if(m_MessageReqLabel[i]==m_nLabel)
				if(m_MessageResponse[i]!="REQ_NONE"){
				psResponse=i
		}}
		i=i+1
	}
	#analyse response
	if(psResponse==-1){
		#no response, wait
		m_unWaitCount=m_unWaitCount-1
		m_selfMessage.State=s2i(m_eState)
		m_selfMessage.ReqLabel=m_nLabel
		m_selfMessage.ReqID=m_unRequestId
		if(m_unWaitCount==0){
			TransitionToFree()
			return
		}
	}
	else{
		if(m_MessageReqID[psResponse]!=m_unRequestId){
			m_vecNodes[m_nLabel].State="ASSIGNING"
			m_vecNodes[m_nLabel].StateAge=m_unJoiningLostPeriod
			TransitionToFree()
    	}
	if(m_MessageReqID[psResponse]==m_unRequestId){
		if(m_MessageResponse[psResponse]=="REQ_GRANTED"){
			TransitionToJoining()
			#TransitionToJoined()
			return
		}
		else{
			TransitionToAsking(m_nLabel)
			return
		}
	}
	}
	m_navigation.x=0.0
	m_navigation.y=0.0
	uav_moveto(m_navigation.x/100.0, m_navigation.y/100.0, 0.0)
}

#
#Do joining
#
function DoJoining(){
	#get information of pred
	var i=0
	var IDofPred=-1
	while(i<m_neighbourCount and IDofPred==-1){
		if(m_MessageLabel[i]==m_vecNodes[m_nLabel].Pred and m_MessageState[i]=="STATE_JOINED")
			IDofPred=i
		i=i+1
	}

	#found pred
	if(IDofPred!=-1){
		m_unWaitCount=m_unJoiningLostPeriod#if see pred, reset the timer

		var P2Target=math.vec2.newp(m_vecNodes[m_nLabel].distance,m_vecNodes[m_nLabel].bearing)
		m_cMeToPred.Range=m_MessageRange[IDofPred]#the poition of self to pred in local coordinate
		m_cMeToPred.Bearing=m_MessageBearing[IDofPred]

		#attention, m_cMeToPred.GlobalBearing is the bearing of self wrt pred in global coordinate
		var S2PGlobalBearing=0

		m_cMeToPred.GlobalBearing=LimitAngle(m_cMeToPred.GlobalBearing)

		if(m_cMeToPred.GlobalBearing>math.pi)
			S2PGlobalBearing=m_cMeToPred.GlobalBearing-math.pi
		else
			S2PGlobalBearing=m_cMeToPred.GlobalBearing+math.pi

		var S2Pred=math.vec2.newp(m_cMeToPred.Range,S2PGlobalBearing)

		#the vector from self to target in global coordinate
		var S2Target=math.vec2.add(S2Pred,P2Target)
		#change the vector to local coordinate of self
		var S2Target_bearing=Angle(S2Target)
		m_bias=m_cMeToPred.Bearing-S2PGlobalBearing
		S2Target_bearing=S2Target_bearing+m_bias

		# Limit the mvt 
		if(math.vec2.length(S2Target)>ROBOT_MAXVEL)
			S2Target = math.vec2.scale(S2Target, ROBOT_MAXVEL/math.vec2.length(S2Target))

		m_navigation=math.vec2.newp(math.vec2.length(S2Target),S2Target_bearing)
		uav_moveto(m_navigation.x/100.0, m_navigation.y/100.0, 0.0)



		#test if is already in desired position
		if(math.vec2.length(S2Target)<m_fTargetDistanceTolerance and S2Target_bearing<m_fTargetAngleTolerance){
			log("JOINED! ", math.vec2.length(S2Target), ", ", S2Target_bearing)
			TransitionToJoined()
			return
		}
	} else{ #miss pred, there is a change the another robot block the sight, keep moving as before for sometime
		m_unWaitCount=m_unWaitCount-1
	}


	if(m_unWaitCount==0){
		TransitionToFree()
		return
	}

	#pack the communication package
	m_selfMessage.State=s2i(m_eState)
	m_selfMessage.Label=m_nLabel

}

#
#Do joined
#
function DoJoined(){
	m_selfMessage.State=s2i(m_eState)
	m_selfMessage.Label=m_nLabel

	#collect all requests
	var mapRequests={}
	var i=0
	var j=0
	var ReqLabel
	var JoiningLabel
	var seenPred=0
	while(i<m_neighbourCount){
		if(m_MessageState[i]=="STATE_ASKING"){
			ReqLabel=m_MessageReqLabel[i]
			if(m_vecNodes[ReqLabel].State=="UNASSIGNED")
				if(m_nLabel==m_vecNodes[ReqLabel].Pred){
					#is a request, store the index
					mapRequests[j]=i
					j=j+1
				}
		}
		if(m_MessageState[i]=="STATE_JOINING"){
			JoiningLabel=m_MessageLabel[i]
			if(m_nLabel==m_vecNodes[JoiningLabel].Pred){
				##joining wrt this dot,send the global bearing
				var m_messageForJoining={.Label=JoiningLabel,.Bearing=m_MessageBearing[i]-m_bias}
				neighbors.broadcast("r",pack_guide_msg(m_messageForJoining))
			}
		}
		#if it is the pred
		if((m_MessageState[i]=="STATE_JOINED" or m_MessageState[i]=="STATE_LOCK") and m_MessageLabel[i]==m_vecNodes[m_nLabel].Pred){
			seenPred=1
			m_unWaitCount=m_unJoiningLostPeriod
		}
		i=i+1
	}

	#get request
	if(size(mapRequests)!=0){
		i=1
		var ReqIndex=0
		while(i<size(mapRequests)){
			#compare the distance
			if(m_MessageRange[mapRequests[ReqIndex]]>m_MessageRange[mapRequests[i]])
				ReqIndex=i
			i=i+1
		}
		#get the best index, whose ReqLabel and Reqid are
		ReqLabel=m_MessageReqLabel[mapRequests[ReqIndex]]
		var ReqID=m_MessageReqID[mapRequests[ReqIndex]]
		m_selfMessage.ReqLabel=ReqLabel
		m_selfMessage.ReqID=ReqID
		m_selfMessage.Response=r2i("REQ_GRANTED")
		m_vecNodes[ReqLabel].State="ASSIGNING"
    	m_vecNodes[ReqLabel].StateAge=m_unJoiningLostPeriod
	}

	#lost pred, wait for some time and transit to free
	if(seenPred==0){
	   m_unWaitCount=m_unWaitCount-1
	   if(m_unWaitCount==0){
	      TransitionToFree()
	      return
	   }
	}


	m_navigation.x=0.0
	m_navigation.y=0.0
	uav_moveto(m_navigation.x/100.0, m_navigation.y/100.0, 0.0)


	#check if should to transists to lock
	#write statues
	v_tag.get(m_nLabel)
	log(v_tag.size(), " of ", ROBOTS, " ready to lock")
	if(v_tag.size()==ROBOTS){
		TransitionToLock()
	}
}

#
#Do Lock
#
function DoLock(){
m_selfMessage.State=s2i(m_eState)
m_selfMessage.Label=m_nLabel
m_navigation.x=0.0
m_navigation.y=0.0
#calculate motion vection
if(m_nLabel==0){
    m_navigation.x=0.25	#change value so that robot 0 will move
    m_navigation.y=0.0
}
if(m_nLabel!=0){
    m_navigation=motion_vector()
}
#move
uav_moveto(m_navigation.x, m_navigation.y, 0.0)
}

function action(){
  statef=action
  UAVSTATE="GRAPH"
}

#
# Executed at init
#
function init() {
	#
	#Adjust parameters here
	#
	m_unResponseTimeThreshold=10
	m_unLabelSearchWaitTime=10
	m_fTargetDistanceTolerance=50
	m_fTargetAngleTolerance=0.1
	m_unJoiningLostPeriod=100

	#
	# Join Swarm
	#
	uav_initswarm()
    v_tag = stigmergy.create(m_lockstig)
  	uav_initstig()
	Reset()
	TARGET_ALTITUDE = 2.5 + id * 1.5
}

#
# Executed every step
#
function step(){
	uav_rccmd()
	uav_neicmd()
  	uav_updatestig()
	#update the graph
	UpdateNodeInfo()
	#reset message package to be sent
	m_selfMessage={.State=s2i("STATE_FREE"),.Label=0,.ReqLabel=0,.ReqID=0,.Response=r2i("REQ_NONE")}
	#
	#act according to current state
	#
	if(UAVSTATE=="GRAPH"){
		if(m_eState=="STATE_FREE")
			DoFree()
		else if(m_eState=="STATE_ESCAPE")
			DoEscape()
		else if(m_eState=="STATE_ASKING")
			DoAsking()
		else if(m_eState=="STATE_JOINING")
			DoJoining()
		else if(m_eState=="STATE_JOINED")
			DoJoined()
		else if(m_eState=="STATE_LOCK")
			DoLock()
	}

	statef()


	debug(m_eState,m_nLabel)
	log("Current state: ", UAVSTATE)
	log("Swarm size: ", ROBOTS)
#	if(id==0)
#    	stattab_print()
	
	#navigation
	#broadcast messag
	neighbors.broadcast("m",packmessage(m_selfMessage))

	#
	#clean message storage
	m_MessageState={}#store received neighbour message
	m_MessageLabel={}#store received neighbour message
	m_MessageReqLabel={}#store received neighbour message
	m_MessageReqID={}#store received neighbour message
	m_MessageResponse={}#store received neighbour message
	m_MessageRange={}#store received neighbour message
	m_MessageBearing={}#store received neighbour message
	m_neighbourCount=0


	#step cunt+1
	step_cunt=step_cunt+1
}

#
# Executed when reset
#
function Reset(){
#    m_vecNodes={}
#    m_vecNodes = parse_graph("/home/dave/ROS_WS/src/rosbuzz/buzz_scripts/include/Graph_drone.graph")#change the .graph file when necessary
#    m_vecNodes_fixed={}
#    m_vecNodes_fixed=parse_graph_fixed("/home/dave/ROS_WS/src/rosbuzz/buzz_scripts/include/Graph_fixed.graph")
	Read_Graph()
    m_nLabel=-1

	#start listening
	start_listen()
	#
	#set initial state, only one robot choose [A], while the rest choose [B]
	#
	#[A]The robot used to triger the formation process is defined as joined,
	if(id==0){
		m_nLabel=0
		TransitionToJoined()
	}
	#[B]Other robots are defined as free.
	else{
		TransitionToFree()
	}
}

#
# Executed upon destroy
#
function destroy() {
	#clear neighbour message
	m_navigation.x=0.0
	m_navigation.y=0.0
	uav_moveto(m_navigation.x/100.0, m_navigation.y/100.0, 0.0)
	m_vecNodes={}
	#stop listening 
	neighbors.ignore("m")
}